JP2010107751A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector which prevents degradation of image quality occurring because an optical axis of the projector is deviated due to heat generation when a screen is made bright by increasing a quantity of light, and in which a cooling system is made compact, so as to prevent portability from being spoiled. <P>SOLUTION: Temperature of a housing rises by heat generated when a laser diode is operated after the laser diode and an optical element are fixed in the housing after their positions and angles are adjusted so that the optical axis of light from each light source may be aligned on the same axial line. In order to prevent the deviation of the aligned optical axis due to distortion of the housing resulting from temperature rise of the housing, cooling structure in a state of floating in the air through a small cavity from the housing is fixed in the housing with heat transfer structure as a supporting beam, and temperature of the cooling structure is made low compared with temperature of the housing, so as to suck a quantity of heat generated from the light source that is a heat generation source fixed on an outer peripheral wall of the housing to the cooling structure and suppress the quantity of heat flowing into the housing to be small. By making the cooling structure and the heat transfer structure thin-plate structure, they are attached in a state of floating through a small gap on the outer wall of the housing, whereby double structure of the housing and a cooling mechanism is obtained. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a small-sized projector, and more particularly, to a cooling structure that efficiently processes heat generated by a light source.

  In recent years, with the improvement of information transmission speed, moving image distribution and the like have become common, and larger moving images that are excellent for presentation have been distributed. In addition, the technology of information terminals has advanced, and mobile phones equipped with high-quality liquid crystal have become widespread. However, in mobile devices such as mobile phones that are assumed to be portable, the screen size cannot be made very large because it is necessary to consider the portability, and it is not possible to make full use of moving images.

  Therefore, as a solution to this problem, Patent Document 1 discloses a portable projector. This is intended to enable a small portable device to project an image on a large external screen for viewing. Patent Document 2 discloses a clamshell-type projector terminal technology that can change the projection direction according to the usage scene, such as when it is held in hand or when used somewhere.

JP 2007-65627 A JP 2007-96542 A

  However, a problem with portable projectors is that the amount of light is small. That is, in the case of a liquid crystal screen, a moving image can be enjoyed on a screen even in a bright place, but the projector type inconveniences that it cannot be used unless the screen to be projected is installed in a dark place. For this reason, it is necessary to brighten the projection screen. However, if the amount of light is increased, the amount of heat generated by the light source increases, and the projector housing is distorted due to thermal deformation. The optical axis of the optical system installed in the housing There is a problem that a bad projection such as misalignment occurs and a beautiful projected image cannot be obtained.

  There is also a method of actively lowering the temperature by attaching radiating fins etc. to the case, but in this case, the temperature difference between the heat generating part and the heat radiating part (cooling part) becomes large and the case has a large temperature distribution The case is distorted due to non-uniform thermal deformation, and the optical axis of the optical system supported by the case is displaced.

  An object of the present invention is to provide a high-quality projector by preventing the optical axis of the optical system from being displaced by the heat generated by the light source even when the projection screen is brightened by increasing the amount of light.

  Another object of the present invention is to provide a projector that does not impair portability by making the cooling system compact.

The present invention includes a plurality of light sources, an optical element for aligning light from each light source on the same axis, and a housing that incorporates the optical element and supports the light source, and the optical elements are aligned on the same axis. In a projector that projects light onto a screen outside the housing by scanning light,
A thermally conductive fixing member that supports the light source by interposing the light source and the housing;
A cooler disposed in a thermally insulated state with the housing;
A heat transfer member that thermally connects the fixing member and the cooler and thermally transports heat generated by the light source from the fixing member to the cooler;
The heat transfer member is disposed in a state of being insulated from the housing.

  In the projector according to the aspect of the invention described above, the cooler may be disposed in the housing via a gap from the housing, and the heat transfer member may be disposed in the housing via the gap. It is characterized by.

  Further, in the projector according to the aspect of the invention, the light source is attached to one side of the casing via a fixing member, the cooler is disposed on the other side of the casing, and the heat transfer member is It is characterized by being arranged symmetrically along the upper and lower parts of the casing.

  In the projector according to the aspect of the invention, the heat transfer member may be disposed outside the housing with a gap from the housing, and may form a double structure surrounding the optical element together with the housing. And

  According to the present invention, in the projector described above, the cooler is a cooler using heat of vaporization.

  According to the present invention, in the projector described above, the cooler includes a hydraulic fluid holding chamber, a hydraulic fluid supply fine channel, a hydraulic fluid evaporation sheet, and a hydraulic fluid evaporation sheet holding lid, and is connected to the hydraulic fluid holding chamber. The supply fine flow path and the hydraulic fluid storage container are connected by a tube. When the hydraulic fluid evaporates from the hydraulic fluid evaporation sheet, the hydraulic fluid is discharged by the negative pressure generated when the amount of fluid in the hydraulic fluid holding chamber is consumed. The working fluid is sucked up from the storage container to the working fluid holding chamber through the tube.

  In the projector according to the invention, a laser diode is used as the light source.

  In the present invention, after adjusting the position and angle of the laser diode and the optical element so that the optical axes of the light from each light source are on the same axis and fixing to the housing via the fixing member, when the laser diode is in operation In order to prevent the temperature of the housing from rising due to the heat generated and causing the optical axis to be displaced due to distortion of the housing, a cooler that has been suspended from the housing through a slight gap The heat transfer member is fixed to the casing as a support beam, the temperature of the cooler is set lower than the casing temperature, and the amount of heat generated from the light source that is a heat source fixed to the outer peripheral wall of the casing is The heat is sucked into the cooler via the heat transfer member, and the amount of heat flowing into the casing is reduced.

  In addition, the cooling system of the cooler and the heat transfer member used in the present invention is made into a thin plate shape, so that the casing is mounted on the outer wall of the casing in a state of being floated through a slight gap, and the optical element is mounted. Surrounded by a double structure of body and cooling system.

  According to the present invention, a bright and high-quality projection screen can be obtained without impairing the compactness of the projector.

  That is, since the amount of heat flowing into the housing is reduced, the temperature distribution of the housing is reduced, and the optical axis misalignment caused by thermal deformation due to the temperature distribution can be prevented. Furthermore, the size of the projector can be made compact by forming the cooling system in an outer shell shape so as to surround the outer periphery of the housing.

Example 1
A first embodiment of the present invention will be described with reference to FIG. This uses an optical element (not shown) that reflects light emitted from three types of laser diodes (light sources) 102, 103, and 104 of red, blue, and green only at a specific wavelength and transmits other wavelengths. As a result, three lights are aligned on the same axis and are emitted out of the casing 101 as light indicated by 100. The light 100 exiting from the housing 101 is projected onto an external screen by the timing of the blinking of the three lights and the scanning of a mirror (not shown).

  When the laser diodes 102, 103, and 104 that are heat sources are attached, the laser diodes 102, 103, and 104 are positioned so that the optical axes of the respective lights are aligned with each other, and are fixed to the housing 101. The individual fixing members 105, 106, and 107 have a U-shape, support the laser diodes 102, 103, and 104 on the central side, and the tips on both sides are fixed to the housing 101. One end of a corresponding individual heat transfer member 108, 109, 110, 111, 112, 113 is fixed to the upper and lower end faces of each individual fixing member, and an individual cooler is attached to the other end of each heat transfer member. The upper and lower ends of 114 are fixed.

  Each fixing member and the cooler 114 are dimensioned so that the upper and lower end surfaces are higher than the housing, and the heat transfer member is in a heat insulating state with a gap from the upper and lower wall surfaces of the housing 101. Passed between and cooler and fixed. In other words, the cooler 114 is fixed to the housing 101 with the heat transfer members 108, 109, 110, 111, 112, 113 as support beams.

  Each of the fixing members is made of SUS (stainless steel) or aluminum having a good thermal conductivity, absorbs heat generated by light emission of the corresponding laser diodes 102, 103, and 104, and heats the corresponding individual heat transfer members. Tell. The heat transfer member is also made of a metal material such as aluminum or silicon (Si) having good heat conductivity, and transports heat from the corresponding fixing member to the cooler 114 side. At this time, since the heat transfer member is in a heat-insulating state with a gap from the upper and lower wall surfaces of the housing 101, it hardly affects the housing 101 thermally.

  Actually, when the laser diode is operated, the heat generated by the laser diode is also transmitted to the housing, but the thermal resistance to which the heat is transmitted to the cooler 114 is smaller by one digit or more than the thermal resistance to which the heat is transmitted to the housing 101. By designing the heat transfer system in this manner, most of the heat generated from the laser diode can be consumed by the cooler 114, and the amount of heat transferred to the housing can be reduced.

  If the amount of heat transfer to the housing is small, the housing temperature in an equilibrium state with the heat radiation from the housing surface does not cause a temperature difference with respect to the outside air temperature. For example, assuming that the surface area of the housing is 0.0036 square meters, if the total heat generation of the laser diode is 2 W and 5% of that flows into the housing, the housing surface temperature is less than 3 ° C with respect to the outside air temperature. The temperature rises. This temperature increase is smaller than the daily temperature fluctuation, and the optical axis shift due to the difference in volume expansion due to heat can be ignored. Note that the housing 101 is made of a metal or a synthetic resin material with little thermal expansion.

  Moreover, when calculating how many times the temperature of the cooler needs to be lowered in order to suppress the temperature rise, the cross-sectional area of the heat transfer member is 15 mm × 1 mm × 6 and the average heat transfer distance is 20 mm. What is necessary is just to set 2 degreeC lower low with respect to external temperature. If this is the case, condensation and other problems are unlikely to occur.

  Laser diodes generate different amounts of heat depending on the colors they emit (red, blue, and green). This is due to the light emission efficiency of laser diodes and the sensitivity to human colors. Currently, green is inefficient because it uses conversion from other colors, and human sensitivity is easy to feel green, red is hard to feel, and blue is in between. For this reason, in order to actually make the human eye feel a uniform color, the amount of heat generated increases in the order of blue, green, and red of the laser diode, and these different amounts of heat are transmitted through individual fixing members and heat transfer members. , Transmitted to a separate cooler. Therefore, each cooler has a different amount of heat, which will be described later.

  Next, the internal state of the housing 101 with the cooler removed will be described with reference to FIG. The laser diodes 102, 103, and 104 are fixed to the outer wall of the housing 101 by individual fixing members 105, 106, and 107, respectively. Lights respectively output from the laser diodes 102, 103, and 104 are indicated by 213, 214, and 215, and their optical paths are bent at right angles by optical elements 211 and 212 installed in a casing that reflects only a specific wavelength. By adjusting the positions and angles of the laser diodes 102, 103, 104 and the optical elements 211, 212 at this time, the optical axes of the three lights 213, 214, 215 are aligned to become the light 100. Here, 208, 209 and 210 are terminals for driving the laser diode.

  Next, the internal state of the casing 101 of the second embodiment with the cooler removed will be described with reference to FIG. 3 which is a sectional view of the casing of the projector. In this embodiment, laser diodes 302, 303, and 304 are arranged in a line on the side surface of the casing 101 and fixed to the outer wall of the casing 101 via individual fixing members 305, 306, and 307. Lights output from the laser diodes 302, 303, and 304 are indicated by reference numerals 314, 315, and 316, and their optical paths are bent at right angles by optical elements 311, 312, and 313 installed in a casing that reflects only a specific wavelength. By adjusting the positions and angles of the laser diode and the optical element at this time, the optical axes of the three lights 314, 315, and 316 are aligned, and the light 100 is obtained. Here, 308, 309, and 310 are laser diode drive terminals.

  With only the above configuration, as shown in the prior art, the temperature difference between the portion where the laser diode is fixed in the housing and the other portion becomes large, and the housing of an integral body made of the same material ( 101), thermal deformation occurs and deviation occurs in the optical axis. When cooling is performed simply by providing a heat radiation fin or the like, the temperature difference between the heat generating part and the cooling part becomes large even if temperature rise to some extent can be prevented, and the optical axis shift due to the temperature distribution cannot be suppressed. Accordingly, when the heat generated by the laser diodes (102, 103, 104) is transmitted to the housing (101) and the temperature rises, the housing (101) made of different materials and the optical elements (211 and 212) have different ratios. Due to the volume expansion, the laser beam (213, 214, 215) is shifted on the same axis. Further, when the output of the laser diode (202, 203, 204) is increased in order to improve the luminance even if the casing is made of aluminum having good thermal conductivity, the laser diode ( 202, 203, and 204) have a large temperature difference from the non-fixed part, and even the one-piece housing (201) made of the same aluminum material is thermally deformed and the optical axis is displaced. To do.

  Next, the configuration relating to cooling of the embodiment of the present invention will be described with reference to the cross-sectional view of FIG.

  The laser diode 402 is fixed to the housing 401 by a fixing member 403. The heat generated from the heat generating portion 402a of the laser diode 402 moves to the fixing member 403 side as indicated by a large arrow in the laser diode 402, and this heat flows in the fixing member 403 as indicated by a middle arrow, as indicated by a small arrow. To the housing 401 from the contact portion with the housing 401. When not cooled, heat is transmitted to the optical element 404 installed in the housing 401, and the relative position between the laser diode 402 and the optical element 404 fixed to the housing 401 due to the difference in thermal expansion coefficient. Deviation occurs.

  Therefore, the heat transfer members 405 and 406 are thermally contacted and fixed to the fixing member 403, and the heat is transported to the cooler 407 side. At this time, the heat conductivity of the housing 401 and the heat conductivity of the heat transfer members 405 and 406 are greatly different from each other, so that most of the heat generated by the laser diode 402 is cooled via the heat transfer members 405 and 406. Flow to vessel 407. Note that it is preferable to increase the temperature transport amount by increasing the temperature difference between both ends of the heat transfer members 405 and 406 by lowering the temperature of the cooler 407 than the surrounding environment.

  The cooler 407 uses heat of vaporization as shown in FIG. In the cooler 407, a fine channel 504 and a working fluid holding chamber 503 communicating with the channel are formed on a glass substrate 505 by a wall member 509 made of single crystal silicon, and a fibrous evaporation sheet 502 and this layer are formed on the upper layer. A silicon mesh-like lid substrate 501 that supports the upper and lower sides of the sheet is formed. Further, projections 506 that increase the surface area are provided on the surface of the sheet 502, and heat transfer members 505 and 506 are thermally connected to the upper and lower ends of the cooler 407. Reference numeral 507 denotes a tube connected to the fine flow path 504, and reference numeral 508 denotes a hydraulic fluid storage container that stores the hydraulic fluid connected to the tube 507.

  The hydraulic fluid is supplied to the hydraulic fluid holding chamber 503 via the fine flow path substrate 504 on the substrate 505, and is sucked up to the evaporation sheet 502 by capillary action. The hydraulic fluid sucked up by the evaporating sheet 502 evaporates from the surface of the sheet 502 and takes heat of vaporization from the surroundings. The amount of evaporation at this time depends on the evaporation area of the protrusion 506 and determines the cooling capacity of the cooler 407.

  When the working fluid in the working fluid holding chamber 503 is consumed from the evaporation sheet 502, the inside of the working fluid holding chamber 503 becomes negative pressure, and the working fluid is discharged from the working fluid storage container 508 via the tube 507 connected to the fine flow path 504. Aspirated and supplied to the hydraulic fluid holding chamber 503.

  When Fluorinert (Trademark, Sumitomo 3M) or the like is used as the working fluid, the temperature of the cooler is adjusted with respect to the ambient temperature by adjusting the void density (surface area where the working fluid evaporates) of the evaporation sheet 502 that evaporates the working fluid. It will be adjusted how much it is lowered. Even when the same evaporation sheet 502 is used, the temperature of the cooling structure can be adjusted by adjusting the area where the sheet is in contact with the outside air.

  If water (low volatility) is used without using a highly volatile working fluid such as florinate, the temperature of the cooler cannot be lowered significantly from the surrounding environment due to the heat of vaporization. In some cases, there is a method of providing a temperature difference using a Peltier element. That is, between the heat transfer members 405 and 406 and the laser diode fixing member 403 shown in FIG. 4, the cooling surface is directed to the fixing jig 403 side, the heat generating surface is directed to the heat transfer members 405 and 406 side, and the Peltier The element 409 is sandwiched and fixed.

  With this configuration, since a temperature difference can be created between the fixing member 403 (low temperature) and the heat transfer members 405 and 406 (high temperature), the heat is transferred from one end of the heat transfer member to the cooler for cooling. The temperature of the vessel can be made higher than the ambient temperature, and the amount of heat released to the surroundings can be increased. Therefore, even a low-volatility hydraulic fluid such as water can transport heat from the fixed member to the cooler.

  As described above, the amount of heat generated differs depending on the color emitted by the laser diode (red, blue, green), and each of the corresponding coolers has a different amount of heat treatment. The heat transfer amount of the system can be increased by using the Peltier element.

1 is an external view of a first embodiment of the present invention. It is sectional drawing of a housing | casing similarly. It is sectional drawing of the housing | casing part of the 2nd Example of this invention. It is sectional drawing of the structure regarding cooling of an Example of this invention. It is sectional drawing which similarly shows the structure of a cooler.

Explanation of symbols

  101, 401 ... casing, 102, 103, 104 ... laser diode (light source), 105, 106, 107 ... fixing member, 108, 109, 110, 111, 112, 113 ... heat transfer member, 114 ... cooler, 208 , 209, 210 ... laser diode terminals, 211, 212 ... optical elements, 213, 214, 215 ... laser diode output light, 302, 303, 304 ... laser diodes, 305, 306, 307 ... fixing members, 308, 309, 310 ... Laser diode terminal, 311, 312, 313 ... Optical element, 314, 315, 316 ... Laser diode output light, 402 ... Laser diode, 402a ... Heat generating part, 403 ... Fixing member, 404 ... Optical element, 405, 406 ... Transmission Thermal member, 407 ... cooler, 408 ... heat of vaporization, 409 ... pel Choi element, 501 ... Mesh-like lid substrate, 502 ... Evaporation sheet, 503 ... Working fluid storage chamber, 504 ... Fine flow path, 505 ... Glass substrate, 506 ... Projection, 507 ... Tube, 508 ... Working fluid storage container, 509 ... Wall member.

Claims (7)

A plurality of light sources, an optical element for aligning light from each light source on the same axis, and a housing that incorporates the optical element and supports the light source, and scans the light aligned on the same axis by the optical element In the projector that projects onto the screen outside the casing by
A thermally conductive fixing member that supports the light source by interposing the light source and the housing;
A cooler disposed in a thermally insulated state with the housing;
A heat transfer member that thermally connects the fixing member and the cooler and thermally transports heat generated by the light source from the fixing member to the cooler;
The projector according to claim 1, wherein the heat transfer member is disposed in a state of being insulated from the casing.   2. The projector according to claim 1, wherein the cooler is disposed in the housing through a gap from the housing, and the heat transfer member is disposed in the housing from the housing through a gap. Projector.   3. The projector according to claim 1, wherein the light source is attached to one side of the casing via a fixing member, the cooler is disposed on the other side of the casing, and the heat transfer member Is a projector disposed symmetrically along the upper and lower portions of the casing.   4. The projector according to claim 1, wherein the heat transfer member is disposed outside the housing with a gap from the housing, and forms a double structure surrounding the optical element together with the housing. A projector characterized by that.   5. The projector according to claim 1, wherein the cooler is a cooler using heat of vaporization.   6. The projector according to claim 5, wherein the cooler includes a hydraulic fluid holding chamber, a hydraulic fluid supply fine channel, a hydraulic fluid evaporation sheet, and a hydraulic fluid evaporation sheet holding lid, and is connected to the hydraulic fluid holding chamber. The micro flow path and the hydraulic fluid storage container are connected by a tube. When the hydraulic fluid evaporates from the hydraulic fluid evaporation sheet, the hydraulic fluid is stored by the negative pressure generated when the amount of fluid in the hydraulic fluid holding chamber is consumed. A projector characterized in that hydraulic fluid is sucked into a hydraulic fluid holding chamber from a container through a tube.   7. The projector according to claim 1, wherein a laser diode is used as the light source.

Images