JP2011043538A - Projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projector for efficiently and sequentially cooling a cooling object such as a liquid crystal display panel according to the calorific value. <P>SOLUTION: This projector 1 includes a plurality of spatial light modulators 21B, 21G and 21R that modulate light coming from an incident surface according to an image signal and ejects it from an ejection surface, and a plurality of cooling flow channels 51, 52 and 53 that are disposed for respective spatial light modulators and in which cooling air for cooling the spatial light modulators flows sequentially. The projector includes a duct 50 for cooling for sequentially cooling the plurality of spatial light modulators, and a blower 40 for feeding cooling air into the duct for cooling. In at least one cooling flow channel 52 of the plurality of cooling flow channels, at least one of the cross section or cross-sectional shape is different from that of the other cooling flow channels 51 and 53 according to the calorific value of the spatial light modulators. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a projector, and more particularly to a technology of a projector including a transmissive liquid crystal display panel.

  Conventionally, a projector has been developed for the purpose of improving projection performance and downsizing. As a projector, for example, a projector including transmissive liquid crystal display panels for red (R) light, green (G) light, and blue (B) light as a spatial light modulator is widely used. The liquid crystal display panel and the polarizing plate provided around the liquid crystal display panel generate heat due to absorption of illumination light. For example, a fan that allows air to flow is used for heat dissipation of the liquid crystal display panel and the polarizing plate.

  As a projector cooling structure, a configuration is known in which air flows in a direction substantially perpendicular to a plane including an optical axis on which a liquid crystal display panel and a polarizing plate are arranged. In this case, while it is possible to supply air evenly to each liquid crystal display panel, it is difficult to reduce the thickness of the projector by arranging a fan and a duct for flowing air above and below the portion where each liquid crystal display panel is disposed. Is an issue. In order to deal with this problem, a technique has been proposed in which a flow path for allowing air to flow in a direction substantially parallel to the surface including the optical axis is provided, and air is sequentially flowed to each liquid crystal display panel and each polarizing plate. For example, in Patent Document 1 and Patent Document 2, in a configuration in which each liquid crystal display panel is arranged around a cross dichroic prism that synthesizes each color light, each liquid crystal display panel is sequentially arranged in a flow path in a cooling duct. A configuration has been proposed in which each liquid crystal display panel is sequentially cooled by cooling air flowing in a cooling duct.

JP 2001-188305 A JP 2001-281613 A

  A liquid crystal display panel may generate a different amount of heat depending on the color of light to be modulated. In particular, green light is required to have a high output because it has higher visibility than other color lights. A liquid crystal display panel in which green light is incident has a larger amount of heat generation and is likely to be hot than a liquid crystal display panel in which red light or blue light is incident. If a cooling duct is used to cool each LCD panel in sequence, if the design is based on cooling the green light LCD panel, the red and blue light LCD panels will be cooled more than necessary. Will be inefficient. In addition, the capacity of the blower fan is increased, making it difficult to reduce the size of the projector. On the other hand, if the liquid crystal display panel for red light or blue light is used as a reference, there is a problem that the air volume and the wind speed are insufficient, and the liquid crystal display panel for green light is insufficiently cooled.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a projector capable of efficient sequential cooling according to the amount of heat generated by a cooling target such as a liquid crystal display panel.

  In order to solve the above-described problems and achieve the object, a projector according to the present invention includes a plurality of spatial light modulation devices that modulate light incident from an incident surface according to an image signal and emit the light from the emission surface, and a plurality of spatial light modulation devices. A cooling duct that is provided for each of the spatial light modulators and that has a plurality of cooling channels through which cooling air for cooling the spatial light modulators sequentially flows, and that cools the plurality of spatial light modulators sequentially, and cooling And at least one of the plurality of cooling channels has at least one of a cross-sectional area and a cross-sectional shape according to the amount of heat generated by the spatial light modulator. It is characterized by being different from other cooling channels.

  Since at least one of the cross-sectional area and the cross-sectional shape of one cooling flow path is different from the other cooling flow paths, the flow velocity or the like of the cooling air flowing through the one flow path can be made different from that of the other flow paths. Therefore, efficient sequential cooling according to the heat generation amount of the cooling target is possible by changing the flow rate of the cooling air according to the heat generation amount of the cooling target such as the liquid crystal panel.

  Moreover, as a preferable aspect of the present invention, it is desirable that the cross-sectional area of one cooling flow path is smaller than the cross-sectional areas of other cooling flow paths. By reducing the cross-sectional area of one cooling channel, the flow velocity of the cooling air flowing through one cooling channel can be increased. Therefore, the cooling efficiency of the spatial light modulation device corresponding to one cooling channel can be increased. Further, since the cross-sectional area of the other cooling channel is larger than the cross-sectional area of one cooling channel, it is possible to suppress an increase in pressure loss in the entire cooling duct, and to reduce the size of the blower and the size of the projector. Can be achieved.

  Moreover, as a preferable aspect of the present invention, it is desirable that the cross-sectional area of the other cooling channel gradually decreases toward one cooling channel. By gradually decreasing the cross-sectional area of the other cooling channel toward one cooling channel, it is possible to suppress a rapid change in the speed of the cooling air in the cooling duct, and to increase the pressure loss of the cooling duct. Therefore, it is possible to reduce the size of the blower and the size of the projector.

  Further, as a preferable aspect of the present invention, it is desirable that the other cooling flow paths are gradually reduced in cross-sectional area by reducing the flow path width in a direction perpendicular to the incident surface of the spatial light modulator. Since the flow path width is changed in a direction perpendicular to the incident surface of the spatial light modulator, the thickness of the cooling structure including the cooling duct is prevented from increasing, which can contribute to the thinning of the projector. .

  Further, as a preferable aspect of the present invention, the other cooling flow path has a cross-sectional area in which the flow path width is reduced in a direction parallel to the incident surface of the spatial light modulator and perpendicular to the flow direction of the cooling air. It is desirable to decrease gradually. Since the flow path width is changed in a direction parallel to the incident surface of the spatial light modulator and perpendicular to the flow direction of the cooling air, the expansion of the planar shape of the cooling structure including the cooling duct is suppressed. be able to. Therefore, the cooling structure including the cooling duct can be prevented from pressing the planar arrangement space of each member in the projector.

  Moreover, as a preferable aspect of the present invention, the apparatus further includes a connection channel that connects one cooling channel to another cooling channel, and the connection channel is one cooling channel from the other cooling channel. It is desirable that the cross-sectional area of the flow path gradually decreases toward the first, and that one cooling flow path and the other cooling flow paths having different cross-sectional areas are connected smoothly. An increase in pressure loss can be suppressed by smoothly connecting one cooling channel having a different cross-sectional area and another cooling channel by a connection channel.

  Moreover, as a preferable aspect of the present invention, it is desirable that the spatial light modulation device corresponding to one cooling channel modulates green light. The cooling efficiency of the spatial light modulation device that modulates the green light can be increased by the cooling air having a large flow velocity flowing through one cooling channel. In addition, since the spatial light modulation device corresponding to the other cooling flow path is cooled by the cooling air having a lower flow velocity than the cooling air flowing through one cooling flow path, it is possible to perform appropriate cooling according to the heat generation amount. Become. Therefore, efficient sequential cooling according to the heat generation amount of the cooling target becomes possible.

FIG. 1 is a diagram illustrating a schematic configuration of a projector according to the first embodiment. FIG. 2 is a plan sectional view showing a sectional configuration of the cooling duct. FIG. 3 is a view showing a cross section of the first cooling flow path and the second cooling flow path. (A) When cut along the line AA shown in FIG. 2, (b) B shown in FIG. The figure which shows the case where it cut | disconnects along a B line. FIG. 4 is a cross-sectional view of the first cooling flow path and the second cooling flow path of the cooling duct according to the first modification of the first embodiment, and (a) cut along the line AA shown in FIG. (B) The figure which shows the case where it cut | disconnects along the BB line | wire shown in FIG. FIG. 5 is a cross-sectional view of the first cooling flow path and the second cooling flow path of the cooling duct according to the second modification of the first embodiment, and (a) cut along the line AA shown in FIG. (B) The figure which shows the case where it cut | disconnects along the BB line | wire shown in FIG. FIG. 6 is a plan sectional view illustrating a sectional configuration of a cooling duct included in the projector according to the second embodiment. FIG. 7 is a diagram illustrating a cross-sectional configuration of a cooling duct included in the projector according to the third embodiment, and is a cross-sectional view taken along the line CC illustrated in FIG. 2.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 shows a schematic configuration of a projector 1 according to a first embodiment of the invention. In FIG. 1, a cooling duct, which will be described in detail later, is omitted. The projector 1 is a front projection type projector that projects projection light onto a screen 32 that is an irradiated surface and observes an image by observing light reflected by the screen 32. The light source 10 is a lamp that emits light including red (R) light, green (G) light, and blue (B) light, for example, an ultra-high pressure mercury lamp. The first integrator lens 11 and the second integrator lens 12 have a plurality of lens elements arranged in an array. The first integrator lens 11 splits the light flux from the light source 10 into a plurality of parts. Each lens element of the first integrator lens 11 condenses the light beam from the light source 10 in the vicinity of the lens element of the second integrator lens 12. The lens element of the second integrator lens 12 forms an image of the lens element of the first integrator lens 11 on the spatial light modulator.

  The light that has passed through the two integrator lenses 11 and 12 is converted into a specific linearly polarized light, for example, s-polarized light by the polarization conversion element 13. The superimposing lens 14 superimposes the image of each lens element of the first integrator lens 11 on the spatial light modulator. The first integrator lens 11, the second integrator lens 12, and the superimposing lens 14 make the intensity distribution of light from the light source 10 uniform on the spatial light modulator. The reflection mirror 15 reflects the light from the superimposing lens 14 to bend the optical path by approximately 90 degrees. The first dichroic mirror 16 reflects the B light that is the first color light among the light incident from the reflection mirror 15 and transmits the G light that is the second color light and the R light that is the third color light. The first dichroic mirror 16 bends the optical path of the B light by approximately 90 degrees by reflection.

  The reflection mirror 17 reflects the B light from the first dichroic mirror 16 and bends the optical path by approximately 90 degrees. The B light field lens 18 </ b> B collimates the B light from the reflection mirror 17. The λ / 2 phase difference plate 19B converts s-polarized light from the B-light field lens 18B into p-polarized light. The B light incident side polarizing plate 20B is provided in the vicinity of the incident surface of the B light spatial light modulator 21B. The incident light polarizing plate 20B for B light transmits p-polarized light.

  The B light spatial light modulation device 21B is a first color light spatial light modulation device that modulates B light according to an image signal, and is a transmissive liquid crystal display device. The spatial light modulation device 21B for B light includes an incident surface on which light is incident and an emission surface on which light is emitted. The B-light exit-side polarizing plate 22 </ b> B is provided between the exit surface of the B-light spatial light modulator 21 </ b> B and the cross dichroic prism 23. The emission side polarizing plate 22B for B light transmits s-polarized light. The s-polarized light converted from the p-polarized light by the modulation with the B-light spatial light modulator 21B passes through the B-light exit-side polarizing plate 22B and enters the cross dichroic prism 23.

  The second dichroic mirror 24 reflects the G light from the first dichroic mirror 16 and transmits the R light. The second dichroic mirror 24 bends the optical path of the G light by approximately 90 degrees by reflection. The G light field lens 18G collimates the G light from the second dichroic mirror 24. The G light incident side polarizing plate 20G is provided in the vicinity of the incident surface of the G light spatial light modulator 21G. The incident light polarizing plate 20G for G light transmits s-polarized light.

  The G light spatial light modulation device 21G is a second color light spatial light modulation device that modulates the G light according to an image signal, and is a transmissive liquid crystal display device. The spatial light modulation device 21G for G light includes an incident surface on which light enters and an exit surface on which light exits. The G light exit-side polarizing plate 22G is provided between the exit surface of the G light spatial light modulator 21G and the cross dichroic prism 23. The exit side polarizing plate 22G for G light transmits p-polarized light. The p-polarized light converted from the s-polarized light by the modulation by the G light spatial light modulator 21G is transmitted through the G light exit-side polarizing plate 22G and enters the cross dichroic prism 23.

  The R light transmitted through the second dichroic mirror 24 is transmitted through the relay lens 25, and then the optical path is bent by reflection at the reflection mirror 26. The R light from the reflection mirror 26 further passes through the relay lens 27, and then the optical path is bent by reflection at the reflection mirror 28. Since the optical path of the R light is longer than the optical path of the B light and the optical path of the G light, relay lenses 25 and 27 are provided in the optical path of the R light in order to make the illumination magnification in the spatial light modulation device equal to that of other color lights. The relay optical system to be used is adopted. The R light field lens 18R collimates the R light from the reflection mirror 28. The λ / 2 phase difference plate 19R converts the s-polarized light from the R light field lens 18R into p-polarized light. The R light incident side polarizing plate 20R is provided in the vicinity of the incident side of the R light spatial light modulator 21R. The R light incident side polarizing plate 20R transmits p-polarized light.

  The R light spatial light modulator 21R is a third color light spatial light modulator that modulates R light according to an image signal, and is a transmissive liquid crystal display device. The spatial light modulation device 21R for R light includes an incident surface on which light enters and an exit surface on which light exits. The R-light exit-side polarizing plate 22R is provided between the exit surface of the R-light spatial light modulator 21R and the cross dichroic prism 23. The R light exit-side polarizing plate 22R transmits s-polarized light. The s-polarized light converted from the p-polarized light by the modulation by the R light spatial light modulator 21R is transmitted through the R light emission-side polarizing plate 22R and enters the cross dichroic prism 23.

  The cross dichroic prism 23 is modulated by the B light modulated by the B light spatial light modulation device 21B, the G light modulated by the G light spatial light modulation device 21G, and the R light spatial light modulation device 21R. It functions as a color combining optical system that combines R light. The cross dichroic prism 23 has two dichroic films 29 and 30 arranged so as to be substantially orthogonal to each other. The first dichroic film 29 reflects B light and transmits G light and R light. The second dichroic film 30 reflects R light and transmits B light and G light. The projection lens 31 projects the light combined by the cross dichroic prism 23 toward the screen 32.

  FIG. 2 shows a cross-sectional configuration of the cooling duct. The blower fan 40 is a blower that supplies a cooling fluid, and is, for example, a sirocco fan. The blower fan 40 takes in air, which is a cooling fluid, from the outside of the housing of the projector 1 and blows out the taken-in air from the air outlet 40a as cooling air. The cooling air blown out from the outlet 40 a of the blower fan 40 is sent into the cooling duct 50.

  The cooling duct 50 includes a first cooling channel 51, a second cooling channel 52, a third cooling channel 53, a first connection channel 54, and a second connection channel 55. The 1st cooling flow path 51 comprises the flow path which makes cooling air flow inside. The 1st cooling flow path 51 accommodates the spatial light modulation device 21B for B light inside. The spatial light modulator for B light 21B is cooled by the cooling air flowing inside the first cooling flow path 51.

  The second cooling channel 52 is provided on the downstream side of the first cooling channel 51 and constitutes a channel for allowing cooling air to flow inside. The second cooling flow path 52 accommodates the G light spatial light modulator 21G inside. The spatial light modulator 21G for G light is cooled by the cooling air flowing inside the second cooling flow path 52.

  The third cooling flow path 53 is provided on the downstream side of the second cooling flow path 52 and constitutes a flow path through which cooling air flows. The third cooling flow path 53 accommodates the R light spatial light modulation device 21R inside. The R light spatial light modulator 21 </ b> R is cooled by the cooling air flowing inside the third cooling flow path 53. In addition, the incident surface of each color light of the cross dichroic prism 23 constitutes a part of the wall surface of each cooling channel 51, 52, 53.

  FIG. 3 is a view showing a cross section of the first cooling flow path and the second cooling flow path. (A) When cut along the line AA shown in FIG. 2, (b) B shown in FIG. It is a figure which shows the case where it cut | disconnects along the -B line. The second cooling channel 52 flows in a direction perpendicular to the incident surface of the G light spatial light modulator 21G (hereinafter simply referred to as the width direction; the same applies to the first cooling channel 51 and the third cooling channel 53). The path width W2 is smaller than the channel width W1 in the width direction of the first cooling channel 51. As a result, the relationship between the cross-sectional area A1 of the first cooling flow path 51 and the cross-sectional area A2 of the second cooling flow path 52 is A1> A2. The flow path width W1 in the width direction of the first cooling flow path 51 is equal to the flow path width W3 in the width direction of the third cooling flow path 53, and the relationship between the cross-sectional areas A1 and A3 is also A1 = A3. It has become. The cooling channels 51, 52, 53 are parallel to the incident surfaces of the color light spatial light modulators 21B, 21G, 21R and are perpendicular to the flow direction of the cooling air (hereinafter simply referred to as the height direction). The channel widths H1, H2, and H3 in FIG.

  The first connection channel 54 is provided between the first cooling channel 51 and the second cooling channel 52, and connects the first cooling channel 51 and the second cooling channel 52. The second connection channel 55 is provided between the second cooling channel 52 and the third cooling channel 53, and connects the second cooling channel 52 and the third cooling channel 53. By connecting the cooling flow paths 51, 52, 53 by the connection flow paths 54, 55, the cooling duct 50 is configured by one flow path, and the cooling air from the blower fan 40 is supplied to each cooling flow 50. It flows to cooling channel 51,52,53 sequentially. The cooling duct 50 accommodates the color light spatial light modulators 21B, 21G, and 21R arranged around the cross dichroic prism 23 in one flow path. Accordingly, the color light spatial light modulators 21B, 21G, and 21R can be sequentially cooled by the cooling air that sequentially flows through the cooling duct 50.

  In each of the connection channels 54 and 55, the cross-sectional area of the channel gradually decreases toward the second cooling channel 52. More specifically, in the first connection flow path 54, the cross-sectional area of the flow path gradually decreases from the upstream side to the downstream side of the cooling air, and the second connection flow path 55 is formed from the downstream side to the upstream side of the cooling air. The cross-sectional area of the flow path gradually decreases toward. Thereby, it is possible to smoothly connect the cooling flow paths 51, 52, and 53 having different cross-sectional areas. By smoothly connecting the cooling channels 51, 52, and 53, an increase in pressure loss can be suppressed. In the present embodiment, the cross-sectional area is gradually reduced by gradually decreasing the width of the channel in the width direction toward the second cooling channel 52.

  The cooling duct 50 is composed of a plate member such as a metal plate. An opening 50a is formed in a portion of the cooling duct 50 through which each color light passes. In the first cooling flow path 51, both the B light incident side polarizing plate 20B and the B light emission side polarizing plate 22B are accommodated inside the flow path. In the 1st cooling flow path 51, a translucent plate member, for example, the glass plate 50b, is attached and the opening 50a is closed.

  In the second cooling flow path 52, the G light emission side polarizing plate 22G is accommodated in the flow path. In the second cooling flow path 52, the G light incident side polarizing plate 20G is attached and the opening 50a is closed. In the third cooling flow path 53, both the R light incident side polarizing plate 20R and the R light emission side polarizing plate 22R are accommodated in the flow path. In the third cooling flow path 53, a translucent plate member, for example, a glass plate 50b is attached, and the opening 50a is closed.

  In general, the polarizing plate provided on the incident surface side of the spatial light modulation device is arranged near the spatial light modulation device, so that the light incident region becomes small, and thus the size can be reduced. Here, in the first cooling channel 51 and the third cooling channel 53, the width of the channel in the width direction is larger than that of the second cooling channel 52, and the incident side polarizing plates 20B and 20R are installed so as to close the opening 50a. If attached, the distance from the spatial light modulator for B light 21B and the spatial light modulator for R light 21R is increased. If the distance from the spatial light modulator for B light 21B and the spatial light modulator for R light 21R is increased, the size of the polarizing plate increases and the cost increases. In the first cooling flow path 51 and the third cooling flow path 53, the incident-side polarizing plates 20B and 20R are accommodated inside the flow path, so that the B light spatial light modulation device 21B and the R light spatial light modulation device are accommodated. The incident-side polarizing plates 20B and 20R are reduced in size by reducing the distance to 21R.

  On the other hand, the second cooling flow path 52 has a smaller width in the width direction than the first cooling flow path 51 and the third cooling flow path 53. Even if the G light incident side polarizing plate 20G is provided so as to close the opening 50a, the distance to the G light spatial light modulator 21G is not easily increased, and the size of the G light incident side polarizing plate 20G is not easily increased. By closing the opening 50a with the G light incident side polarizing plate 20G, the glass plate 50b becomes unnecessary, and the number of components can be reduced. In this way, by selecting the positions where the polarizing plates 20B, 20G, and 20R are arranged in accordance with the distances between the spatial light modulation devices 21B, 21G, and 21R for each color light and the wall surface of the cooling duct 50, the cost can be reduced. Suppression and reduction of the number of parts can be achieved.

  Here, since the G light has higher visibility than other color lights, it is required to have a high output, and the G light spatial light modulation device 21G on which the G light is incident is used for the other color light spatial light modulations. Compared with the devices 21B and 21R, the calorific value is large and the temperature tends to increase. Therefore, the G light spatial light modulator 21G is required to have higher cooling efficiency than the other color light spatial light modulators 21B and 21G. In the present embodiment, the cross-sectional area A2 of the second cooling flow path 52 is smaller than the cross-sectional areas A1 and A3 of the other cooling flow paths 51 and 53. Therefore, the cooling air that sequentially flows through the cooling duct 50 increases its flow velocity when flowing through the second cooling flow path 52. By increasing the flow velocity of the cooling air flowing through the second cooling flow path 52, the cooling efficiency of the G light spatial light modulator 21G accommodated therein can be increased.

  On the other hand, the spatial light modulators 21B and 21R accommodated in the first cooling channel 51 and the third cooling channel 53 have a smaller amount of heat generation than the G light spatial light modulator 21G. The flow rate of the cooling air necessary for cooling the spatial light modulators 21B and 21R is smaller than the flow rate required by the spatial light modulator for G light 21G. If the cooling air is caused to flow through the cooling duct 50 at a flow rate sufficient to cool the G light spatial light modulator 21G, the other color light spatial light modulators 21B and 21R are cooled more than necessary. Efficiency. In addition, the capacity required for the blower fan 40 is increased, leading to an increase in the size of the blower fan 40 and making it difficult to reduce the size of the projector 1. In this embodiment, since the cross-sectional area A1 of the first cooling channel 51 and the cross-sectional area A3 of the third cooling channel 53 are larger than the cross-sectional area A2 of the second cooling channel 52, the first cooling flow The flow velocity of the cooling air flowing through the passage 51 and the third cooling passage 53 can be lowered. Therefore, appropriate cooling according to the calorific value of the spatial light modulators 21B and 21R becomes possible. In addition, the pressure loss of the cooling duct 50 as a whole can be suppressed by expanding the cross-sectional area and decreasing the flow velocity, and the capacity required for the blower fan 40 can be suppressed. That is, by making the cross-sectional areas different for each of the cooling flow paths 51, 52, and 53, efficient cooling according to the amount of heat generated by the cooling target such as the spatial light modulator can be performed.

  The temperatures of the incident-side polarizing plates 20B, 20G, and 20R and the emission-side polarizing plates 22B, 22G, and 22R also rise due to absorption of illumination light. Among these polarizing plates, the B-light incident-side polarizing plate 20B, the R-light incident-side polarizing plate 20R, and the emission-side polarizing plates 22B, 22G, and 22R are accommodated in the cooling channels 51, 52, and 53, respectively. Therefore, the cooling duct 50 can be cooled by the cooling air that sequentially flows. Further, the G light incident-side polarizing plate 20G attached to the opening 50a is also in contact with the cooling air through the opening 50a, so that it can be cooled with the cooling air like the other polarizing plates.

  In addition, since the cooling duct 50 extends so as to surround the periphery of the cross dichroic prism 23, the cooling structure including the cooling duct 50 can have a thickness substantially the same as the thickness of the cross dichroic prism 23. This can contribute to the reduction in thickness.

  In this embodiment, the cross-sectional area of each cooling channel is made different by changing the channel width in the width direction of the cooling channel, but of course, the channel width in the height direction is made different. The cross-sectional areas of the cooling channels may be different. In addition, the magnitude relationship between the cross-sectional area A1 of the first cooling flow path 51, the cross-sectional area A2 of the second cooling flow path 52, and the cross-sectional area A3 of the third cooling flow path 53 is A2 <A1 = A3. The cross-sectional area A1 and the cross-sectional area A3 may be larger than the cross-sectional area A2. For example, A3 = A2 <A1. In this case, by increasing the flow rate of the cooling air in the second cooling channel 52 and increasing the cooling efficiency, the sectional area of the first cooling channel 51 is increased. The pressure loss of the cooling duct 50 as a whole can be suppressed.

  The spatial light modulators are arranged in the order of the B light spatial light modulator 21B, the G light spatial light modulator 21G, and the R light spatial light modulator 21R from the upstream side of the cooling air. It is not restricted to this, You may arrange | position in the order different from this. In this case, the cooling efficiency of the G light spatial light modulator 21G is increased by making the cross sectional area of the cooling flow path corresponding to the G light spatial light modulator 21G smaller than the cross sectional area of the other cooling flow paths. Can do.

  Moreover, although the opening 50a of the 1st cooling flow path 51 and the 3rd cooling flow path 53 is block | closed with the glass plate 50b, you may block | close with the field lens 18B for B light, or the field lens 18R for R light instead. In this case, the glass plate 50b is unnecessary, and the number of parts can be reduced.

  FIG. 4 is a cross-sectional view of the first cooling flow path and the second cooling flow path of the cooling duct according to the first modification of the first embodiment, and (a) cut along the line AA shown in FIG. (B) It is a figure which shows the case where it cut | disconnects along the BB line shown in FIG. In FIG. 4, a spatial light modulation device and the like housed inside are omitted. In the first modification, the first cooling flow path 51 and the second cooling flow path 52 have different cross-sectional areas without changing their cross-sectional shapes. That is, the first cooling flow path 51 and the second cooling flow path 52 have different widths in the width direction and in the height direction, and the relationship is W1: W2 = H1: H2. The With this configuration, the cross-sectional area is changed without changing the cross-sectional shape, the flow velocity of the cooling air flowing through the second cooling flow path 52 is increased, and the cooling efficiency of the G light spatial light modulator 21G is increased. be able to. In addition, the 1st connection flow path 54 is the 1st cooling flow path from which a cross-sectional area differs by gradually reducing both the flow path width of a width direction, and the flow width of a height direction toward the 2nd cooling flow path 52. 51 and the 2nd cooling flow path 52 can be connected smoothly.

  FIG. 5 is a cross-sectional view of the first cooling flow path and the second cooling flow path of the cooling duct according to the second modification of the first embodiment, and (a) cut along the line AA shown in FIG. (B) It is a figure which shows the case where it cut | disconnects along the BB line shown in FIG. In FIG. 5, a spatial light modulation device and the like housed inside are omitted. In the second modification, the first cooling flow path 51 and the second cooling flow path 52 have different cross-sectional shapes without changing their cross-sectional areas. By making the cross-sectional shape of the 2nd cooling flow path 52 into a free cross-sectional shape with respect to the cross-sectional shape of the 1st cooling flow path 51 which is rectangular shape, the cross-sectional area of both cooling flow paths is made equal. Thereby, without changing the flow velocity of the cooling air flowing through the cooling duct 50, the cooling air can be sent to a necessary portion to improve the cooling efficiency. For example, cooling air may be blown onto the incident surface and the exit surface of the spatial light modulator. Further, in order to appropriately shield the light from the spatial light modulation device, a large amount of cooling air may be sent to the exit side polarizing plate side where the amount of heat generation is likely to be larger than that of the spatial light modulation device.

  FIG. 6 is a plan sectional view showing a sectional configuration of a cooling duct included in the projector according to the second embodiment of the invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In the second embodiment, the width of the first cooling channel 51 in the width direction decreases toward the second cooling channel 52, so that the cross-sectional area of the first cooling channel 51 becomes the second cooling channel 52. Decrease gradually toward Thereby, the rapid flow velocity change of the cooling air in the cooling duct 50 can be suppressed, and an increase in the pressure loss of the cooling duct 50 can be suppressed. Further, since the flow path width is changed in the width direction, an increase in the thickness of the cooling structure including the cooling duct 50 can be suppressed, and the projector can be made thinner.

  In the second embodiment, the width of the channel in the width direction is reduced only by the first cooling channel 51, but the third cooling channel 53 is also a channel in the width direction toward the second cooling channel 52. The width may be reduced. Of course, the first cooling channel 51 may have a constant width in the width direction, and the third channel may be reduced toward the second cooling channel 52 only by the third cooling channel 53.

  FIG. 7 is a diagram illustrating a cross-sectional configuration of the cooling duct included in the projector according to the third embodiment of the invention, and is a cross-sectional view taken along the line C-C illustrated in FIG. 2. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In the third embodiment, the bottom surface 51 a of the first cooling channel 51 is inclined, and the channel width in the height direction is reduced toward the second cooling channel 52. The cross-sectional area gradually decreases toward the second cooling channel 52. Thereby, the rapid flow velocity change of the cooling air in the cooling duct 50 can be suppressed, and an increase in the pressure loss of the cooling duct 50 can be suppressed. Moreover, since the flow path width is changed in the height direction, it is possible to suppress the expansion of the planar shape of the cooling structure including the cooling duct 50. Therefore, the cooling structure including the cooling duct 50 can be prevented from pressing the planar arrangement space of each member in the projector.

  In the third embodiment, the width of the channel in the width direction is reduced only by the first cooling channel 51, but the third cooling channel 53 also flows in the height direction toward the second cooling channel 52. The road width may be reduced. Of course, in the first cooling channel 51, the channel width in the height direction may be constant, and the channel width in the height direction may be reduced toward the second cooling channel 52 only by the third cooling channel 53. . Moreover, you may combine the reduction | decrease of the channel width of the width direction demonstrated in the said Example 2, and the reduction | decrease of the channel width of the height direction demonstrated in the present Example 3. FIG. For example, in the first cooling channel 51, the channel width in the width direction is reduced toward the second cooling channel 52 to gradually reduce the cross-sectional area, and in the third cooling channel 53, the height toward the second cooling channel is increased. The cross-sectional area may be gradually reduced by reducing the channel width in the vertical direction.

  Further, the projectors of the above embodiments are not limited to the configuration using an ultrahigh pressure mercury lamp as the light source 10. The light source 10 may be configured to use a lamp other than an ultra-high pressure mercury lamp, a light emitting diode element (LED), a laser light source, or the like. The projector may be a so-called rear projector that supplies light to one surface of the screen and observes an image by observing light emitted from the other surface of the screen.

  DESCRIPTION OF SYMBOLS 1 Projector, 10 Light source, 11 1st integrator lens, 12 2nd integrator lens, 13 Polarization conversion element, 14 Superimposition lens, 15, 17 Reflection mirror, 16 1st dichroic mirror, 18B B light field lens, 18G G light Field lens, 18R R light field lens, 19B, 19R λ / 2 phase difference plate, 20B B light incident side polarizing plate, 20G G light incident side polarizing plate, 20R R light incident side polarizing plate, 21B B light Spatial light modulation device, 21G G light spatial light modulation device, 21R R light spatial light modulation device, 22B B light emission side polarizing plate, 22G G light emission side polarizing plate, 22R R light emission side polarizing plate , 23 Cross dichroic prism, 24 Second dichroic mirror, 25, 27 Relay lens, 26, 2 Reflection mirror, 29 1st dichroic film, 30 2nd dichroic film, 31 projection lens, 32 screen, 40 blower fan, 40a air outlet, 50 cooling duct, 50a opening, 50b glass plate, 51 1st cooling flow path, 51a Bottom surface, 52 second cooling channel, 53 third cooling channel, 54 first connection channel, 55 second connection channel

Claims (7)

A plurality of spatial light modulators that modulate light incident from an incident surface according to an image signal and emit the light from an emission surface;
A cooling unit that is provided for each of the plurality of spatial light modulators and that has a plurality of cooling passages through which cooling air for cooling the spatial light modulators sequentially flows, for cooling the plurality of spatial light modulators sequentially. Ducts,
A blower for sending cooling air to the cooling duct,
According to the amount of heat generated by the spatial light modulator, at least one of the plurality of cooling channels is different in at least one of the cross-sectional area and the cross-sectional shape from the other cooling channels. Projector.   The projector according to claim 1, wherein a cross-sectional area of the one cooling flow path is smaller than a cross-sectional area of the other cooling flow path.   The projector according to claim 2, wherein a cross-sectional area of the other cooling channel gradually decreases toward the one cooling channel.   The projector according to claim 3, wherein the other cooling flow path has a flow path width that is reduced in a direction perpendicular to an incident surface of the spatial light modulator, and a cross-sectional area gradually decreases.   The other cooling flow path is characterized in that the flow path width is reduced in a direction parallel to the incident surface of the spatial light modulator and perpendicular to the flow direction of the cooling air, so that the cross-sectional area gradually decreases. The projector according to claim 3. A connection flow path for connecting the one cooling flow path and the other cooling flow path;
The connection channel has a cross-sectional area gradually decreasing from the other cooling channel toward the one cooling channel, and the first cooling channel and the other cooling channel having different cross-sectional areas. The projector according to claim 2, wherein the projectors are connected smoothly.   The projector according to claim 2, wherein the spatial light modulation device corresponding to the one cooling channel modulates green light.

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