LCD projector

A liquid crystal projector comprises an equipment body containing projection device and cooling device and including an air intake port and an air exhaust port, a case for housing the equipment body, and a sliding device for sliding the case so as to take a first state in which the equipment body is pulled out of the case and a second state in which the equipment body is housed in the case. The air intake port and the air exhaust port are closed at the first state and are opened outside at the second state.

BACKGROUND OF THE INVENTION

The present invention relates to a liquid crystal projector which contains cooling means and in which noise due to a ventilation fan of the cooling means is reduced.

In a liquid crystal projector which magnifies and projects on a screen an image imaged on a liquid crystal panel, a high-illuminant high-voltage discharge lamp is used as a light source for illumination of a liquid crystal panel in order to obtain a high brightness projection image. The lamp emits high intensity thermal radiation, so, the vicinity of the lamp and the liquid crystal panel become high temperature, and an inner side of a housing of the liquid crystal projector (hereinafter, referred to as equipment housing) also becomes high temperature. Thus, the characteristics of each components may be adversely effected. Therefore, cooling means including a ventilation fan is provided in such a equipment housing, which, using the ventilation fan, intakes cool air from outside, passes it through the equipment housing, and exhausts it outside to radiate the heat generated in the equipment housing, outside.

In such a situation, if such cooling means is provided in the equipment housing, there has been a problem of noise occurring during use of the liquid crystal projector, because the hissing sound of the ventilation fan, or the sound of rotation of a motor driving the ventilation fan is emitted outside as a noise from an air exhaust port provided in the equipment housing. Conventionally, various methods for preventing such a noise have been proposed.

One of these methods involves setting ventilation fans to predetermined positions in the equipment housing to reduce noise emitted from an air intake port or an air exhaust port (for example, refer to JP-A-2002-40562).

Conventionally, the fan for air intake or air exhaust is provided near the air intake port or air exhaust port, but, in this method, these fans are provided apart from the air intake port or the air exhaust port by prescribed distances (for example, equal to or greater than the diameters of rotation portion of these ventilation fans multiplied by 0.4). In addition, ducts are provided between the air intake port and the air intake fan or between the air exhaust port and the air exhaust fan, and sound absorbing material on an inner surface of the ducts to further reduce the noise.

Another method proposed is to emit noise from the air exhaust port provided in the equipment housing, wherein the emitting direction can be set to any arbitrary direction (for example, refer to JP-A-2000-660306).

This method involves providing a duct in the air exhaust port on an external surface of the equipment housing, wherein the direction of the duct end can be changed. Thus, by turning the duct end to a direction where no viewer is present, air is exhausted and noise is also emitted in the direction so that no viewer would be bothered with noise.

Though the art described in JP-A-2002-40562 can reduce the noise of ventilation fans, since these ventilation fans, an air intake fan and air exhaust fan, are provided apart from the air intake port and the air exhaust port by prescribed distances, there are spaces in the equipment housing between the air intake fan and the air intake port on the inner side where the air intake port is provided, and also between the air exhaust fan and the air exhaust port on the inner side where the air exhaust port is provided. Such spaces are provided only for noise suppression, resulting in a large size of the equipment housing on account of only noise suppression. Therefore, when the liquid crystal projector is stored upon being unused, it requires larger storage space and also becomes bulky, being inconvenient to carry.

In addition, the art described in JP-A-2000-66306 can suppress noise without enlarging equipment housing itself, but, a duct is attached to the equipment housing with a shape protruding from the equipment housing, therefore, when the liquid crystal projector is stored or carried, the duct becomes an obstacle, so, the equipment being inconvenient.

An object of the present invention is to provide a liquid crystal projector which eliminates these problems, effectively reduces the noise emitted from cooling means, and can be small to be handled easily.

SUMMARY OF THE INVENTION

To achieve the above object, according to the present invention, a liquid crystal projector is provided which contains projection means and cooling means, and includes an equipment body which has an air intake port and an air exhaust port, a case for housing the equipment body, and a sliding device sliding the case to a pulled out state in which the equipment body is pulled out from the case and to a retracted state in which the equipment body is retracted into the case, and wherein the air intake port and the air exhaust port are closed with the equipment body retracted, and opened with the equipment body pulled out.

The air intake port is provided on a bottom surface and the air exhaust port is provided on a back side of the equipment body, respectively. Means for closing and opening the air intake port comprises intake ventilation holes, which are provided on a bottom surface of the case, align with the air intake port when the projector is used and does not align with the air intake port when the projector is not used. Means for closing and opening the air exhaust port comprises exhaust ventilation holes, which are provided on a top surface of the case, are closed by the equipment body when the projector is not used, and opened by the closing of the equipment body being released when the projector is used.

The projector further comprises an attitude control legs which can be brought into and out of the equipment body on a front side of the bottom surface of the equipment body, a lock mechanism for locking and unlocking the attitude control legs, and release buttons for operating the lock mechanism by pushing operation to release the locked state of the attitude control legs, wherein the release buttons are provided on the equipment body so that the buttons are pushed by the case when the projector is not used and are released from the pushing by the case when the projector is used.

According to the present invention, it is possible to make the whole of projector small and it easy to be handled at least when it is used, and further, it is possible to reduce the effect of the noise emitted from the ventilation holes provided for cooling the inside of the projector.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1is a front perspective view illustrating a first embodiment of a liquid crystal projector according to the present invention, in whichFIG. 1(a) shows a state when the projector is used, andFIG. 1(b) shows a state when the projector is not used. Reference numeral1denotes a liquid crystal projector according to the first embodiment. Reference numeral2denotes an equipment body,2aa front surface,2ba top surface, and2cside surfaces. Reference numeral3denotes a case,3aa top surface,4a projection lens,5a start button,6an operation key,7a lens knob,8release buttons,9a recess,10exhaust ventilation holes, and11attitude control legs.

The liquid crystal projector1comprises the equipment body2and the case3, and the equipment body2is assembled into the case3to form a structure in which the equipment body2and the case3are slidable relative to one another.

When the liquid crystal projector1is used, a part of the front surface side is protruded from the case3. The start button5and the operation key6are provided on the top surface2bof the protruded part of the equipment body2, thus they are in an operative state. The operation key6has a circular shape and the top surface is flush with the top surface2bof the equipment body2, a generally semicircular part is positioned in the circular recess9formed in a front edge of the top surface3aof the case3. That is, because of the existence of the recess, the whole of operation key6is exposed outside thus allowed to be operated9.

A recess with the projection lens4is also provided on the right side of the front surface2aof the equipment body2, and a recess with the lens knob7for focusing or zooming of the projection lens4is formed on the top surface2bof the equipment body2.

Further, as described below, the release button8for unlocking the attitude control legs11protruding from the bottom surface of the equipment body2to downward through the bottom surface of the case3is provided on the part of side surface2cof the equipment body2exposed from the case3, and s similar release button8is provided on another side surface (not shown) opposite to the side surface2c. When these release buttons8are pushed into, the attitude control legs11are released from the locked state, and, by a mechanism described below, they tend to protrude further from the equipment body2. Thus, the height of the front surface2aof the equipment body2of the liquid crystal projector1can be adjusted to control the attitude of the liquid crystal projector1, by pushing the equipment body2from the front surface2bto the mounting plane of the liquid crystal projector with the release button pushed, or loosing the pushing. One of the two attitude control legs alone can be controlled in the height by the above adjustment with the release button8of one side surface2cof the equipment body pushed, and the liquid crystal projector1can take a corresponding attitude.

The rear surface (opposite side to the front surface2aof the equipment body2) has no wall and is open to the outside, though it cannot be shown because it is in the case3.

The exhaust ventilation holes10are provided on the top surface3aof the case3at a rear side portion.

When the case3is pushed in the direction of arrow A in the above state of the liquid crystal projector1, the equipment body2is inserted into the case3. At the same time, the release buttons8of the both side surfaces2cof the equipment body2are pushed into the equipment body2by the inner surface of the case3, whereby the lock of the attitude control legs11are released. Further, as the equipment body2is inserted further into the case3, the attitude control legs11are pushed into the equipment body2by an inner bottom surface of the case3, and as shown inFIG. 1(b), the whole of equipment body2is inserted into the case3with only the front surface2aexposed outside. This state is the state when the liquid crystal projector1is not used and it becomes smaller in comparison with the state when the projector1is not used as shown inFIG. 1(a).

In this “not used state”, the attitude control legs11are pushed into the equipment body2by the case3, and only the start button5provided on the top surface2bof the equipment body2is exposed outside from the recess9provided on the top surface3aof the case3.

Thus, when the liquid crystal projector1having been in use is collapsed for carrying, or stored, by retracting the equipment body2into the case3, the release buttons8are pushed by the case3to unlock the attitude control legs11and the attitude control legs11are retracted into the equipment body2by the case3. On the other hand, when the liquid crystal projector1is brought into service, the equipment body2is pulled out from the case3only by operating the start button5, and at the same time, the attitude control legs11emerge from the equipment body. Accordingly, it is not necessary to retract and pull out the attitude control legs11, thereby making the liquid crystal projector1easy to be handled.

When the start button5of the equipment body2is pushed in an used state, the liquid crystal projector1is powered on, and at the same time, the case3travels in a direction towards the rear surface (direction shown by the arrow B) with respect to the equipment body2. As the case3travels, the front surface2aof the equipment body2protrudes from the case3. During the travel, the release buttons8are being pushed by the inner side surfaces of the case3, and the attitude control legs11, stored in the equipment body2by the inner bottom surface of the case3, protrudes outside from the bottom of the equipment body2through the bottom of the case3.

When the travel of the case3is completed, the equipment body2is in maximum protrusion allowed by the case3, which is the in-use state as shown inFIG. 1(a).

FIG. 2is a perspective view of the liquid crystal projector1according to the first embodiment viewed from the bottom surface. Reference number2ddenotes a bottom surface of the equipment body2,3ba bottom of the case3,12a reference leg,13intake ventilation holes,14openings,15a through hole, and16aair intake ports. Parts corresponding toFIG. 1are designated by the same references, eliminating duplicated descriptions.

A protruding area of the bottom surface2dof the equipment body2from the case3is provided with the air intake ports16aof cooling means (not shown) contained in the equipment body2. Further, similar air intake ports16bare also provided in an area of the bottom surface2dof the equipment body2, which is in the case3and cannot be shown.

Openings14are provided on the bottom3bof the case3at both sides of the front side. As shown in the drawing, when the liquid crystal projector1is in use, the attitude control legs11protrude through the openings14. Further, the intake ventilation holes13are provided on the bottom3b, and, in the used state, communicate with the air intake ports16bprovided in the bottom surface2dof the equipment body2at the portion in the case3.

Then, in the used state, by the ventilation fan of the cooling means, not shown, in the equipment body,2cool air is sucked into the equipment body2from the air intake ports16aof the equipment body2at the area exposed from the case3, and from the intake ventilation holes13on the bottom3bof the case3and the air intake ports16b, not shown, on the bottom surface2dof the equipment body2. At the same time, air is exhausted out of the equipment body2from the opened rear surface of the equipment body2through the exhaust ventilation holes10on the top3aof the case3.

In addition, when the liquid crystal projector1is not used as shown inFIG. 1(b), the air intake ports16a,16bprovided on the bottom surface2dof the equipment body2, are closed by the case3, and the exhaust ventilation holes10on the top3aof the case3are closed by the top surface2aof the equipment body2.

In addition, one through hole15is provided in the bottom3bof the case3at a center of a rear side portion, and the reference leg12protrudes from the bottom surface2dof the equipment body2through the through hole15. The extension height of the reference leg12from the through hole15is constant, so the height of the rear side of the liquid crystal projector1is kept constant by the reference leg12, so that, for example, even if it is set in any attitude by the attitude control leg11, the bottom3bof the case3does not come into contact with a surface on which the liquid crystal projector1is mounted. As shown in the drawing, when the liquid crystal projector1is in the used state, the reference leg12protrudes through the through hole15, but, as the equipment body2is inserted into the case3, it is pushed into the equipment body2by the case3. Therefore, in the not used state as shown inFIG. 1(b), neither the attitude control legs11nor the reference leg12protrude from the bottom3bof the case3.

FIG. 3is a perspective view of the liquid crystal projector1according to the first embodiment viewed from the rear side. Reference number3cdenotes a rear surface of the case3,18various types of connectors,17a slide door, and19a power cord. Parts corresponding toFIG. 1are designated by the same references, eliminating duplicated descriptions.

Various types of connectors18for connecting a power cord image source, and so on, are provided on a rear surface side of the case3in a location that can be opened and closed by the slide door17so that when the liquid crystal projector1is in the used state, it can be connected to the power cord19etc. In the not used state, the locations are closed by the slide door17so that various types of connectors18do not remain exposed outside.

FIG. 4is a plan view of the liquid crystal projector1, in the used state shown inFIG. 1toFIG. 3, viewed from the top side. Reference number6adenotes a jog dial,6ba cursor key,20a picture source name, and21a transparent cover. Parts corresponding to the parts shown in the above-described drawings are designated by the same references, eliminating duplicated descriptions.

The operation key6comprises a disk-shaped cursor key6bdisposed centrally and a ring-shaped jog dial6adisposed around the key. The cursor key6bis provided with triangle marks indicating up and down and right and left. The cursor on the screen, not shown, on which an image is projected, can be moved up and down and right and left by pushing any one of the marks. In addition, the jog dial6ais used for selectively switching the picture sources of the liquid crystal projector1, and by rotating it to the direction of arrow C, C′ around the center, a desired image source can be chosen, and the expanded image from the source can be projected on the screen, not shown. For this selection, image source names20indicating the image sources are displayed around the jog dial6aon the top surface2bof the equipment body2.

FIG. 5is an enlarged view showing an area P inFIG. 4including the operation key6. As shown in the drawing, image source names20indicating the image source types, such as TV set, video, and personal computer, are displayed around the jog dial6a. The image source name20chosen by the jog dial6ais lighted by the lighting of a display device such as EL (electro luminescence) device provided for the name, and clearly shown by the lighted cursor22. Therefore, when the jog dial6ais rotated, the lighted cursor22moves correspondingly, and when the operation of the jog dial6ais completed, the lighted cursor22stops at the location of the image source name20correspondingly, indicating that the image source name20is chosen.

Returning toFIG. 4, a transparent cover21is provided removably from the top surface part of the equipment body2, which protrudes from the case3, and a sheet, on which character string such as an image source name20etc. and decoration such as a pattern, a figure, and a photograph are printed, is fitted between the transparent cover21and the top surface2b. Of course, the transparent cover21and the sheet are removed at the parts of the lens knob7, the operation key6, and the start button5, so that they are easily handled. The sheet can be replaced by removing the transparent cover21from the top surface2a, and thereby the decoration on the top surface2bof the equipment body2can be replaced.

FIG. 6is a horizontal sectional view showing an example of a schematic inner structure of the liquid crystal projector1according to the first embodiment. Reference number23denotes a high voltage discharge lamp,24a collimating lens,25an optical path,26R,26G, and26B liquid crystal panels,27a dichroic prism, and28a ventilation fan of the cooling means. Parts corresponding to the parts shown in the above-described drawings are designated by the same references, eliminating duplicated descriptions.

The equipment body2is provided with a projection mechanism and the cooling means. The projection mechanism comprises a high-voltage discharge lamp23as a light source for lighting, a collimating lens24for converting the white light from the high-voltage discharge lamp23into collimated light, a liquid crystal panel26R for imaging a R(red color) image, a liquid crystal panel26G for imaging a G(green color) image, a liquid crystal panel26B for imaging a B(blue color) image, an optical path25for separating the collimated light from the collimating lens24into primary lights of R, G, and B, and guiding the lights to the liquid crystal panels26R,26G, and26B, respectively, a dichroic prism27for combining the R, G, B image lights modulated by the images of the liquid crystal panels26R,26G, and26B to generate a color image light, and a projection lens4for expanding and projecting a color image on the screen, not shown, on which the color image light enters.

In addition, when the liquid crystal projector1is in the used state, the cooling means sucks cool air into the equipment body2from the air intake ports16a,16bby rotating the ventilation fan28, passes it through the surrounding of the projection mechanism and exhausts it from the opened rear surface of the equipment body2, and further exhausts it outside through the exhaust ventilation holes10provided on the top of the case3. Thereby, the heat generated from heating elements such as the high-voltage discharge lamp23and the liquid crystal panels26R,26G, and26B is absorbed by the air and emitted outside together with the air through the exhaust ventilation holes10, thus, the inner side of the equipment body2is cooled. In addition, inFIG. 6, the position of the ventilation fan28is provisionally, so, the position can be determined appropriately.

FIG. 7is views showing comparatively the positions of the ventilation fans28in the case3, between in the used state and in the not used state.FIG. 7(a) is a longitudinal sectional view in the used state, being the same asFIG. 1(a) andFIG. 2.FIG. 7(b) is a longitudinal sectional view in the not used state, being the same asFIG. 1(b). Reference number2edenotes a rear side of the equipment body2. Parts corresponding to the parts shown in the above-described drawings are also designated by the same reference, eliminating descriptions. The equipment body2itself is shown only a main structure. In addition, the exhaust ventilation holes10, the air intake holes16aand16b, and the intake ventilation holes13are composed of an array of many through holes, but, here, for clarify, each of them is represented as one large through hole.

In the used state shown inFIG. 7(a), the front surface side of the equipment body2is protruded from the case3, so that the air intake ports16b, provided on the bottom surface2dof the equipment body2, communicates with the intake ventilation holes13, provided on the bottom3bof the case3. As shown by a broken arrow, cool air is sucked into the equipment body2from outside through the intake ventilation holes13and the air intake port16b.

In addition, the rear side of the equipment body2is substantially not shielded and is opened, and the exhaust ventilation holes10provided on the top surface3aof the case3are also opened. Thereby, the cool air sucked from the ventilation fan27absorbs the heat generated in the equipment body2, and, as shown by broken arrow, the air is emitted from the rear side2eof the equipment body2, and, further, the air is exhausted outside through the exhaust ventilation holes10of the case3.

In the not used state shown inFIG. 7(b), the projector1is in the state in which the equipment body2is pushed into the case3. Thus, the air intake ports16aand16bon the equipment body2are closed by the bottom3bof the case3, and the intake ventilation holes13and the exhaust ventilation holes10on the case3are also closed by the bottom surface2dand the top surface2bof the equipment body2, respectively.

Then, the states ofFIG. 1(a) and1(b) are compared. Now, if the distance between the ventilation fan28and the exhaust ventilation holes10of the case3in the not used state shown inFIG. 7(b) is determined to be “L” and the protruded distance of the equipment body2from the case3in the used state shown inFIG. 7(a) is determined to be ΔL, the distance between the ventilation fan28and the exhaust ventilation holes10of the case3in the used state shown inFIG. 7(a) becomes L+ΔL, so the ventilation fan28further departs from the exhaust ventilation holes10by ΔL. Thus, the noise of the rotation of the ventilation fan28emitted from the exhaust ventilation holes10can be reduced.

As for the intake side of the cool air, since the air intake ports16aand16band the intake ventilation holes13are provided on the bottom side of the liquid crystal projector1, the effect of the noise emitted from them is small.

In addition, in the not used state, as shown inFIG. 7(b), the whole of equipment body2is pushed into the case3, thereby, the whole size of the liquid crystal projector1becomes smaller than in the used state, being not bulky and easily to be carried or stored.

Further, in the not used state, since the equipment body2is shielded from ambient air, the liquid crystal projector1can be protected from moisture or dust, notwithstanding the environment where it is carried or the environment where it is stored.

Thus, according to the first embodiment, in the used state, the noise generated by the ventilation fan28can be effectively reduced by enlarging the distance between the ventilation fan28and the exhaust ventilation holes10for discharging air outside, and, in the not used state, the whole of liquid crystal projector1becomes small and easy to be carried or stored, while it can effectively protect the intrusion of moisture or dust from outside.

In the first embodiment, cool air is sucked from outside from the front side of the bottom surface, and exhausted outside from the rear side of the top surface.FIG. 8is schematic perspective views showing other examples of other air intake positions and air exhaust positions. Here, with regard to a liquid crystal projector1, an air intake position and an air exhaust position are shown by arrows, reference number1adenotes a front surface of the liquid crystal projector1,1ba top surface,1ca rear surface,1dside surfaces, and1ea bottom surface.

FIG. 8(a) shows examples where air is sucked from the front surface1a, and the air is exhausted from the rear surface1c(A-1), from the top surface1bnear neighbor side of the rear surface1c(A-2) on the top surface1b(A-2), and from the side surface1dnear the neighbor of the rear surface1c(A-3) on the side surface1d(A-3), respectively.

FIG. 8(b) shows examples where air is sucked from the bottom surface1e, and the air is exhausted from the front surface1a(B-1: air is sucked from the bottom surface1enear the neighbor of the rear surface1c), from the rear surface1c(B-2: air is sucked from the bottom surface1enear the neighbor of the front surface1a), and from the side surface1d(B-3: air is sucked from the bottom surface1dnear the neighbor of the front surface1a, the air is exhausted from the side surface1dnear the neighbor of the rear surface1c; alternatively, not shown, air may be sucked from the bottom surface1dnear the neighbor of the rear surface1c, the air may be exhausted from the side surface1dnear the neighbor of the front surface1a), respectively.

FIG. 8(c) shows examples where air is sucked from the rear surface1c, and the air is exhausted from the front surface1a(C-1), from the top surface1bnear the neighbor of the rear surface1c(C-2), and from the side surface1dnear the neighbor of the rear surface1c(C-3), respectively.

All of the examples are composed of an equipment body and a case shown in the preceding drawings. Therefore, in the used state, the distance between a ventilation fan and a exhaust ventilation fan is enlarged, in each of examples A-1to A-3shown inFIG. 8(a), and in each of examples B-2and B-3shown inFIG. 8(b), and the distance between a ventilation fan and an intake ventilation fan is enlarged, in an example B-1shown inFIG. 8(b), and in each of examples C-1to C-3shown inFIG. 8(c). Thus, the noise from the exhaust ventilation holes and the intake ventilation holes can be reduced.

In the examples A-1to A-3shown inFIG. 8(a), the distance between the air intake port and the ventilation fan is not changed, and in the examples B-1shown inFIG. 8(b) and C-1shown inFIG. 8(c), the distance between the air exhaust port and the ventilation fan is not changed between the in the used state and the not used state of the liquid crystal projector1. The air intake port and air exhaust port are, however, disposed on the front surface side of the liquid crystal projector1, and noise emitted from them is directed towards the screen, thus the influence to the viewers of the screen is reduced.

In addition, in the examples C-2and C-3, shown inFIG. 8(c), a ventilation path for circulating the sucked air is formed in the projector1so as to effectively cool the projection means, and the cool air, sucked from the intake ventilation holes on the rear surface1cof the liquid crystal projector1, passes through the ventilation path. Thus, the air with absorbed heat is exhausted from the exhaust ventilation holes provided on the top surface1bor on a rear side part of the side surface1dof the liquid crystal projector1. In this case, an air intake fan is provided on the side of intake ventilation holes, and an air exhaust fan is provided on the side of exhaust ventilation holes, for smoothly circulating air. These fans are provided on the equipment body of the liquid crystal projector1, and, as described above, in the used state, since the equipment body travels with respect to the case, and thereby a part of the equipment body is protruded from the case, the distances between the intake ventilation holes and the air intake fan, and between the exhaust ventilation holes and the air exhaust fan are elongated respectively, thus, the noise from the intake ventilation holes and the exhaust ventilation holes can be reduced. In addition, in the not used state, the liquid crystal projector1can be made small and the exhaust ventilation holes can be closed.

Further, in the example A-1shown inFIG. 8(a) or B-2shown inFIG. 8(b), a shielding part is provided at the part opposite to the exhaust ventilation holes provided on the rear surface of the case3in the rear portion2e(FIG. 7)of the equipment body2and the remaining part is opened and used as air exhaust holes. In the not used state shown inFIG. 7(b), the exhaust ventilation holes are closed by the shielding part. Therefore, the intrusion of by moisture or dust from the exhaust ventilation holes can be protected, in the not used state. This is similar to the examples C1to C3shown inFIG. 8(c), so, the intrusion of moisture or dust from the intake ventilation holes provided on the rear surface of the case can be protected, in the not used state.

FIG. 9is a structural view showing an example of attaching mechanism of the attitude control legs11shown inFIG. 2. Reference number29denotes a body fixing part,29aand29bholding parts,30a through hole,31a screw shaft,32a holding member,33a compression spring,34a lock member,34aan engagement part,35a connection shaft,36a compression spring, and32a holding member. Parts corresponding to the parts shown in the preceding drawings are also designated by the same symbols, eliminating duplicated descriptions. In addition, a X direction is a longitudinal direction of the liquid crystal projector1shown inFIG. 2(the traveling direction of the equipment body2with respect to the case3), a Y–Y′ direction is the width direction of the same, and a Z–Z′ direction is the thickness direction of the same.

The body fixing part29is fixed in the equipment body2, and both ends are folded in a square bracket shape and constitute the holding parts29aand29bfor holding the screw shaft31. The holding parts29aand29bhave a through hole30(not shown in the holding part29b) and are arranged in a vertical direction (the Z–Z′ direction). The holding part29ais disposed on a top surface side of the equipment body2, and the holding part29bis disposed on a bottom surface side of the same, respectively. In addition, the screw shaft31is passed through the through holes30, and therefore, the longitudinal direction of the screw shaft31becomes the Z–Z′ direction, and the screw shaft31is movably hold by the holding parts29aand29bin the vertical direction (the Z–Z′ direction).

An end, in the holding part29aside, of the screw shaft31is fixed to the attitude control legs11, and a holding member32(for example, disk) is fixed and attached to the screw shaft31between the holding parts29aand29b.

A compression spring33is provided between the holding member32and holding part29a, and arranged so that the screw shaft31passes through a substantial central axis of the compression spring33. One end of the compression spring33is fixed to the holding part29a, while the other end is only placed on the holding member32. On account of the compression spring33, the holding member32is biased in a direction away from the holding part29a, that is, in a direction (toward Z′) where the attitude control legs11goes away from the holding part29athrough the screw shaft31.

In addition, the screw shaft31passes through a frame-shaped lock member34between the holding members29aand29b. The lock member34is connected to the release button8by a connection shaft35passing through a through hole of a holding member37fixed to the equipment body2. The lock member34, the connection shaft35, and the release button8are disposed in the Y–Y′ direction and attached together so that they can travel in the Y–Y′ direction together. The connection shaft35is supported by a bearing, not shown, and thereby, the positional relation, in the vertical direction (the Z–Z′ direction) between the lock member34and the holding parts29aand29b, is fixed. In addition, a compression spring36is attached between the release button8and the holding member37so that the connection shaft35passes through the compression spring. So, the release button8is biased toward Y direction in which the button tends go away from the holding member37.

An engagement part34ais provided on an inner surface of the frame-shaped lock member34opposite to an attached part of the connection shaft35. On account of an urging force of the compression spring36, the lock member34, the connection shaft35, and the release button8are biased in the maximum traveled state toward the Y direction. At this time, the engagement part34aof the lock member34engages with a root between threads of the screw shaft31, to make the shaft fixed with respect to the body fixing part29. Thereby, the attitude control legs11are kept locked with respect to the liquid crystal projector1. In addition, as shown inFIG. 4, the release button8is protruded from the side surface2cof the equipment body2.

When the release button8is pushed with the attitude control legs11being locked, the connection shaft35and the lock member34travel against the force exerted by the compression spring36toward the Y′ direction opposite to the Y direction, and the engagement part34aare disengaged from the screw shaft31. Thereby, the holding member32is pushed by the force applied by the compression spring33, and the screw shaft31, and therefore, the attitude control legs11travel toward the Z′ direction in which the attitude control legs11go away from the holding member29b. Thereby, as shown inFIG. 2, the attitude control legs11protrude from the bottom surface of the liquid crystal projector1.

When the liquid crystal projector1is placed on a table etc. to fix the vertical position of the attitude control legs11and then a front surface side of the liquid crystal projector1is pushed toward the Z′ direction from the upper side with the release button8pushed (accordingly, with the lock, of the screw shaft31by the lock member34, released), the front surface side of the liquid crystal projector1is lowered toward the Z′ direction and the body fixing part29and the holding member37fixed to the equipment body2also are lowered toward the Z′ direction and at the same time, the lock member34, the connection shaft35, the compression spring36, and the release button8also are lowered. In addition, as the body fixing part29is lowered, the compression spring33is compressed to the holding member32fixed to the screw shaft31by the holding part29a. When the pushing of the release button8is released, the engagement part34aengages with a root of the screw shaft31, and the height of the front surface side of the liquid crystal projector1is set to new height such determined.

In addition, when the liquid crystal projector1is in such pushed state, the compression spring33is in a compressed state, because the height of the holding member32is kept constant. Thereby, when the release button8is pushed in such situation, the engagement part34aof the lock member34is disengaged from the root of the screw shaft31. Therefore, the lock by the lock member34is released, and the body fixing part29etc., and therefore the front surface side of the liquid crystal projector1is raised toward the Z direction by the biasing force of the compression spring33.

In this manner, the height of the front surface side of the liquid crystal projector1can be adjusted, by operating the release button8and pushing the front surface side of the liquid crystal projector1onto the mounting plane5. In addition, as shown inFIG. 2, since the attitude control legs11provided on both sides of width direction of the front surface side of the bottom of the liquid crystal projector1are provided with respective release buttons8, as shown inFIG. 4, they can be independently adjusted in the protruding height, from the bottom of the liquid crystal projector1, respectively. Accordingly, as shown inFIG. 10, the front surface height of the liquid crystal projector1can be adjusted, by a user operation in which the release button8is operated and the front surface side of the liquid crystal projector1is pushed onto a mounting plane38with the front surface side of the liquid crystal projector1being held. As shown inFIG. 11, inclination with respect to the mounting plane38in the longitudinal direction of the liquid crystal projector1can be appropriately set. In addition, as shown inFIGS. 12(a) and12(b), even if the mounting plane38of the liquid crystal projector1is inclined in the width direction of the liquid crystal projector1, the attitude of the attitude control legs11in the width direction can be adjusted horizontally by adjusting the protruded height of the individual attitude control legs11from the liquid crystal projector1.

FIG. 13is a perspective view showing a second embodiment of a liquid crystal projector according to the present invention.FIG. 13(a) shows the used state, andFIG. 13(a) shows the not used state. Reference number3ddenotes a front surface of the case3,3eside surfaces of the case3,39a notch,39aan upper side,40a fitting part,40aa front end surface, and40ba top end surface. Parts corresponding to the parts shown in the preceding drawings are designated by the same reference numbers, eliminating duplicated descriptions.

A part of the case3from the front surface3dby a prescribed length R, and from a lower portion (lower half, for example) of one side surface3eto a lower portion of the other side surface3ethrough the bottom surface is cut away and with this, notches39with length R and height h are formed on the side surfaces3e. In addition, the equipment body2is provided with a fitting part40, with the length R and the height h, from the front surface2a. The fitting part40has a shape which extends from the one side surface2cof the equipment body2to the other side surface2cthrough the bottom surface, and the front end40aof the fitting part40is substantially flush with the front surface2aof the equipment body2.

The side surface portions of the fitting part40fixed to the side surfaces2cof the equipment body2are fitted into the notches39of the side surfaces3eof the case3. As the equipment body2travels with respect to the case3, the upper ends40bof the fitting part40slide on the upper side surfaces39aof the notches39. In addition, as shown inFIG. 13(a), when the equipment body2is pulled out of the case3, and the front surface side of the equipment body2protrudes from the front surface3dof the case3(that is, in the used state of the liquid crystal projector1), the notches39of the case3are opened. However, as shown inFIG. 13(b), when the equipment body2is retracted into the case3, and the front surface2aof the equipment body2is substantially flush with the front surface3dof the case3(that is, in the not used state of the liquid crystal projector1), the notches39of the case3are closed by the fitting part40of the equipment body2. Therefore, the fitting part40functions as a part of the case with respect to the equipment body2.

In this liquid crystal projector1, an air inlet port, not shown, is provided at a position of the bottom surface of the equipment body2corresponding to the air inlet port16bshown inFIG. 7. When the liquid crystal projector1is in the not used state and the notches39of the case3are closed by the fitting part40of the equipment body2shown inFIG. 13(b), the air inlet port is positioned on the deeper side than the position of the notches39of the case3, thereby, closed by the bottom surface of the case3. In contrast, when the liquid crystal projector1is in the used state shown inFIG. 13(a), the air inlet port on the bottom surface of the equipment body2is pulled out to the position of the notches40of the case3, thereby opening the notches40resulting in the air inlet port being opened.

Thus, also in the second embodiment, the air inlet port provided on the bottom surface of the equipment body2is opened in the used state and closed by the case3in the not used state. In addition, since the other structure is the same as the first embodiment, the same advantage is also obtained in the second embodiment.

FIG. 14is a perspective view showing a third embodiment of a liquid crystal projector1according to the present invention. Reference number41denotes a case part. Parts corresponding to the parts shown in the preceding drawings are designated by the same reference numbers, eliminating duplicated descriptions.

In the third embodiment, compared with the first embodiment shown inFIG. 1, the projection lens4is disposed on the side surface2cof the equipment body2, and a case part41, with equal thickness and width to the case3, is provided on the front surface side of the equipment body2.

The state illustrated inFIG. 14is the used state of the liquid crystal projector1. By pushing the case3toward the case part41(that is, toward the direction of arrow A), the equipment body2is pushed into the case3, and closed by the case3and the case part41with the case3abutting against the case part41. This state is the not used state.

In addition, pulling the case3with respect to the case part41in the direction of arrow B in this not used state, the equipment body2is pulled out from the case3, and brought into the used state shown inFIG. 14. The top surface2bprotruded from the case3of the equipment body2, is provided with the operation key, the lens knob, and so on shown inFIG. 1(a), and the top surface of the case part41is provided with the start button5.

Since the other structure is the same as the first embodiment, the same advantage is obtained also in the third embodiment.

FIG. 15is a perspective view showing a fourth embodiment of a liquid crystal projector according to the present invention. Reference number42denotes a duct and reference number43denotes exhaust ventilation holes. Also, similar toFIG. 8, reference number1adenotes the front surface of the liquid crystal projector1,1bthe top surface, and1cside surfaces. Parts corresponding to the parts shown in the preceding drawings are designated by the same reference numbers.

The fourth embodiment is not similar to the first to third embodiments comprising a case and an equipment body, but has one housing in which provided is means for enlarging the distance between a contained ventilation fan and the exhaust ventilation holes (hereinafter, referred to as distance enlarging means).

The fourth embodiment shown inFIG. 15(a) has the distance enlarging means comprising a duct42on the top surface1bof the housing of the liquid crystal projector1. An opening of the duct42faces the front surface side of the housing of the liquid crystal projector1, and the top surface42aof the duct42is inclined so that it is lowered as it goes away from the front surface1aof the housing. An opening is provided on a rear side of the top surface1bof the housing of the liquid crystal projector1, and communicates with the duct42. Therefore, the distance from the ventilation fan (not shown) to the exhaust ventilation holes43is longer than the above-described embodiments by the distance from the opening to the exhaust ventilation holes43.

The duct42may be fixed onto the top surface1bof the housing, however, when the liquid crystal projector1is in the not used state, it can be designed to be pushed into the housing. When the liquid crystal projector1is pushed into the housing, the top surface42aof the duct42is flush with the top surface1bof the housing. In addition, when the liquid crystal projector1is in the not used state, it is brought into service by operating a start button, not shown. With this operation, the duct42protrudes from the housing to form a exhaust ventilation path, as shown.

FIG. 15(b) shows a modification of the fourth embodiment in which the distance enlarging means comprising the duct is provided on the side surface1dof the liquid crystal projector1, and the structure is the same as that shown inFIG. 15(a).

According to the fourth embodiment, since the distance between the ventilation fan and the exhaust ventilation holes43can be comparatively long with the size kept small in the used state as well as in the not used state and the exhaust ventilation holes43can be disposed on the screen side, the noise can be reduced effectively. In addition, by the configuration in which the duct42can be pushed into the housing, the intrusion of moisture or dust can be prevented in the not used state.

Further, by providing the inside of the duct42with sound arresting material, the noise is further reduced.

FIG. 16is a perspective view showing a fifth embodiment of a liquid crystal projector according to the present invention. Reference number44denotes a support leg and reference number45denotes an opening. Parts corresponding to the parts shown in the preceding drawings are designated by the same reference numbers.

The above-described embodiments are ones used with the projector placed horizontally on the mounting plane such as a table. In the first to the third embodiments in which the projector comprises the equipment body2and the case3, the case3travels with respect to the equipment body2in parallel with the mounting plane. However, in the fifth embodiment, the projector is used with the projector placed vertically.

The projector1comprising the equipment body2and the case3is used with itself placed vertically on a table plane etc., not shown. The equipment body2is provided with a support leg44on a bottom surface and the support leg44is placed on the mounting plane, not shown. When the liquid crystal projector1is not used, the whole of equipment body2except the support leg44is retracted into the case3. When the projector1is placed on the mounting plane and a start button, not shown, provided on the top surface3bor on the side surface3eof the case3, is operated, the case3is raised with respect to the equipment body2by a prescribed distance (arrow E direction). When the case3is raised by the prescribed distance, it is locked to the equipment body2, and the liquid crystal projector1is brought into the used state. In addition, in the used state, when the case3is pushed from the upper side, the lock is released and the case3is lowered in the direction of arrow E′. When the whole of equipment body2except the support leg44is retracted into the case3, the case3becomes locked to the equipment body2. This is the not used state of the liquid crystal projector1.

An opening45is provided in the front surface3aof the case3at an upper location. When the liquid crystal projector1is in the used state, a central axis of the opening45aligns with an optical axis of the projection lens (not shown) provided on the equipment body2and an image can be magnified and projected to a screen (not shown) through the opening45. In addition, operation means such as the operation key6, and the lens knob7, shown inFIG. 1, are provided on the top surface3bor on the side surface3eof the case3, not shown.

In addition, there is provided an air intake port, not shown, on a portion adjacent to the support leg44and exposed from the case3in the used state of the equipment body2. There is provided exhaust ventilation holes, not shown, on the top surface3b, or an upper portion of the side surfaces3eof the case3. Though, air exhaust holes are provided on the top surface (inside the case3) of the equipment body2, the air exhaust holes do not face the exhaust ventilation holes provided on the case3. When the liquid crystal projector1is not used, the air intake port is closed by the case3, and the exhaust ventilation holes are also closed by the top surface (not shown) of the equipment body2. When the liquid crystal projector1is used, the air intake holes are opened and the exhaust ventilation holes, provided on the case3, further depart from the air exhaust holes of the equipment body2, by the distance that the case3is raised in the direction of arrow E.

Thus, also in the fifth embodiment, similar to each of the above-described embodiments, when the projector is not used, it can be made small and the intrusion of moisture or dust etc. from the air intake holes or the air exhaust holes can be prevented. When the projector is used, the noise from the exhaust ventilation holes can be reduced.

With regard to the air intake holes, by providing intake ventilation holes on the lower portion of the front surface3aof the case3and by providing the air intake holes on the front surface of the equipment body2so that the air intake holes align with the intake ventilation holes in the used state, when the liquid crystal projector1is not used, the air intake holes can be closed by the case. In addition, even in the used state, since the air intake holes faces the screen, the effect of noise emitted from them can be reduced.