Projection device

Abstract

This invention provides a preferred configuration for a projection device in which a single heat sink with a single cooling capacity is used in common for the red liquid crystal display element, the green liquid crystal display element, and the blue liquid crystal display element. [Solution] Red liquid crystal display elements, green liquid crystal display elements, and blue liquid crystal display elements are each fixed to a heat sink 2R for red, a heat sink 2G for green, and a heat sink 2B for blue, which have the same shape and size as each other. A single optical base 40 is directly or indirectly attached to the red heat sink 2R, the green heat sink 2G, the blue heat sink 2B, and the light source 7. On the optical base 40, the heat sink to which the liquid crystal display element that generates the most heat is fixed is positioned closer to the light source 7 than the heat sinks to which the other liquid crystal display elements are fixed.

Description

Technical Field

[0001] The present invention relates to a projection device.

Background Art

[0002] Projection devices including a liquid crystal display element for red, a liquid crystal display element for green, and a liquid crystal display element for blue that modulate liquid crystal according to each of a red signal, a green signal, and a blue signal constituting a video signal have become widespread (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Since the liquid crystal display element generates heat by irradiation of illumination light, a heat sink is attached to the liquid crystal display element. By blowing air onto the heat sink by a fan, the heat sink can be cooled and the temperature of the liquid crystal display element can be lowered. When the projection device is operating, the amount of heat generated is different among the liquid crystal display element for red, the liquid crystal display element for green, and the liquid crystal display element for blue. The liquid crystal display element for green becomes the hottest, and the liquid crystal display element for red becomes the coldest.

[0005] Because the red, green, and blue liquid crystal display elements generate different amounts of heat, resulting in different temperatures, it is desirable to attach a heat sink with a cooling capacity appropriate to the temperature of each liquid crystal display element. However, since equipping the projection device with individual heat sinks for each liquid crystal display element would significantly increase costs, a heat sink of the same shape and size is used for all three elements. In this case, a heat sink with sufficient cooling capacity to adequately cool the green liquid crystal display element, which generates the highest temperature, is used.

[0006] Therefore, the temperature of the red liquid crystal display element, which does not get as hot as the green liquid crystal display element, can become too low. This temperature variation among the red, green, and blue liquid crystal display elements can disrupt the color balance, making it impossible to obtain a high-quality projected image.

[0007] The present invention aims to provide a preferred configuration for a projection device in which a single heat sink having a single cooling capacity is used in common for red liquid crystal display elements, green liquid crystal display elements, and blue liquid crystal display elements. [Means for solving the problem]

[0008] The present invention relates to a red liquid crystal display element, a green liquid crystal display element, and a blue liquid crystal display element that modulate liquid crystals according to the red, green, and blue signals that constitute a video signal, respectively; a red heat sink, a green heat sink, and a blue heat sink fixed to the red, green, and blue liquid crystal display elements, respectively, and having the same shape and size; a light source that emits illumination light to irradiate the red, green, and blue liquid crystal display elements; and the red heat sink to which the red, green, and blue liquid crystal display elements are fixed. The present invention provides a projection device comprising a sink, the green heat sink, the blue heat sink, and the light source, to which a single optical base is directly or indirectly attached, wherein on the optical base, the heat sink to which the liquid crystal display element that generates the most heat when the red liquid crystal display element, the green liquid crystal display element, and the blue liquid crystal display element are fixed is positioned closer to the light source than the heat sinks to which the other liquid crystal display elements are fixed. [Effects of the Invention]

[0009] According to the projection device of the present invention, a preferred configuration can be achieved in which a single heat sink with a single cooling capacity is used in common for the red liquid crystal display element, the green liquid crystal display element, and the blue liquid crystal display element. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a perspective view showing a projection device according to the first embodiment. [Figure 2] Figure 2 is a perspective view showing the display element assembly used in the projection device according to each embodiment. [Figure 3]Figure 3 is a perspective view of the display element assembly used in each embodiment of the projection device, viewed from the back side. [Figure 4] Figure 4 is a perspective view showing the projection device according to the first embodiment, with a cap placed over the red liquid crystal display element. [Figure 5] Figure 5 is a perspective view showing the projection device according to the first embodiment with the duct attached. [Figure 6] Figure 6 is an enlarged perspective view of the duct. [Figure 7] Figure 7 is an enlarged perspective view showing the duct with the first and second blower fans connected. [Figure 8] Figure 8 is an enlarged perspective view of the red heatsink. [Figure 9] Figure 9 is a perspective view showing the cap of the comparative example. [Figure 10] Figure 10 is an enlarged perspective view showing the red heatsink with the cap attached. [Figure 11] Figure 11 is a perspective view showing how the temperature measuring element is fixed to the display element assembly. [Figure 12] Figure 12 is an enlarged perspective view showing a cap used in the projection device according to the second embodiment. [Figure 13] Figure 13 is a perspective view showing a method for fixing the cap in a projection device according to the second embodiment. [Figure 14] Figure 14 is an enlarged perspective view showing a cap used in the projection device according to the third embodiment. [Figure 15] Figure 15 is an enlarged perspective view showing other caps used in the projection device according to the third embodiment. [Figure 16] Figure 16 is an enlarged perspective view showing yet another cap used in the projection device according to the third embodiment. [Figure 17] Figure 17 is an enlarged perspective view showing yet another cap used in the projection device according to the third embodiment. [Figure 18] Figure 18 is a perspective view showing a projection device according to the fourth embodiment.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, a projection device according to each embodiment will be described with reference to the accompanying drawings.

[0012] <First Embodiment> The first embodiment provides a projection device that can obtain a high-quality projection image as a preferable configuration in a projection device in which a heat sink having a single cooling capacity is commonly used for a liquid crystal display element for red, a liquid crystal display element for green, and a liquid crystal display element for blue.

[0013] In FIG. 1, a projection device 100 according to the first embodiment includes a red heat sink 2R, a green heat sink 2G, and a blue heat sink 2B for cooling a liquid crystal display element for red, a liquid crystal display element for green, and a liquid crystal display element for blue, respectively, inside a housing 101. The liquid crystal display element for red, the liquid crystal display element for green, and the liquid crystal display element for blue are abbreviated as an R display element, a G display element, and a B display element, respectively. The R display element, the G display element, and the B display element are reflective liquid crystal display elements.

[0014] The red heat sink 2R, the green heat sink 2G, and the blue heat sink 2B are abbreviated as an R heat sink 2R, a G heat sink 2G, and a B heat sink 2B, respectively. The R heat sink 2R, the G heat sink 2G, and the B heat sink 2B are collectively referred to as a heat sink 2. The heat sink 2 is formed of aluminum. As will be described later, in the projection device 100 according to the first embodiment, a cap 10 (see FIG. 4) is put on the R heat sink 2R. In FIG. 1, a state where the cap 10 is removed is shown to show the R heat sink 2R.

[0015] As shown in the enlarged perspective views of Figures 2 and 3, heat sinks 2R for R, 2G for G, and 2B for B are fixed to the R display element 1R, G display element 1G, and B display element 1B, respectively. Flexible printed circuit boards 4R, 4G, and 4B, which connect to a main board (not shown), are connected to the R display element 1R, G display element 1G, and B display element 1B, respectively.

[0016] Heat sinks 2R, 2G, and 2B are equipped with temperature measuring elements 5R, 5G, and 5B, respectively, for measuring the temperatures of the R display element 1R, the G display element 1G, and the B display element 1B. Temperature measuring elements 5R, 5G, and 5B can be composed of thermistors. Although temperature measuring elements 5R, 5G, and 5B are wired to the main board, the wiring to the main board is not shown in the diagram.

[0017] The main board and flexible printed circuit boards 4R, 4G, and 4B modulate the liquid crystals in the liquid crystal layers of the R display element 1R, G display element 1G, and B display element 1B, respectively, according to the red, green, and blue signals that constitute the video signal. The red, green, and blue signals are abbreviated as R signal, G signal, and B signal, respectively.

[0018] The heatsinks 2R for R, 2G for G, and 2B for B have the same shape and size. Heatsink 2 is a heatsink that has sufficient cooling capacity to adequately cool the G display element 1G, which generates the highest temperature. A single heatsink 2 with a single cooling capacity is used in common for the R display element 1R, the G display element 1G, and the B display element 1B.

[0019] The components including the R display element 1R, G display element 1G, and B display element 1B to which the heat sink 2 is fixed will be referred to as display element assemblies 1AR, 1AG, and 1AB, respectively. Here, display element assemblies 1AR, 1AG, and 1AB also include flexible printed circuit boards 4R, 4G, and 4B, and metal members such as aluminum plates 3R, 3G, and 3B, respectively.

[0020] Returning to Figure 1, the display element assemblies 1AR, 1AG, and 1AB are fixed to the base 6 by metal members 3R, 3G, and 3B, and are positioned in the arrangement shown in Figure 1. Display element assemblies 1AR and 1AB are separated by a predetermined distance and face each other. Display element assembly 1AG is positioned in a direction perpendicular to the direction connecting display element assemblies 1AR and 1AB.

[0021] Red, green, and blue illumination light, generated based on light emitted from the light source 7, are irradiated onto the R display element 1R, G display element 1G, and B display element 1B, respectively. The light source 7 includes, for example, a laser diode. The red, green, and blue illumination light are modulated by liquid crystal according to the R, G, and B signals, reflected by the reflective electrode, and emitted from the R display element 1R, G display element 1G, and B display element 1B. A composite prism (not shown) combines the modulated light emitted from the R display element 1R, G display element 1G, and B display element 1B and emits it to the projection lens 9 inside the lens barrel 8. The projection lens 9 projects the combined light onto a screen (not shown).

[0022] The heatsinks 2R for R, 2G for G, and 2B for B are configured to be cooled by blowing air from a fan (described later) through a duct (described later). By cooling each heatsink 2, the temperatures of the R display element 1R, the G display element 1G, and the B display element 1B can be lowered. As described above, since heatsink 2 has sufficient cooling capacity to cool the G display element 1G, which gets the hottest, the temperature of the R display element 1R may become too low.

[0023] Therefore, as shown in Figure 4, the heat sink 2R for R, which is fixed to the R display element 1R, is covered with a cap 10 that reduces the cooling effect of the heat sink 2R on the R display element 1R. The cap 10 is placed only on the heat sink 2R for R. The cap 10 is made of plastic resin or rubber.

[0024] Figure 5 shows the projection device 100 in the state shown in Figure 4 with the duct 23 attached. Figure 6 is an enlarged perspective view of the duct 23, and Figure 7 shows the duct 23 with the first blower fan 22a and the second blower fan 22b connected. As shown in Figure 5, the projection device 100 is equipped with intake fans 21a and 21b that are mounted facing the outside of the housing 101. The intake fans 21a and 21b draw outside air into the housing 101.

[0025] As shown in Figures 6 and 7, the duct 23 has a first duct 23a and a second duct 23b. As shown in Figures 5 and 7, the projection device 100 includes a first blower fan 22a and a second blower fan 22b that send air taken into the housing 101 by intake fans 21a and 21b to the first duct 23a and the second duct 23b, respectively. The first blower fan 22a is a blower fan for supplying air to the heat sink 2R for R, and the second blower fan 22b is a blower fan for supplying air to the heat sink 2G for G and the heat sink 2B for B. The first blower fan 22a and the second blower fan 22b are, for example, sirocco fans.

[0026] The first duct 23a directs the air blown by the first blower fan 22a to the heat sink 2R for R. The second duct 23b directs the air blown by the second blower fan 22b to the heat sink 2G for G and the heat sink 2B for B. As shown in Figures 6 and 7, the second duct 23b has, beyond the branching point 23b0, a first branch duct 23b1 that divides the air blown by the second blower fan 22b and directs the divided first air to the heat sink 2G for G, and a second branch duct 23b2 that directs the divided second air to the heat sink 2B for B. The portions of the first branch duct 23b1 and the second branch duct 23b2 in the second duct 23b are curved toward the heat sink 2G for G and the heat sink 2B for B.

[0027] Since the G display element 1G becomes hotter than the B display element 1B, it is preferable to make the cross-sectional area of ​​the first branch duct 23b1 wider than the cross-sectional area of ​​the second branch duct 23b2 so that the airflow rate of the first wind is greater than that of the second wind.

[0028] The heatsinks for G (2G) and B (2B) are positioned such that the heatsink for G (2G) is towards the back of the second blower fan (22b) and the heatsink for B (2B) is towards the front. The first branch duct (23b1) is positioned on the outside and the second branch duct (23b2) on the inside so that the distance from the branch point (23b0) in the second duct (23b) to the heatsink for G (2G) is long and the distance to the heatsink for B (2B) is short.

[0029] A curved duct has the property that the airflow is greater on the outside than on the inside. Therefore, the air blown by the second blower fan 22b flows more through the first branch duct 23b1, which is located on the outside of the curved first branch duct 23b1 and the second branch duct 23b2. As a result, the airflow of the first air that flows through the first branch duct 23b1 to the heat sink 2G for G is greater than the airflow of the second air that flows through the second branch duct 23b2 to the heat sink 2B for B. In addition to the fact that the cross-sectional area of ​​the first branch duct 23b1 is larger than that of the second branch duct 23b2, the first branch duct 23b1 is located on the outside of the curve, so the airflow of the first air can be made greater than that of the second air, thereby increasing the cooling capacity of the G display element 1G.

[0030] In the projection device 100 according to the first embodiment, let's assume that the cap 10 is not placed over the heat sink 2R for R. Since the R display element 1R is the least likely to heat up, the temperature of the R display element 1R may become too low, and the temperature variation between the R display element 1R, the G display element 1G, and the B display element 1B may disrupt the color balance, making it impossible to obtain a high-quality projected image. In the projection device 100 according to the first embodiment, since the cap 10 is placed over the heat sink 2R for R, the temperature of the R display element 1R does not become too low, making it possible to obtain a high-quality projected image.

[0031] In the projection device 100 according to the first embodiment, the duct 23 is composed of a first duct 23a and a second duct 23b. The first duct 23a guides the air blown by the first blower fan 22a to the heat sink 2R for R. The second duct 23b guides the air blown by the second blower fan 22b to the G display element 1G and the B display element 1B. With this configuration, when the temperature of the R display element 1R is too low compared to the temperatures of the G display element 1G and the B display element 1B, the airflow from the first blower fan 22a can be reduced or the first blower fan 22a can be stopped.

[0032] Therefore, according to the projection device 100 of the first embodiment, it is possible to appropriately control the temperatures of the R display element 1R, the G display element 1G, and the B display element 1B.

[0033] <Second Embodiment> The second embodiment aims to provide a preferred configuration for a cap that covers a heat sink and a preferred method for fixing a cap, as a preferred configuration for a projection device in which a single heat sink having a single cooling capacity is used in common for red liquid crystal display elements, green liquid crystal display elements, and blue liquid crystal display elements.

[0034] The overall configuration of the projection device 100 according to the second embodiment is the same as that of the projection device 100 according to the first embodiment. In the projection device 100 according to the second embodiment, parts that are substantially the same as those in the projection device 100 according to the first embodiment are denoted by the same reference numerals, and their descriptions may be omitted. The projection device 100 according to the second embodiment is characterized by the configuration of the cap 10 and the method of fixing the cap 10.

[0035] A robot (not shown) grasps each heatsink 2 of the display element assemblies 1AR, 1AG, and 1AB and positions them on the base 6 as shown in Figure 1. The positional accuracy of the R display element 1R, G display element 1G, and B display element 1B on the base 6 is important for obtaining high-quality projected images without registration misalignment of the R, G, and B signals. The robot accurately positions the R display element 1R, G display element 1G, and B display element 1B, to which the heatsink 2 is fixed, on the base 6, and the R display element 1R, G display element 1G, and B display element 1B are fixed on the base 6 with adhesive or the like.

[0036] As shown in the enlarged view of Figure 8, the heat sink 2R for R has recesses 202 formed therein, which serve as engaged parts for the robot's engaging portion when it grips the heat sink 2R for R. The recesses 202 are formed near the lower ends of the two outermost fins 201. The recesses 202 are formed in a total of four locations: on the front end faces of the two fins 201 and on the rear end faces of the two fins 201 that are not visible in Figure 8. The heat sink 2G for G and the heat sink 2B for B have the same configuration. It is sufficient for the recesses 202 to be formed in at least two locations so that the robot can grip the heat sink 2.

[0037] The cap 10, which is placed over the heat sink 2R for R, needs to be fixed to the display element assembly 1AR so that it does not easily come off the heat sink 2R for R. One possible solution is to fix the cap 10' to the heat sink 2R for R by providing four claws 102 that engage with four recesses 202 on the heat sink 2R for R, as shown in Figure 9.

[0038] When the cap 10' is placed over the R heatsink 2R, the robot cannot grasp the R heatsink 2R. Therefore, the robot positions the display element assembly 1AR, which does not have the cap 10' placed over the R heatsink 2R, on the base 6, and then a person places the cap 10' over the R heatsink 2R. However, when done this way, the position of the display element assembly 1AR, which is precisely positioned on the base 6, shifts slightly, causing registration misalignment. For this reason, it is not preferable to use the cap 10' shown in Figure 9.

[0039] Therefore, as shown in the enlarged view of Figure 10, the cap 10 has notches 103 formed therein that expose each recess 202 corresponding to each recess 202. Because the cap 10 has notches 103 that expose each recess 202, the robot can grasp the heat sink 2R for R shown in Figure 10 with the cap 10 placed over it and position the display element assembly 1AR on the base 6. Thus, the position of the display element assembly 1AR, which is precisely positioned on the base 6, will not shift.

[0040] As shown in Figure 11, a projection 203 is formed at the lower end of the fin 201 on the most flexible printed circuit board 4R, 4G, 4B side of the heat sink 2. A through hole is formed in the projection 203 for passing a screw 31 through. Projections with through holes are formed at the ends of the temperature measuring elements 5R, 5G, 5B. The projection 203 and the projections at the ends of the temperature measuring elements 5R, 5G, 5B are superimposed, and the temperature measuring elements 5R, 5G, 5B and the heat sink 2 are fixed to the metal members 3R, 3G, 3B by screws 31.

[0041] It is preferable to fix the cap 10 to the display element assembly 1AR in the following manner. As shown in Figure 12, a protrusion 104 is formed on the cap 10. A through hole 105 is formed in the protrusion 104. As shown in Figure 13, the protrusion 203 of the heat sink 2R for R, the protrusion at the end of the temperature measuring element 5R, and the protrusion 104 of the cap 10 are superimposed, and the cap 10, temperature measuring element 5R, and heat sink 2R for R are fixed to the metal member 3R by screws 31.

[0042] In this way, by fastening the protruding portion 104 of the cap 10 together with the protruding portion of the temperature measuring element 5R, it is not necessary to provide a separate independent configuration for fixing the cap 10 to the display element assembly 1AR, and the cap 10 can be fixed to the display element assembly 1AR.

[0043] As described above, in the projection device 100 according to the second embodiment, one or more fins 201 of the heat sink 2 are formed with at least two recesses 202 for engaging with an engaging portion provided by the robot to grip the heat sink 2. The cap 10 has notches 103 that expose each recess 202, corresponding to each recess 202. According to the projection device 100 according to the second embodiment, there is no obstruction to the robot gripping the heat sink 2.

[0044] The projection device 100 according to the second embodiment employs the following method for positioning the display element assembly 1AR. The liquid crystal display element (R display element 1R), to which the heat sink 2 (heat sink 2R for R) is fixed, has a cap 10 pre-placed over the heat sink 2 of the display element assembly 1AR and is fixed to the metal member 3R. The cap 10 reduces the cooling effect of the heat sink 2R for R on the R display element 1R. The display element assembly 1AR, with the cap 10 placed over the heat sink 2, is positioned on the base 6.

[0045] With this positioning method, the positions of the R display element 1R, G display element 1G, and B display element 1B, which are precisely positioned on the base 6, do not shift, thus enabling the acquisition of high-quality projected images.

[0046] <Third Embodiment> The third embodiment aims to provide a preferred configuration for a cap that covers a heat sink, as a preferred configuration for a projection device in which a single heat sink having a single cooling capacity is used in common for red liquid crystal display elements, green liquid crystal display elements, and blue liquid crystal display elements.

[0047] The overall configuration of the projection device 100 according to the third embodiment is the same as that of the projection device 100 according to the first embodiment. In the projection device 100 according to the third embodiment, parts that are substantially the same as those in the projection device 100 according to the first embodiment are denoted by the same reference numerals, and their descriptions may be omitted. The projection device 100 according to the third embodiment is characterized by the configuration of the cap 10. The cap 10 in the third embodiment will be referred to as caps 10A to 10D.

[0048] As shown in Figure 14, the cap 10A has, for example, a square opening 106 formed in the center of its upper surface. The shape of the opening 106 is not limited to a square, but may be a rectangle, circle, ellipse, or other shape. The position of the opening 106 is not limited to the center of the upper surface. Because the cap 10A has an opening 106 on its upper surface, air that cools the R display element 1R enters the interior of the cap 10A through the opening 106. Therefore, the cap 10A can reduce the effect of cooling the R display element 1R more effectively than the cap 10 which does not have an opening 106.

[0049] If using a cap 10 without the opening 106 would excessively reduce the cooling effect of the heat sink 2R on the R display element 1R, then cap 10A can be used. Providing the opening 106 in the center of the top surface reduces the effect of reducing the cooling effect of the R display element 1R compared to providing it at the edge of the top surface.

[0050] As shown in Figure 15, the cap 10B has openings 107 formed at the four corners of its top surface. As shown in Figure 16, the cap 10C has an opening 106 in the center of its top surface and openings 107 formed at the four corners. The positions and number of openings on the top surface of the cap 10 can be set as appropriate.

[0051] As shown in Figure 17, the cap 10D has notches 108 formed on the surface facing the end faces that form the thickness of each fin 201 of the multiple fins 201 of the heat sink 2, exposing the end faces of each fin 201. By forming notches 108 that expose the end faces of each fin 201, the air that cools the R display element 1R enters between each fin 201 through the notches 108, making it possible to significantly reduce the effect of reducing the cooling effect on the R display element 1R. By adjusting the height of the notches 108, the degree to which the effect of reducing the cooling effect on the R display element 1R is reduced can be adjusted.

[0052] In addition, the cap 10D has multiple protruding walls 109 that are inserted between two adjacent fins 201 in the plurality of fins 201. The protruding walls 109 protrude downward from the inner upper end surface. If the cap 10D is formed of an elastic material such as rubber, and the thickness of the protruding walls 109 is equal to the distance between two adjacent fins 201, the plurality of protruding walls 109 can be fitted between the plurality of fins 201, and the cap 10D can be fixed to the heat sink 2R for R.

[0053] If the cap 10D is fixed to the R-type heat sink 2R by fitting multiple protruding walls 109 between multiple fins 201, then it is not necessary to insert the screw 31 into the through hole 105 provided in the protruding part 104 and fasten the protruding part 104 together with the protruding part of the temperature measuring element 5R. Therefore, the cap 10D does not need to have a protruding part 104. Since the cap 10D can be fitted onto the R-type heat sink 2R so that the multiple protruding walls 109 fit between multiple fins 201, the step of fixing the cap 10D with the screw 31 can be eliminated.

[0054] The cap 10D shown in Figure 17 has an opening 106 in the center of its upper surface, but the opening 106 may be omitted. In the cap 10D, the protruding wall 109 may be omitted, and only notches 108 that expose the end faces of each fin 201 may be formed. In the cap 10D, the notches 108 may also be omitted. However, if the notches 108 are omitted, notches 103 that expose the recesses 202 formed in the heat sink 2R for R may be formed.

[0055] <Fourth Embodiment> The fourth embodiment aims to provide a projection device that can obtain high-quality projected images by using a single heat sink with a single cooling capacity in common for the red liquid crystal display element, the green liquid crystal display element, and the blue liquid crystal display element, as a preferred configuration for the projection device.

[0056] The overall configuration of the projection device 100 according to the fourth embodiment is the same as that of the projection device 100 according to the first embodiment. In the projection device 100 according to the fourth embodiment, parts that are substantially the same as those in the projection device 100 according to the first embodiment are denoted by the same reference numerals, and their descriptions may be omitted. In the projection device 100 according to the fourth embodiment, the positions of the display element assemblies 1AR, 1AG, and 1AB are different from those in the projection device 100 according to the first embodiment.

[0057] The projection device 100 according to the fourth embodiment shown in Figure 18 omits the components shown in Figure 1 or Figure 5, such as the intake fans 21a and 21b, the first blower fan 22a, the second blower fan 22b, the duct 23, and the housing 101. As shown in Figure 18, various components such as the display element assemblies 1AR, 1AG, and 1AB are directly or indirectly arranged or connected on a single aluminum die-cast optical base 40.

[0058] In detail, the R display element 1R, G display element 1G, and B display element 1B, respectively, are fixed to the R heat sink 2R, G heat sink 2G, B heat sink 2B, light source 7, etc., which are arranged directly or indirectly on the horizontal base 401 of the optical base 40. The lens barrel 8 is passed through a circular opening formed in the vertical base 402 of the optical base 40 and is indirectly connected to the vertical base 402.

[0059] It is common practice to use separate aluminum die-casts for the optical base on which the R display element 1R, G display element 1G, and B display element 1B are arranged, and for the optical base on which the light source 7 is arranged. As in the fourth embodiment, costs can be reduced by arranging the R display element 1R, G display element 1G, B display element 1B, and light source 7 on a single aluminum die-cast optical base 40.

[0060] The optical base 40 has a large heat capacity on the side where the light source 7 is located, resulting in a high heat dissipation effect. Therefore, when the R display element 1R, G display element 1G, and B display element 1B are operating (i.e., when the projection device 100 is operating), the optical base 40 has a lower temperature on the R side and a higher temperature on the L side, as shown in Figure 18. Accordingly, in the projection device 100 according to the fourth embodiment, a heat sink 2G for G, to which the G display element 1G, which generates the most heat and reaches the highest temperature, is fixed, is placed at the lower temperature position on the optical base 40.

[0061] Specifically, on the optical base 40, among the heatsinks 2R for R, 2G for G, and 2B for B, the heatsink 2 to which the liquid crystal display element that generates the most heat when each liquid crystal display element is operating is fixed is positioned closer to the light source 7 than the heatsinks 2 to which the other liquid crystal display elements are fixed.

[0062] In Figure 18, the R heatsink 2R, to which the coldest R display element 1R is fixed, is positioned at a high temperature location on the optical base 40. To prevent an excessive temperature drop in the R display element 1R, the cap 10 may be placed only on the R heatsink 2R. Caps 10A to 10D may be used instead of cap 10.

[0063] According to the projection device 100 of the fourth embodiment, since the G display element 1G is located at a low temperature position on the optical base 40, temperature variations between the R display element 1R, G display element 1G, and B display element 1B are reduced, and a high-quality projected image can be obtained without disrupting the color balance.

[0064] The present invention is not limited to the first to fourth embodiments described above, and can be modified in various ways without departing from the spirit of the invention. The first to fourth embodiments can be combined in any combination of two or more embodiments. In the first to fourth embodiments, the caps 10, 10A to 10D are placed only on the heat sink 2R for R, but if the display element 1B becomes too cold, the caps 10, 10A to 10D may also be placed on the heat sink 2B for B. The caps 10, 10A to 10D may also be placed on at least one heat sink 2 other than the heat sink 2 to which the liquid crystal display element that generates the most heat is fixed. [Explanation of Symbols]

[0065] 1B Blue liquid crystal display element 1G Green Liquid Crystal Display Element 1R Red Liquid Crystal Display Element 1AB, 1AG, 1AR Display Element Assembly 2B Blue Heatsink 2G Green Heatsink 2R Red Heat Sink 3B,3G,3R Metal parts 4B, 4G, 4R Flexible Printed Circuit Boards 5B, 5G, 5R Temperature Measuring Elements 6 Base 7 light source 8 Lens barrel 9. Projection lens 10, 10A~10D Cap 21a, 21b Intake fan 22a First blower fan 22b Second blower fan 23 Duct 23a First duct 23b Second duct 23b0 Branch point 23b1 First branch duct 23b2 Second branch duct 31 screws 40 Optical Base 100 Projection device 101 cabinets 103,108 notches 104,203 Projection 105 Through hole 106,107 aperture 109 Projecting wall 201 Fins 202 recess 401 Horizontal Base 402 Vertical Base

Claims

1. A liquid crystal display element for red, a liquid crystal display element for green, and a liquid crystal display element for blue, which modulate the liquid crystal according to the red, green, and blue signals that constitute the video signal, respectively. A heat sink for the red liquid crystal display element, a heat sink for the green liquid crystal display element, and a heat sink for the blue liquid crystal display element are fixed to each of them, and each heat sink has the same shape and size as the other, A light source that emits illumination light to irradiate the red liquid crystal display element, the green liquid crystal display element, and the blue liquid crystal display element, A single optical base to which the red liquid crystal display element, the green liquid crystal display element, and the blue liquid crystal display element are directly or indirectly attached is a single optical base, the red heat sink, the green heat sink, and the blue heat sink, to which the red liquid crystal display element, the green liquid crystal display element, and the blue liquid crystal display element are respectively fixed, Equipped with, On the optical base, the red heatsink, the green heatsink, and the blue heatsink, each of which has the red liquid crystal display element, the green liquid crystal display element, and the blue liquid crystal display element fixed, are positioned closer to the light source than the heatsinks to which the other liquid crystal display elements are fixed. Projection device.

2. The red heat sink, the green heat sink, and the blue heat sink have the same shape and size as each other. The cooling capacity of the red heatsink, the green heatsink, and the blue heatsink is matched to the heat generated by the liquid crystal display element with the highest heat output. The projection device according to claim 1.

3. The projection apparatus according to claim 1 or 2, wherein at least one heat sink other than the heat sink on which the liquid crystal display element generating the most heat is fixed is covered with a cap that reduces the cooling effect of the heat sink on the liquid crystal display element.

Images