Projector

A projector includes a light source, an optical modulation device to form an optical image, a projection optical device, and a projection position adjusting device to adjust the projection position. The projection position adjusting device includes a fixed member, a moving member a dial knob, a drive mechanism that transmit rotation of the dial knob, and a reference position detecting mechanism. The reference position detecting mechanism includes a spiral rail guiding section having a groove shape provided to a side face of the dial knob adjacent to the fixed member, along the rotational direction of the dial knob, a sliding section that slides in the guiding section with the rotation of the dial knob, and an engaging section provided to the guiding section, and engages with the sliding section upon the projection position of the projection optical device reaching the projection reference position.

BACKGROUND

1. Technical Field

The present invention relates to a projector.

2. Related Art

In the past, a projector provided with a light source lamp, a liquid crystal panel for modulating light beam emitted from the light source lamp in accordance with image information, and a projection lens in an enlarged manner for projecting the modulated light beam to the outside has been known.

When using a projector, there are some cases in which the projected image needs to be displayed shifted in a vertical or a horizontal direction on the screen while keeping the setting posture of the projector. In accordance with such a need, a projector equipped with a projection position adjusting device has been provided (for example, refer to JP-A-2004-205686). The projection position adjusting device is a device capable of moving the projection lens along a plane perpendicular to the projection direction. The projector equipped with such a projection position adjusting device cam display the projection image shifted in a vertical or a horizontal direction on the screen.

Specifically, the projection position adjusting device is provided with a dial knob exposed from a housing of the projector, and drives the projection lens utilizing the rotational operation of the dial knob.

When the dial knob is turned in one direction by a user, the projection position adjusting device moves the projection lens to the left, for example, along the plane perpendicular to the projection direction. Then, the projected image also moves on the screen to the left. When the dial knob is turned in the opposite direction by a user, the projection position adjusting device moves the projection lens to the right along the plane perpendicular to the projection direction. Then, the projected image also moves on the screen to the right.

As described above, the projection lens reciprocates on a moving path perpendicular to the projection direction in accordance with the rotational direction of the dial knob.

However, in the projector described in JP-A-2004-205686, the user might lose a certain projection reference position in the moving path such as the center point of the moving path while adjusting the projection position of the projector by rotating the dial knob.

SUMMARY

An advantage of the invention is to provide a projector with preferable operability.

In order to gain the advantage, a projector according to an aspect of the invention includes a light source, an optical modulation device that modulates light beam emitted from the light source in accordance with image information to form an optical image, a projection optical device that projects the optical image formed by the optical modulation device in an enlarged manner, a projection position adjusting device that moves the projection optical device in a plane perpendicular to a projection direction to adjust the projection position of the projection optical device, wherein, the projection position adjusting device includes a fixed member fixed to the projector, a moving member capable of moving along the plane perpendicular to the projection direction with respect to the fixed member, a dial knob supported rotatably with respect to the fixed member and operable by a user, a drive mechanism that is engaged with the moving member and the dial knob, and transmits rotation of the dial knob to the moving member to move the moving member, a reference position detecting mechanism that is disposed between the fixed member and the dial knob, and detects a projection reference position of the projection optical device, the reference position detecting mechanism including a guiding section provided to a side face of the dial knob adjacent to the fixed member, along the rotational direction of the dial knob, and shaped like a groove, a sliding section that is provided to the fixed member, and slides in the guiding section in accordance with the rotation of the dial knob, and an engaging section that is provided to the guiding section, and engages with the sliding section in the case in which the projection position of the projection optical device reaches the projection reference position.

Here, as the projection reference position, for example, the center position of the adjustable range of the projection position, namely, the moving path of the projection optical device in a plane perpendicular to the projection direction can be cited.

According to this aspect of the invention, the user adjusts the projection position of the projector while rotating the dial knob by hand. Then, in the projection position adjusting device of the projector, the moving member is moved in accordance with the rotation of the dial knob, and the projection optical device supported by the moving member is moved along the moving path in a plane perpendicular to the projection direction. In this case, in the reference position detecting mechanism, sliding section slides along the guiding section in accordance with the rotation of the dial knob.

When the projection position of the projection optical device eventually reaches the projection reference position, the sliding section engages with the engaging section in the guiding section of the reference position detecting mechanism. And, if the dial knob is continued to be rotated, the engagement between the sliding section and the engaging section is released, and the sliding section slides again in the guiding section in accordance with the rotation of the dial knob. In this case, the engagement and release between the sliding section and the engaging section causes the dial knob a slight vibration and click sound. The user who is rotating the dial knob can feel the vibration by hand.

Thus, while a user is adjusting the projection position turning the dial knob, the user can recognize the projection position when the vibration of the dial knob or the click sound is felt as the reference position. Therefore, according to the projector of this aspect of the invention, it is possible to notice the user that the projection position reaches the reference position in adjusting the projection position, with relatively simple configuration and in a manner easy-to-understand to the user.

In the projector according to another aspect of the invention, the engaging section is preferably a recessed section provided to the bottom of the guiding section, and the sliding section preferably slides in accordance with the rotation of the dial knob while pressing the bottom of the guiding section and engages with the engaging section in the case in which the projection position of the projection optical device reaches the projection reference position.

According to this aspect of the invention, the sliding section pressing the bottom of the guiding section moves in the pressing direction to engage with the engaging section as a recessed section formed on the bottom of the guiding section. Thus, the vibration caused on the dial knob by the engagement becomes clear. Therefore, the user can clearly feel the vibration of the dial knob, and can clearly recognize that the projection position reaches the reference position.

Further, the engaging section, which is a recess section of the bottom of the guiding section, can easily be formed. Further, according the pressing force, the configuration of the sliding section to be engaged with the recessed section can also be simplified.

In the projector according to another aspect of the invention, the guiding section preferably has a spiral shape along the rotational direction of the dial knob, and the sliding section is preferably attached to the fixed member movably in a direction perpendicular to the rotational axis of the dial knob.

In the projection position adjusting device having a relatively large moving range of the moving member, the dial knob is rotated plural revolutions to move the moving member in one direction. However, if the projection reference position is unique in the moving path, for example, the projection reference position is the center of the moving path of the projection optical device, it is preferable that the engagement and release between the sliding section and the engaging section occurs only once in the one way rotation of the dial knob.

Here, according to this aspect of the invention, the sliding section slides in the guiding section having the spiral shape, and reciprocates on the fixed member in the direction perpendicular to the rotational axis direction according to the position in the spiral. Therefore, in the rotation of the dial knob in one way, the sliding section never slides on the same position of the guiding section more than once.

Namely, if the engaging section formed in the guiding section is unique, in the one-way rotation of the dial knob, engagement and its release between the sliding section and the engaging section occur only once. Therefore, this aspect of the invention can applied to a projector having a projection position adjusting device with large movement range of the moving member.

In the projector according to another aspect of the invention, the sliding section preferably includes a sliding body including a sliding head that engages with the engaging section, and a base section that is attached to the fixed member, and supports the sliding body so that the sliding head swings according to the rotational direction of the dial knob.

In this case, a configuration can be adopted in which, as the drive mechanism, for example, a plurality of gears meshed with each other are provided, and these gears are driven in accordance with the rotation of the dial knob to move the moving member.

However, when the dial knob is rotated in the inverse direction from the direction in which the dial knob has been rotated, the backlash in accordance with the engagement gap between the gears is caused, and an error that the position of engagement between the sliding section and the engaging section is shifted from the projection reference position might be caused in the reference position detecting mechanism.

In response, according to this aspect of the invention, the sliding body is supported by the base section so that the sliding body can swing in the rotational direction of the dial knob, and therefore, if the dial knob is rotated, the sliding body swings in the rotational direction around the base section with the help of friction caused between the sliding head and the guiding section. By making the displacement of the sliding head in the rotational direction caused by the swinging operation correspond to the backlash of the gears, while the gap is caused in the mesh of the gears, it is possible to prevent the sliding head from sliding along the guiding section. Therefore, the projector according to the invention can reduce the error in detecting the reference position which is caused by the backlash of the gears.

In the projector according to another aspect of the invention, the base section is provided with a pair of projections projected towards the sliding body at positions symmetrical with the rotational direction of the dial knob with respect to the sliding head in the condition in which the base section supports the sliding body, and the sliding body is preferably provided with a pair of insertion holes to which the pair of projections are respectively inserted.

In the projector according to this aspect of the invention, in the sliding section, a pair of insertion holes in the sliding body and a pair of projections in the base section are formed at positions symmetrical in the rotational direction, and the projections are respectively inserted in the insertion holes. Accordingly, if the sliding body is caused to swing in the direction perpendicular to the rotational direction of the dial knob, the edge of the insertion hole engages with the projection, and therefore, swinging movement of the sliding body in the direction perpendicular to the rotational direction of the dial knob is prevented. Therefore, according to this aspect of the invention, jerky movement of the sliding body in the direction perpendicular to the rotational direction of the dial knob with respect to the base section can be prevented.

In the projector according to another aspect of the invention, the guiding section is preferably provided with a rotation stopper, which engages with the sliding section to stop rotation of the dial knob, at a position corresponding to a moving termination position of the moving member.

According to this aspect of the invention, in the projection position adjusting device, when the moving member is moved by the drive mechanism to the moving termination position, sliding section is abutted by the rotation stopper in the reference position detecting mechanism. Since the sliding section is abutted on the rotation stopper, the dial knob becomes impossible to be rotated any further. Namely, according to the projector of this aspect of the invention, when the moving member reaches the moving termination position, the rotation of the dial knob is restricted.

Therefore, in the projector according to this aspect of the invention, it can be prevented that load is applied to various members in the projection position adjusting device when the dial knob is further rotated after the moving member reaches the moving termination position.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

An embodiment of the invention will hereinafter be explained with reference to the accompanying drawings.

1. External Configuration

FIGS. 1 and 2are the perspective views showing the external appearance of a projector1. Specifically,FIG. 1is the perspective view showing the projector1viewed from an upper front side thereof.FIG. 2is the perspective view of the projector1viewed from an upper rear side thereof.

The projector1is for forming an optical image by modulating an optical beam emitted from the light source in accordance with image information, and projecting the formed optical image on a screen (not shown) in an enlarged manner. As shown inFIG. 1or2, the projector1is provided with a substantially cuboid shaped exterior chassis2, and a projection lens3as the projection optical device exposed from the exterior chassis2.

The projection lens3is configured as a set of lenses composed of a plurality of lenses housed in a cylindrical body tube, and performs enlarged projection of the image light modulated by a main body of the projector1in accordance with the image information.

The exterior chassis2is made of synthetic resin, and houses the main body of the projector1. As shown inFIG. 1or2, the exterior chassis2is provided with an upper case21covering the upper part of the main body of the device, a lower case22covering the lower part of the main body of the device, and a front case23(seeFIG. 1) covering the front face of the main body of the device.

The upper case21is, as shown inFIG. 1or2, composed of a top face section21A, side face sections21B (seeFIG. 2),21C (seeFIG. 1), a back face section21D (seeFIG. 2), and a front face section21E (seeFIG. 1) forming the top face, a part of the side face, a part of the back face, and a part of the front face of the exterior chassis2, respectively.

The top face section21A has, as shown inFIG. 1or2, a substantially rectangular shape in the plan view, and smoothly curves from substantially the center section thereof to the front face side, side face sides, and the back face side, thus forming a convex curve shape.

In a front right area of the top face section21A viewed from the front side thereof, there are formed two opening sections21A1,21A2as shown inFIG. 1or2. And, the two opening sections21A1,21A2each expose a part of respective one of dial knobs861,871capable of operating the projection lens3for performing projection position adjustment of a projection image projected on the screen (not shown).

Specifically, as shown inFIG. 1, the opening section21A1on the front side of the top face and right in the front view from the front exposes the dial knob861forming a projection position adjusting device8(seeFIGS. 6 and 7) described later. The opening section21A2positioned left in view from the front exposes the dial knob871similarly forming the projection position adjusting device8.

As shown inFIG. 1or2, when the dial knob861out of the two dial knobs861,871is turned in the Y1direction (towards the front side), the projection lens3moves in the −Y direction (downward), and when the dial knob861is turned in the Y2direction (towards the back side), the projection lens3moves in the +Y direction (upward). Further, when the dial knob871is turned in the X1direction (to the right viewed from the back side of the projector1), the projection lens3moves in the −X direction (to the right), and when the dial knob871is turned in the X2direction (to the left viewed from the back side of the projector1), the projection lens3moves in the +X direction (to the left).

It should be noted that the detailed structure of the projection position adjusting device8will be described later.

Further, as shown inFIG. 1or2, in a rear side of the openings21A1of the top face section21A, there is provided an operation panel24for performing start-up and adjustment operations of the projector1extending in a longitudinal direction. When operation buttons241of the operation panel24are properly pushed down, they contact tactile switches mounted on a circuit board (not shown) disposed inner than the operation buttons241, thereby making desired operations possible. Further, a light emitting diode (LED, not shown) is attached to the circuit board, and is arranged to emit light in accordance with a predetermined operation.

It should be noted that the circuit board of the operation panel24is electrically connected to a control board (not shown), and operation signals caused by pushing down the operation buttons241are output to the control board.

The side face sections21B,21C, the back face section21D, and the front face section21E are sections substantially hanging from respective edges of the rectangular shape in the plan view of the top face section21A as shown inFIG. 1or2.

In the back face section21D among these sections, in the left side area thereof viewed from the back face side, there is formed a notch21D1shaped like a bracket in the plan view from the lower edge towards the upper side as shown inFIG. 2.

Further, in the front face section21E, as shown inFIG. 1, there is formed a notch21E1shaped like a bracket in the plan view from the lower edge towards the upper side.

The lower case22is, as shown inFIG. 1or2, composed of a bottom face section22A, side face sections22B (seeFIG. 2),22C (seeFIG. 1), a back face section22D (seeFIG. 2), and a front face section22E (seeFIG. 1) forming the bottom face, a part of the side face, a part of the back face, and a part of the front face of the exterior chassis2, respectively.

The bottom face section22A, although not shown specifically in the drawings, is composed of a substantially rectangular flat face. And, the bottom face section22A is provided with a plurality of foot sections for grounding on a grounding face such as a desk, and an air intake for leading the cooling air into the projector1from the outside.

The side face sections22B,22C, the back face section22D, and the front face section22E are sections standing from respective edges of the rectangular shape in the plan view of the bottom face section22A as shown inFIG. 1or2.

In the back face section22D among these sections, in the left side area thereof viewed from the back face side, there is formed a notch22D1shaped like a bracket in the plan view from the upper edge towards the lower side as shown inFIG. 2. And, the notches21D1,22D1are connected to each other to form an opening section25in the condition in which the upper case21and the lower case22are combined with each other. In the opening section25, as shown inFIG. 2, there is fitted to be fixed a connecting terminal installing section26having an outline shape corresponding to the shape of the opening section25.

The connecting terminal installing section26, as shown inFIG. 2, hollows inward from the end faces of the back face sections21D,22D to form a cross-sectional shape of a substantially bracket shape, and provided with a plurality of holes261formed therein. And, as shown inFIG. 2, a plurality of connecting terminals27for inputting an image signal, an audio signal, and so on from external electronic equipment are exposed through the plurality of holes261. Further, inside the connecting terminal installing section26, there is disposed an interface board (not shown) for processing the signals input from the connecting terminals27.

It should be noted that the interface board is electrically connected to a control board (not shown), and the signals processed in the interface board are output to the control board.

Further, in the back face section22D, under the notch22D1, there are formed two opening sections22D2,22D3as shown inFIG. 2. And, as shown inFIG. 2, an inlet connector28is exposed through the opening section22D2located left in a back side view, making it possible to supply the main body of the projector1with electricity from the outside. Further, as shown inFIG. 2, a power switch29is exposed through the opening section22D3located right in the back side view, and by switching the power switch29, it becomes possible to switch ON or OFF the main power of the projector1.

It should be noted that the power switch29is electrically connected to the control board (not shown), and an operation signal caused by switching of the power switch29is output to the control board.

Further, in the front face section22E, as shown inFIG. 1, there is formed a notch22E1shaped like a bracket in the plan view from the upper edge towards the lower side. And, the front case23is fixedly supported by an inner section of the bracket-shaped notch21E1of the front face section21E and an inner section of the bracket-shaped notch22E1of the front face section22E in the condition in which the upper case21and the lower case22are combined.

The front case23, as shown inFIG. 1, has a substantially oval shape elongated in a horizontal direction, and closes up the opening section formed of the notches21E1,22E1when the upper case21and the lower case22are connected to each other.

In the right area of the front case23in the front view, as shown inFIG. 1, there is formed a concave hollowing towards the inside of the exterior chassis2and having substantially circular opening231at the bottom thereof. And, the opening231exposes a tip portion of the projection lens3.

Further, in the front case23, at substantially the central section in the longitudinal direction, there is formed a sensor window232for remote control, as shown inFIG. 1. And further, on the inner side of the sensor window232for the remote control, there is disposed a remote control sensor module (not shown) for receiving an operation signal from a remote controller (not shown).

It should be noted that the remote controller is provided with similar things to the start-up switch, the adjusting switch, and so on provided to the operation panel24described above. And, when the remote controller is operated, an infrared signal is output from the remote controller, and the infrared signal is received by the sensor module for remote control via the sensor window232for remote control, and then processed by the control board (not shown).

Further, in the front case23, in the left area in the front view, there is formed an air outlet233having a substantially rectangular shape in the plan view for discharging air heated inside the projector1to the outside as shown inFIG. 1.

Further, the periphery section of the air outlet233is formed to have a tubular shape protruding towards the inside as shown inFIG. 1. More specifically, the periphery section of the air outlet233is formed to have a tubular shape protruded towards a direction coming close to the projection lens3at a predetermined angle with the projection direction of the projection lens3. And, in the inside of the tubular shape section of the air outlet233, there are formed a plurality of louver boards233A each built from the top to the bottom thereof and extended in the direction of the protrusion of the periphery section of the air outlet233as shown inFIG. 1.

2. Internal Configuration

FIGS. 3 and 4are the views showing the internal configuration of the projector1. Specifically,FIG. 3is a perspective view of the condition with the upper case21and the control board removed therefrom viewed from the upper front side thereof.FIG. 4is a perspective view of the condition with the upper case21and the control board removed therefrom viewed from the upper back side thereof.

Inside the exterior chassis2, there is housed a main body of the projector1as shown inFIG. 3or4. The main body of the device is composed of an optical unit4as an image projection unit, a power supply unit5, a cooling unit6, and so on.

It should be noted that, although not shown in the drawings, the main body of the device is provided with the control board disposed above the optical unit4and for controlling the projector1as a whole, besides the optical unit4, the power supply unit5, and the cooling unit6.

3. Detailed Configuration of Optical Unit

FIG. 5is a plan view schematically showing the optical system of the optical unit4.

The optical unit4forms an image light beam in accordance with image information under control of the control board. The optical unit4has an L-shape in the plan view extending in a lateral direction along the back face sections22D and extending towards the front along the side face section22B inside the exterior chassis2as shown inFIG. 3or4.

The optical unit4is provided with an integrator illuminating optical system41, a color separator optical system42, a relay optical system43, an electro-optic device44, and an optical component chassis45made of synthetic resin for housing these optical components41through44and for fixedly supporting the projection lens3at a predetermined position as shown inFIG. 5.

The integrator illuminating optical system41is an optical system for substantially equally illuminating an image forming area of each of liquid crystal panels described below forming the electro-optical device44. The integrator illuminating optical system41is provided with a light source device411, a first lens array412, a second lens array413, a polarization converter414, and an overlapping lens415as shown inFIG. 5.

The light source device411is provided with a light source lamp411A as a light source for emitting radial light beams, a reflector411B for reflecting the radial light beams emitted from the light source lamp411A, and a lamp housing411C (seeFIGS. 3 through 5). As the light source lamp411A, a halogen lamp, a metal halide lamp, or a high-pressure mercury vapor lamp is often used. As a reflector411B, a parabolic mirror is used. It should be noted that, besides the parabolic mirror, an ellipsoidal mirror can be used together with a concave collimation lens.

The lamp housing411C is for accommodating the light source lamp411A and the reflector411B inside thereof, and is fixed to the bottom section of the lower case22and connected to the optical components chassis45.

The first lens array412has a configuration in which small lenses each having a substantially rectangular outline viewed in the optical axis direction are arranged in a matrix. The small lenses divide the beam emitted from the light source lamp411A into a plurality of partial light beams.

The second lens array413has substantially the same configuration as the first lens array412, namely the configuration having small lenses arranged in a matrix. The second lens array413, in conjunction with the overlapping lens415, has a function of focusing the image of the small lenses of the first lens array412on the liquid crystal panel described below.

The polarization converter414is disposed posterior to the second lens array in the optical path. Such a polarization converter414is for converting the light from the second lens array413into a substantially single polarized light beam, and thus enhancing the light efficiency in the electro-optic device44.

Specifically, each of the partial light beams converted into a substantially single polarized light beam by the polarization converter414is finally overlapped substantially on each of the liquid crystal panels of the electro-optic device44described later by the overlapping lens415. In the projector1of the present embodiment using a type of the liquid crystal panel of converting polarized light beams, since only a single polarized light beam is available, almost a half of the light beam from the light source lamp411A emitting other random polarized light beams is not available. Therefore, by using the polarization converter414, almost whole of the light beam emitted from the light source lamp411A is converted into a single polarized light beam, thereby enhancing light efficiency in the electro-optic device44.

The color separator optical system42is provided with two dichroic mirrors421,422and a reflecting mirror423, and has a function of separating the plurality of partial light beams emitted from the integrator illuminating optical system41into three colored light beams of red, green, and blue by the dichroic mirrors421,422.

The relay optical system43is provided with an entrance lens431, a relay lens433, and reflecting mirrors432,434, and has a function of guiding the colored light beams separated by the color separator optical system42to the liquid crystal panel for the blue light beam.

In this case, the dichroic mirror421of the color separator optical system42transmits the blue light component and the green light component of the light beam emitted from the integrator illuminating optical system41, and reflects the red light component thereof. The red light beam reflected by the dichroic mirror421is further reflected by the reflecting mirror423and reaches the liquid crystal panel for the red light beam through a field lens417. The field lens417converts each of the partial light beams emitted from the second lens array413into a light beam parallel to the center axis (principal ray). The same applies to other field lenses417each provided to the light entrance side of the respective liquid crystal panels for green light and blue light.

Out of the blue light beam and the green light beam transmitted through the dichroic mirror421, the green light beam is reflected by the dichroic mirror422, and reaches the liquid crystal panel for the green light beam through the field lens417. Meanwhile the blue light beam is transmitted through the dichroic mirror422, passes through the relay optical system43, and then reaches the liquid crystal panel for the blue light beam through the field lens417. It should be noted that the relay optical system43is used for the blue light beam for preventing degradation of light efficiency caused by the diffusion of the blue light beam, which has the optical path longer than the optical paths of other colored light beams. Namely, it is provided for transmitting the partial light beams entering the entrance lens431directly to the field lens417. It should be noted that, although it is configured that the blue light beam out of the three colored light beams is transmitted in the relay optical system43, the configuration is not limited thereto, and it can also be configured that the red light beam is transmitted therein, for example.

The electro-optic device44is provided with three liquid crystal panels441(assuming that a liquid crystal panel for the red light beam is denoted with441R, a liquid crystal panel for the green light beam is denoted with441G, and a liquid crystal panel for the blue light beam is denoted with441B) forming an optical modulation device, polarization plates442, field angle correction plates444, and a cross dichroic prism443.

The liquid crystal panel441uses, for example, polysilicon thin film transistors (TFT) as switching elements, and each of the colored light beams separated off by the color separator optical system42is modulated by respective one of the three liquid crystal panels441and polarization plates442disposed on both entrance and exit sides of the liquid crystal panel, respectively, in accordance with the image information to form the optical image.

The polarization plate442is provided with an entrance polarization plate442A and an exit polarization plate442B disposed on anterior and posterior of the liquid crystal panel441, respectively, in the optical path.

The entrance polarization plate442A is for transmitting only a polarized light beam with a predetermined polarizing direction out of each of the colored light beams separated off by the color separator optical system42and absorbing other light beams, and is composed of a substrate made of quartz crystal, sapphire, or the like with a polarization film attached thereto. And, the entrance polarization plate442A is disposed so that the position of the entrance polarization plate can be adjusted with respect to a predetermined illuminating optical axis defined inside the optical component chassis45by a position adjusting mechanism described later forming the optical component chassis45.

The exit polarization plate442B is also configured similarly to the entrance polarization plate442A, and is for transmitting only the polarized light beam with the predetermined polarizing direction out of the light beams emitted from the liquid crystal panel441and absorbing other light beams. Further, it can be realized by attaching the polarization film to the cross dichroic prism443without using the substrate, or by attaching the substrate to the cross dichroic prism443.

The entrance polarization plate442A and the exit polarization plate442B are arranged to have polarization axes, respectively, whose directions are perpendicular to each other.

The field angle correction plate444is provided with an optical conversion film formed on the substrate and having a function of correcting the field angle of the optical image formed by the liquid crystal panel441. By disposing such a field angle correction plate444as described above, light leakage on the black screen can be reduced, thus the contrast of the projected image can dramatically be improved. And, similarly to the entrance polarization plate442A, the field angle correction plate444is disposed so that the position of the field angle correction plate can be adjusted with respect to a predetermined illuminating optical axis defined inside the optical component chassis45by a position adjusting mechanism described later forming the optical component chassis45.

The cross dichroic prism443is for combining images each modulated for corresponding colored light beam emitted from respective one of the three liquid crystal panels441to form a color image. It should be noted that the cross dichroic prism443is composed of a dielectric multilayer film for reflecting red light and a dielectric multilayer film for reflecting blue light formed along the boundary faces of four rectangular prisms to form a substantially X shape, and the three colored light beams are combined by these dielectric multilayer films.

The optical systems41through44as described above are housed inside the optical component chassis45.

As shown inFIGS. 3 through 5, the illuminating optical axis A (seeFIG. 5) of the light beam emitted from the light source device411is defined inside the optical component chassis45, and the optical component chassis45is composed of a component housing member451(seeFIGS. 3 and 5) shaped like a container provided with grooves (not shown) for respectively fitting the optical components412through415,417,421through423,431through434,442A, and444described above by sliding them from above, a lid member452shaped like a lid for closing the upper opening of the component housing member451, and the position adjusting mechanism445(seeFIGS. 3 and 4) including a part of the lid member452and for performing the position adjustment of both of the entrance polarization plate442A and the field angle correction plate444.

Further, in one end of the optical component chassis45having a substantially L-shape in the plan view, there is disposed the light source device411at a predetermined position with respect to the illuminating optical axis A (seeFIG. 5), and in the other end thereof, there is fixed the projection lens3at a predetermined position with respect to the illuminating optical axis A. Still further, the electro-optic device44is fixed anterior to the projection lens3in the optical path. Further, the body tube of the projection lens3is fixed to the projection position adjusting device8described later.

4. Configuration of Power Supply Unit

The power supply unit5is for supplying each of the composing members with electricity supplied from the outside via the inlet connector28(seeFIG. 2). As shown inFIG. 3or4, the power source unit5is disposed at the side of the light source device411of the optical unit4and along the side face section22C of the exterior chassis2. As shown inFIG. 3or4, the power supply unit5is provided with a power supply block51and a lamp drive block52.

The power supply block51is disposed at the side of the light source device411, and supplies the lamp drive block52, the control board, and so on with the electricity supplied form the outside via the inlet connector28. The power supply block51is provided with a circuit board (not shown) having a transformer for converting alternating current voltage into a predetermined voltage, a converter circuit for converting the output of the transformer into a predetermined direct current voltage, and so on mounted on one surface thereof, and a box-like member511for covering the circuit board.

As shown inFIG. 3or4, the box-like member511has a shape extending in the anteroposterior direction so as to form substantially an L-shape together with the light source device411. And, the box-like member511is provided with a first inlet511A (seeFIG. 4) formed in the back face side and for leading the air from the cooling unit6inside thereof, and an outlet511B (seeFIG. 3) formed inner end face of the substantially L-shaped block formed in conjunction with the light source device411and for discharging the inside air to the outside. Further, although not shown in the drawings, the box-like member511is provided with a second inlet formed on the end face distant from the light source device411and for introducing the air discharged from the lamp drive block52.

The lamp drive block52is disposed at the side of the power supply block51and along the side face sections21C,22C, and provided with a circuit board (not shown) having a converter circuit for supplying the light source device411with electricity with a stable voltage and so on mounted on one surface thereof, and the commercial alternating current input from the power supply block51is rectified or converted by the lamp drive block52into direct current or alternating current rectangular wave, and supplied to the light source device411. Further, the circuit board of the lamp drive block52is housed inside a box-like member521similarly to the power supply block51.

As shown inFIG. 3or4, the box-like member521has a shape extending in the anteroposterior direction in parallel to the box-like member511. And, the box-like member521is provided with an inlet521A (seeFIG. 4) formed on the back face side and for leading the air from the cooling unit6inside thereof, and an outlet (not shown) for discharging the inside air to the outside formed on the end face opposing the box-like member511and corresponding to the second inlet of the box-like member511.

5. Configuration of Cooling Unit

The cooling unit6is for cooling the composing elements inside the projector1. As shown inFIG. 3or4, the cooling unit6is composed of a power supply unit cooling section61for cooling mainly the power supply unit5, a light source device cooling section62for discharging the air inside the projector1to the outside, and so on.

It should be noted that, although not specifically shown in the drawings, the cooling unit6is also provided with a liquid crystal panel cooling section composed of a cooling fan and a duct for cooling each of the liquid crystal panels441and the polarization converter414, and so on.

As shown inFIG. 3or4, the power source unit cooling section61is disposed in a space between a block composed of the light source device411and the power supply unit5and the back face sections21D,22D of the exterior chassis2. As shown inFIG. 3or4, the power supply unit cooling section61is provided with an air inlet duct611, a sirocco fan612, and a first air outlet duct613. And, the power supply unit cooling section61drives the sirocco fan612to lead the cooling air outside the projector1to the inside of the box-like members511,521along an air flow path connecting the air inlet (not shown) provided to the lower case22, the air inlet duct611, the sirocco fan612, and the air outlet duct613, and via each of the inlets511A,521A of the respective box-like members511,521forming the power supply unit5. The air led inside the box-like member521of the power supply unit5is led inside the box-like member511through the outlet (not shown) of the box-like member521and the second inlet of the box-like member511(not shown). In the inside of the box-like member521, the circuit board for the lamp drive block52is cooled while the air flows from the inlet521A to the outlet. Further, the air led inside the box-like member511of the power supply unit5is discharged to an area surrounded by the substantially L-shaped block composed of the box-like member511and the light source device411through the outlet511B. In the inside of the box-like member511, the circuit board for the power source block51is cooled while the air flows from the first inlet511A and the second inlet to the outlet511B.

As shown inFIG. 3or4, the light source device cooling section62is disposed in an area surrounded by the substantially L-shaped block composed of the light source device411and the box-like member511. As shown inFIG. 3or4, the light source cooling section62is provided with an axial fan621and a second air outlet duct622. And, the light source device cooling section62drives the axial fan621to discharge the air (the air discharged through the power supply unit5) in the space surrounded with the substantially L-shaped block composed of the light source device411and the box-like member511and the air in other spaces to the outside of the projector1in a direction receding from the projection direction of the projection lens3along an air flow path connecting the axial fan621and the second air outlet duct622and via the air outlet233of the front case23. More specifically, as shown inFIG. 3or4, the lamp housing411C forming the light source device411is provided with a plurality of openings411C1allowing the air to circulate between inside and outside thereof formed in each of the end faces facing in the anteroposterior direction, and when the axial fan621is driven, the inside air of the lamp housing411C is sucked in by the axial fan621through the plurality of openings411C1. In the lamp housing411C, while the air circulates through the plurality of openings411C1, the light source lamp411A and the reflector411B are cooled.

6. Configuration of Projection Position Adjusting Device8

FIGS. 6 through 8are views for showing the structure of the projection position adjusting device8. Specifically,FIG. 6is a perspective view of the projection position adjusting device8viewed from the back side thereof in the optical path,FIG. 7is a perspective view thereof viewed from the front side in the optical path, andFIG. 8is an exploded perspective view of the projection position adjusting device8.

It should be noted that, inFIGS. 6 through 8, it is assumed that the projection direction of the projection lens3is denoted as Z-axis and two axes perpendicular to the Z-axis are denoted as X-axis (horizontal axis) and Y-axis (vertical axis) for the sake of explanation.

6-1. Configuration of Projection Position Adjusting Device8

The projection position adjusting device8is for adjusting the projection position of the projection lens3. As shown inFIG. 8, the projection position adjusting device8is provided with a fixed plate81, a first moving plate82, a second moving plate83, an auxiliary plate84, a supporting plate85, a first adjusting drive section86, a second adjusting drive section87, a biasing member88, and a shift cover89.

It should be noted that among these components, the auxiliary plate84and the supporting plate85correspond to a fixed member of the invention, the first moving plate82and the second moving plate83correspond to a moving member of the invention, and the first adjusting drive section86and the second adjusting drive section87correspond to a drive mechanism of the invention.

The fixed plate81is fixed to the optical component chassis45(seeFIG. 5), and supports the whole of the projection position adjusting device8. The fixed plate81has a substantially rectangular shape in the plan view as shown inFIG. 8.

The fixed plate81is provided with an opening section811having a substantially circular shape in the plan view formed at substantially the center section thereof for allowing the body tube31of the projection lens3to be inserted.

And, it is arranged that the first moving plate82slides on the periphery section of the opening section811in the end face in the +Z-axis direction of the fixed plate81.

The fixed plate81is provided with four fixing holes812formed surrounding the opening section811. And, screws (not shown) are installed in screw holes (not shown) provided to the side face of the optical component chassis45via the fixing holes812, thereby fixing the fixed plate81to the optical component chassis45.

Further, in the fixed plate81, on the periphery of the end face of the fixed plate81perpendicular to the Z-axis direction, five fixing holes813penetrate in the Z-axis direction as shown inFIG. 8. Screws (not shown) are inserted to the fixing holes813, and the screws are installed in the fixing tubes842of the auxiliary plate84described later, thereby connecting the fixed plate81and the auxiliary plate84to each other.

In the fixed plate81, on the +Y-axis direction end side (upper end side) of the +X-axis direction end face, there is formed a fixing tube814protruding towards the +X-axis direction. The fixing tube814is provided with a threaded hole from the +X-axis direction end face to the −X-axis direction.

Further, in the fixed plate81, on the −Y-axis direction end side (lower end side) of the +X-axis direction end face, there is formed a threaded hole815towards the −X-axis direction.

And, in the fixed plate81, on the +Y-axis direction end face (upper end face), there are formed two threaded holes816and a locating lug817for fixing the shift cover89as shown inFIG. 8.

Further, in the fixed plate81, on the +Z-axis direction end face, there is erected a plurality of strengthening ribs818as shown inFIG. 8. By providing such strengthening ribs818, influence of the external force to the projection position adjusting device8can be eased, thus preventing the projection position from being shifted by the external force.

The first moving plate82has a substantially rectangular shape in the plan view smaller than the fixed plate81, and is disposed in the +Z-axis side of the fixed plate81as shown inFIGS. 6 and 8. As shown inFIG. 8, the first moving plate82is configured to abut on the periphery section of the opening section811on the +Z-axis direction end face in the fixed plate81, and to be movable in the Y-axis direction and the X-axis direction. Further, the first moving plate82fixedly supports the projection lens3and moves, thereby moving the projection lens3in the Y-axis direction and the X-axis direction.

In the first moving plate82, at substantially the center section thereof, there is formed an opening section821capable of inserting the body tube31of the projection lens3as shown inFIG. 8.

The opening section821is formed to have a diameter approximated to the outside diameter of the body tube31in order for reducing the gap with the outer periphery of the body tube31. By thus forming the opening section821, it can be prevented that the light leaks from the gap between the body tube31and the opening section821, and that dusts enter inside the projector1.

In the first moving plate82, at four corners in the periphery of the opening section821, there are formed fixing holes822corresponding to fixing holes321in a flange32of the projection lens3as shown inFIG. 8. And, screws (not shown) are installed in the fixing holes822from the +Z-axis direction (the inverse direction of the projection direction) through the fixing holes321in the flange section32in the condition in which the body tube31of the projection lens3is inserted in the opening section821, thereby fixing the projection lens3to the first moving plate82. Namely, the first moving plate82fixedly supports the projection lens3on the surface facing the fixed plate81.

Further, in the first moving plate82, at four corners on the +Z-axis direction end face, there are formed biasing holes823as shown inFIG. 8. And, these biasing holes823are each provided with a biasing member88described later.

And, in the first moving plate82, in the +X-axis direction end section side of the +Z-axis direction end face, there is formed a rail groove824hollowing in the −Z-axis direction and extending along the Y-axis direction as shown inFIG. 8.

Further, in the first moving plate82, in substantially the center section in the Y-axis direction of the +X-axis direction end face, there are formed moving lugs825,826so as to protrude in the +X-axis direction as shown inFIG. 8.

The moving lugs825,826are both inserted in a tracking slit856in the supporting plate85both described later. Among the above, the moving lug825is engaged with a drive gear of the first adjusting drive section86described later in the −X-axis direction side of the supporting plate85to absorb the force of the drive gear. These moving lugs825,826are each provided with a threaded hole (not shown) from the +X-axis direction end face to the −X-axis direction.

It should be noted that on the +Y-axis direction side of the moving lug826, there is formed a reinforcing plate826A protruding from the +X-axis direction end face of the first moving plate82along the moving lug826. The reinforcing plate826A is formed to be integrated with the moving lug826in the −Y-axis direction end section thereof.

The moving lugs825,826are provided with a bridge member827described later bridged therebetween on the +X-axis direction end face thereof as shown inFIG. 8.

The bridge member827is an elongated member extending in the Y-axis direction, and is provided with fixing holes827A,827B formed on both end sections (upper and lower ends) in the Y-axis direction, respectively, so as to penetrate the bridge member827in the X-axis direction. The distance between the fixing holes827A,827B in the Y-axis direction corresponds with the distance between the moving lugs825,826in the Y-axis direction.

And, by screws827C installed in screw holes of the moving lugs825,826via the fixing holes827A,827B of the bridge member, the bridge member827is bonded with the +X-axis direction end face of the moving lugs825,826.

By forming and bonding the moving lug826and the bridge member827, the strength in the Y-axis direction of the moving lug825can be reinforced. Namely, since the force from the drive gear acts on the moving lug825, it might be apt to be broken in the Y-axis direction. However, since the moving lug826is formed at the −Y-axis side of the moving lug825, and further, the bridge member827is bridged between the moving lugs825,826in the Y-axis direction, the force applied to the moving lug825can be dispersed to the moving lug826and the bridge member827. Further more, since the reinforcing plate826A is provided to the moving lug826, the moving lug826can be made hard to be broken, thus further reinforcing the moving lug825.

Further, the first moving plate82is moved together with the second moving plate83in the X-axis direction. The moving lugs825,826and the reinforcing plate826A have enough lengths in the X-axis direction so that the first moving plate82can move in the −X-axis direction as far as possible with respect to the supporting plate81.

In the first moving plate82, on the +Z-axis direction end face, there is erected a plurality of strengthening ribs828as shown inFIG. 8. By providing such strengthening ribs828, influence of the external force to the projection position adjusting device8can be eased, thus preventing the projection position from being shifted by the external force.

The second moving plate83has a similar shape to the first moving plate82, and disposed at the +Z-axis direction side of the first moving plate82as shown inFIG. 8. The second moving plate83is configured to be movable in the X-axis direction, and moves the first moving plate82in the X-axis direction while engaging with the first moving plate82.

In the second moving plate83, on the −Z-axis direction end face there is formed a sliding projection830extending along the Y-axis direction in a position corresponding to the rail groove824of the first moving plate82. The sliding projection830is engaged with the rail groove824of the first moving plate82in a condition in which the projection position adjusting device8is completed. Thus, the first moving plate82is guided by the rail groove824and the sliding projection830to be moved in the Y-axis direction with respect to the second moving plate83. Further, the first moving plate82is moved in the X-axis direction in conjunction with the movement of the second moving plate83in the X-axis direction with the help of the rail groove824and the sliding projection830.

In the second moving plate83, at substantially the center section thereof, there is formed an opening section831capable of inserting the body tube31of the projection lens3as shown inFIG. 8.

The opening section831has a shape greater than the outer periphery of the body tube31in diameter so that the outer periphery of the body tube31and the inner periphery of the opening section831do not mechanically interfere with each other when the first moving plate82moves with respect to the second moving plate83to move the projection lens3.

Further, in the second moving plate83, on a corner portion of +Y-axis direction side (upper direction) of the +Z-axis direction end face, there is formed a recessed section832hollowing towards the −Z-axis direction as shown inFIG. 8. And, the recessed section832is provided with a dial gear, an intermediate gear, and a drive gear configuring the second adjusting drive section87disposed respectively. And, the recessed section832is provided with a moving lug833protruding in the +Z-axis direction and engaging with the drive gear to absorb the force from the drive gear as shown inFIG. 8.

Further more, in the second moving plate83, in the −Y-axis direction end section side of the +Z-axis direction end face, there is formed an engaging projection834protruding in the +Z-axis direction and extending along the X-axis direction and engaging with the auxiliary plate84as shown inFIG. 8.

Further, in the second moving plate83, at substantially the center section in the X-axis direction of the +Y-axis direction end section (upper end section), there is formed a recessed section835having a substantially hemicycle cross-sectional shape in the X-Y plane as shown inFIG. 8. And, the recessed section835is provided with the biasing members88described later.

In the second moving plate83, on the +Z-axis direction end face except the recessed section832, there is erected a plurality of strengthening ribs836as shown inFIG. 8. By providing such strengthening ribs836, influence of the external force to the projection position adjusting device8can be eased, thus preventing the projection position from being shifted by the external force.

The auxiliary plate84has a similar shape to the fixed plate81, and is disposed at the +Z-axis direction side of the second moving plate83to hold the first moving plate82and the second moving plate83with the fixed plate81therebetween as shown inFIG. 8.

In the auxiliary plate84, at substantially the center section thereof, there is formed an opening section841capable of inserting the body tube31of the projection lens3as shown inFIG. 8.

The opening section841has a shape greater than the periphery shape of the body tube31in size so that the outer periphery of the body tube31and the inner periphery of the opening section841do not mechanically interfere with each other when the projection lens3moves.

In the auxiliary plate84, in the −Z-axis direction end face, there are formed five fixing tubes842for connecting to the fixed plate81and protruding in the −Z-axis direction corresponding to the positions of the five fixing holes813of the fixed plate81as shown inFIG. 8.

These fixing tubes842are provided with threaded holes formed inside thereof towards +Z-axis direction. And, screws are installed in the threaded holes of the fixing tubes842via the fixing holes813in the condition in which the fixing tubes842abut on the fixing holes813of the fixed plate81, thus the auxiliary plate84is fixed to the fixed plate81.

Further, in the auxiliary plate84, on a corner portion in the −X-axis direction side and +Y-axis direction side (upper direction) of the +Z-axis direction end face, there is formed a recessed section843hollowing towards the −Z-axis direction as shown inFIG. 8. And, on the recessed section843, there is disposed a dial knob871forming the second adjusting drive section87.

Further, in the recessed section843, there is formed a pivot section844protruding towards the +Z direction and provided with an insertion hole844A formed therein as shown inFIG. 8. And, a rotating shaft of a dial gear forming the second adjusting drive section87is inserted in the insertion hole844A, thus the pivot section844rotatably supports the dial knob871and the dial gear.

On the back face (−Z-axis direction end face) of the recessed section843, there is formed a rotational shaft845A (seeFIG. 10) rotatably supporting the intermediate gear of the second adjusting drive section87. Further, on the −Z-axis direction end face, there is formed a rotational shaft845B (seeFIG. 10) for rotatably supporting the drive gear of the second adjusting drive section87at the −Y-axis direction side (lower side) of the rotational shaft845A.

In the auxiliary plate84, on the +Y-axis direction end section (upper end section) there are formed two locating lugs846A for positioning the shift cover89and two threaded holes846B for fixing the shift cover89as shown inFIG. 8.

Further, in the auxiliary plate84, on the +X-axis direction end face, there are formed fixing tubes847A,847B (seeFIG. 10) for fixing the supporting plate85, and rotational shafts848A,848B,848C (seeFIGS. 9 and 10) for rotatably supporting a dial gear, a second intermediate gear and a drive gear of the first adjusting drive section86, respectively. It should be noted that the fixing tubes847A,847B are provided with threaded holes formed towards the −X-axis direction.

Further, in the auxiliary plate84, on the +Z-axis direction end face, there is erected a plurality of strengthening ribs849as shown inFIGS. 6 through 8. By providing such strengthening ribs849, influence of the external force to the projection position adjusting device8can be eased, thus preventing the projection position from being shifted by the external force.

In the auxiliary plate84, on the −Z-axis direction end face, there is formed an engaging recessed section840(seeFIG. 10) extending along the X-axis direction at a position corresponding to the engaging projection834of the second moving plate83. The engaging recessed section840is formed to have a length greater than a total of the length in the X-axis direction of the engaging projection834and the moving distance in the X-axis direction of the second moving plate83. In the condition in which the projection position adjusting device8is completed, the engaging projection834of the second moving plate83is inserted in the engaging recessed section840of the auxiliary plate84. And, the second moving plate83is moved in the X-axis direction with respect to the auxiliary plate84while being guided by the engaging projection834and the engaging recessed section840.

The supporting plate85is disposed at the +X-axis direction of the fixed plate81, the first moving plate82, the second moving plate83, and the auxiliary plate84as shown inFIGS. 6 through 8, and supports the first adjusting drive section86, and reinforces the connection state between the fixed plate81and the auxiliary plate84.

In the supporting plate85, a portion852in the −Y-axis direction side (lower side) is bulged out from a portion851in the +Y-axis direction side (upper side) in the +X-axis direction as shown inFIG. 8.

In the supporting plate85, at the +Y-axis direction side (upper side) of the portion851there is formed a pivot section853penetrating from the front to the back as shown inFIG. 8. And, a shaft portion of a dial gear forming the first adjusting drive section86is inserted in the pivot section853, and the dial knob861and the dial gear are rotatably supported by the pivot section853.

Further, in the supporting plate85, a corner section at the +Y-axis direction side (upper side) of the portion851and on the +Z-axis direction side, and a portion at the −Y-axis direction side (lower side) of the portion851and on the +Z-axis direction side, there are formed fixing holes854A,854B.

By screws installed in the threaded holes of the fixing tubes847A,847B of the auxiliary plate84via the fixing holes854A,854B, the supporting plate85is fixed to the auxiliary plate84.

Further, in the supporting plate85, in the portion851, there are formed fixing holes855A,855B in the positions corresponding to the fixing tube814and the fixing threaded hole815of the fixed plate81, respectively, as shown inFIG. 8. And, screws are installed in the fixing tube814and the fixing threaded hole815of the fixed plate81through the fixing holes855A,855B, thus the supporting plate85is fixed to the fixed plate81.

And, in the supporting plate85, as shown inFIG. 8, there is formed the tracking slit856from the portion851to the portion852at a position corresponding to the moving lugs825,826of the first moving plate82. The tracking slit856is formed so as to extend in the Y-axis direction as shown inFIG. 8.

In the condition in which the projection position adjusting device8is completed, the moving lugs825,826are inserted in the tracking slit856, it is prevented that the moving lugs825,826mechanically interfere with the supporting plate85in accordance with the movement of the first moving plate82.

FIG. 9is a view showing the structure of the first adjusting drive section86. Specifically,FIG. 9is a view of the condition with the supporting plate85removed from the projection position adjusting device8viewed from the +X-axis direction. It should be noted that, inFIG. 9, similarly toFIGS. 6 through 8, it is assumed that the projection direction of the projection lens3is denoted as Z-axis and two axes perpendicular to the Z-axis are denoted as X-axis (horizontal axis) and Y-axis (vertical axis).

The first adjusting drive section86is for moving the first moving plate82in the Y-axis direction in accordance with an operation of a user, thereby changing the projection position of the projector lens3in the Y-axis direction. The first adjusting drive section86is provided with the dial knob861(seeFIG. 8), the dial gear862, the first intermediate gear863, a second intermediate gear864, and the drive gear865as shown inFIG. 8or9.

The dial knob861is a operation section partially exposed from the top face of the upper case21of the exterior chassis2, and operated by the user. The dial knob861has a substantially cylindrical shape as shown inFIG. 8, and is formed like a lid having a space inside thereof and disposed at the +X-axis side of the supporting plate85. At the center section of the dial knob861, there is formed a fixing hole.

The dial gear862is for engaging with the dial knob861, rotating together with the dial knob861, and transmitting the rotation to the first intermediate gear863, and is disposed at the −X-axis direction side of the supporting plate85as shown inFIG. 8. The dial gear862is composed of a shaft section862A and a gear862B as shown inFIG. 8or9.

The shaft section862A has a cylindrical shape, and provided with a threaded hole (not shown) formed from the tip face towards the gear862A side. A screw is installed in the threaded hole of the shaft section862A through the center hole of the dial knob861and the pivot section853of the supporting plate85from the +X-axis direction, thus the dial knob861is pivotally supported by the supporting plate85.

The gear862B is connected to a proximal end portion of the shaft section862A, and meshes with the first intermediate gear863to transmit the rotation of the dial knob861to the first intermediate gear863. As shown inFIG. 9, at the rotational center of the gear862B, there is formed a circular hole862B1, and in the condition in which the projection position adjusting device8is completed, the rotational shaft848A of the auxiliary plate84is inserted in the circular hole862B1, thus the dial gear862is rotatably supported by the rotational shaft848A.

The first intermediate gear863meshes with the gear862B of the dial gear862and the gear864A of the second intermediate gear864, and is disposed on the −X-axis direction side of the supporting plate85. The first intermediate gear863transmits the rotation of the dial gear862to the second intermediate gear864.

The second intermediate gear864is configured, as shown inFIG. 8, to have a first gear wheel864A with larger diameter and a second gear wheel864B with smaller diameter integrated with each other, and is disposed on the −X-axis direction side of the supporting plate85.

The first gear wheel864A is for meshing with the first intermediate gear863.

The second gear wheel864B is for meshing with the engaging section of the drive gear865, and transmits the rotation of the first intermediate gear863to the drive gear865in cooperation with the first gear wheel864A. And, as shown inFIG. 9, at the rotational center of the second intermediate gear864, there is formed a circular hole864C, and in the condition in which the projection position adjusting device8is completed, the rotational shaft848B of the auxiliary plate84is inserted in the circular hole864C, thus the second intermediate gear864is rotatably supported by the rotational shaft848B.

The drive gear865has a sector form in the plan view, as shown inFIG. 8or9, and is disposed on the −X-axis direction side of the supporting plate85. The drive gear865is composed of a gear main body865A and a meshing section865B as shown inFIG. 9.

The gear body865A is a section to be rotatably supported by the rotational shaft848C of the auxiliary plate84, and is provided with a circular hole865C, to which the rotational shaft848C can be inserted, formed in a proximal end section thereof.

Further, the gear main body865A is provided with a tracking slit865D formed extending in a direction radially expanding from the center position of the circular hole865C. And, in the condition in which the projection position adjusting device8is completed, the moving lug825of the first moving plate82is inserted in the tracking slit865D.

The meshing section865B is formed in an arc section on the tip portion of the gear main body865A, and meshes with the second gear wheel864B of the second intermediate gear864.

According to the configuration as described above, when a user turns the dial knob861in the Y1direction (seeFIG. 9), the rotation of the dial knob861is transmitted to the drive gear865via the dial gear862, the first intermediate gear863, and the second intermediate gear864, and the drive gear865then rotates in the Y5(seeFIG. 9) direction around the rotational shaft848C.

In this case, the moving lug825is guided by the tracking slit865D, and the first moving plate82is moved in the −Y-axis direction (downward). And, the projection lens3is moved in the −Y-axis direction (downward) in conjunction with the first moving plate82, thus the projection position is adjusted in the −Y-axis direction (downward).

Further, when a user turns the dial knob861in the Y2direction (seeFIG. 9), contrary to the above, the drive gear865rotates in the Y6direction (seeFIG. 9) around the rotational shaft848C. In this case, the moving lug825is guided by the tracking slit865D, and the first moving plate82is moved in the +Y-axis direction (upward), thus the projection position is adjusted in the +Y-axis direction (upward).

FIG. 10is a view showing the structure of the second adjusting drive section87. Specifically,FIG. 10is a view of a condition of the second adjusting drive section87disposed on the auxiliary plate84viewed from the −Z-axis direction. It should be noted that, inFIG. 10, similarly toFIGS. 6 through 8, it is assumed that the projection direction of the projection lens3is denoted as Z-axis and two axes perpendicular to the Z-axis are denoted as X-axis (horizontal axis) and Y-axis (vertical axis).

In the second adjusting drive section87, the second moving plate83is moved in the X-axis direction by an operation of a user, the first moving plate82is moved in conjunction with the movement of the second moving plate83, thus the projection position of the projection lens3is changed in the X-axis direction. The second adjusting drive section87is provided with the dial knob871(including a hole871A (see FIG.13)), a dial gear872(including a shaft section872A, a gear872B, and a circular hole872B1), an intermediate gear873(including a first gear wheel873A, a second gear wheel873B, and a circular hole873C), and a drive gear874(including a gear main body874A, a meshing section874B, a circular hole874C, and a tracking slit874D), respectively similar to the dial knob861(including the hole in the reverse side), the dial gear862(including the shaft section862A, the gear862B, and the circular hole862B1), the second intermediate gear864(including the first gear wheel864A, the second gear wheel864B, and the circular hole864C), and the drive gear865(including a gear main body865A, a meshing section865B, a circular hole865C, and a tracking slit865D) of the first adjusting drive section86, respectively.

The dial knob871is partially exposed from the top face of the upper case21of the exterior chassis2, and is a operating section operated by a user, and disposed on the +Z-axis direction side of the auxiliary plate84in the recessed section843of the auxiliary plate84as shown inFIG. 8.

The dial gear872is, as shown inFIG. 8, disposed on the −Z-axis direction side of the auxiliary plate84. And, as shown inFIG. 8, the dial gear872has the shaft section872A inserted in the insertion hole844A of the auxiliary plate84in the condition in which the projection position adjusting device8is completed. And, the threaded hole of the shaft section872A and the hole871A (seeFIG. 13) in the reverse side of the dial knob871are fixed with a screw, thus the dial knob871is rotationally supported by the auxiliary plate84.

The intermediate gear873is, as shown inFIG. 10, disposed on the −Z-axis direction side of the auxiliary plate84. And, as shown inFIG. 10, in the condition in which the projection position adjusting device8is completed, the rotational shaft845A of the auxiliary plate84is inserted in the circular hole873C of the intermediate gear873, thus the intermediate gear873is rotatably supported by the rotational shaft845A.

The drive gear874is, as shown inFIG. 8, disposed on the −Z-axis direction side of the auxiliary plate84. And, as shown inFIG. 10, in the condition in which the projection position adjusting device8is completed, the rotational shaft845B of the auxiliary plate84is inserted in the circular hole874C of the drive gear874, thus the drive gear874is rotatably supported by the rotational shaft845B. Further, in the condition in which the projection position adjusting device8is completed, the moving lug833of the second moving plate83is inserted in the tracking slit874D of the drive gear874.

According to the configuration as described above, when a user turns the dial knob871in the X1direction (seeFIG. 10), the rotation of the dial knob871is transmitted to the drive gear874via the dial gear872and the intermediate gear873, and the drive gear874then rotates in the X5(seeFIG. 10) direction around the rotational shaft845B. In this case, the moving lug833is guided by the tracking slit874D, and the second moving plate83is moved in the −X-axis direction. In this case, the first moving plate82is moved in the −X-axis direction in conjunction with the second moving plate83with the help of the sliding projection830of the second moving plate83and the rail groove824of the first moving plate82. And, the projection lens3is moved in the −X-axis direction in conjunction with the first moving plate82, thus the projection position is adjusted in the −X-axis direction.

Further, when a user turns the dial knob871in the X2direction (seeFIG. 10), contrary to the above, the drive gear874rotates in the X6direction (seeFIG. 10) around the rotational shaft845B. In this case, the moving lug833is guided by the tracking slit874D, and the second moving plate83and the first moving plate82are moved in the +X-axis direction, thus the projection position is adjusted in the +X-axis direction.

As shown inFIGS. 6 through 8, the shift cover89is disposed on the +Y-axis direction end section side (upper end side) of the projection position adjusting device8and at the +Y-axis direction side (upper side) of the projection lens3.

The shift cover89is a part to be fixed to the fixed plate81and the auxiliary plate84, and is composed of a plate member with a rectangular shape in the plan view.

The shift cover89is provided with four fixing holes89A each formed corresponding to respective one of the two threaded holes816of the fixed plate81and two threaded holes846B of the auxiliary plate84as shown inFIG. 8. Further, there are formed three locating holes89B in accordance with the locating lug817of the fixed plate81and the two locating lugs846A of the auxiliary plate84.

And, by inserting the locating lugs817,846A in the three locating holes89B, respectively, the shift cover89is positioned with respect to the members81through84. And, by installing screws (not shown) in the threaded holes816,846B of the fixed plate81and the auxiliary plate84through the four fixing holes89A, the shift cover89is fixed to the members81through84.

Further, the shift cover89is provided with an opening section89C formed in accordance with the dial knob871of the second adjusting drive section87as shown inFIG. 8. Namely, it is arranged that a part of the dial knob871is exposed through the opening section89C in the condition in which the shift cover89is fixed to the members81through84.

The biasing member88is composed of four first biasing members88A disposed between the first moving plate82and the second moving plate83and a second biasing member88B disposed between the second moving plate83and the shift cover89as shown inFIG. 8.

The four first biasing members88A are each composed of a stopper88A1and a spring88A2. And, as shown inFIG. 8, the spring88A2is inserted in each of four biasing holes823of the first moving plate82from the +Z-axis direction, and further the stopper88A1is then fitted therein via the spring88A2thus inserted. Therefore, the biasing force in the Z-axis direction acts on the stopper88A1.

Accordingly, in the condition in which the projection position adjusting device8is completed, these first biasing members88A bias the first moving plate82against the fixed plate81while biasing the second moving plate83against the auxiliary plate84.

Thus, the second moving plate83can be biased with respect to the first moving plate82and the auxiliary plate84in the condition in which the projection position adjusting device8is completed. Therefore, the gaps between the second moving plate83and both of the first moving plate82and the auxiliary plate84caused by the manufacturing tolerances can be eliminated by the first biasing members88A, thus it becomes possible to preferably move the second moving plate83without any jerky movements when moving the second moving plate83in the X-axis direction. Further, by thus providing the first biasing members88A therebetween, the first moving plate82is also biased against the fixed plate81, thus the first moving plate82can also be moved preferably with respect to the fixed plate81. Therefore, surging motion of the projection position can be eliminated when moving the moving plates82,83to adjust the projection position, thus the projection position can be adjusted with further accuracy.

The second biasing member88B is a molding with a cylindrical shape, as shown inFIG. 8, formed from a resin material using a molding process. And, the second biasing member88B is disposed in the recessed section835of the second moving plate83so that the cylindrical axis is set towards the Z-axis direction. And, in the condition in which the projection position adjusting device8is completed, the second biasing member88B biases the second moving plate83against the auxiliary plate84in the −Y-axis direction (downward). Namely, the engaging projection834of the second moving plate83is biased against the engaging recessed section840of the auxiliary plate84in the −Y-axis direction (downward).

Accordingly, the gaps between the second moving plate83and the auxiliary plate84caused by the manufacturing tolerances can be eliminated by the second biasing member88B, thus it becomes possible to preferably move the second moving plate83without any jerky movements when moving the second moving plate83in the X-axis direction. Therefore, surging motion of the projection position can be eliminated when moving the second moving plate83in the X-axis direction to adjust the projection position in the X-axis direction, thus the projection position can be adjusted with further accuracy.

6-2. Configuration of Projection Lens3

FIG. 11is an exploded perspective view showing the structure of the projection lens3. It should be noted that, inFIG. 11, similarly toFIGS. 6 through 8, it is assumed that the projection direction of the projection lens3is denoted as Z-axis and two axes perpendicular to the Z-axis are denoted as X-axis (horizontal axis) and Y-axis (vertical axis).

The projection lens3is provided with the body tube31and the flange section32as shown inFIG. 11. And, the body tube31is provided with a lens section91, zoom adjustment ring92, a flange ring93, and a focus adjustment ring94.

The lens section91is provided with a lens911and a lens frame912for supporting the lens911. The lens911is a circular lens with a diameter substantially equal to the cylinder diameter of the body tube31of the projection lens3. The lens section91is disposed inside the body tube31.

The zoom adjustment ring92is fitted to the body tube31and makes the body tube31change the position of the lens section91in accordance with the movement of a knob921, thus performing magnification adjustment of the projected image.

Specifically, the zoom adjustment ring92is, as shown inFIG. 11, a member having a substantially cylindrical shape with a larger diameter than the body tube31of the projection lens3. The zoom adjustment ring92is provided with the knob921formed on the outer periphery surface of the cylindrical shape so as to protrude outside as shown inFIG. 11. And, when the knob921is operated by a user to be moved in the circumferential direction, the zoom adjustment ring92is rotated around the cylindrical axis.

The zoom adjustment ring92is attached to a member (not shown), which rotates to change the position of the lens section91for performing magnification adjustment of the projected image, among various members forming the body tube31, and makes the member rotate by the circumferential rotation thereof.

Further, on the −Z-axis direction end section of the cylindrical side face of the zoom adjustment ring92, there is formed a ring frame section922bulged outward from the circumference of the cylinder. On the outer circumference of the ring frame section922, there is formed an engaging groove923hollowing towards the cylindrical center along the circumference of the cylinder.

The flange ring93is, as shown inFIG. 11, a ring-like member fitted to the circumference of the cylindrical zoom adjustment ring92, and composed of a first flange931and a second flange932as extending segments.

Each of the first and the second flanges931,932is a semicircular plate member defined by expanding on the circumference a semicircle centered on the axis of the cylinder of the body tube31along a plane perpendicular to the Z-axis direction. And, the inner circumference of each of the first and the second flanges931,932has substantially the same diameter as the outer circumference of the ring frame section922.

In the first flange931, in one peripheral end section, there is formed a locking projection931A having a slightly thinner Z-axis direction size than the Z-axis direction size of the first flange931and protruding along the circumferential direction. And, in the other peripheral end section of the first flange931, there is formed an engaging recessed section931B having a slightly thinner Z-axis direction size than the Z-axis direction size of the first flange931and hollowing towards the −Z-axis direction.

In the peripheral end sections of the second flange932, there are respectively formed a locking projection (not shown) and an engaging recessed section932B similar to the locking projection931A and the engaging recessed section931B of the first flange931.

The first flange931and the second flange932are fitted to the engaging groove923of the ring frame section922at the inner circumferential ends, thus the first and the second flanges are attached to the zoom adjusting ring92. And, the locking projection931A of the first flange931and the engaging recessed section932B of the second flange932are engaged along the peripheral direction and the locking projection of the second flange932and the engaging recessed section931B of the first flange931are engaged along the peripheral direction, while fitting the inner circumferential ends of the first and the second flanges931,932to the engaging groove923of the ring frame section922, thereby forming the flange ring93.

The focus adjustment ring94is attached to a member (not shown), which rotates to change the position of the lens section91for performing focus adjustment of the projected image, among various members forming the body tube31, and makes the member rotate by the circumferential rotation thereof. The focus adjustment ring94is formed to have a circular frame shape in the plan view as shown inFIG. 11.

7. Configuration of Reference Position Detecting Mechanism10

The reference position detecting mechanism10will now be explained with reference toFIGS. 12 through 15.FIG. 12is a view showing an overall view of the reference position detecting mechanism10.FIGS. 13 and 14are views showing some members configuring the reference position detecting mechanism10.FIG. 15is a diagram for explaining the operation of the reference position detecting mechanism10.

It should be noted that, inFIGS. 12 and 15, similarly toFIGS. 6 through 8, it is assumed that the projection direction of the projection lens3is denoted as Z-axis and two axes perpendicular to the Z-axis are denoted as X-axis (horizontal axis) and Y-axis (vertical axis).

The reference position detecting mechanism10, in the present embodiment, detects the center position of a moving path of the projection position moving in a plane perpendicular to the projection direction as the projection reference position, namely, the center of the moving range in the X-axis direction, in which the projection lens3is moved by the projection position adjusting device8, and the center of the moving range in the Y-axis direction, in which the projection lens3is moved by the projection position adjusting device8, are detected as the projection reference position.

The reference position detecting mechanism10is respectively disposed between the supporting plate85and the dial knob861, and between the auxiliary plate84and the dial knob871as shown inFIG. 12. Among the above, the reference position detecting mechanism10intervening between the supporting plate85and the dial knob861detects the center of the moving range in the Y-axis direction of the projection lens3. On the contrary, the reference position detecting mechanism10intervening between the auxiliary plate84and the dial knob871detects the center of the moving range in the X-axis direction of the projection lens3.

Either of the reference position detection mechanisms10have the same configurations and the same operational advantages. Therefore, in the following descriptions, the reference position detecting mechanism10intervening between the dial knob871and the auxiliary plate84is explained as a representative.

The reference position detecting mechanism10is provided with a spiral rail11formed on the dial knob871, a sliding member12as a sliding section, and a vertical motion rail13formed on the auxiliary plate84as shown inFIG. 12.

FIG. 13is a perspective view showing the configuration of the reverse side (the side of the auxiliary plate84) of the dial knob871.

As shown inFIG. 13, the reverse side of the dial knob871is hollowed out towards the adverse side.

The spiral rail11is erected on the bottom of the hollowed area, and is composed of a spiral erected section871B formed in a spiral manner centered on the hole871A and towards the periphery of the dial knob871. Namely, the spiral rail11is a groove formed in a spiral manner along the rotational direction of the dial knob. It should be noted that the spiral rail11corresponds to a guide section according to the invention.

Further, the spiral rail11is, as shown inFIG. 13, provided with rotation stoppers111and a rail engaging hole112.

The rotation stoppers111are erected at a position adjacent to the hole871A and at a position adjacent to the periphery of the dial knob871, respectively, so as to be perpendicular to the running direction of the spiral rail11to terminate the spiral rail11.

As described above, in the projection position adjusting device8(seeFIGS. 6 through 8), the second moving plate83(seeFIG. 8) is reciprocated in the X-axis direction in accordance with the rotation of the dial knob871. The two rotation stoppers111are respectively formed at positions where a sliding head1226for sliding in the spiral rail11is abutted in the rotational direction when the second moving plate83reaches the terminal positions in the moving range in the X-axis direction with respect to the auxiliary plate84(seeFIG. 8).

The rail engaging hole112corresponds to a engaging section of the invention, and hollowed on the bottom of the groove of the spiral rail11to have a circular shape. The rail engaging hole112is formed at the middle of two rotation stoppers111on the spiral rail11.

FIG. 14is an exploded perspective view showing the configuration of a sliding member12.

The sliding member12is a symmetric member having a crescent shape, and is provided with a base section121, a sliding body122supported by the base section121, and a spring123intervening between the base section121and the sliding body122as shown inFIG. 14.

The base section121is provided with a base plate1211, a hollow support1212, a pair of cylindrical projections1213as a projection section, two tip posts1214, and four small circular lugs1215.

Among the above, the base plate1211is a plate member having a substantially crescent shape.

The hollow support1212is erected at the center (on the axis of symmetry of the substantially crescent shape) of the base plate1211. The hollow support1212is provided with a cylindrical space1216and valley sections1217.

The cylindrical space1216is formed by penetrating in the protruding direction in the hollow support1212so as to have a circular cross-sectional shape. And, the cylindrical space1216is connected to a hole formed on the base plate1211. The valley sections1217is formed by notching the hollow support in the valley-shape along the chord of the substantially crescent shape of the base plate1211from the both sides of the hollow support1212towards the cylindrical space1216.

The two cylindrical projections1213are protruded to form cylinders and disposed in parallel to each other along the chord direction across the hollow support1212. Namely, a line connecting the two cylindrical projections1213and the valley sections1217described above are formed in line.

The two tip posts1214are erected on the base plate1211at the both acute-angled end sections.

The four small circular lugs1215are formed in the outer periphery side face of the base plate1211on the two side faces parallel to the direction of the axis of symmetry of the substantially crescent shape, two by two along the direction of the axis of symmetry. The small circular lugs1215each protrude from the side faces of the base plate1211along the chord direction having a cylindrical face on the tip thereof.

The sliding body122is a member to be stacked on the base section121to be assembled as described above, and is a symmetric member with substantially Y-shape as shown inFIG. 14. The sliding body122is provided with a wing section1221, two handy-grip sections1222, and a pivot shaft1223as an axis of symmetry.

The wing section1221is composed of two substantially cuboid members1224disposed in parallel to each other in the chord direction on a plane parallel to the base plate1211of the base section121. The substantially cuboid member1224is hollowed out from the opposite side face to the base section121towards the base section121, and the bottom of the hollowed area is provided with an insertion hole1225penetrating in the overlapping direction with the base section121. As shown inFIG. 15, the pair of cylindrical projections1213of the base section121are respectively inserted in the pair of insertion holes1225.

The two handy-grip sections1222are each extended from an inner end face of the respective one of the substantially cuboid members1224of the wing section1221. Specifically, the handy-grip section1222is a plate-like member parallel to the surface defined by the chord direction and the overlapping direction, and extended in the overlapping direction receding from the base section121. The pair of handy-grip sections1222is, as shown inFIG. 15, respectively inserted in the pair of valley sections1217formed on the hollow support1212of the base section121.

The pivot shaft1223is a cylindrical shaft member supported by the two handy-grip sections1222and extended in the overlapping direction. The pivot shaft1223is provided with a cylindrical space (not shown) and the sliding head1226.

The cylindrical space is hollowed in the pivot shaft1223from the side of the base section121along the overlapping direction to form a cylindrical shape. The inner diameter of the cylindrical space is substantially the same as the cylindrical space1216formed in the hollow support1212of the basic section121.

The sliding head1226is a tip portion of the pivot shaft1223on the side opposite to the base section121, and is formed to have a hemispheric shape. The sliding head1226slidably abuts on the inside of the spiral rail11of the dial knob871in accordance with the rotation of the dial knob871, as shown inFIG. 15, in the condition in which the reference position detecting mechanism10is completed.

The spring123has a spiral form with substantially the same diameter as the cylindrical space1216of the base section121and the cylindrical space formed in the pivot shaft1223of the sliding body122. Further, the size of the spring123in the overlapping direction is substantially the same as the total of the sizes of these two cylindrical spaces in the overlapping direction. It should be noted that the spring123is fitted in the cylindrical space1216in one end, and is fitted in the cylindrical space of the sliding body122in the other end thereof.

As described above, since the base section121and the sliding body122are assembled with the spring123intervening therebetween, the sliding body122becomes retractable in the overlapping direction against the base section121, and further, pivotable around the pivot shaft1223with respect to the base section121.

In the condition in which the reference position detecting mechanism10is completed, the sliding head1227always presses the reverse face of the dial knob871under the action of the spring123, and is pivoted, in accordance with rotation of the dial knob871, in the direction of the rotation.

It should be noted that if the sliding body122is caused to pivot in the direction traversing the chord direction, the edge of the insertion hole1225of the sliding body122is stopped by the cylindrical projections1213of the base section121, thus the pivoting movement of the sliding body122in the direction traversing the chord direction is restricted. Further, since the handy-grip section1222is inserted in the valley section1217, the pivoting movement of the sliding body122in the direction traversing the chord direction is also restricted here.

Namely, in the condition in which the reference position detecting mechanism10is completed, the pivoting movement of the sliding body122in the direction traversing the rotational direction of the dial knob871is restricted.

The vertical motion rail13is a rail protruding towards the +Z-axis direction on the recessed section843of the auxiliary plate84as shown inFIG. 15.

The vertical motion rail13is composed of two vertical rails131extending in the −Y-axis direction from positions at a predetermined distance from the pivot section844in the X-axis direction on both sides, and horizontal rails132extending from the +Y-axis direction side end section of each of the vertical rails131to the pivot section844. It should be noted that the distance in the X-axis direction between the two vertical rails131is substantially equal to the size of the base plate1211(seeFIG. 14) of the sliding member12in the chord direction.

Further, on a substantially rectangular area of the auxiliary plate84surrounded by the two vertical rails131and the horizontal rails132, there is formed a recessed face133(seeFIG. 8) further hollowed from the recessed section843in the −Z-axis direction.

As shown inFIG. 15, the recessed face133is provided with a sliding member12disposed so that the chord direction becomes parallel to the X-axis direction, and in side faces of the two vertical rails131adjacent to the recessed face133, there are abutted tips of the small circular lugs1215of the base section121.

The operation of the reference position detecting mechanism10in accordance with rotation of the dial knob871will be explained with reference toFIG. 15.

Firstly, the case in which the dial knob871is rotated in the X2direction is considered.

In the sliding member12, when the dial knob871starts turning in the X2direction, the sliding head1226receives the force in the rotational direction (−X-axis direction) of the dial knob871caused by the friction with the bottom face of the groove of the spiral rail11. Thus, the sliding body122inclines in the rotational direction (−X-axis direction) around the hollow support1212(seeFIG. 14). And, when the dial knob871is continuously turned in the X2direction, the sliding head1226slides on the bottom of the groove of the spiral rail11along the rotational direction while inclining in the rotational direction (−X-axis direction).

As described above, when the sliding head1226slides on the bottom face of the groove of the spiral rail11in accordance with the rotation of the dial knob871in the X2direction, the position in the spiral rail11where the sliding head1226slides is moved from an outer part of the spiral to an inner part of the spiral. Then, the sliding head1226, which abuts on the bottom face of the groove of the spiral rail11, receives the force in the +Y-axis direction from the wall face of the groove of the spiral rail11. Accordingly, the sliding member12moves +Y-axis direction with respect to the auxiliary plate84while sliding the small circular lugs1215on the vertical rails131.

Then, the case in which the dial knob871is rotated in the X1direction is considered. Since the rotational direction of the dial knob871is reversed, the operation directions of the members of the reference position detecting mechanism10are reversed from the case with the X2direction described above.

Namely, in the sliding member12, when the dial knob871starts turning in the X1direction, the sliding head1226receives the force in the rotational direction (+X-axis direction) of the dial knob871caused by the friction with the bottom face of the groove of the spiral rail11. Thus, the sliding body122inclines in the rotational direction (+X-axis direction) around the hollow support1212. And, when the dial knob871is continuously turned in the X1direction, the sliding head1226slides on the bottom of the groove of the spiral rail11along the rotational direction while inclining in the rotational direction (+X-axis direction).

As described above, when the sliding head1226slides on the bottom face of the groove of the spiral rail11in accordance with the rotation of the dial knob871in the X1direction, the position in the spiral rail11where the sliding head1226slides is moved from an inner part of the spiral to an outer part of the spiral. Then, the sliding head1226, which abuts on the bottom face of the groove of the spiral rail11, receives the force in the −Y-axis direction from the wall face of the groove of the spiral rail11. Accordingly, the sliding member12moves −Y-axis direction with respect to the auxiliary plate84while sliding the small circular lugs1215on the vertical rails131.

By the vertical movement of the sliding member12as described above, the sliding head1226smoothly slides on the spiral rail11, and accordingly the dial knob871is smoothly rotated.

The operation of the reference position detecting mechanism10in the case in which the rotational direction of the dial knob871is switched, for example, the dial knob871in the rotational operation in the X2direction is started rotating in the X1direction, will now be explained.

In this case, the sliding body122inclining in the rotational direction of X2(−X-axis direction) around the hollow support1212inclines in the rotational direction of X1(+X-axis direction) according to the friction caused between the sliding head1226and the spiral rail11. The displacement of the sliding head1226in the rotational direction caused by the pivoting movement corresponds to an amount of backlash caused between the gears872through874in the second adjusting drive section87(seeFIG. 8).

According to such a configuration and the operation, it is possible not to slide the sliding head1226along the spiral rail11while the backlash is caused in the mesh between the gears872through874in accordance with switching of rotational direction of the dial knob871. Therefore, in the projector1, an error in detecting the center of the moving range of the projection lens3in the X-axis direction caused by the backlash between the gears872through874can be reduced.

As described above, when the sliding head1226continues to slide on the bottom face of the groove of the spiral rail11in accordance with the rotation of the dial knob871, the sliding head1226is eventually engaged with the rail engaging hole112formed on the bottom face of the groove of the spiral rail11. In this case, the sliding head1226expands to the side of the dial knob871(+Z-axis direction) with the help of restoring force of the spring123. Further, the dial knob871is further rotated, the spring123is contracted to release the engagement between the sliding head1226and the rail engaging hole112. And, the sliding head1226slides again on the bottom face of the groove of the spiral rail11. The engagement and release between the sliding head1226and the rail engaging hole112cause the dial knob871a slight vibration and click sound. The user who is rotating the dial knob871can feel the vibration of the dial knob871by hand.

As described above, the rail engaging hole112is formed at the position where the sliding head1226is engaged therewith when the projection lens3reaches the center position of the movable range. Namely, when the slight vibration and the click sound are caused on the dial knob871under rotation, the projection lens3locates at the center of the movable range in the X-axis direction, and accordingly it can be assumed that the projection position is also located at the center of the moving path in the X-axis direction.

Thus, while a user is adjusting the projection position turning the dial knob871, the user can recognize the projection position when the vibration of the dial knob871or the click sound is felt as the central position in the moving path in the X-axis direction. Therefore, according to the projector1, it is possible to notice the user that the projection position reaches the center position of the moving path in the X-axis direction in adjusting the projection position, with relatively simple configuration and in a manner easy-to-understand to the user.

Further, the sliding body122pressing the bottom face of the groove of the spiral rail11moves in the pressing direction to be engaged with the rail engaging hole112. The vibration caused on the dial871and the click sound caused by the engagement become clear. Therefore, the user can clearly feel the vibration of the dial knob871and the click sound, it can more clearly be recognized that the projection position reaches the center position of the moving path in the X-axis direction.

Further, when the dial knob871is further rotated, and the second moving plate83is moved by the second adjusting drive section87to the moving termination position in the projection position adjusting device8, the sliding head1226abuts on the rotation stopper111in the reference position detecting mechanism10. Since the sliding head1226is abutted on the rotation stopper111, the dial knob871becomes impossible to be rotated any further. Namely, in the projector1, when the second moving plate83reaches the moving termination position, the rotation of the dial knob871is restricted.

Therefore, in the projector1, it can be prevented that load is applied to various members in the projection position adjusting device8when the dial knob871is further rotated after the second moving plate83reaches the moving termination position.

According to the embodiment, the sliding head1226slides on inside the spiral rail11, and reciprocates in the Y-axis direction on the auxiliary plate84in accordance with the position in the spiral. Accordingly, the sliding head1226never slides on the same position on the spiral rail11twice while the dial knob871is rotated in the same direction.

Namely, if the rail engaging hole112formed on the spiral rail11is unique, the engagement and release between the sliding head1226and the rail engaging hole112is performed only once in rotating the dial knob871in the same direction. Therefore, the invention can be applied to a projector equipped with the projection position adjusting device8having a large moving area of the second moving plate83in the X-axis direction.

8. Modification of Embodiment

Although the most preferable configuration for putting the invention into practice and so on are disclosed in the above descriptions, the invention is not limited thereto. Namely, the embodiments described above are not for limiting the invention thereto, and accordingly a description using names of components without using a part of or the whole of the limitations thereof such as shapes or materials is included in the invention.

Although in the embodiment, the projection reference position is assumed to be the center of the moving range of the projection lens3, the invention is not limited thereto.

Although in the embodiment, the spiral rail11is adopted as the guiding section, a circumferential rail can also be adopted in the invention. According to this configuration, by forming a single rail engaging hole112in the circumferential rail, the dial knobs861,871vibrate every revolution of respective dial knobs861,871. Namely, the user can recognize a predetermined amount of movement of the projection lens3by the vibrations of the dial knobs861,871.

Although in the embodiment described above, the spiral rail11is assumed to be a rail with a groove having a rectangular cross-sectional shape as shown inFIG. 13, the invention is not limited thereto. For example, the spiral rail11can be configured to be a groove having a semicircular cross-sectional shape corresponding to the shape of the sliding head1226. Accordingly, the jerky movement of the sliding head1226inside the spiral rail11in the direction traversing the rotational direction of the dial knobs861,871can be prevented.

In the invention, it is sufficient for the sliding section and the engaging section to have shapes to be engaged with each other. For example, the engaging section can be a projection slightly projected from the bottom face of the groove of the spiral rail11.

Although in the embodiment, the first moving plate82is moved in the Y-axis direction by driving the first adjusting drive section86, and the second moving plate83is moved in the X-axis direction by driving the second adjusting drive section87, it is not a limitation. For example, a configuration in which the first moving plate is moved in the X-direction by driving the first adjusting drive section and the second moving plate is moved in the Y-direction by driving the second adjusting drive section can also be adopted.

Although in the embodiment the projection position adjusting device8it is assumed that the projection lens3can be moved in both of the X-axis and Y-axis directions perpendicular to the projection direction, the projection position adjusting device8in the invention can have a configuration in which the projection lens3can only be moved in either one of those directions.

Although in the embodiment the configuration with the optical unit4having a substantially L-shape in the plan view is explained, it is not a limitation. For example, a configuration with a substantially U-shape in the plan view can also be adopted.

Although in the embodiment, the projector1using three liquid crystal panels441is only cited, the invention can be applied to a projector using only one liquid crystal panel, a projector using two liquid crystal panels, or a projector using four or more of liquid crystal panels.

Although in the embodiment, the transmissive liquid crystal panel having the entrance surface and the exit surface separately is used, the reflective liquid crystal panel having a common surface used as both the entrance surface and the exit surface can also be used.

Although the liquid crystal panel is used as the optical modulation device, an optical modulation device other than the liquid crystal panel such as a device using micromirror can also be adopted. In this case, the polarization plates in the light beam entrance side and in the light beam exit side can be eliminated.

Although in the embodiment, only an example of the front type of projector for performing projection from the direction in which the screen is observed is cited, the invention can be applied to rear projectors for performing projection from the direction opposite to the direction in which the screen is observed.

The invention can be applied to a projector.

The entire disclosure of Japanese Patent Application No. 2005-257906 filed Sep. 6, 2005 is expressly i ncorporated by reference herein.