JP2005106974A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector capable of securing brightness and color balance in a displayed image by efficiently and uniformly cooling a light source. <P>SOLUTION: In the projector 1 provided with the light source 10, a light guide means 20 for guiding the light emitted from the light source 10, an optical modulator 30 for modulating the light from the light guide means and a projection lens 50 for projecting the modulated light from the optical modulator, the light source 10 is cooled by a meandering narrow tube type heat pipe 110. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to cooling of a projector light source.

  The projector includes a light source, a light guide unit that guides light from the light source, a light modulation element such as a liquid crystal panel or a micromirror array device that modulates the light emitted from the light guide unit based on an image signal, A projection lens that projects the modulated light.

  In recent years, projectors have been reduced in size, increased brightness, extended life, reduced noise, reduced cost, and the like. For example, with respect to miniaturization, the size of the liquid crystal panel (light modulation element) has been reduced to a size of just over 1/6 in terms of area ratio with the diagonal of 1.3 in being 0.5 in.

  On the other hand, as the light source, for example, a discharge lamp such as a metal halide lamp, an ultra-high pressure mercury lamp, or a halogen lamp is generally used. Since these light sources generate heat during light emission, there is a problem that the characteristics of the light source lamp itself change, or heat propagates to the liquid crystal panel and optical components, resulting in thermal degradation. Has been taken.

  However, the heat generation from the light source is increasing as the discharge type lamp is reduced in size and brightness, and countermeasures against heat generation are becoming difficult with the generally used forced air cooling method using a fan. In addition to heat, discharge lamps have other problems to be improved. For example, even if the lamp and power supply are large and heavy and cannot be turned on / off instantaneously, improvements are required from the viewpoint of downsizing the projector and improving performance.

  As means for solving the problems of the discharge lamp as described above, recently, adoption of light-emitting elements such as organic EL light-emitting elements (for example, see Patent Document 1) and LEDs (for example, see Patent Document 2) has been studied. Yes. Light sources using these light emitting elements have lower heat generation than discharge lamps, are small in size including the power supply, can be turned on / off instantaneously, have a wide color reproducibility and a long life span. For example, it has advantages as a light source for projectors and other illumination light sources. Further, since it does not contain harmful substances such as mercury, it is preferable from the viewpoint of environmental protection.

Japanese Patent Laid-Open No. 10-333129 JP 11-52889 A

  In projectors, ensuring the brightness of the displayed image is a major issue. In this respect, all of the above-described light emitting elements are insufficient in brightness as a light source, and at least improvement for ensuring brightness at a discharge lamp level is required. If the supply current to the light emitting element is increased in order to ensure brightness, the amount of light emission can be increased. However, since the amount of heat generation increases as the amount of emitted light increases, there is a problem that the light emitting element light source cannot be efficiently cooled with the above-described conventional technology. In this case, the temperature of the light emitting element rises and the light emission efficiency decreases, and the amount of light emission cannot be increased effectively even if the supply current to the light emitting element is increased. In addition, the temperature of the light emitting element rises and the light emitting element may be thermally damaged.

  Furthermore, in Patent Document 1, heat generated from each organic EL light source that emits light of each color of red (R), green (G), and blue (B) is converted into a heat receiving plate, a wick (capillary) heat pipe, and heat dissipation. Each plate is provided to dissipate heat. For this reason, when securing heat pipe performance, there are problems such as restrictions on the arrangement of light sources, an increase in space due to an increase in the number of components, and an increase in cost. Further, in the above-mentioned Patent Document 2, the three-color LED light sources of R, G, and B are arranged and cooled on the same substrate, but the substrate cooling mechanism to be used is not specifically mentioned. Further improvements in cooling capacity and cooling uniformity were desired. Since each of R, G, and B LEDs has different luminous efficiency and temperature characteristics, improvement in cooling capacity and cooling uniformity has been a major issue in securing the color balance of the display image.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a projector capable of ensuring brightness and color balance of a display image by efficiently and uniformly cooling a light source. To do.

  In order to achieve the above object, a projector according to the present invention includes a light source, a light guide unit that guides light from the light source, a light modulation element that modulates light from the light guide unit, and the light modulation unit. A projector having a projection lens for projecting modulated light from an element, wherein the light source can be cooled by a meandering capillary tube heat pipe.

  As described above, a method using a heat pipe for light source cooling has already been disclosed, but a conventional heat pipe is used. A conventional heat pipe is composed of a container (metal tube), a wick (a material having a capillary action), and a working fluid. The operation principle is that the working fluid evaporates in the heating unit (heat receiving unit), and the vapor of the working fluid moves to the cooling unit (heat radiating unit) and condenses. Here, the latent heat of vaporization is transferred, and the condensed working fluid is returned to the heating portion by the capillary action of the wick in the tube. By repeating this, heat is transferred from the heating unit to the cooling unit. At this time, since the reflux is strongly influenced by gravity, when the heat dissipating part is arranged below the heat receiving part, the reflux is hindered and the heat transport capability is greatly reduced. Accordingly, there is a restriction on the arrangement of the heat generator such as the light source and the heat pipe. In addition, since the conventional heat pipe is loaded with a wick, the shape of the heat pipe is usually a straight pipe. Therefore, it is necessary to arrange a heat receiving plate and a heat radiating plate (usually equipped with fins) at both ends of the heat pipe from the need to ensure a heat transfer area. In this case, a problem arises in cost and size reduction due to an increase in the number of parts.

  The meandering capillary heat pipe used in the present invention is an improvement of the limitations and problems of the above-described conventional heat pipe. For example, a meandering capillary heat pipe manufactured by TS Thermonics Co., Ltd. can be used. The meandering capillary heat pipe has features such as few restrictions on arrangement, high thermal conductivity, a flat plate that can be bent freely, and small and light.

  According to the configuration of the present invention, even when the light emitting element generates heat together with light emission, it can be forcibly cooled by the meandering capillary tube heat pipe and kept at a low temperature. The heat transmitted from the light emitting element to the meandering capillary tube heat pipe is rapidly and efficiently diffused throughout the heat pipe by the working medium filled in the meandering capillary tube, and is radiated from the heat pipe surface. Therefore, the light source can be efficiently cooled, and the light emission efficiency of the light emitting element can be prevented from decreasing due to the temperature rise. As a result, a projector with a bright display image can be obtained.

  In the projector according to the aspect of the invention, it is preferable that the non-light emitting surface of the light source is mounted in thermal contact with the meandering capillary heat pipe. According to this configuration, the heat generated by the light emitting element along with the light emission is efficiently transmitted directly from the non-light emitting surface to the meandering capillary heat pipe, and the light emitting element can be kept at a low temperature. Therefore, the light source can be efficiently cooled, and the light emission efficiency of the light emitting element can be prevented from decreasing due to the temperature rise. As a result, a projector with a bright display image can be obtained.

  In the projector according to the aspect of the invention, the light source may be a light emitting element array light source in which a plurality of light emitting elements that emit different color lights are arranged in an array. According to this configuration, even if the amount of heat generated from each light emitting element emitting different colored light is different, the heat from each light emitting element can be efficiently transferred to the meandering capillary tube heat pipe. The light emitting element can be held at a low temperature and with little temperature variation between the light emitting elements. Therefore, the light source can be efficiently cooled, and the light emission efficiency of the light emitting element can be prevented from being lowered due to the temperature rise, and the color balance can be secured. As a result, it is possible to obtain a projector in which the display image is bright and the color balance is secured.

  In the projector according to the aspect of the invention, the light source includes a first light emitting element array light source in which a plurality of light emitting elements that emit first color light are arranged in an array, and a plurality of light emitting elements that emit second color light. A second light emitting element array light source that is arranged in an array and a third light emitting element array light source that is formed by arranging a plurality of light emitting elements that emit third color light in an array. There may be. According to this configuration, even if the amount of heat generated from each light emitting element array light source that emits different color light is different, the heat from each light emitting element array light source can be efficiently transmitted to the meandering capillary heat pipe. Thus, each light emitting element constituting each light source can be held at a low temperature and with little temperature variation between the light emitting elements. Therefore, it becomes possible to cool each light source efficiently, and it is possible to prevent a decrease in the light emission efficiency of the light emitting element due to a temperature rise and to secure a color balance. As a result, it is possible to obtain a projector in which the display image is bright and the color balance is secured.

  In the projector according to the aspect of the invention, it is preferable that the meandering capillary heat pipe is provided with a cooling unit. According to this configuration, the heat generated by the light emitting element along with light emission is transmitted to the meandering capillary heat pipe. The transmitted heat is efficiently diffused throughout the heat pipe by the working medium filled in the meandering tubule, and is radiated from the surface of the heat pipe, and the heat radiation is further promoted by the provided cooling means. Therefore, it becomes possible to cool the light source more efficiently, and it is possible to prevent a decrease in the light emission efficiency of the light emitting element due to a temperature rise and to secure a color balance. As a result, it is possible to obtain a projector in which the display image is bright and the color balance is secured.

  In the projector according to the aspect of the invention, it is preferable that the meandering capillary heat pipe and at least the light guide unit or the light modulation element are thermally connected through a heat conductive member. According to this configuration, the heat generated by the light emitting element along with light emission is dissipated from the surface of the heat pipe by the same action as described above, while the meandering capillary heat pipe and at least the light guide means or the light modulation element are heated. Since it is thermally connected through the conductive member, the heat of the light guide means and the light modulation element is transmitted to the meandering capillary heat pipe through the heat conductive member and radiated from the surface of the heat pipe. By using the cooling means in combination, the heat dissipation capability can be further increased. Therefore, it becomes possible to efficiently cool the light source and at least the light guide means or the light modulation element, prevent a decrease in the light emission efficiency of the light emitting element due to a temperature rise, ensure a color balance, and at least It is possible to prevent thermal deterioration and characteristic change of the light guide means or the light modulation element. As a result, it is possible to obtain a projector with a bright display image, a well-balanced color balance, and excellent reliability.

  According to the projector of the present invention, the light source, the light guide means for guiding the light from the light source, the light modulation element for modulating the light from the light guide means, and the modulated light from the light modulation element are projected. The projector has a projection lens that can cool the light source with a meandering capillary heat pipe, so that it is possible to prevent a decrease in light emission efficiency of the light emitting element due to a temperature rise. A projector with a bright display image can be obtained. In addition, it is possible to obtain a projector in which uniform cooling is possible and color balance is ensured. Furthermore, the light guide means or the light modulation element can be cooled by thermally connecting the meandering capillary heat pipe and at least the light guide means or the light modulation element, thereby preventing their thermal deterioration and property change. it can. As a result, the reliability of the projector can be improved. On the other hand, since the meandering capillary heat pipe can support and fix at least the light guide means or the light modulation element, a base plate for supporting and fixing them becomes unnecessary, and the number of parts can be reduced. Contributes to miniaturization and weight reduction.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing used in the following description, the scale of each member is appropriately changed so that each member can be easily recognized.

  First, Embodiment 1 of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram illustrating an overall configuration of a projector 1 according to the present embodiment. FIG. 2 is a schematic top view (a) and a schematic side sectional view (b) of a meandering capillary heat pipe 100 used in this embodiment.

  A projector 1 according to this embodiment shown in FIG. 1 is a single-plate projector using one liquid crystal panel (light modulation element). A single-plate projector is a projector that modulates light source light by a single light modulation element. In this embodiment, a color sequential driving method is adopted as a driving method of the liquid crystal panel (light modulation element) 30. As shown in FIG. 1, the projector 1 includes an LED array light source 10, a rod lens (light guide unit) 20, a liquid crystal panel 30, a projection lens 50, a housing 60, and a meandering capillary tube heat pipe 110. The outgoing light from 50 is displayed on the screen 70 as a display image. For the sake of simplicity, FIG. 1 does not show an electrode wiring for controlling lighting of the LED light source, a power supply circuit, a light source control circuit, and a light modulation element driving circuit for driving the light modulation element.

  In FIG. 1, the LED array light source 10 includes a plurality of, for example, two-dimensionally integrated red (R) LEDs 11 R, green (G) LEDs 11 G, and blue (B) LEDs 11 B, which are monochromatic LEDs, and are mounted on a substrate 12. Yes. Each LED is fixed by soldering to the substrate 12 in which the positive and negative lead wires of each LED correspond to the arrangement of the LEDs and the insert hole is formed. The LED array light source 10 is provided with a light emitting surface having an area substantially equal to the cross-sectional area of the rod lens 20, so that the emitted light directions of the LEDs are aligned in the same direction. Each LED 11R, 11G, 11B is connected to a light source control circuit (not shown). By the light source control circuit, it is possible to emit color light from each of the LEDs 11R, 11G, and 11B in time order.

  A rod lens (light guide means) 20 is disposed behind the LED array light source 10. The light emitted radially from each color LED of the LED array light source 10 enters the rod lens 20, is totally reflected on its side surface, and is irradiated onto the display area of the liquid crystal panel (light modulation element) 30. Since the light from each color LED is averaged by the rod lens 20, the display area of the liquid crystal panel 30 can be illuminated uniformly.

  A liquid crystal panel 30 is disposed behind the rod lens 20. The liquid crystal panel 30 is connected to a light modulation element driving circuit (not shown). This light modulation element driving circuit controls the timing for driving the liquid crystal panel 30 and can drive the liquid crystal panel 30 in time sequence in accordance with the color light from each color LED. That is, the liquid crystal panel 30 is driven in synchronization with the light emission of each color of the LED array light source 10, and a color image is formed.

  The color image formed by the liquid crystal panel 30 is enlarged and projected on the screen 70 via the projection lens 50. As described above, image display is performed.

  In the configuration of the projector 1 of the present embodiment described above, the back surface (non-light emitting surface) of the LED array light source 10 is attached to the inner back portion of the meandering capillary heat pipe 110 that is bent into a concave shape. Bonded directly using epoxy adhesive. Further, inside the meandering capillary heat pipe 110 bent into a concave shape, a rod lens (light guide means) 20 and a liquid crystal panel (light modulation element) 30 are meandering narrow tubes in addition to the LED array light source 10 bonded. It arrange | positions so that the recessed part of the type | mold heat pipe 110 may be enclosed.

Here, the meandering capillary heat pipe 100 will be described with reference to FIG.
As shown in FIG. 2, the meandering capillary tube heat pipe 100 includes metal plates 101 and 101 ′ having a predetermined thickness, a meandering capillary portion 102, and a working medium 103. In addition, the enclosure port for enclosing the working medium 103 into the meandering thin tube portion 102 is not shown. The meandering thin tube portion 102 is formed by forming meandering narrow grooves in the flat plate portions of the respective metal flat plates 101 and 101 ′ so as to have a target shape, and then superimposing the processing surfaces so that, for example, welding joining is performed. Is formed. The meandering structure is formed by ordinary machining such as cutting, electric discharge machining, or press working. It is also possible to form by replication processing by injection molding. Examples of applicable materials include metals having excellent thermal conductivity such as stainless steel, aluminum, magnesium, copper, and titanium, and alloys thereof. The working medium 103 enclosed in the meandering narrow tube portion 102 is a liquid medium such as water.

  In the meandering capillary tube heat pipe 100 having the above configuration, the working medium 103 is vaporized by heat absorption from the heating element, and the generated steam moves from the high pressure side of the heat receiving portion to the low pressure side of the heat radiating portion, thereby transferring latent heat. It is carried out. On the other hand, simultaneously with the movement of the vapor, the liquid phase part also moves from the heat receiving part to the heat radiating part to transport sensible heat. That is, due to the mixed transport of latent heat and sensible heat, the meandering capillary heat pipe 100 has a larger heat transport capability than the conventional heat pipe. In addition, the conventional heat pipe cannot be bent because a wick is loaded inside the tube, but the meandering capillary tube heat pipe 100 can be freely deformed into an arbitrary shape. Furthermore, since the meandering capillary heat pipe 100 has a flat plate shape, it is possible to mount the heating element, and there is no restriction on the arrangement of the heat receiving part and the heat radiating part. Have

  A meandering capillary tube heat pipe 110 used in the projector 1 shown in FIG. 1 is obtained by bending the flat meandering capillary tube heat pipe 100 shown in FIG. 2 into a concave shape, and has the same heat dissipation characteristics. Is.

  In the configuration of the present embodiment described above, the heat generated when the LED array light source 10 is turned on is a meandering capillary type from the back surface (non-light emitting surface) of the LED array light source 10 via, for example, a heat conductive epoxy adhesive. Heat is transferred to the heat pipe 110.

  Since each color LED constituting the LED array light source 10 has different light emission efficiency, it is necessary to change the current supplied to each color LED in accordance with the light emission efficiency in order to make the luminous flux of the light emitted from each LED the same. As a result, the amount of heat generated from an LED with low luminous efficiency is greater than that of an LED with high luminous efficiency. Usually, the luminous efficiency of the LED decreases as the temperature of the LED increases. Unless the input current is changed, the emitted light beam from each color LED decreases with time and the color balance also shifts.

  In the present embodiment, the heat of the LED array light source 10 is transferred to the meandering capillary heat pipe 110. The heat from each color LED is efficiently transferred from the entire back surface (non-light emitting surface) of the LED array light source 10 to the meandering capillary heat pipe 110 (heat receiving portion). The transferred heat is efficiently transported by heat to the low temperature portion (heat radiating portion) in the meandering capillary heat pipe 110 and radiated from the surface portion of the meandering capillary heat pipe 110. As a result, the temperature rise of the entire LED array light source 10 can be prevented, and the temperature difference between the LEDs can be minimized. As a result, it is possible to prevent a decrease in the light emission efficiency of the LED array light source 10 accompanying a temperature rise, and a projector with a bright display image can be obtained. In addition, it is possible to obtain a projector in which uniform cooling is possible and color balance is ensured.

  On the other hand, in this embodiment, in addition to the LED array light source 10 directly bonded, a rod lens (light guide means) 20 and a liquid crystal panel (light modulation) are disposed inside the meandering capillary heat pipe 110 bent into a concave shape. (Element) 30 is arranged so as to be surrounded by the meandering capillary tube heat pipe 110. Therefore, the leaked light that could not enter the rod lens 20 from the LED array light source 10 is absorbed as heat from the inner surface of the meandering capillary heat pipe 110, and the temperature rise of the optical system can be prevented. Further, the radiant heat from the rod lens 20 and the liquid crystal panel 30 is also absorbed as heat from the inner surface of the meandering capillary tube heat pipe 110, and further the temperature rise of the optical system can be prevented. As a result, it is possible to prevent thermal degradation and characteristic changes of the optical system, and reliability is improved.

  The second embodiment of the present invention relates to a modification of the projector 1 described in the first embodiment and will be described with reference to FIG. FIG. 3 is a schematic diagram showing the overall configuration of the projector 1 in this embodiment. The difference from the first embodiment is that the cooling fins 90 are arranged on the three outer surfaces of the meandering capillary heat pipe 110 bent into a concave shape. The same parts as those in the first embodiment are denoted by the same reference numerals, and the description of the configuration is omitted.

  In FIG. 3, the cooling fins 90 are fixed to three surfaces of the outer surface of the meandering capillary tube heat pipe 110 bent into a concave shape by using a heat conductive adhesive, for example, an epoxy adhesive. As a fixing method, methods other than the adhesive method (for example, metal solder bonding, screwing, etc.) may be used.

  In the configuration of the present embodiment described above, the heat of the LED array light source 10 is transferred to the meandering capillary tube heat pipe 110 as in the first embodiment. Heat from each color LED is efficiently transferred from the entire back surface (non-light emitting surface) of the LED array light source 10 to the meandering capillary heat pipe 110 (heat receiving portion). The transferred heat is efficiently transported by heat to the low temperature portion (heat radiating portion) in the meandering capillary heat pipe 110 and radiated from the surface portion of the meandering capillary heat pipe 110. Furthermore, heat radiation is further promoted from the cooling fins 90 disposed in the meandering capillary heat pipe 110, and the cooling efficiency of the LED array light source 10 can be enhanced. From the above, it becomes possible to prevent a decrease in the light emission efficiency of the LED array light source 10 accompanying a temperature rise, and a projector with a bright display image can be obtained. In addition, it is possible to obtain a projector in which uniform cooling is possible and color balance is ensured.

  On the other hand, as shown in FIG. 3, in addition to the LED array light source 10 directly bonded, a rod lens 20 and a liquid crystal panel 30 are provided inside the meandering capillary heat pipe 110 bent into a concave shape. It is arrange | positioned so that it may be surrounded by the meandering thin tube type heat pipe 110 provided with. Accordingly, it is possible to prevent the temperature of the optical system from rising more stably, prevent thermal deterioration of the optical system and change in characteristics, and improve reliability.

  The third embodiment of the present invention relates to a modification of the projector 1 described in the first embodiment, and is a further modification of the second embodiment. The third embodiment will be described with reference to FIG. FIG. 4 is a schematic diagram showing the overall configuration of the projector 1 in this embodiment. The difference from the first embodiment is that the cooling fins 90 are arranged on the three outer surfaces of the meandering capillary heat pipe 110 bent into a concave shape. Further, the difference from Example 1 and Example 2 is that the meandering capillary tube heat pipe 110, the rod lens (light guide means) 20, and the liquid crystal panel (light modulation element) 30 are fixed parts (thermal conductive members). They are thermally connected through 65 and 66. The same parts as those in the first embodiment and the second embodiment are denoted by the same reference numerals, and the description of the configuration is omitted.

  In FIG. 4, the rod lens (light guide means) 20 includes a metal fixing component (thermal conductivity) that connects the inner surfaces of both ends of the meandering capillary heat pipe 110 bent into a concave shape and the side surfaces of the rod lens 20. Member) 65 and bonded and fixed by a heat conductive adhesive. The fixing component 65 is provided with a groove in accordance with the dimension of the side surface portion of the rod lens 20, and the rod lens 20 is sandwiched in the groove and bonded and fixed by a heat conductive adhesive. The fixed part 65 and the meandering capillary tube heat pipe 110 are bonded and fixed to each other with a heat conductive adhesive. The shape and fixing method of the fixing component 65 can be changed within a range that does not impair the light guide function of the rod lens (light guide means) 20. The liquid crystal panel (light modulation element) 30 is also bonded and fixed to the meandering capillary tube heat pipe 110 through a metal fixing part (thermal conductive member) 66 in the same manner as the rod lens (light guide means) 20. ing.

  In the configuration of the present embodiment described above, the rod lens 20 and the liquid crystal panel 30 are thermally connected to the meandering capillary heat pipe 110 bent into a concave shape via metal fixing parts (thermally conductive members) 65 and 66. It is connected to the. Accordingly, the heat of the rod lens 20 and the liquid crystal panel 30 is transmitted to the meandering capillary tube heat pipe 110 as radiant heat, and is also transmitted through the metal fixed parts (thermal conductive members) 65 and 66. Accordingly, it is possible to prevent the temperature of the optical system from rising more stably, prevent thermal deterioration of the optical system and change in characteristics, and improve reliability. Further, since the rod lens 20 and the liquid crystal panel 30 are fixed to the meandering capillary tube heat pipe 110 using the fixing components 65 and 66, a base plate for supporting and fixing them becomes unnecessary, and the number of components can be reduced. This contributes to miniaturization and weight reduction of projectors.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic diagram showing the overall configuration of the projector 2 according to the present embodiment.

  The projector 2 of the present embodiment shown in FIG. 5 is a three-plate projector using three liquid crystal panels (light modulation elements). A three-plate projector is a projector that modulates light source light by three light modulation elements corresponding to the three primary colors. As shown in FIG. 5, the projector 2 includes LED array light sources 10R, 10G, and 10B, rod lenses (light guide means) 20R, 20G, and 20B, liquid crystal panels (light modulation elements) 30R, 30G, and 30B, a dichroic prism 40, The projection lens 50, the housing 60, and the meandering capillary heat pipe 120 are provided, and the light emitted from the projection lens 50 is displayed on the screen 70 as a display image.

  In FIG. 5, each of the LED array light sources 10R, 10G, and 10B includes a plurality of, for example, two-dimensionally integrated red (R) LEDs 11R, green (G) LEDs 11G, and blue (B) LEDs 11B that are single color LEDs. And mounted on the corresponding substrates 12R, 12G, and 12B. Each color LED is fixed by being soldered to the boards 12R, 12G, and 12B on which insert holes are formed so that the positive and negative lead wires of each color LED correspond to the arrangement of each color LED. The LED array light sources 10R, 10G, and 10B are aligned so that the emitted light directions of the respective color LEDs face the same direction for each light source. Each light source includes a light emitting surface having an area substantially equal to each cross-sectional area of the rod lenses 20R, 20G, and 20B corresponding to each light source.

  Rod lenses 20R, 20G, and 20B are disposed behind the LED array light sources 10R, 10G, and 10B, respectively. The light emitted radially from the LED array light sources 10R, 10G, and 10B is incident on the rod lenses 20R, 20G, and 20B and totally reflected on the side surfaces thereof, and the light from the light sources is averaged. Each averaged color light is uniformly applied to each display area of the liquid crystal panels (light modulation elements) 30R, 30G, and 30B disposed behind the rod lens.

  The three color lights modulated by the respective liquid crystal panels (light modulation elements) 30R, 30G, and 30B are incident on the dichroic prism 40. This prism is formed by bonding four right-angle prisms, and a dielectric multilayer film 40R that reflects red light and a dielectric multilayer film 40B that reflects blue light are formed in a cross shape on the inner surface thereof. These dielectric multilayer films combine three color lights to form light representing a color image. The formed color image is enlarged and projected onto the screen 70 via the projection lens 50. As described above, image display is performed.

  In the configuration of the projector 2 of the present embodiment described above, the back surfaces (non-light emitting surfaces) of the LED array light sources 10R, 10G, and 10B are bent into three concave portions so as to correspond to the three LED array light sources. For example, an epoxy adhesive having excellent thermal conductivity is directly bonded to the inner back of each concave portion of the meandering capillary heat pipe 120. Further, in each concave portion of the meandering capillary heat pipe 120, in addition to each LED array light source directly bonded, each rod lens and each liquid crystal panel are arranged so as to be surrounded by each concave portion of the meandering capillary heat pipe 120. ing.

  A meandering capillary tube heat pipe 120 used in the projector 2 shown in FIG. 5 is obtained by bending the flat meandering capillary tube heat pipe 100 shown in FIG. The heat dissipation characteristics are equivalent.

  In the above-described configuration of the present embodiment, heat generated by lighting each LED array light source 10R, 10G, 10B is efficiently transferred from the back surface (non-light emitting surface) of each light source to the meandering interstitial heat pipe 120. Is done.

  Since each color LED constituting each LED array light source 10R, 10G, 10B has different light emission efficiency, when trying to make the luminous flux of the light emitted from each LED array light source the same, the current to be supplied to each color LED is adjusted according to the light emission efficiency. Need to change. As a result, an LED with low luminous efficiency generates more heat than an LED with high luminous efficiency. Therefore, the amount of heat generated by each LED array light source 10R, 10G, 10B is different. Normally, the luminous efficiency of the LED decreases as the temperature of the LED increases. Therefore, if the input current is not changed, the emitted light beam from each LED array light source decreases with time and the color balance also shifts.

  In this embodiment, the heat of each LED array light source 10R, 10G, 10B is transferred to the meandering capillary heat pipe 120. Heat from each color LED is efficiently transferred from the entire back surface (non-light emitting surface) of each light source to the meandering capillary heat pipe 120 (heat receiving portion). The transferred heat is efficiently transported by heat to the low temperature portion (heat radiating portion) in the meandering capillary heat pipe 120 and radiated from the surface portion of the meandering capillary heat pipe 120. As a result, even if the heating amounts of the LED array light sources 10R, 10G, and 10B are different from each other, it is possible to prevent the temperature rise of the entire light sources and minimize the temperature difference between the light sources. As a result, it is possible to prevent a decrease in the light emission efficiency of each light source accompanying a temperature rise, and a projector with a bright display image can be obtained. In addition, it is possible to obtain a projector in which uniform cooling is possible and color balance is ensured.

  On the other hand, in the present embodiment, as shown in FIG. 5, inside the concave portions of the meandering capillary heat pipe 120, which is bent into three concave portions so as to correspond to the three LED array light sources 10R, 10G, 10B. In addition to the directly bonded light sources, the rod lenses 20R, 20G, 20B and the liquid crystal panels 30R, 30G, 30B are arranged so as to be surrounded by the meandering capillary heat pipe 120. From this, leakage light that could not be incident on each rod lens from each light source is absorbed as heat from the inner surface of the meandering capillary heat pipe 120, and temperature rise of the optical system can be prevented. Further, the radiant heat from each rod lens and each liquid crystal panel is also absorbed as heat from the inner surface of the meandering capillary tube heat pipe 120, and the temperature rise of the optical system can be prevented. As a result, it is possible to prevent thermal degradation and characteristic changes of the optical system, and reliability is improved.

  The fifth embodiment of the present invention relates to a modification of the projector 2 described in the fourth embodiment and will be described with reference to FIG. FIG. 6 is a schematic diagram showing the overall configuration of the projector 2 in the present embodiment. A difference from the fourth embodiment is that, as shown in FIG. 6, the outer surface of a meandering capillary heat pipe 120 that is bent into three concave portions so as to correspond to the three LED array light sources 10R, 10G, and 10B. The cooling fins 90 are respectively arranged on the nine surfaces. Further, the meandering capillary heat pipe 120 bent at three locations in a concave shape, the rod lenses 20R, 20G, and 20B and the liquid crystal panels 30R, 30G, and 30B are each made of metal fixed parts (thermal conductive members). They are thermally connected through 65 and 66. The same parts as those in the fourth embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In FIG. 6, each of the rod lenses (light guide means) 20R, 20G, 20B is formed by connecting the inner surface of each concave portion of the meandering capillary heat pipe 120 bent into a concave shape and the side surfaces of the rod lenses 20R, 20G, 20B. It is bonded and fixed via a fixed part (thermally conductive member) 65 made of metal. The fixing component 65 is provided with a groove according to the dimension of the side surface portion of each rod lens, and the rod lens 20 is sandwiched in the groove and bonded and fixed by a heat conductive adhesive. Each fixed part 65 and the meandering capillary tube heat pipe 120 are bonded and fixed to each other with a heat conductive adhesive. The shape and fixing method of the fixing component 65 can be changed within a range that does not impair the light guide function of each rod lens. Each of the liquid crystal panels (light modulation elements) 30R, 30G, and 30B is also bonded and fixed to the meandering capillary heat pipe 120 via a metal fixing part (thermal conductive member) 66 in the same manner as the rod lens. Yes.

  In the above-described configuration of the present embodiment, each of the rod lenses (light guiding means) 20R, 20G, 20B and each of the liquid crystal panels (light modulation elements) 30R, 30G, 30B are arranged in three LED array light sources 10R, 10G, 10B. Correspondingly, it is thermally connected to a meandering capillary heat pipe 120 that is bent into a concave shape at three locations via metal fixing parts (thermal conductive members) 65 and 66. Therefore, the heat of each rod lens and each liquid crystal panel is transmitted to the meandering capillary tube heat pipe 120 as radiant heat, and is also transmitted through the metal fixed parts (thermal conductive members) 65 and 66. Accordingly, it is possible to prevent the temperature of the optical system from rising more stably, prevent thermal deterioration of the optical system and change in characteristics, and improve reliability. Furthermore, since each rod lens and each liquid crystal panel are fixed to the meandering capillary tube heat pipe 120 using fixing parts 65 and 66, a base plate for supporting and fixing them becomes unnecessary, and the number of parts can be reduced. This contributes to miniaturization and weight reduction of projectors.

  The projector according to the embodiment of the present invention has been described above, but the embodiment can be freely changed within the scope of the gist of the present invention. For example, in the second, third, and fifth embodiments, a plurality of cooling fins (changeable) are used as the cooling means, but other cooling means (for example, a Peltier element or an air cooling fan) may be used alone, or The effect of the present invention can be obtained even when used in combination with cooling fins. Moreover, although LED demonstrated as light source in embodiment, this invention is applicable also to other light emitting elements, such as a semiconductor laser. Furthermore, in the embodiment, the rod lens is used as the light guide unit. However, the present invention can be applied to other light guide units (uniformization unit) such as a fly-eye lens. In the embodiment, the liquid crystal panel is used as the light modulation element. However, the effects of the present invention can also be obtained for a micromirror array device. The light source configuration of the present invention is also effective for applications that require a light source with a good color balance and a bright color.

1 is a schematic configuration diagram of a projector 1 in a first embodiment. The upper surface schematic (a) and side surface schematic sectional drawing (b) of the meandering thin tube type heat pipe which concern on each Example. The schematic block diagram of the projector 1 in a 2nd Example. The schematic block diagram of the projector 1 in a 3rd Example. The schematic block diagram of the projector 2 in a 4th Example. The schematic block diagram of the projector 2 in a 5th Example.

Explanation of symbols

1, 2, Projector 10, 10R, 10G, 10B LED array light source 20, 20R, 20G, 20B Rod lens (light guide means)
30, 30R, 30G, 30B Liquid crystal panel (light modulation element)
65, 66 Fixed parts (thermally conductive members)
90 Cooling fin (cooling means)
100, 110, 120 Serpentine capillary tube heat pipe

Claims (6)

A projector having a light source, a light guide unit that guides light from the light source, a light modulation element that modulates light from the light guide unit, and a projection lens that projects modulated light from the light modulation element A projector characterized in that the light source can be cooled by a meandering capillary tube heat pipe. The projector according to claim 1, wherein the non-light emitting surface of the light source is mounted in thermal contact with the meandering capillary heat pipe. 3. The projector according to claim 1, wherein the light source is a light emitting element array light source formed by arranging a plurality of light emitting elements emitting different color lights in an array. The light source includes a first light emitting element array light source in which a plurality of light emitting elements that emit first color light are arranged in an array, and a plurality of light emitting elements that emit second color light in an array. 3. A second light emitting element array light source, and a third light emitting element array light source formed by arranging a plurality of light emitting elements emitting third color light in an array. The projector described. 5. The projector according to claim 1, wherein the meandering capillary tube heat pipe is provided with a cooling means. 6. The meandering capillary heat pipe and at least the light guide means or the light modulation element are thermally connected to each other through a heat conductive member. Projector.

Images