Patent Description:
In recent years, a projector on which an image forming panel, such as a liquid crystal display or a digital micromirror device (DMD), is mounted has been widespread and the performance of the projector has been improved.

<CIT> discloses a liquid crystal projector that irradiates a transmission-type liquid crystal panel with light emitted from a light source and enlarges and projects an image, which is displayed on the liquid crystal panel, onto a screen through a projection lens.

A liquid crystal projector of <CIT> includes a projection lens which has two reflective members that bend an optical axis, so that light flux from a liquid crystal panel illuminated by a light source is bent into a U shape by the two reflective members and projected onto a screen. The U-shaped projection lens can reduce the size of the projector body and the size of the entire projector system including the projector and the screen.

According to the preamble of claim <NUM>, <CIT> discloses a projector in which the protruding section is constituted by a mount ring provided in an opening of the central section of the housing, wherein the central section constitutes substantially the entire housing. That is to say, the light from the light source leaves the housing through the mount ring.

<CIT> discloses a projector having plural lenses and a mirror for bending the optical axis between the lenses. One lens is embodied as a rotating part centered on the incident light axis with respect to the mirror.

However, in the projector of <CIT>, in order to avoid interference between the optical path of the projection lens and the projector body, the projection lens is disposed at a position where its tip end side (projection side optical system) projects from the projector body. Accordingly, the projection lens protrudes from the projector body and becomes large, which may interfere with transportation of the projector. In addition, the optical system and the lens barrel may be damaged due to contact, and since the end face of the projection optical system is exposed when not in use, there is a concern that dust or the like may be attached.

The invention has been made in consideration of the above-mentioned circumstances, and an object of the invention is to provide a compact projector that can be hardly obstructive when it is not in use.

In order to achieve the object, a projector of the present application includes the features of claim <NUM>. Dependent claims define preferred embodiments.

According to the invention, it can be provided a compact projector that can be hardly obstructive when it is not in use, such as during transportation.

[First example not covered by the claims] As shown in <FIG> and <FIG>, a projector <NUM> of this example includes a projection lens <NUM>, and a projector body <NUM>.

As shown in <FIG>, the projection lens <NUM> includes a first optical system <NUM>, a second optical system <NUM>, a third optical system <NUM>, a first mirror <NUM> serving as a first reflective member, a second mirror <NUM> serving as a second reflective member, a first holding member <NUM>, a second holding member <NUM>, and a third holding member <NUM>. The first to third holding members <NUM> to <NUM> form a lens barrel <NUM>.

The first optical system <NUM> includes a first lens <NUM> and a second lens <NUM>. Each of these first and second lenses <NUM> and <NUM> is shown as a single lens for simplification in the figure, but is actually formed of a plurality of lens groups. In the first optical system <NUM>, light beams from image forming panels <NUM> to <NUM> are incident and guided to the projection target side. In this example, the first optical system <NUM> forms an image, which is formed on the image forming panels <NUM> to <NUM>, on an imaging plane <NUM> as an intermediate image.

The first holding member <NUM> integrally holds the first optical system <NUM>. The first holding member <NUM> includes a first body part <NUM>, a first lens frame <NUM>, and a first mounting tube <NUM>. And the light with an optical axis CL1 passes through the first holding member <NUM>. The first lens frame <NUM> holds the first lens <NUM>. The first body part <NUM> has a fitting portion <NUM> and a mounting flange <NUM> and holds the first lens frame <NUM> in the center. The fitting portion <NUM> fits into a fitting hole 61A provided in a housing <NUM> of the projector body <NUM>.

The fitting hole 61A is a through-hole opened from a mounting surface 61B (a first surface), which is a side surface of the housing <NUM>, to the inside of the housing <NUM>. The mounting surface 61B is a surface that constitutes a storage section <NUM> provided in the housing <NUM> described later, and is a surface on the side where the image forming panels <NUM> to <NUM> are located in the storage section <NUM>.

The first holding member <NUM> is inserted until the mounting flange <NUM> is abutted against the mounting surface 61B with the fitting portion <NUM> fitted into the fitting hole 61A, and the mounting flange <NUM> is fixed to the housing <NUM> for example by screwing. The first holding member <NUM> attached to the housing <NUM> is inserted to the position where a tip face 21A of the first lens <NUM> (a tip face on the image forming panels <NUM> to <NUM> side) is placed inside the housing <NUM>.

The first mounting tube <NUM> is connected to the first body part <NUM> and holds the second lens <NUM> inside. The first mounting tube <NUM> has a cylindrical shape, and the central axis coincides with the optical axis CL1 of the first optical system <NUM>. The second holding member <NUM> is attached to the first mounting tube <NUM> as described later.

The second holding member <NUM> holds the first mirror <NUM> integrally. The second holding member <NUM> has a second mounting tube <NUM>, a second body part <NUM>, and a third mounting tube <NUM>. The second mounting tube <NUM> has a cylindrical shape, and its inner peripheral surface is rotatably fitted to the outer peripheral surface of the first mounting tube <NUM>. That is, the second holding member <NUM> is supported rotatably about the optical axis CL1 of the first optical system <NUM>, with the first mirror <NUM>, the third holding member <NUM> described later, the second optical system <NUM>, the third optical system <NUM>, and the second mirror <NUM>. The second holding member <NUM> passes light with an optical axis CL2 obtained by bending the optical axis CL1. Note that a retaining member (not shown) is provided between the first mounting tube <NUM> and the second mounting tube <NUM>, so that the second mounting tube <NUM> is prevented from detaching from the first mounting tube <NUM> in a direction parallel to the optical axis CL1.

The second body part <NUM> is connected to the second mounting tube <NUM>. The second body part <NUM> is formed of a square tube having a substantially rectangular parallelepiped shape. One corner of a lower plate 31a of the second body part <NUM> is cut obliquely, so that an inclined surface portion 31b is formed. The first mirror <NUM> is fixed to the inner surface of the inclined surface portion 31b.

The first mirror <NUM> is arranged between the first optical system <NUM> and the imaging plane <NUM> of the intermediate image by the first optical system <NUM>. The first mirror <NUM> bends the optical axis CL1 of the first optical system <NUM> by reflection to the optical axis CL2. In this example, the first mirror <NUM> bends the optical axis CL1 by <NUM> ° to the optical axis CL2.

The third mounting tube <NUM> is fixed to the second body part <NUM> by for example screwing, and is arranged orthogonal to the second mounting tube <NUM> through the second body part <NUM>. The third mounting tube <NUM> has a cylindrical shape, and to which the third holding member <NUM> is attached.

The third holding member <NUM> holds the second optical system <NUM>, the second mirror <NUM>, and the third optical system <NUM> integrally. The second optical system <NUM> is composed of a third lens <NUM> and a fourth lens <NUM>. The third optical system <NUM> is composed of a fifth lens <NUM> and a sixth lens <NUM>. The sixth lens <NUM> is located at the tip of the projection lens <NUM> and corresponds to an exit lens that emits light. Each of the third to sixth lenses <NUM> to <NUM> is shown as a single lens for simplification in the figure, but is actually formed of a plurality of lens groups.

The second optical system <NUM> receives the light beam from the first optical system <NUM> and guides it to the projection target side. The third optical system <NUM> receives the light beam from the second optical system <NUM> and guides it to the projection target side. In this example, the second optical system <NUM> and the third optical system <NUM> enlarge the intermediate image, which is formed on the imaging plane <NUM> by the first optical system <NUM>, and projects the enlarged intermediate image onto, for example, a screen <NUM> that is a projection target. The first to third optical systems <NUM> to <NUM> are described in detail, for example, in "Projection Optical System and Projection Display Device" of <CIT>, <CIT>, or the like, and optical systems described in these can be used as the first to third optical systems <NUM> to <NUM>.

The second mirror <NUM> is arranged between the second optical system <NUM> and the third optical system <NUM>. The second mirror <NUM> bends the optical axis CL2 by reflection to an optical axis CL3. In this example, the second mirror <NUM> bends the optical axis CL2 by <NUM> ° to the optical axis CL3.

In this example, as described above, the optical axis CL1 on the incident side of the first optical system <NUM> is reflected by the first mirror <NUM> and bent by <NUM> ° to become the optical axis CL2 on the output side. The optical axis CL2 on the incident side of the second optical system <NUM> is reflected by the second mirror <NUM> and bent by <NUM> ° to become the optical axis CL3 on the output side. Accordingly, the optical axis CL3 is parallel to the optical axis CL1 in a plane including the optical axis CL1 and the optical axis CL2. That is, the projection lens <NUM> projects the light beam from the image forming panels <NUM> to <NUM> illuminated by the a light source <NUM> onto the projection target by bending the optical axis with the first mirror <NUM> and the second mirror <NUM>. Note that the optical axes CL1 to CL3 correspond to first to third optical axes of the invention.

Furthermore, since the projection lens <NUM> has a U-shaped optical path, the lens barrel <NUM>, which holds the first optical system <NUM>, the second optical system <NUM>, the first mirror <NUM>, and the second mirror <NUM>, is a U-shaped barrel.

The third holding member <NUM> has a second lens frame <NUM>, a third body part <NUM>, and a third lens frame <NUM>. The second lens frame <NUM> has a cylindrical shape and holds the second optical system <NUM>, that is, the third lens <NUM> and the fourth lens <NUM>. The outer peripheral surface of the second lens frame <NUM> fits into the inner peripheral surface of the third mounting tube <NUM>.

The third body part <NUM> is connected to the second lens frame <NUM>. The third body part <NUM> is formed of a square tube having a substantially rectangular parallelepiped shape. One corner of an upper plate 39a of the third body part <NUM> is cut obliquely, so that an inclined surface portion 39b is formed. The second mirror <NUM> is fixed to the inner surface of the inclined surface portion 39b.

The third lens frame <NUM> holds the third optical system <NUM>, that is, the fifth lens <NUM> and the sixth lens <NUM>. Further, a flange 41a is formed at the incidence-side end face of the third lens frame <NUM>. The third lens frame <NUM> is fixed by, for example, screwing the flange 41a to the third body part <NUM>, and is arranged perpendicular to the second lens frame <NUM> through the third body part <NUM>.

Note that in this example, the third lens <NUM> and the fourth lens <NUM> constituting the second optical system <NUM> are arranged between the first mirror <NUM> and the second mirror <NUM>. However, the projection lens <NUM> only needs to have a U-shaped optical path. For example, the lens constituting the second optical system <NUM> may not be arranged between the first mirror <NUM> and the second mirror <NUM>.

As shown in <FIG> and <FIG>, the housing <NUM> of the projector body <NUM> has a central section 55E and a first protruding section 55F, and the first protruding section 55F includes a power switch <NUM>, an operation button <NUM> and so on. By being provided at the protruding section, the user can easily operate buttons and switches.

The projector body <NUM> contains a light source unit <NUM>, a color separation unit <NUM>, an image forming unit <NUM>, and a control unit <NUM> (see <FIG>) in the housing <NUM>. In the following description, the optical axis CL1 corresponds to an X-axis direction (first direction), an up-down direction of the housing <NUM> orthogonal to the X-axis direction is referred to as a Z-axis direction, and a lateral direction of the housing <NUM> orthogonal to the X-axis direction and the Z-axis direction is referred to as a Y-axis direction (second direction).

The housing <NUM> is provided with a storage section <NUM>. The storage section <NUM> is an opening formed by cutting a part of the housing <NUM>. Specifically, the opening is cut out from an upper surface 55A and one side surface 55C. The upper surface 55A is a second surface of the housing <NUM> having a substantially rectangular parallelepiped shape. The upper surface 55A, which is the second surface, intersects the mounting surface 61B, which is the first surface. The storage section <NUM> is an opening having a square cross section formed in accordance with the outer shape of the projection lens <NUM>.

The projection lens <NUM> is attached to the mounting surface 61B in the X-axis direction (first direction). Since the first mounting tube <NUM> and the second mounting tube <NUM> are pivotably fitted as mentioned above, the projection lens <NUM> is rotatably supported around the optical axis CL1 between a second position (protruding position) where the optical axis CL2 is parallel to the Z-axis direction (the state shown in <FIG>) and a first position (storage position) where the optical axis CL2 is parallel to the Y-axis direction (the state shown in <FIG>).

As shown in <FIG> and <FIG>, when the projection lens <NUM> is at the first position, the second holding member <NUM> faces along the long side direction of the mounting surface 61B of the housing <NUM> (see <FIG>). Accordingly, in the state shown in <FIG>, the projection lens <NUM> is arranged inside the storage section <NUM>. Specifically, the projection lens <NUM> is housed in a position where it does not protrude from the upper surface 55A, a bottom surface 55B and the side surfaces 55C, 55D of the housing <NUM> in the Z-axis direction and the Y-axis direction. In other words, the diameter of the sixth lens <NUM> (see <FIG>) located at the tip of the projection lens <NUM> is shorter than the length of the mounting surface 61B in the short side direction. In addition, in the side view, the end of the projection lens <NUM> is located inside the long side end of the mounting surface 61B.

As shown in <FIG>, when the projection lens <NUM> including the second holding member <NUM> is at the second position, the projection lens <NUM> is disposed at a position protruding from the upper surface 55A of the housing <NUM> in the side view. Specifically, the projection lens <NUM> projects from the upper surface 55A of the housing <NUM> in the Z-axis direction, and the sixth lens <NUM> of the third optical system <NUM> is exposed.

With the above configuration, since the third optical system <NUM> is exposed when the projection lens <NUM> is at the second position, the light path of the projection lens <NUM> and the projector body <NUM> do not interfere with each other so that the light beam can be projected onto the projection target. On the other hand, when the projection lens <NUM> is at the first position, the projection lens <NUM> is housed in a position that does not protrude from the housing <NUM>, so that the projector <NUM> can be made compact without the projection lens <NUM> being an obstacle during transportation of the projector <NUM>. Further, damage due to contact between the sixth lens <NUM> and the lens barrel <NUM> can be prevented. Furthermore, when the projection lens <NUM> is at the first position, since it is stored in a position that does not protrude from the housing <NUM>, the sixth lens <NUM> is not exposed so that performance degradation due to dust or the like adhering to the lens surface of the sixth lens <NUM> can be prevented.

As shown in <FIG>, the light source unit <NUM> includes the light source <NUM> that emits light, and supplies light from the light source <NUM> to the color separation unit <NUM>. The color separation unit <NUM> separates light emitted from the light source unit <NUM> into three color lights of red, green, and blue. Each color light of red, green, and blue separated by the color separation unit <NUM> is given an image by the image forming unit <NUM>, exits from the projection lens <NUM>, and is projected on the screen <NUM>.

The light source unit <NUM> includes the light source <NUM>, a reflector <NUM>, a pair of fly-eye lenses <NUM> and <NUM>, a polarization converting element <NUM>, a mirror <NUM>, a condenser lens <NUM>, and so on. The light source <NUM> is a high-intensity lamp such as a xenon lamp, a metal halide lamp, or a super high-pressure mercury lamp, and emits natural white light having no specific polarization direction. The reflector <NUM> condenses the irradiation light irradiated by the light source <NUM> in one direction.

Since the light path of irradiation light is bent by the mirror <NUM> etc., the light source <NUM> is offset with respect to the optical axis CL1 of the projection lens <NUM>, and is arranged at a different position from the first optical system <NUM> in the Y-axis direction. Further, the light source <NUM> is arranged in the X-axis direction at a position protruding to the projection lens <NUM> side than the tip face 21A of the first lens <NUM> of the projection lens <NUM>.

As described above, the projection lens <NUM> has the optical paths of the first optical axis CL1 traveling in the X-axis direction (the first direction), of the second optical axis CL2 traveling in the Y-axis direction (the second direction), and of the third optical axis CL3 traveling in the opposite direction of the first optical axis CL1. As shown in <FIG>, since it has the U-shaped optical path, when the projection lens <NUM> is set to the first position, the optical axis CL3 of the third optical system <NUM> on the projection side is offset from the optical axis CL1 of the first optical system <NUM>. That is, when the projection lens <NUM> is set to the first position, the third optical system <NUM> is arranged in a position shifted from the first optical system <NUM> in the Y-axis direction. In this example, when the projection lens <NUM> is at the first position, the third optical system <NUM> is positioned on the same side as the light source <NUM> with respect to the optical axis CL1 in the Y-axis direction. In addition, the mounting surface 61B is located between the projection lens <NUM> and the light source <NUM>.

With the above configuration, since the third optical system <NUM> and the light source <NUM> are positioned on the same side of the optical axis CL1 in the Y-axis direction when the projection lens <NUM> is at the first position, the dimension in the Y-axis direction can be reduced, and the projector <NUM> as a whole can be made compact. Further, since the light source <NUM> is arranged at a position protruding to the projection lens <NUM> side than the tip face 21A of the first lens <NUM> in the X-axis direction, also the size in the X-axis direction can be reduced, contributing to compactness.

The fly-eye lenses <NUM> and <NUM> make the light beam converged by the reflector <NUM> substantially parallel. The fly-eye lenses <NUM> and <NUM> are composed of a microlens array or the like, uniformize the light amount distribution in the irradiation surface of the incident irradiation light, and cause the irradiation light to enter the polarization converting element <NUM>.

The polarization converting element <NUM> aligns the polarization direction of the incident irradiation light. The irradiation light whose polarization direction is aligned by the polarization converting element <NUM> is incident on the mirror <NUM>. The mirror <NUM> changes the direction of the incident irradiation light by reflection. The condenser lens <NUM> directs the irradiation light, changed in direction by the mirror <NUM>, to the color separation unit <NUM>. Accordingly, the irradiation light is supplied from the light source unit <NUM> to the color separation unit <NUM>.

The color separation unit <NUM> includes two dichromic mirrors <NUM> and <NUM>, a relay lens <NUM>, a mirror <NUM>, and a relay lens <NUM>. The color separation unit <NUM> separates the irradiation light emitted from the light source unit <NUM> into red (R), green (G), and blue (B) color lights by the dichromic mirrors <NUM> and <NUM>.

The dichromic mirror <NUM> is arranged so that the irradiation light supplied from the light source unit <NUM> is incident thereon. Further, the dichromic mirror <NUM> is formed in a substantially plate shape, and is inclined at approximately <NUM> degrees with respect to the optical axis of the irradiation light. The dichromic mirror <NUM> has the property of reflecting red light and transmitting green light and blue light. Therefore, of the irradiation light that is white light, only the red light component is reflected, and the green light component and the blue light component are transmitted.

The red light reflected by the dichromic mirror <NUM> goes to the image forming unit <NUM>. On the other hand, the green light and the blue light transmitted through the dichromic mirror <NUM> go to the dichromic mirror <NUM>.

Like the dichromic mirror <NUM>, the dichromic mirror <NUM> is formed in a substantially plate shape, and is inclined by approximately <NUM> degrees with respect to the optical axis of the irradiation light. The dichromic mirror <NUM> has the property of reflecting green light and transmitting blue light. Therefore, of the green light component and the blue light component of the irradiation light transmitted through the dichromic mirror <NUM>, the green light component is reflected and the blue light component is transmitted.

The green light reflected by the dichromic mirror <NUM> goes to the image forming unit <NUM>. On the other hand, the blue light transmitted through the dichromic mirror <NUM> is guided to the relay lens <NUM> and heads for the mirror <NUM>. Like the dichromic mirrors <NUM> and <NUM>, the mirror <NUM> is formed in a substantially plate shape, and is inclined at approximately <NUM> degrees with respect to the optical axis of the irradiation light. The blue light reflected by the mirror <NUM> is guided to the relay lens <NUM> and heads for the image forming unit <NUM>.

The image forming unit <NUM> is composed of an image forming panel <NUM> for red light, an image forming panel <NUM> for green light, an image forming panel <NUM> for blue light, mirrors <NUM>, <NUM>, a condenser lens <NUM>, a cross dichroic prism <NUM>, and so on.

Of the three color lights separated by the dichromic mirrors <NUM> and <NUM>, the red light goes to the image forming panel <NUM> for red light via the mirror <NUM>, the green light goes to the image forming panel <NUM> for green light via the condenser lens <NUM>, and the blue light goes to the image forming panel <NUM> for blue light via the mirror <NUM> and the condenser lens <NUM>.

The image forming panel <NUM> for red light is, for example, a transmission-type LCD, and is disposed between the condenser lens <NUM> and the cross dichroic prism <NUM>. The image forming panel <NUM> for red light generates red image light with image information of red component by modulating the transmitted red light, and makes the red image light incident on the cross dichroic prism <NUM>.

The image forming panel <NUM> for green light, which has the same configuration as the image forming panel <NUM> for red light, generates green image light with image information of green component by modulating the transmitted green light, and makes the green image light incident on the cross dichroic prism <NUM>. The image forming panel <NUM> for blue light, which has the same configuration as the image forming panel <NUM> for red light, generates blue image light with image information of blue component by modulating the transmitted blue light, and makes the blue image light incident on the cross dichroic prism <NUM>.

The cross dichroic prism <NUM> is formed in a substantially cubic shape using a transparent material such as glass, and includes dichroic surfaces 82a and 82b that cross each other. The dichroic surface 82b has a characteristic of reflecting red light and transmitting green light and blue light. The dichroic surface 82a has a characteristic of reflecting blue light and transmitting red light and green light. The red image light incident on the cross dichroic prism <NUM> is reflected by the dichroic surface 82b and incident on the projection lens <NUM>. The green image light passes through the dichroic surfaces 82a and 82b and enters the projection lens <NUM>. The blue image light is reflected by the dichroic surface 82a and is incident on the projection lens <NUM>.

In this way, the cross dichroic prism <NUM> causes the incident image light of each color to be incident on the projection lens <NUM> as combined image light on the same optical axis. As a result, the combined image light to which image information of each color of red, green, and blue is given is projected by the projection lens <NUM>, and a full-color image is displayed on a screen or the like.

As shown in <FIG>, the housing <NUM> accommodates the light source <NUM>, the cross dichroic prism <NUM>, and so on, and is divided into a central section 55E to which the projection lens <NUM> is connected and a protruding section protruding from the central section 55E. The protruding section has the first protruding section 55F and a second protruding section <NUM> connected to the first protruding section 55F. The projection lens <NUM> is positioned between the central section 55E and the second protruding section <NUM>. Accordingly, the housing <NUM> protects the projection lens <NUM>. Further, the mounting position of the projection lens <NUM> (the center of the fitting hole 61A) is shifted from the center position of the Y-axis direction (the second direction) of the housing <NUM>. More specifically, the mounting position of the projection lens <NUM> and the first protruding section 55F are located on the same side with respect to the center position in the Y-axis direction (the second direction) of the housing <NUM>. With this arrangement, the housing <NUM> can accomodate the projection lens <NUM> with a large size.

As shown in <FIG>, the projector body <NUM> is provided with the control unit <NUM>, the power switch <NUM>, the operation button <NUM>, the light source <NUM>, the image forming panels <NUM> to <NUM>, an image processing unit <NUM>, an media I/F (interface) <NUM>, and an angular position sensor <NUM>.

The image processing unit <NUM> is controlled by the control unit <NUM> to process the image data from a storage medium <NUM> read by the media I/F <NUM> and display the RGB three-color image on the image forming panels <NUM> to <NUM>. The image processing unit <NUM> also adjusts the size of the image projected on the screen <NUM> upon operation of the operation button <NUM>.

When the power switch <NUM> is turned on, the control unit <NUM> starts to detect the angular position of the projection lens <NUM> by the angular position sensor <NUM>. The angular position sensor <NUM> detects the angular position of the projection lens <NUM> around the optical axis CL1.

When the projection lens <NUM> is at the first position, the control unit <NUM> does not supply power to each part in the housing <NUM> such as the light source <NUM> and the image forming panels <NUM> to <NUM>. When the angular position sensor <NUM> detects that the projection lens <NUM> has been rotated from the first position to the second position, the control unit <NUM> supplies power to each part in the housing <NUM>. When the angular position sensor <NUM> detects that the projection lens <NUM> has been rotated from the second position to the first position, the control unit <NUM> stops supplying power to each part in the housing <NUM>.

With the above configuration, when the power switch <NUM> is turned on, the control unit <NUM> lights the light source <NUM> and drives the image forming panels <NUM> to <NUM> and so on just by rotating the projection lens <NUM> from the first position to the second position. Therefore, the projection onto the screen can be started immediately. To end projection on the screen, the light source <NUM> is turned off and drive of the image forming panels <NUM> to <NUM> is stopped just by rotating the projection lens <NUM> from the second position to the first position. Therefore, it can be prevented from forgetting to turn off the light source <NUM>.

The electrical configuration of the projector is not limited to that shown in <FIG>. As shown in <FIG>, the projector may be configured to include a drive unit <NUM> that drives the projection lens <NUM> between the first position and the second position. The drive unit <NUM> includes a drive motor that rotates the projection lens <NUM> about the optical axis CL1. In this case, the power switch <NUM> functions as an operation switch for starting/stopping power supply to each part in the housing <NUM> such as the light source <NUM>, the image forming panels <NUM> to <NUM>, and the drive unit <NUM>. When the power switch <NUM> is turned on, the control unit <NUM> controls the drive unit <NUM> to drive the projection lens <NUM> from the first position to the second position after the start of power supply. When the power switch <NUM> is turned off, the drive unit <NUM> is controlled to drive the projection lens <NUM> from the second position to the first position, and then power supply is stopped.

In the first example, the storage section <NUM> is provided in the projector body <NUM>, and when the projection lens <NUM> is at the first position, the storage section <NUM> is arranged inside the storage section <NUM>. However, the second example described below may be used. As shown in <FIG> and <FIG>, it may be configured to include a cover member that is connected to housing and covers the projection lens <NUM> when the projection lens <NUM> is at the first position.

In this example, a projector <NUM> includes a projector body <NUM>, the projection lens <NUM>, and a cover member <NUM>. The projector body <NUM> has a substantially rectangular parallelepiped shape, and has a rear face on which the projection lens <NUM> is attached. The internal structure of the projector body <NUM> is the same as that of the projector body <NUM> of the first example.

An engagement protrusion 93A for connection is provided on both sides of a housing <NUM> of the projector body <NUM>. The cover member <NUM> is formed in a box shape that houses the projection lens <NUM>, and a locking piece 92A is provided at a position corresponding to the engagement protrusion 93A.

The locking piece 92A has an engagement hole 92B. When the cover member <NUM> covers the projection lens <NUM>, the engagement protrusion 93A engages the engagement hole 92B to lock the locking piece 92A. Thereby, the cover member <NUM> is connected to the projector body <NUM>.

As same as in the first example, when at the first position, the projection lens <NUM> is housed in a position that does not project from an upper surface 93B, a bottom surface 93C which is the second surface of the housing <NUM>, and side surfaces 93D and 93E in the Z-axis direction and the Y-axis direction. Further, when the projection lens <NUM> is at the first position, the cover member <NUM> is connected to the projector body <NUM>, so that the projection lens <NUM> can be prevented from being damaged or performance deterioration due to dirt.

On the other hand, as same as in the first example, when at the second position, the projection lens <NUM> projects from the upper surface 93B of the housing <NUM> in the Z-axis direction, and the sixth lens <NUM> of the third optical system <NUM> is exposed.

In the first and second examples, a transmissive liquid crystal panel is used for the image forming panels <NUM> to <NUM>. However, in the embodiment of the invention described below, a DMD panel may be used as shown in <FIG>.

As shown in <FIG> and <FIG>, a projector <NUM> includes a projector body <NUM> and the projection lens <NUM>. The storage section <NUM> same as in the first example is provided in a housing <NUM> of the projector body <NUM>. The projection lens <NUM> is arranged inside the storage section <NUM> when at the first position, as same as in the first example. That is, the projection lens <NUM> is housed in a position that does not protrude from the housing <NUM> in the Z-axis direction and the Y-axis direction. On the other hand, when the projection lens <NUM> is at the second position, the projection lens <NUM> is disposed at a position protruding from the housing <NUM>. That is, the projection lens <NUM> projects from the upper surface of the housing <NUM> in the Z-axis direction, and the sixth lens <NUM> is exposed.

The housing <NUM> of the projector body <NUM> contains a light source unit <NUM>, a color wheel <NUM>, an illumination optical system <NUM>, a prism device <NUM>, and a DMD panel <NUM>.

The light source unit <NUM> includes a light source <NUM> that emits white light with high luminance and a reflector <NUM>. The color wheel <NUM> includes each color filter that transmits only red light, green light, and blue light on a disk serving as a substrate at a predetermined interval in the circumferential direction. As the color wheel <NUM> rotates, the white light from the light source <NUM> is color-separated by a predetermined time unit and is incident on the illumination optical system <NUM>. The illumination optical system <NUM> converts the color-separated light source light into illumination light having a uniform light amount distribution so that the image projected on the screen <NUM> does not have deviation in brightness.

The illumination optical system <NUM> includes a rod integrator <NUM>, relay lenses <NUM> and <NUM>, and mirrors <NUM> and <NUM>. The rod integrator <NUM> is made of, for example, glass formed in a quadrangular prism shape, and light transmitted through the color wheel <NUM> enters from one end. The light that has entered the rod integrator <NUM> undergoes total internal reflection a plurality of times, becomes irradiation light with uniform brightness, and exits from the other end. The light emitted from the light source unit <NUM> is superimposed on the projection lens <NUM>. The light then enters the rod integrator <NUM>. The irradiation light emitted from the rod integrator <NUM> enters the prism device <NUM> via the relay lenses <NUM> and <NUM> and the mirrors <NUM> and <NUM>, and then enters the projection lens <NUM>. That is, the light emitted from the light source unit <NUM> has a long optical path length because the light uses the inside of the first protruding section 55F and the inside of the central section 55E as the optical path.

Note that the light source unit <NUM>, the color wheel <NUM>, and the illumination optical system <NUM> are disposed below the prism device <NUM>, the projection lens <NUM>, and the storage section <NUM> in the Z-axis direction. In this embodiment, since the optical path of the irradiation light is bent by the mirrors <NUM>, <NUM>, and so on, the light source <NUM> is offset with respect to the optical axis CL1 of the projection lens <NUM>, and the light source <NUM> is arranged in a position shifted from the first optical system <NUM> in the Y-axis direction. Further, the light source <NUM> is shifted from the first optical system <NUM> also in the Z-axis direction.

As described above, when the projection lens <NUM> is set to the first position, the third optical system <NUM> is arranged in a position shifted from the first optical system <NUM> in the Y-axis direction. In this embodiment, when the projection lens <NUM> is at the first position, the third optical system <NUM> is located on the same side as the light source <NUM> with respect to the optical axis CL1 in the Y-axis direction. Thereby, when the projection lens <NUM> is set to the first position as same as in the first embodiment, the dimension in the Y-axis direction can be reduced, and the projector <NUM> as a whole can be made compact.

The irradiation light incident on the prism device <NUM> is incident on the DMD panel <NUM>. As is well known, the DMD panel <NUM> is provided with a number of micro mirrors that reflect irradiation light, and modulates the irradiation light for each pixel to image light having image information. The prism device <NUM> guides the irradiation light to the DMD panel <NUM> and emits the image light from the DMD panel <NUM> to the projection lens <NUM>. The projection lens <NUM> forms the image light on the screen <NUM>, so that the image is enlarged and projected.

Note that as a modification of the embodiment, as shown in <FIG>, the irradiation light may be incident on the prism device <NUM> without bending the optical path of the illumination optical system <NUM>. In this case, the light source unit <NUM>, the color wheel <NUM>, and the illumination optical system <NUM> are arranged at positions facing the prism device <NUM> and the DMD panel <NUM> without using the mirrors <NUM> and <NUM>. Also in this case, in the Y-axis direction, the third optical system <NUM> is located on the same side as the light source <NUM> with respect to the optical axis CL1. Thereby, when the projection lens <NUM> is set to the first position as same as in the above embodiment, the dimension in the Y-axis direction can be reduced, and the projector <NUM> as a whole can be made compact.

In each of the above examples and embodiment has been described in the state in which the projector is placed on a table. However, the present invention can be applied to a state in which the projector is suspended from a ceiling or the like. Further, although the example in which an image is projected onto the screen <NUM> has been described, the projection target is not limited to the screen <NUM>, and a projector can project an image onto various projection targets.

Claim 1:
A projector (<NUM>) comprising:
an image forming panel (<NUM>) for displaying images;
a light source (<NUM>) that illuminates the image forming panel
a housing (<NUM>) that houses the image forming panel (<NUM>) and the light source (<NUM>), and includes a first side surface (61B) and an upper surface (55A)_as a second surface intersecting the first side surface; and
a projection lens (<NUM>) attached to the first side surface (61B), the projection lens (<NUM>) including a first holding member through which light with a first optical axis (CL1) passes, a first reflective member (<NUM>) which bends the first optical axis (CL1) to form a second optical axis (CL2), and a second holding member through which the light with the second optical axis passes,
wherein the projection lens (<NUM>) is rotatable around the first optical axis (CL1) between a first position where the second holding member faces along the long side direction of the first side surface (61B) and a second position where the second holding member protrudes from the second surface (55A) in a side view,-and
wherein the housing (<NUM>) includes a central section (55E) and a protruding section (55F) protruding from the central section (55E), and light emitted from the light source (<NUM>) enters the projection lens (<NUM>) using the central section (55E) and the protruding section (55F) as an optical path,
characterized in that the projector further comprises:
a control unit that supplies power to each part of the housing when the projection lens is rotated from the first position to the second position, and stops supplying power to each part in the housing when the projection lens is rotated from the second position to the first position.