JP6547127B2 - Prism cooling device and projection type image display device - Google Patents

Description

  The present disclosure relates to a projection-type image display apparatus for projecting an image, and a prism cooling device used therein.

  There are commercially available projection type video display devices that use digital micro mirror devices (hereinafter referred to as "DMD") as image forming elements. Along with the advancement of the performance of projection type image display apparatuses, high resolution and high brightness are required. In order to increase the brightness, the DMD is irradiated with strong illumination light, and at this time, the temperature of the DMD is increased by the absorption of the light of the DMD. Thus, the DMD is provided with a structure to cool it.

  Patent Document 1 discloses a structure for cooling a DMD and a prism. This projection type image display apparatus is provided with a cooling structure which combines cooling of the DMD and cooling of the prism. Thereby, cooling of the DMD and the prism can be compatible.

Republished WO 02-020027

  The present disclosure reduces the thermal distortion of the prism due to the increase in brightness, and provides a high-quality projection type image display device.

  The prism cooling device in the present disclosure includes a TIR prism in which a light reflecting surface of a first triangular prism and a light incident surface of a second triangular prism are disposed opposite to each other with a predetermined gap, and a TIR prism. A first heat dissipating member attached to one of the two side surfaces except the light incident surface, the light transmitting surface, and the light reflecting surface of the triangular prism 1; and a second heat dissipating member attached to the other side A first cooling fan for blowing cooling air to the first heat radiating member, a second cooling fan for blowing cooling air to the second heat radiating member, a first temperature sensor attached to the first heat radiating member, and a second heat radiation And a controller that controls rotation of the first cooling fan and the second cooling fan based on detection results of the first temperature sensor and the second temperature sensor attached to the member.

  The prism cooling device in the present disclosure can reduce temperature distortion of the prism, and can achieve high image quality and high brightness.

The figure which shows the whole structure of the projection type video display apparatus in embodiment The figure which shows the fluorescent substance wheel used by embodiment. A diagram showing a configuration near a prism in the embodiment Schematic diagram of the main part in the embodiment The schematic diagram which shows the structure of the thermal radiation member in embodiment, a heat conduction member, and a prism The schematic diagram which shows the decomposition | disassembly state of the heat radiating member in embodiment, a heat conducting member, and a prism A schematic diagram showing a control configuration in the embodiment Flow chart for explaining control operation in the embodiment

  Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, the detailed description may be omitted if necessary. For example, detailed description of already well-known matters and redundant description of substantially the same configuration may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art.

  It should be noted that the attached drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and they are not intended to limit the claimed subject matter.

Embodiment
The embodiment will be described below with reference to FIGS.

[1-1. Configuration Description]
[1-1-1. Overall configuration]
FIG. 1 is a figure for demonstrating the structure of the optical system of the projection type video display apparatus of this indication which used the fluorescent substance wheel apparatus.

  For convenience of the following description, an XYZ orthogonal coordinate system shown in FIG. 1 is used in FIG.

  First, the illumination optical system 20 of the projection type video display device will be described.

  The laser light source 201, which is an excitation light source, is a blue semiconductor laser, and is configured of a plurality of semiconductor lasers in order to realize a high-intensity lighting device. Although five blue semiconductor lasers are exemplarily illustrated as juxtaposed in FIG. 1, a plurality of blue semiconductor lasers are arranged on a plane in a matrix. Laser light which is excitation light emitted from each of the laser light sources 201 is collimated by the corresponding collimator lens 202. The light emitted from the collimating lens 202 is substantially parallel light. The entire light flux is collected by the lens 203 by the lens 203, passes through the diffusion plate 204, and is collimated again by the lens 205. The laser beam substantially collimated by the lens 205 is incident on the dichroic mirror 206 disposed at approximately 45 degrees to the optical axis.

  The diffusion plate 204 is a flat glass plate, and a diffusion surface to which fine asperities are formed is formed on one side. In addition, the dichroic mirror 206 has a characteristic of reflecting the wavelength range of the blue semiconductor laser 201 and transmitting light of other wavelength ranges.

  The laser beam incident on the dichroic mirror 206 in the -X direction in the figure is reflected by the dichroic mirror 206 and is emitted in the -Z direction in the figure. Thereafter, the laser light is condensed by the lens 207 and the lens 208 to excite the phosphor formed on the phosphor wheel device 10.

  As shown in the side view of FIG. 2A, the phosphor wheel device 10 is composed of a motor 101 and a rotating base 102 made of a disk-shaped plate that is rotationally driven about the rotation axis of the motor 101. Ru.

  As shown in the front view of FIG. 2B, the rotary base 102 is red with a predetermined width W inside and outside the circumference on the circumference separated by a distance R1 from the rotation axis A of the phosphor wheel as shown in the front view of FIG. A phosphor portion 103, a green phosphor portion 104 and an opening 105 are formed.

  When the laser light of the blue semiconductor laser 201 is condensed on the red phosphor portion 103 of the phosphor wheel device 10 and the red phosphor portion 103 is excited, red light is emitted.

  Further, the laser light of the blue semiconductor laser 201 is condensed on the green phosphor portion 104 on the phosphor wheel 10, and emits green light when the green phosphor portion 104 is excited.

  Furthermore, when the light collected on the phosphor wheel 10 is collected on the opening 105, the light of the blue semiconductor laser 201 is transmitted through the opening 105.

  The red light and the green light obtained by the phosphor wheel device 10 are emitted from the phosphor wheel device 10 in the + Z direction. Of the light emitted from the fluorescent substance, the fluorescent light emitted in the -Z direction is reflected by the rotary base 102 and emitted in the + Z direction. The red light and the green light are collimated by the lenses 208 and 207 and transmitted through the dichroic mirror 206, condensed by the condenser lens 217, and enter the rod integrator 218.

  On the other hand, the blue light of the blue semiconductor laser 201 that has passed through the opening 105 travels along the path of the lens 209, the lens 210, the mirror 211, the lens 212, the lens 212, the mirror 213, the lens 214, the mirror 215, and the lens 216, and is reflected by the dichroic mirror 206. The light is collected by the collecting lens 217 and enters the rod integrator 218. The lenses 212, 214, 216 function as relay lenses.

  The light emitted from the rod integrator 218 passes through a lens 230, a lens 231, and a lens 232, and enters a TIR (total reflection prism) 235 composed of a pair of prisms of a first triangular prism 233 and a second triangular prism 234. In the DMD (Digital Mirror Device) 236, which is a modulation element, incident light is modulated by the video signal and emitted as video light P. The lenses 230 and 231 are relay lenses, and the lens 232 has a function of focusing the light of the exit surface of the rod integrator 318 on the DMD 236.

  The light emitted from the DMD is incident on the projection lens 237, and the light emitted from the projection lens 237 is enlarged and projected as image light P on the screen.

[1-1-2. Configuration of main part]
FIG. 3 is a schematic view showing the arrangement of the TIR prisms 235 in the entire projection display apparatus.

  The power supply unit 40 of the projection display apparatus is disposed on one side surface (side surface 233 e, side surface 234 e described later) of the TIR prism 235. In addition, the illumination optical system 20 is disposed on the side of the other side (a side 233 d and a side 234 d described later). The TIR prism 235 is disposed at an angle of 45 degrees with respect to the X axis in the figure as shown in FIG. Therefore, the TIR prism 235 is configured at positions where the surrounding environment is different, such as space degrees of freedom and ambient temperature on each side. For example, in the embodiment of FIG. 3, the space surrounded by one side of the TIR prism 235, the power supply unit 40, and the cabinet bottom of the projection display 30 is compared to the space on the other side of the TIR prism 235. The temperature of the air warmed by the heat source such as the power supply unit 40 and the TIR prism also increases. In FIG. 3, the Y-axis direction is the projection direction of the projection display apparatus.

  FIG. 4A shows a schematic view of the main part of the projection type video display according to the embodiment. The TIR prism 235 is configured of a triangular prism-shaped second triangular prism 234 similar to the triangular prism-shaped first triangular prism 233. Of the surfaces of the first triangular prism 233, the illumination light reflecting surface 233b that reflects the illumination light I collected by the lens 232 and the image light P from the DMD 236 of the surfaces of the second triangular prism 234 are incident The image light incident surface 234a is disposed opposite to an air layer of a predetermined distance. The first triangular prism 233 has an internal absorbency of 1% or less at a thickness of 10 mm for light in a wavelength range of 380 nm to 780 nm.

  The illumination light collected by the lens 232 is transmitted through the illumination light incident surface 233a of the first triangular prism 233, totally reflected by the illumination light reflection surface 233b, and emitted from the transmission surface 233c. The illumination light I transmitted through the transmission surface 233 c enters the DMD 236. The illumination light I incident on the DMD 236 is then modulated based on the video signal and is emitted as the video light P. The image light P emitted from the DMD 236 is incident from the transmission surface 233c of the first triangular prism 233, passes through the illumination light reflection surface 233b, and is incident on the image light incident surface 234a and the light emission surface 234b of the second triangular prism 234. Go along the route.

  Of the surfaces of the first triangular prism 233 constituting the TIR prism 235, of the side surfaces excluding the illumination light incident surface 233a, the illumination light reflection surface 233b, and the transmission surface 233c through which the illumination light I and the image light P pass. A first heat sink 310 and a second heat sink 320 are attached to one side surface 233 d. The first heat sink 310 and the second heat sink 320 are an example of a first heat dissipation member. The cooling fan 400 is a device for blowing cooling air to the first heat sink 310 and the second heat sink 320.

  Of the surfaces of the second triangular prism 234 constituting the TIR prism 235, one of the two side surfaces in the direction perpendicular to the light path passing through the image light incident surface 234a and the light exit surface 234b A fifth heat sink 610 is attached. The fifth heat sink 610 is an example of a third heat dissipation member.

  FIG. 4 (b) shows the opposite side of FIG. 4 (a). The third heat sink 710 and the fourth heat sink 720 are attached to the illumination light incident surface 233a, the illumination light reflection surface 233b, and the side surface 233e excluding the transmission surface 233c and the side surface 233d through which the illumination light I and the image light P pass. It is done. The third heat sink 710 and the fourth heat sink 720 are an example of a second heat dissipation member. The cooling fan 410 is a device for blowing a cooling air to the third heat sink 710 and the fourth heat sink 720.

  Of the surfaces of the second triangular prism 234 constituting the TIR prism 235, the other side surface 234e of the two side surfaces in the direction perpendicular to the light path passing through the image light incident surface 234a and the light exit surface 234b , A sixth heat sink 620 is attached. The sixth heat sink 620 is an example of a fourth heat dissipation member.

  FIG. 5 is a schematic view showing the attachment of the first heat sink 310, the second heat sink 320 and the third heat sink 710, and the fourth heat sink 720 to the first triangular prism 233, and FIG. It is a schematic diagram of the decomposition state of 5.

  As shown in FIG. 5, a heat conductive sheet 510 is provided between the first triangular prism 233 and the first heat sink 310. In addition, a heat conduction sheet 520 is provided between the first triangular prism 233 and the second heat sink 320. Similarly, a heat conductive sheet 540 is provided between the first triangular prism 233 and the third heat sink 710, and a heat conductive sheet 540 is provided between the first triangular prism 233 and the fourth heat sink 720. . The thermally conductive sheet 510, the thermally conductive sheet 520, the thermally conductive sheet 530, and the thermally conductive sheet 540 have thermal conductivity of 0.1 W / m · K or more, and have a reflectance of 90% to light in the wavelength range of 380 nm to 780 nm. Those having the following characteristics are used.

As the heat conductive sheets 510, 520, 530, and 540, it is possible to use an adhesive phase change sheet having such thermal conductivity and reflectance characteristics. If a phase change sheet is used, the first heat sink 310 and the second heat sink 320 can be closely fixed to the first triangular prism 233 without particularly using an adhesive due to the adhesion thereof.
Similarly, the third heat sink 710 and the fourth heat sink 720 can be closely fixed to the first triangular prism 233. The heat transfer sheets 510, 520, 530, and 540 are examples of heat transfer members.

  In the present embodiment, in order to enhance the heat radiation effect, the first heat sink 310, the second heat sink 320, the plurality of heat sink fins 311, and the heat sink fins 321 are provided. At this time, the cooling air from the cooling fan 400 is blown in the −X direction (−Y direction in FIG. 4) in FIG. 5, and the cooling fan 400 is disposed to apply the cooling air to the heat sink fins 311 and 321. . Also in the third heat sink 710 and the fourth heat sink 720, a plurality of heat sink fins 711 and heat sink fins 721 are provided. At this time, the cooling air from the cooling fan 410 is blown in the X direction in FIG. 5 (the -Y direction in FIG. 4), and the cooling fan 410 is disposed so as to apply the cooling air to the heat sink fins 711 and 721.

  As shown in FIG. 5, stray light S generated from the light beam of the illumination light I and the light beam of the image light P from the DMD passes through the inside of the first triangular prism 233 and is irradiated to the side surface of the first triangular prism. A part of the stray light S irradiates the heat conductive sheet 510 and the heat conductive sheet 520, the heat conductive sheet 530 and the heat conductive sheet 540.

  Due to the internal absorptivity of the first triangular prism 233, when the illumination light I passes through the first triangular prism 233, it becomes heat and the temperature of the first triangular prism 233 rises. When the temperature of the first triangular prism 233 rises, the prism thermally expands to cause thermal distortion. The amount of distortion of the illumination light reflection surface 233b of the first triangular prism 233 changes by 1 μm in height every 10 μm when heat absorption of 2 watts (W) occurs. When thermal distortion occurs, displacement occurs in the first triangular prism 233, so that the positional relationship between the DMD 236, the first triangular prism 233, the second triangular prism 234, and the projection lens 237 deviates, and enlargement projection is performed on the screen. Image quality is degraded.

  Therefore, in the present embodiment, the heat of the first triangular prism 233 is conducted to the first heat sink 310 and the second heat sink 320 via the heat conduction sheet 510 and the heat conduction sheet 520, The heat conducted to the first heat sink 310 and the second heat sink 320 is cooled by the wind sent from the cooling fan 400.

  In addition, the thermal distortion due to the temperature gradient caused by the heat of the first triangular prism 233 cooling only the side on which the first heat sink 310 and the second heat sink 320 are attached is also suppressed. The heat of the triangular prism 233 is conducted to the third heat sink 710 and the fourth heat sink 720 through the heat conduction sheet 530 and the heat conduction sheet 540. Then, the heat conducted to the third heat sink 710 and the fourth heat sink 720 is cooled by the wind sent from the cooling fan 410.

  As a result, the temperature of the first triangular prism 233 drops, the thermal distortion of the prism is reduced, and the thermal distortion at the temperature gradient is also suppressed. Therefore, the positional deviation of the first triangular prism 233 is reduced, and the image quality of the image enlarged and projected on the screen is improved.

  As described above, due to the arrangement of the TIR prisms 235, the temperature tends to be higher on one side surface (side surface 233e and side surface 234e described later) of the TIR prism 235 than on the other surface side. Therefore, the sizes of the fins of the third heat sink 710 and the fourth heat sink 720 are larger than the fins of the first heat sink 310 and the second heat sink 320, and the heat dissipation performance is made different. Heat balance is achieved.

  Further, when stray light S is incident on the heat conduction sheet 510, the heat conduction sheet 520, the heat conduction sheet 530, and the heat conduction sheet 540, the stray light S of the heat conduction sheet 510 and the heat conduction sheet 520, the heat conduction sheet 530, and the heat conduction sheet 540. Since the reflectance is 90% or less, 10% or more of the stray light S is absorbed by the heat conduction sheet 510, the heat conduction sheet 520, the heat conduction sheet 530, and the heat conduction sheet 540. Therefore, stray light S projected on the screen through the projection lens 237 is reduced.

  The heat conductive sheet preferably has a volatilized amount as small as possible, but may be 0.2% or less after 24 hours in a 150 ° C. environment.

  FIG. 7 is a schematic view showing a control configuration in the present embodiment. The first heat sink 310 is connected to a controller 800 configured of a microcomputer via a temperature sensor 830 to detect the temperature of the first heat sink 310. The second heat sink 320 is similarly connected to the controller 800 via the temperature sensor 840. The third heat sink 710 is connected to the controller 800 via the temperature sensor 860, and the fourth heat sink 720 is connected to the controller 800 via the temperature sensor 850 to detect the temperature. Cooling fan 400 is connected to controller 800 via control line 810. The cooling fan 410 is connected to the controller 800 via a control line 820. The temperature sensor 830 and the temperature sensor 840 are an example of a first temperature sensor. The temperature sensor 850 and the temperature sensor 860 are examples of a second temperature sensor.

  In the present embodiment, the cooling fan 400 and the cooling fan 410 use the temperature information obtained through the temperature sensors of the first heat sink 310, the second heat sink 320, the third heat sink 710, and the fourth heat sink 720. Controlled individually. The control maintains the temperature of the TIR prism 235 at an appropriate temperature and suppresses the thermal distortion due to the temperature difference between the side surfaces of the TIR prism 235. As an example, when the first heat sink 310 and the second heat sink 320 are below the proper temperature and the third heat sink 710 and the fourth heat sink 720 are above the proper temperature, the output of the cooling fan 410 is improved and appropriate Do not exceed the temperature. In addition, when the temperature of each of the first heat sink 310, the second heat sink 320, the third heat sink 710, and the fourth heat sink 720 is below the appropriate temperature, the output of the cooling fan 400 and the cooling fan 410 is reduced to generate noise. It can be suppressed. In the selection of the heat sink, it is desirable to set the optimum thermal resistance value and use it by combining the cooling fans, since the peripheral environment differs on each side.

  FIG. 8 is a diagram showing an operation flowchart of the controller in the configuration of FIG.

  When the projection display is started, the controller 800 detects the temperature by the temperature sensor (S1). As a result of this temperature detection, when it is determined that either the first heat sink 310 or the second heat sink 320 exceeds the set temperature T0 (S2), the controller 800 increases the rotational speed of the cooling fan 400 (S3) . Next, when the controller 800 determines that either the third heat sink 710 or the fourth heat sink 720 exceeds the set temperature T0 (S4), the number of rotations of the cooling fan 410 is increased. Thereafter, after a predetermined time for reflecting the setting contents of the fan rotational speed has elapsed, as a result of continuously detecting the temperature, either the first heat sink 310 or the second heat sink 320 of the controller 800 does not exceed the set temperature T0 If it is determined (S2) that one of the first heat sink 310 and the second heat sink 320 is lower than the set temperature T0 (S7), the number of rotations of the cooling fan 400 is decreased (S8). In step 7 (S7), when controller 800 determines that one of first heat sink 310 and second heat sink 320 does not fall below set temperature T0 (S7), a predetermined time elapses in step 6 (S6). After that, the temperature is continuously detected (S1).

  At step 4 (S4), the controller 800 determines that either the third heat sink 710 or the fourth 720 does not exceed the set temperature T0 (S4), and the first heat sink 310 or the second 720 If it is determined that one of the temperatures is lower than the set temperature T0 (S9), the number of rotations of the cooling fan 410 is decreased (S10). In step 9 (S9), when the controller 800 determines that one of the third heat sink 710 and the fourth heat sink 720 does not fall below the set temperature T0 (S9), a predetermined time elapses in step 6 (S6). After that, the temperature is continuously detected (S1).

  It is not necessary to attach the heat sink to the second triangular prism if the effect is achieved simply by attaching the heat sink to the side of the first triangular prism of the TIR prism. However, also in the second triangular prism, in a situation where heat generation by the image light from the DMD can not be neglected due to high brightness, the fifth heat sink and the sixth heat sink are also used in the second triangular prism as in the present embodiment. It is preferable to attach the In that case, the fifth heat sink and the sixth heat sink can be attached by the same method and structure as the first to fourth heat sinks.

[1-2. Effect etc]
According to the present embodiment, the heat generated by the TIR prism can be effectively dissipated by the illumination light that illuminates the DMD, and the thermal distortion of the prism can be reduced. At the same time, by controlling the cooling fans of both sides of the TIR prism, thermal distortion due to the temperature difference between both sides can be suppressed. Thereby, the image quality of the image enlarged and projected on the screen can be improved. In addition, since a heat conductive sheet having a reflectance of 90% or less is used, 10% or more of stray light is absorbed, and the image quality on the screen is improved.

(Other embodiments)
As described above, the embodiment has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which changes, replacements, additions, omissions, and the like have been made. Moreover, it is also possible to combine each component demonstrated by the said embodiment, and to set it as a new embodiment.

  Therefore, other embodiments will be exemplified below.

  In the embodiment, a heat sink is used as an example of the heat radiating member, but the heat radiating member is not limited to the heat sink. If a Peltier element and a heat sink are used as the heat dissipation member, it is possible to obtain a further reduction effect of the thermal distortion of the prism. Moreover, you may use the member with adhesiveness other than a phase change sheet as a heat conductive sheet. If a heat conducting member is used as the bonding means, the effect of heat radiation can be obtained.

  In addition, since the above-mentioned embodiment is for illustrating the technique in this indication, various change, substitution, addition, omission, etc. can be performed in a claim or its equivalent range.

  The present disclosure is applicable to a projection type video display device such as a projector.

Reference Signs List 20 illumination optical system 233 first triangular prism 233a illumination light incident surface 233b illumination light reflection surface 233c transmission surface 233d side surface 233e side surface 234 second triangular prism 234a image light incident surface 234b light emission surface 234d side surface 234e side surface 235 TIR prism 236 DMD
310 first heat sink 320 second heat sink 400, 410 cooling fan 510, 520, 530, 540 heat conduction sheet 610 fifth heat sink 620 sixth heat sink 710 third heat sink 720 fourth heat sink 800 controller 830, 840 , 850, 860 temperature sensor

Claims (4)

A TIR prism in which a light reflecting surface of the first triangular prism and a light incident surface of the second triangular prism are disposed opposite to each other with a predetermined gap therebetween;
The first heat radiation member attached to one of the two side surfaces except the light incident surface, the light transmission surface, and the light reflection surface of the first triangular prism that constitutes the TIR prism, and the other side surface A second heat dissipating member attached to the
A first cooling fan for blowing a cooling air to the first heat radiation member;
A second cooling fan for blowing a cooling air to the second heat radiation member;
A first temperature sensor attached to the first heat radiation member;
A second temperature sensor attached to the second heat radiation member;
A prism cooling device, comprising: a controller that controls rotation of the first cooling fan and the second cooling fan based on detection results of the first temperature sensor and the second temperature sensor.   The prism cooling device according to claim 1, wherein heat dissipation performance of the first heat dissipation member is different from heat dissipation performance of the second heat dissipation member. A third heat dissipating member attached to one of two side surfaces perpendicular to the light path passing through the light incident / exit surface of the second triangular prism, and a fourth attached to the other side surface And a heat dissipation member,
The first heat dissipation member and the third heat dissipation member are disposed on the same side, and the second heat dissipation member and the fourth heat dissipation member are disposed on the same side.
The first cooling fan blows cooling air to the first heat radiation member and the third heat radiation member, and the second cooling fan blows cooling air to the second heat radiation member and the fourth heat radiation member. The prism cooling device according to claim 1. The projection type video display apparatus provided with the prism cooling device of Claim 1.