Light source housing, light source device, and image projection apparatus

A light source housing to which a light source lamp having a light emission tube and a reflector is attached includes a pair of flow paths bifurcating onto upper and lower sides of the light emission tube from an air intake port for introducing a cooling air; a flow path open and close unit that slides in a direction of the gravitational force so as to open the flow path on the upper side of the light emission tube and close the flow path on the lower side of the light emission tube; and an air outtake port that outtakes the cooling air introduced into the reflector from the flow path on the upper side of the light emission tube to an outside of the reflector.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention generally relates to a light source housing to which a light source lamp is attached, a light source device including a light source lamp and a light source housing, and an image projection apparatus including the light source device.

2. Description of the Related Art

Because an upper side of a light emission tube (a bulb) inside a light source lamp of an image projection apparatus becomes hot, the upper side of the light emission tube is blown by a fan. Because a point where heat is concentrated shifts depending on a direction of installing a light emission tube inside an image projection apparatus, there is a technique of controlling an air blowing direction for example, a blow plate in conformity with the direction of installing the light emission tube.

Referring to Patent Document 1, a switch plate (an air direction plate, an open and close mechanism) rotates by its own weight so as to cool a light source lamp in conformity with the direction of installing the image projection apparatus.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a novel and useful light source housing, a light source housing, and an image projection apparatus solving one or more of problems of the related art.

One aspect of the embodiments of the present invention may be to provide a light source housing to which a light source lamp having a light emission tube and a reflector is attached including a pair of flow paths bifurcating onto upper and lower sides of the light emission tube from an air intake port for introducing a cooling air; a flow path open and close unit that slides in a direction of the gravitational force so as to open the flow path on the upper side of the light emission tube and close the flow path on the lower side of the light emission tube; and an air outtake port that outtakes the cooling air introduced into the reflector from the flow path on the upper side of the light emission tube to an outside of the reflector.

Additional objects and advantages of the embodiments will be set forth in part in the description which follows, and in part will be clear from the description, or may be learned by practice of the invention. Objects and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

However, in a case where a blow direction is controlled, a drive source for driving a blow plate is necessary. Therefore, the apparatus becomes large and complicated.

Further, in a technique of rotating by its own weight, a freely rotatable switch plate probably opens or closes by a blow. Then, an air may inversely flow and a flow path is not stabilized to thereby prevent a cooling performance from stabilizing.

A description is given below, with reference to theFIG. 1throughFIG. 26Bof embodiments of the present invention. Where the same reference symbols are attached to the same parts, repeated description of the parts is omitted.

FIG. 1is a perspective view of a projector apparatus1which is an electronic apparatus of an embodiment.

Hereinafter, referring toFIGS. 1 to 16, a common structure of the projector apparatus of embodiments of the present invention is described.FIG. 1is a perspective view of a projector apparatus1which is an electronic apparatus of the embodiment.

The projector apparatus1is a compact tower-type apparatus and is formed by surrounding an inner structure with a casing10.

The outer shape of the casing of the projector apparatus1illustrated inFIG. 1is long in the vertical direction and is substantially a rectangular parallelepiped as a whole. Referring toFIG. 1, a width direction (a direction of a single axis on the horizontal face) of the projector apparatus1is designated as an X axis direction, a depth direction (a direction orthogonal to the X axis direction on the horizontal face) of the projector apparatus1is designated as a Y axis direction, and a height direction (a vertical direction) of the projector apparatus1is designated as a Z axis direction.

Referring toFIG. 1, an outer structure of the projector apparatus1is described.

An exterior (a casing)10covering a main body includes a front cover10a, a rear cover10b, and a bottom wall10c. The material of the casing10is relatively light and tough such as a plastic (a hard resin).

Referring toFIG. 1, a light receiving sensor13, a sound emission port14, and a focusing lever15aare arranged on a front wall (a wall on a side of −Y being opposite to a projection direction) from an upper side to a lower side of the front wall.

The light receiving sensor13receives a light signal from a remote controller (not illustrated) and converts the light signal to an electric signal and outputs the electric signal to a control device81(seeFIG. 2B).

The sound emission port14is formed of multiple through holes for emitting a sound output from a speaker (not illustrated).

The focusing lever15ais provided inside a window15being an area for operation. A user operates the focusing lever15ato adjust a focal position (a focus) of a projection lens131included in a projection optical unit130(seeFIG. 3).

The focusing lever15ais structured so as to be slidable in the X-axis direction, which is a width direction of the projector apparatus1. The focusing lever15ais mechanically connected to the projection lens131through a driving force transmission mechanism (not illustrated) such as a gear. The driving force transmission mechanism moves a part of a lens element forming the projection lens131along with a slide motion of the focusing lever15a. With this, the focal position of the projection lens131can be adjusted.

Specifically, in adjusting the position of the projector apparatus1, after locating the projector apparatus1, the focusing lever15ais used to adjust the focus. When the focusing lever15ais driven in one of the X-axis directions (or one of the Z-axis directions), a position (the focal position) where a light projected through the projection lens131forms an image becomes far. On the other hand, when the focusing lever15ais driven in the other one of the X-axis directions (or the other one of the Z-axis directions), a position (the focal position) where a light projected through the projection lens131forms an image becomes near.

Further, as illustrated inFIG. 1, a light projection port16and an operation unit20are provided on the upper surface of the casing10(the upper wall in the direction of “+Z”). The light projection port16is an opening formed on a side near a projection side on the upper wall of the casing10and having a shape of polygon (e.g., a hexagon) in its plan view. The light projection port16is closed by a transparent or a translucent lid member. A light from the projection optical unit130can be projected to an outside of the casing through the lid member closing the light projection port16.

The operation unit20has multiple parts (for example, six operation buttons) provided on the upper surface of the casing10. A power button21, an input button22(an input output switching button), a mute button23, and an enter button24(a determination button) are arranged on the upper surface of the casing10in an area of the direction of “−X” of the light projection port16from left to right onFIG. 1.

Short legs11are provided on the lower side of the casing10. The number of the legs11is at least three and the legs11are not arranged on the same straight line. In the projector apparatus1, each structural element is arranged inside the casing10so that a weight balance is shifted to a side of the direction of “−Y” (heavier on the direction of “−Y” than on the direction of “+Y”). Therefore, the center of gravity is positioned in the direction of “−Y” (on the side of projecting the image) from the center of the casing10. With this structure, the upper surface having the light projection port16can tilt toward a projection face side where the screen is arranged.

In order to set the center of gravity in this way, according to the embodiment, two legs11among the three legs11are arranged at a corner of the directions of “−Y” and “+X” and a corner of the directions of “−Y” and “−X” on the bottom wall10cof the casing10, and the remaining one leg is arranged at the center of an edge in the direction of “+Y”. With this arrangement, the projector apparatus1is supported by the three legs11on a predetermined horizontal surface so as to tilt while being hard to fall down. The positions of the three legs11are not limited to that described above. It is sufficient that the three legs11are positioned at appropriate positions depending on a weight balance of the projector apparatus1.

FIG. 2Ais a right side view of the projector apparatus1.FIG. 2Bis left side view of the projector apparatus1. Referring toFIG. 2A, the apparatus air intake vent17is provided. Under the apparatus air intake vent17, a connector unit19having multiple terminals is formed. The apparatus air intake vent17is connected to an air intake fan71(seeFIG. 3B) through a duct or the like.

Under the apparatus air intake vent17, the connector unit19having the multiple connection terminals is formed. The reference symbol97designates a power connection terminal for connecting to an outer power source. Six connection terminals among seven connection terminals are arranged at two stages in the vertical direction in the connector unit19inside a recess90formed on the right side wall of the casing10. At the upper stage inside the recess90, a USB terminal91for inputting into an external device (e.g., an external memory such as a USB memory), and a HDMI terminal (“HDMI” is a registered trademark)92for connecting to AV equipment are sequentially arranged from the direction of “−Y” to the direction of “Y”. At the lower stage of the recess90, a LAN terminal93for communication, a computer terminal94, a video input terminal95, and an audio input terminal96are sequentially arranged from the direction of “−Y” to the direction of “Y”.

Referring toFIG. 2B, an apparatus air outtake vent18is provided on the other side surface in the direction of “−X”. Referring toFIG. 3B, in the vicinity of the apparatus air outtake vent18, an air outtake fan72is provided.

Here, the projector apparatus generates an image based on image data input from a personal computer, a video camera, or the like and projects the image onto the screen2or the like (seeFIG. 1). In recent years, among projector apparatuses, a liquid crystal projector is especially advancing in terms of a higher definition of a liquid crystal panel, an improvement of brightness along with a higher efficiency of a light source lamp, and a lower price. Further, among the liquid crystal projectors, there is a small sized and light weighted liquid crystal projector using digital micro-mirror device (DMD), which are widely used in business offices, schools, and homes. Especially, a liquid crystal projector of a front type has an improved portability and is used for a small meeting of several persons.

In recent years, it is requested for the projector apparatus to “enable to project a large sized screen image (a larger projection screen)” and to “enable to minimize a projection space required outside the projector apparatus”.

In order to respond to this request, the following internal structure is adopted in the projector apparatus1of the embodiment.

Referring toFIG. 3AtoFIG. 10, the internal structure of the projector apparatus1is described.FIGS. 3A and 3Bare perspective views of the projector apparatus1with its exterior cover removed and viewed from different directions.

As the internal structure, the projector apparatus1includes a light source device6, an optical engine100(seeFIG. 5), a control device81, and so on inside a casing (the exterior cover)10.

The control device81performs various control operations in conformity with a command content corresponding to the electric signal converted by the light receiving sensor13and a signal received from the operation unit20. The control device82is connected to the connector unit19and relays the input information received from the terminal to the control device81or an image display element unit120.

FIG. 4is a perspective view of an optical system including the light source device6and the optical engine100of the projector apparatus1.

Referring toFIG. 4, as an example, the light source device6includes a light source lamp30that includes a light emission tube32and a reflector31surrounding the light emission tube32and having an opening directing along the direction of “+X” (the left side ofFIG. 6) and so on. Here, the light emission tube32is, for example, a high-pressure mercury lamp. For example, the reflector31is shaped like a cup having an inner wall surface being a reflection surface.

The light source device6further includes a light source housing60, to which the light source lamp30is attached, and a light source base member40for mounting the light source housing60on the light source base member40. The light source device60retains the light source lamp30and cools the light source lamp30by circulating an air. The air intake fan71and the air outtake fan72(seeFIG. 3B) are connected to the light source housing60through a duct. The air intake fan71takes an outer air from the apparatus air intake vent17(seeFIG. 2A), and the air outtake fan72sends the air from the apparatus air outtake vent18(seeFIG. 2B) to the outside.

A part of a light (a white light) emitted from the light emission tube32directly goes out from the opening and another part of the light (the white light) emitted from the light emission tube32reflects on the inner wall surface (the reflection surface) of the reflector31and goes out from the opening. A synthetic light including the part and the other part of the light (the white light) emitted from the light emission tube32goes out from the light source lamp30of the light source device6. The light going out from the light source lamp30enters a color wheel111(seeFIG. 6) of the illumination optical unit110.

FIG. 5is a perspective view of the optical engine100. Referring toFIG. 5, the optical engine100includes an illumination optical unit110, an image display element unit (an image forming unit)120, and a projection optical unit130. The illumination optical unit110disperses the white light from the light source lamp30to RGB (three primary colors of light) and guides the dispersed light to the image display element unit120. The image display element unit120modulates the light from the illumination optical unit110in response to an image signal from the external device to generate an image. The projection optical unit130enlarges the generated image and projects the enlarged image.

FIG. 6illustrates a structure and a light path of the illumination optical unit110. Referring toFIG. 6, the illumination optical unit110includes the color wheel111, a light tunnel112, a relay lens113, a cylindrical mirror114, a concave mirror115, and an OFF light plate116(seeFIG. 8). The color wheel111is disk-like color filters that convert the white light from the light source lamp30to each color of RGB every unit time. Thus, repeatedly changing RBG color lights can go out from the color wheel111. The light tunnel112is formed like a tube by cementing flat glasses and guides the light from the color wheel111. The relay lens113is formed of a combination of two lenses and converges the light from the light tunnel while correcting a chromatic aberration of the light. The cylindrical mirror114reflects the light from the relay lens113. The concave mirror115reflects the light reflected by the cylindrical mirror toward a DMD element121of the image display element unit120.

FIG. 7is a perspective view of the image display element unit120. Referring toFIGS. 6 and 7, the image display element unit120includes the DMD element121, a DMD printed circuit board122, a heatsink123, and a fixed plate124.

The DMD element121includes multiple micro-mirrors and reflects the light from the concave mirror115of the illumination optical unit115of the illumination optical unit110while performing a time-division drive of each micro-mirror so that an image (an image light) based on image information is generated. The DMD element121reflects the light used to generate the image toward the projection lens131of the projection optical unit130and the light (a discarded light) unnecessary to generate the image toward the OFF light plate116(seeFIG. 8).

The DMD element121is mounted on the DMD printed circuit board122. The heatsink123cools the DMD element121and the DMD printed circuit board122, which generate heat. The fixed plate124pushes the heatsink123onto the DMD printed circuit board122.

FIG. 8illustrates the illumination optical unit110, the image display element unit120, and a projection lens131of the projection optical unit130. The light reflected by the DMD elements and used to generate the image is reflected toward the projection lens131, and the discarded light is reflected toward the OFF light plate116.

FIG. 9is a perspective view illustrating the projection optical unit13.FIG. 10is a side view of a state where the projection optical unit130is projecting the image to a screen2. Referring toFIGS. 9 and 10, the projection optical unit132includes an illumination housing132retaining the projection lens132, a return mirror133, and a free curved surface mirror134. At the return mirror133, the light path of the image light enlarged by the projection lens131is returned. The free curved surface mirror134reflects and enlarges the image light from the return mirror133. The projection optical unit130is an optical system having an extremely short focal length.

By adopting the projection optical unit130having the optical system having the extremely short focal length for the projector apparatus1of the embodiment, the projector apparatus1can be arranged close to the screen2to which the light is projected. Thus, the compact tower type projector apparatus1requiring a small installation area is obtainable.

FIG. 11is a side cross-sectional view of the light source lamp30of the light source device6. Referring toFIG. 11, the reference symbol31designates a reflector, the reference symbol32designates a light emission tube (the bulb), and the reference symbol33designates a sealing portion on a reflector hole side. A standard value in a predetermined temperature range of a temperature at a time lighting the light source lamp30is provided for a longer lifetime.

By an influence of thermal convection or the like, a temperature increase is greater on the upper side of the direction of the gravitational force and therefore the light emission tube32is apt to cause a temperature difference between the upper and lower sides. If the temperature excessively increases on the upper side of the light emission tube32, a base material of the light emission tube will recrystallize. Therefore, white turbidity may be caused. If the temperature excessively decreases on the lower side of the light emission tube32, a halogen cycle of the base material of the light emission tube cannot be normally performed and the base material is attached to the inner wall of the light emission tube. Therefore, the light emission tube may be blackened. The white turbidity and the blacked light emission tube cause a shorter lamp lifetime and the light emission tube is apt to be broken or degraded by a temperature increase.

Therefore, it is necessary to more effectively cool the upper side more than the lower side so as not to cause a temperature difference between the upper and lower sides of the light emission tube32.

Because the upper side of the light emission tube32moves depending on the posture of installing the image projection apparatus, it is necessary to cool the upper side of the light emission tube32regardless of the posture of installing the image projection apparatus in order to maintain a longer lifetime of the light source lamp30.

As an example, the posture of installing the projector apparatus1can be classified into an ordinary projection posture as illustrated inFIG. 12Aand a projection posture of suspending from a ceiling as illustrated inFIG. 12B. Said differently, the projector apparatus1can be used in two different postures of installing the projector apparatus1where the upper and lower positions of the light source device (a light source unit)6are different.

Specifically, in the ordinary projection posture, an image is projected on the screen2, which is vertically extended, in an obliquely upward direction from an obliquely downward position as illustrated inFIG. 12A. In the projection posture of suspending from the ceiling, the ordinary projection posture is turned by 180° around the X-axis and the image is projected on the screen2, which is vertically extended, in an obliquely downward direction from an obliquely upward position as illustrated inFIG. 12B.

As clearly shown fromFIGS. 12A and 12B, a part positioned on an upper side of the light emission tube32, namely a part of the light emission tube32to have a high temperature, changes depending on the posture of installing the light source device6.

Therefore, it is necessary to cool the upper side of the light emission tube (the part of the light emission tube32to have the high temperature) in any posture of installing the projector apparatus1(the light source device6), in order to obtain a longer lifetime of the light emission tube32.

Therefore, in the embodiment of the present invention, the following structure is adopted to cool the light source lamp30of the projector apparatus (the image projection apparatus)1.

FIG. 13is a perspective view of the light source housing60(60-1,60-2,60-3,60-4) in the ordinary projection mode of the embodiments of the present invention.

An air intake port61being an opening formed on a side surface of the light source housing60is connected to an air intake fan (a cooling fan)71illustrated inFIG. 3B, and an air outtake port64being an opening formed on another side surface of the light source housing60is connected to an air outtake fan72illustrated inFIG. 3B.

In the light source housing60of the first to fourth embodiments of the present invention, flow paths62aand62bare formed so as to bifurcate a cooling duct (a passage way) from the air intake port to the upper and lower sides of the light emission tube32and a partition plate50slidable by its own weight is provided so as to cool the light emission tube32of the light source lamp30. When one of the flow paths62aand62bis closed by the slide motion of the partition plate50by its own weight, it is possible to cool the upper side of the light emission tube32of the light source lamp regardless of the posture of installing the projector apparatus1. Detailed operation is described below.

First Embodiment

FIGS. 14A and 14Bare cross-sectional views of the light source housing60illustrating, for example, a state where the projector apparatus1is placed on a desk and a light is projected toward a wall. Specifically,FIG. 14Ais a cross-sectional view of the light source housing60taken along a line A-A and viewed against the projection direction of the light source lamp30. Specifically,FIG. 14Bis a cross-sectional view of the light source housing60taken along a line B-B and viewed from a direction orthogonal to the projection direction of the light source lamp30.

In the light source housing60of the first embodiment, a cooling air blown from the air intake fan71(seeFIG. 3B) and passes through the apparatus air intake vent17is introduced into the air intake port61. The cooling air introduced into the air intake port61passes through the flow paths (the cooling ducts)62aand62b, and is further introduced from communication ports63aand63binto the light source lamp30. The cooling air introduced into the light source lamp30cools the light emission tube32and thereafter exhausted from the air outtake port64outside the light source lamp30. The air outtake fan72causes the air used for the cooling and heated to pass through apparatus air outtake vent18(seeFIG. 2B) so as to be exhausted outside the projector apparatus1.

The pair of the flow paths62aand62bare arranged so as to bifurcate the cooling air introduced from the air intake port61. The communication port63ais formed on the downstream side of the flow path62aso as to communicate with the reflector31in a direction of the gravitational force. The communication port63bis formed on the downstream side of the flow path62bso as to communicate with the reflector31in the direction of the gravitational force. The communication port63ais positioned on the upper side of the light emission tube32. The communication port63bis positioned on the lower side of the light emission tube32.

The light source housing60is a casing and includes a reflector retaining part67and a casing outer wall68being an outer wall of the housing. An end of the reflector31is engaged with a reflector retaining part67, which is shaped like a box, surrounds the end of the reflector31, and retaining the reflector31. Referring toFIG. 14A(on the near side of the light source housing60inFIG. 13), a side wall67S, a half of a ceiling67B, and a half of a bottom surface67C of the reflector retaining part67are externally surrounded by a casing outer wall68. The flow paths62aand62bare formed by spaces among the side wall67S, the ceiling67B, and inner surfaces of the casing outer wall68. The reflector retaining side wall67S does not include an opening such as the communication ports63aand63b, the air outtake port64, or the like.

The light source housing60includes the casing outer wall68, which is a casing, the reflector retaining part67, and the partition plate (i.e., a switching mechanism, or the flow path open and close unit)50, which is a plate-like member slidable in the direction of the gravitational force by its own weight. The position of the partition plate50is determined when the partition plate50contacts the inner surface of the casing outer wall68in the flow path62aor the flow path62b, which exists in the direction of the gravitational force.

Within the first embodiment, the reflector retaining side wall67S has a double-walled structure, and the partition plate50is slidable between two walls of the reflector retaining side wall67S. Instead of the double-walled structure of the reflector retaining side wall67S of the light source housing60, rails69may be formed to protrude from inner side surfaces of the casing outer wall68, and the partition plate50may be installed between the protruding rails69and a reflector retaining side wall67S1as illustrated inFIG. 18.

With this structure, it is possible to selectively close the flow path62aor the flow path62bwhen the partition plate50slidably moves in the direction of the gravitational force by its own weight.

FIGS. 15A and 15Billustrate an air flow flowing inside the light source housing60in the ordinary projection mode illustrated inFIGS. 14A and 14B. When the projector apparatus1is set for the ordinary projection mode, the partition plate50moves downward in the direction of the gravitational force (the downward direction inFIGS. 15A and 15Bso as to close the flow path62b.

In this state, the cooling air introduced from the air intake port61into the light source housing60passes through the flow path62aand is introduced from the communication port63ainto the light source lamp30. The cooling air introduced into the light source lamp30moves downward along the inner surface of the reflector31and cools the upper side of the light emission tube32. The cooling air heated while cooling the light emission tube32is exhausted outside the light source lamp30from the air outtake port64.

At this time, although the cooling air is introduced inside the flow path62bafter passing through the communication port63b, the partition plate50prevents a back flow from occurring. Because the cooling air collides with the partition plate50in a direction perpendicular to the slide direction of the partition plate50, even if the air flow rate of the cooling air increases, the partition plate50does not slide so as to open the flow path62b. Therefore, the cooling air does not flow back.

FIG. 16illustrates the air flow in the projection mode of suspending from the ceiling inside the light source housing60illustrated inFIGS. 14A and 14B. When the projector apparatus1is set for the projection mode of suspending from the ceiling, the partition plate50moves downward in the direction of the gravitational force (the downward direction inFIGS. 16A and 16Bso as to close the flow path62a.

In this state, the cooling air introduced from the air intake port61into the light source housing60passes through the flow path62band is introduced from the communication port63binto the light source lamp30. The cooling air introduced into the light source lamp30moves downward along the inner surface of the reflector31and cools the upper side of the light emission tube32. The cooling air heated while cooling the light emission tube32is exhausted outside the light source lamp30from the air outtake port64.

At this time, although the cooling air is introduced inside the flow path62aafter passing through the communication port63a, the partition plate50prevents a back flow from occurring. Because the cooling air collides with the partition plate50in a direction perpendicular to the slide direction of the partition plate50, even if the air flow rate of the cooling air increases, the partition plate50does not slide so as to open the flow path62a. Therefore, the cooling air does not flow back.

As described above, in the light source housing60of the first embodiment in any one of the ordinary projection posture and the projection posture of suspending from the ceiling, the cooling air can be blown onto the upper side of the light emission tube32so as to cool the upper side of the light emission tube32.

When one of the flow paths62aand62bis closed by the slide motion of the partition plate50by its own weight, it is possible to cool the upper side of the light emission tube32of the light source lamp30regardless of the posture of installing the projector apparatus (the image projection apparatus)1.

The length of the partition plate50in the direction of the gravitational force is the sum of the height of the side wall67S of the reflector retaining part67and the heights inside the flow paths62aand62bin the direction of the gravitational force. The partition plate50is made of a resin such as liquid crystal polymer (LCP) or a metal and has a thickness of 1 to 2 mm.

Because the partition plate50is installed so as to be movable in the direction perpendicular to the flow path and has a sufficiently great volume and weight in comparison with the cross-sectional area of the flow path, even when the flow path is closed, the air direction plate does not move so as to stabilize the air flow.

Second Embodiment

FIGS. 17A and 17Billustrate an air flow in a light source housing60-1in the ordinary projection mode of a second embodiment. Specifically,FIG. 17Ais a cross-sectional view of the light source housing60-1taken along a line A-A and viewed against the projection direction of the light source lamp30. Specifically,FIG. 17Bis a cross-sectional view of the light source housing60-1taken along the line B-B and viewed in a direction orthogonal to the projection direction of the light source lamp30.

Within the second embodiment, the partition plate50-1has a protruding part51at a position where the cooling air from the air intake port61bifurcates to the flow paths62aand62b. In either posture illustrated inFIGS. 17A and 17BorFIGS. 19A and 19B, when a tip end of the protruding part51closes an entrance of the flow paths62aor62b, which exists on the lower side, the protruding part51is arranged so as to contact the lower end of the air intake port61.

FIG. 18Ais a transparent perspective view of the light source housing60-1in the ordinary projection mode of the second embodiment. Within the first embodiment, the partition plate50is interposed between the reflector retaining side wall67S. However, within the second embodiment, the protruding part51of the partition plate50-1prevents the partition plate50-1from being installed between the two walls of the reflector retaining side wall67S.

FIG. 18Bis an enlarged cross-sectional view around the partition plate50-1. As illustrated inFIG. 18, the rails69protrude from inner surfaces of the casing outer wall68. The partition plate50-1including the protruding part51is slidable in the direction of the gravitational force while being interposed between the rail69and the reflector retaining side wall67S1.

When the projector apparatus1is set for the ordinary projection mode, the partition plate50-1moves downward in the direction of the gravitational force (the downward direction inFIG. 18A) so as to close the flow path62b. Further, the protruding part51and the bifurcation part prevent the cooling air from flowing into the flow path62B.

In this state, the cooling air introduced from the air intake port61into the light source housing60-1passes through the flow path62awithout entering into the flow path62bfrom the bifurcation part and is introduced from the communication port63ainto the light source lamp30. The cooling air introduced into the light source lamp30moves downward along the inner surface of the reflector31and cools the upper side of the light emission tube32. The cooling air heated while cooling the light emission tube32is exhausted outside the light source lamp30from the air outtake port64.

At this time, although the cooling air is introduced inside the flow path62bafter passing through the communication port63b, the partition plate50prevents a back flow from occurring. Because the cooling air collides with the partition plate50-1in a direction perpendicular to the slide direction of the partition plate50-1, even if the air flow rate of the cooling air increases, the partition plate50does not slide so as to open the flow path62b. Therefore, the cooling air does not flow back.

FIGS. 19A and 19Billustrate the air flow in the light source housing60-1in the projection mode of suspending from a ceiling of the second embodiment. When the projector apparatus1is set for the projection mode of suspending from the ceiling, the partition plate50-1moves downward in the direction of the gravitational force (the downward direction inFIGS. 19A and 19B) so as to close the flow path62a. Further, in the projection mode of suspending from the ceiling, the protruding part51prevents the cooling air from being introduced into the flow path62aat the bifurcation part.

With this, the cooling air introduced from the air intake port61into the light source housing60-1passes through the flow path62bwithout entering into the flow path62afrom the bifurcation part and is introduced from the communication port63binto the light source lamp30. The cooling air introduced into the light source lamp30moves downward along the inner surface of the reflector31and cools the upper side of the light emission tube32. The cooling air heated while cooling the light emission tube32is exhausted outside the light source lamp30from the air outtake port64.

At this time, although the cooling air is introduced inside the flow path62aafter passing through the communication port63a, the partition plate50-1prevents a back flow from occurring. Because the cooling air collides with the partition plate50-1in the direction perpendicular to the slide direction of the partition plate50-1, even if the air flow rate of the cooling air increases, the partition plate50does not slide so as to open the flow path62a. Therefore, the cooling air does not flow back.

As described, within the second embodiment, the flow path62aor62bcan be closed with an enhanced sealing capability to prevent the cooling air from being introduced into the flow path on the lower side.

Then, the upper side of the light emission tube32is effectively cooled and an excessive cooling of the lower side of the light emission tube32is prevented. Accordingly, it becomes hard to cause a temperature difference between the upper side and the lower side of the light emission tube32.

Modified Example of Second Embodiment

FIGS. 20A and 20Billustrate the air flow in a light source housing60-2in the ordinary projection mode of a modified example of the second embodiment. In this modified example, a slant is formed in the protruding part51-2of the partition plate50-2. In either posture illustrated inFIGS. 20A and 20BorFIGS. 21A and 21B, when a tip end of a protruding part51-2closes an entrance of the flow paths62aor62b, which exists on the lower side, the protruding part51-2is arranged so as to contact the lower end of the air intake port61.

The slant of the protruding part51-2smoothly introduces the cooling air introduced from the air intake port61toward the flow path62awithout entering into the flow path62bfrom the bifurcation part. The partition plate50-2having the protrusion51-2, in which the slant is provided, is structured so as to be slidable by engaging with the rail69like the protrusions51and51-1as illustrated in the cross-sectional view ofFIG. 18B.

FIGS. 21A and 21Billustrate the air flow in the light source housing60-1in the projection mode of suspending from the ceiling of the modified example of the second embodiment. The slant of the protruding part51-2smoothly guides the cooling air introduced from the air intake port61toward the flow path62bwithout entering into the flow path62afrom the bifurcation part.

Third Embodiment

FIGS. 22A and 22Billustrate the air flow in a light source housing60-3in the ordinary projection mode of a third embodiment. Specifically,FIG. 22Ais a cross-sectional view of the light source housing60-3taken along the line A-A and viewed against the projection direction of the light source lamp30.FIG. 22Bis a cross-sectional view of the light source housing60-3taken along the line B-B and viewed in a direction orthogonal to the projection direction of the light source lamp30.

Within the third embodiment, recesses (grooves)65aand65bare formed on an inner ceiling or an inner bottom surface of a casing outer wall68-3so as to inward dent at positions engaging with the partition plate50-3.

When the projector apparatus1is set in the ordinary projection mode, the partition plate50-3moves downward in the direction of the gravitational force by its own weight so that the lower end of the partition plate50-3engages the recess on the recess65bon the bottom surface inside a casing outer wall68C to close the flow path62b. A sealing capability is enhanced in closing the flow path62busing the partition plate50-3by the existence of the recess65b. Thus, a leak of the cooling air between the inner surface (the inner bottom surface of the casing outer wall68) of the flow path62band the partition plate50-3is prevented.

FIGS. 23A and 23Billustrate the air flow in the light source housing60-3corresponding toFIGS. 22A and 22Bin the projection mode of suspending from the ceiling of the third embodiment.

The partition plate50-3moves downward in the direction of the gravitational force by its own weight, and the lower end of the partition plate50-3engages with the recess on the inner bottom surface of the casing outer wall68-3so as to close the flow path62a. With this, a sealing capability is enhanced in closing the flow path62ausing the partition plate50-3by the existence of the recess65a. Thus, a leak of the cooling air between the inner surface (the inner bottom surface of the casing outer wall68) of the flow path62aand the partition plate50-3is prevented.

As described, in the light source housing60-3of the third embodiment, the flow path62aor62bcan be closed with the enhanced sealing capability both in the ordinary projection posture and the projection posture of suspending from the ceiling. Further, the air direction plate (the partition plate50-3) does not move by the force of the cooling air and a flow of the cooling air can be stabilized.

Fourth Embodiment

FIGS. 24A and 24Billustrate the air flow in a light source housing60-4in the ordinary projection mode of a fourth embodiment. Specifically,FIG. 24Ais a cross-sectional view of the light source housing60-4taken along a line A-A and viewed against the projection direction of the light source lamp30. Specifically,FIG. 24Bis a cross-sectional view of the light source housing60-4taken along the line B-B and viewed in the direction orthogonal to the projection direction of the light source lamp30.

Within the fourth embodiment, a casing outer wall68-4is formed such that ends of the flow paths62aand62bin the vicinity of the communication ports63aand63bare end openings66aand66b, respectively. Second partition plates55aand55bslidable in direction of the gravitational force by these own weights are provided so as to open and close the end openings66aand66b, respectively. The second partition plates55aand55bare held so as to be slidable by second partition plate retaining parts70aand70barranged in the end openings66aand66b.

FIGS. 25A and 25Billustrate structures including the second partition plate in the light source housings60-4A and60-4B in the projection mode of suspending from the ceiling of the fourth embodiment of the present, respectively.

An end part70of the casing outer wall68-4, positioned in the vicinity of the end openings66aand66b, is in a cylindrical shape as illustrated inFIG. 25Aso that a sliding motion of the second partition plate55aand55bcan be stopped. Referring toFIG. 26B, protrusions56aand56bmay be respectively provided in the partition plates55aand55bon sides far from the casing outer wall so that the protrusions56aand56bof the partition plates55aand55bare stopped by the second partition plate retaining parts70aand70b.

Alternatively, the second partition plate retaining parts70aand70billustrated inFIGS. 24A and 24Bmay be formed to have open ends toward the outside. By arranging the light source housing60-4so as to closely contact another structural object inside the projector apparatus1, the second partition plate may stop by contacting the other structural object.

Within the fourth embodiment, when the projector apparatus1is set for the ordinary projection mode, a partition plate50-3moves downward in the direction of the gravitational force (the downward direction inFIGS. 25A and 25B) so as to close the flow path62b.

At this time, an end opening66aof the flow path62ais closed by the partition plate55aand an end opening66bof the flow path62bis opened by the partition plate55b.

Therefore, the cooling air introduced into the light source lamp30from the communication port63ais introduced from the communication port63binto the flow path62b, and is exhausted from the opening66b, which is opened by the second partition plate55b. Because the communication port63bis positioned opposite to the communication port63ainterposing the light emission tube32, the cooling air introduced inside the light source lamp30from the communication port63acan be exhausted from the communication port63bwithout interruption. In comparison with a case where the cooling air is exhausted from only the air outtake port64as an opening, cooling becomes more efficient. The air outtake port64may not be closed to enhance a cooling efficiency.

FIGS. 26A and 26Billustrate the air flow in the light source housing60-4corresponding toFIGS. 24A and 24Bin the ordinary projection mode of the fourth embodiment.

When the projector apparatus1is set for the ordinary projection mode, the partition plate50-4moves downward in the direction of the gravitational force (the downward direction inFIGS. 26A and 26B) so as to close the flow path62b. Further, the second partition plate55acloses the flow path62a. Further, the second partition plate55bopens the flow path62b.

Therefore, the cooling air introduced into the light source lamp30from the communication port63ais introduced from the communication port63binto the flow path62b, and is exhausted from the opening66b, which is opened by the second partition plate55b. Because the communication port63bis positioned opposite to the communication port63ainterposing the light emission tube32, the cooling air introduced inside the light source lamp30from the communication port63acan be exhausted from the communication port63bwithout interruption. In comparison with a case where the cooling air is exhausted from only the air outtake port64as the opening, cooling becomes more efficient. The air outtake port64may not be closed to enhance the cooling efficiency.

As described above, in any one of the ordinary projection posture and the projection posture of suspending from the ceiling in the light source housing60-4of the fourth embodiment, by exhausting the cooling air introduced inside the light source lamp30without interruption, the cooling efficiency can be improved.

This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2014-037503, filed on Feb. 27, 2014, the entire contents of which are incorporated herein by reference.