PROJECTION OPTICAL APPARATUS AND PROJECTOR

A projection optical apparatus according to an aspect of the present disclosure includes an optical system that image light enters, a reflector that reflects the image light that exits out of the optical system, and an enclosure that houses the optical system and at least part of the reflector, and the reflector includes a base having a first surface on which the image light is incident and a second surface opposite from the first surface, a reflection layer provided at the first surface of the base, and a heat dissipation member provided at the second surface of the base and including a protrusion protruding from the second surface.

The present application is based on, and claims priority from JP Application Serial Number 2022-117788, filed Jul. 25, 2022, the disclosure of which is hereby incorporated by reference herein in its entirety.

BACKGROUND

1. Technical Field

The present disclosure relates to a projection optical apparatus and a projector.

2. Related Art

In recent years, there has been a demand for short-focal-length projectors that are compact yet capable of displaying large projected images. As such a short-focal-length projector, there is a technology using a projection optical apparatus having a configuration in which lenses are combined with a concave mirror to enlarge an image reflected off the mirror and project the enlarged image onto a screen (see, JP-A-2011-085922, for example).

In the short-focal-length projector described above, image light is incident on the mirror of the projection optical apparatus with the image light focused into a spot on the mirror. The mirror may therefore be deformed due to heat generated by the locally high illuminance of the image light. The image light reflected off the deformed mirror is undesirably projected at a position off a predetermined position on the screen. There is therefore a problem of deterioration in the quality of the projected image due to the partial shift of the projected image light.

SUMMARY

To solve the problem described above, according to an aspect of the present disclosure, there is provided a projection optical apparatus including an optical system that image light enters, a reflector that reflects the image light that exits out of the optical system, and an enclosure that houses the optical system and at least part of the reflector, and the reflector includes a base having a first surface on which the image light is incident and a second surface opposite from the first surface, a reflection layer provided at the first surface of the base, and a heat dissipation member provided at the second surface of the base and including a protrusion protruding from the second surface.

According to another aspect of the present disclosure, there is provided a projector including a light source apparatus that outputs light, a light modulator that modulates the light from the light source apparatus, and the projection optical apparatus according to the aspect described above that projects modulated image light from the light modulator.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

Embodiments of the present disclosure will be described below in detail with reference to the drawings. In the drawings used in the description below, a characteristic portion is enlarged for convenience in some cases for clarity of the characteristic thereof, and the dimension ratio and other factors of each component are therefore not always equal to actual values.

An example of a projector according to an embodiment of the present disclosure will be described.

The projector according to the present embodiment is a projection-type image display apparatus that displays a full-color image on a screen (projection receiving surface). The projector includes three light modulators formed of liquid crystal light valves that modulate color light formed of red light, green light, and blue light.

FIG.1shows a schematic configuration of the projector according to the present embodiment.

A projector1according to the present embodiment includes a body section20, an exterior enclosure2a, and a projection optical apparatus6, as shown inFIG.1. The body section20is housed in the exterior enclosure2a. The exterior enclosure2ais made, for example, of a resin material, and has a configuration in which a plurality of members are combined with each other.

The projection optical apparatus6is disposed so as to partially protrude from the exterior enclosure2a. The projection optical apparatus6according to the present embodiment is a projection lens unit capable of ultra-short focal length projection. With the projection optical apparatus6attached, the projector1can be installed at a position close to the screen and project an image. The projection optical apparatus6is, however, not necessarily detachable from and attachable to the body section20. The configuration of the projection optical apparatus6will be described later in detail.

The body section20includes a light source apparatus2as an illumination system, a color separation system3, light modulators11R,11G, and11B, and a light combining system5.

The light source apparatus2includes a light source21, a first lens array22, a second lens array23, a polarization converter24, and a superimposing lens25. The first lens array22and the second lens array23each have a configuration in which a plurality of microlenses are arranged in a matrix in a plane perpendicular to the optical axis.

In the projector1according to the present embodiment, a lamp that is a discharge-type light source is employed as the light source21, but the light source21is not limited to a discharge-type light source. The light source21may, for example, be a solid-state light source, such as a light emitting diode and a laser, or a light source apparatus including a wavelength converter containing a phosphor that emits fluorescence when irradiated with excitation light.

Light emitted from the light source21is divided by the first lens array22into a plurality of sub-luminous fluxes. The plurality of sub-luminous fluxes are superimposed by the second lens array23and the superimposing lens25on one another in an effective display region of each of the three light modulators11R,11G, and11B, which are each an illumination target. That is, the first lens array22, the second lens array23, and the superimposing lens25form an optical integration system that illuminates the light modulators11R,11G, and11B with the light emitted from the light source21and having a substantially uniform illuminance distribution.

The polarization converter24converts the light emitted from the light source21, which is non-polarized light, into linearly polarized light that can be used by the three light modulators11R,11G, and11B.

The color separation system3separates illumination light WL from the light source apparatus2into red light LR, green light LG, and blue light LB. The color separation system3generally includes a first dichroic mirror7a, a second dichroic mirror7b, a first total reflection mirror8a, a second total reflection mirror8b, a third total reflection mirror8c, a first relay lens9a, and a second relay lens9b.

The first dichroic mirror7aseparates the illumination light WL from the light source apparatus2into the red light LR and other light formed of the green light LG and blue light LB. The first dichroic mirror7atransmits the separated red light LR and reflects the separated green light LG and blue light LB. On the other hand, the second dichroic mirror7breflects the green light LG and transmits the blue light LB to separate the other light into the green light LG and the blue light LB.

The first total reflection mirror8ais disposed in the optical path of the red light LR and reflects the red light LR having passed through the first dichroic mirror7atoward the light modulator11R. On the other hand, the second total reflection mirror8band the third total reflection mirror8care disposed in the optical path of the blue light LB and guide the blue light LB having passed through the second dichroic mirror7bto the light modulator11B. The green light LG is reflected off the second dichroic mirror7btoward the light modulator11G.

The first relay lens9aand the second relay lens9bare disposed downstream from the second dichroic mirror7bin the optical path of the blue light LB.

The light modulator11R modulates the red light LR in accordance with image information to form image light corresponding to the red light LR. The light modulator11G modulates the green light LG in accordance with image information to form image light corresponding to the green light LG. The light modulator11B modulates the blue light LB in accordance with image information to form image light corresponding to the blue light LB.

The light modulators11R,11G, and11B are each, for example, a transmissive liquid crystal panel. Pixels are arranged in each of the liquid crystal panels and modulate the light incident thereon on a pixel basis in accordance with the image information. Polarizers that are not shown are disposed on the light incident side and the light exiting side of each of the liquid crystal panels.

Field lenses10R,10G, and10B are disposed at the light incident side of the light modulators11R,11G, and11B, respectively. The field lenses10R,10G, and10B parallelize the red light LR, the green light LG, and the blue light LB to be incident on the respective light modulators11R,11G, and11B.

The light combining system5receives the image light from the light modulator11R, the image light from the light modulator11G, and the image light from the light modulator11B. The light combining system5combines the image light corresponding to the red light LR, the image light corresponding to the green light LG, and the image light corresponding to the blue light LB with one another and outputs the combined image light toward the projection optical apparatus6. The light combining system5is formed, for example, of a cross dichroic prism. The combined light generated by the light combining system5exits toward the projection optical apparatus6.

The combined light having exited out of the body section20is projected as image light IL via the projection optical apparatus6onto the projection receiving surface, such as the screen that is not shown.

The projection optical apparatus6will be described below.

The projection optical apparatus6according to the present embodiment projects an image displayed in the reduction-side conjugate plane into the enlargement-side conjugate plane to generate a projected image. In the present embodiment, the reduction-side conjugate plane corresponds to a display surface of the liquid crystal panel of each of the light modulators11R,11G, and11B, and the enlargement-side conjugate plane corresponds to the screen, which is the projection receiving surface.

The projection optical apparatus6according to the present embodiment forms an intermediate image of the displayed image at the position conjugate to the display surface of each of the light modulators11R,11G, and11B, which is the reduction-side conjugate plane, and enlarges and projects the intermediate image onto the screen, which is the enlargement-side conjugate plane.

The following description with reference to the drawings will be made by using an XYZ orthogonal coordinate system as required. The axis Z is an axis along the upward-downward direction of an image projected by the projection optical apparatus6onto the screen. The axis X is an axis parallel to an optical axis AX1of the projection optical apparatus6. The axis Y is an axis perpendicular to the axes X and Z and extending along the rightward-leftward direction of an image projected by the projection optical apparatus6onto the screen.

FIG.2is a cross-sectional view showing a schematic configuration of the projection optical apparatus6according to the present embodiment.FIG.2is a cross-sectional view of the projection optical apparatus taken along a plane parallel to the plane XZ.

The projection optical apparatus6includes a lens group (optical system)61, a first reflection mirror (reflector)62, and a first lens unit enclosure (enclosure)63, which houses the lens group61and the first reflection mirror62, as shown inFIG.2.

The lens group61is formed of a plurality of lenses and causes the image light IL from the body section20to exit toward the first reflection mirror62. In the lens group61, the plurality of lenses are arranged along the optical axis AX1. The plurality of lenses that constitute the lens group61include lenses having a variety of shapes, such as convex and concave lenses. The number, shape, dimensions, and arrangement of the lenses that constitute the lens group61are not limited to specific ones.

The first reflection mirror62reflects the image light IL having exited out of the lens group61and deflects the optical path of the image light IL. The first reflection mirror62projects the reflected image light IL onto the projection receiving surface, which is the enlargement-side conjugate plane. A reflection surface62aof the first reflection mirror62is formed of an aspherical mirror that reflects the image light IL while angularly widening the image light IL. The first reflection mirror62is so disposed that the reflection surface62afaces upward (side facing positive end of direction Z) and the side opposite from the side toward which the light exits out of the lens group61(side facing negative end of direction X). In the present embodiment, the first reflection mirror62reflects the chief ray of the image light IL, which travels along the optical axis AX1of the lens group61, obliquely backward at an acute angle with respect to the optical axis AX1. The image light IL reflected off the first reflection mirror62exits toward the screen via a light exiting section633of the first lens unit enclosure63, which will be described later.

Based on the configuration described above, the projection optical apparatus6according to the present embodiment can enlarge and project the image light IL onto the screen disposed at a short distance from the projector1.

The first lens unit enclosure63includes a lens barrel630, a mirror holder631, a light incident section632, the light exiting section633, and a first cover member634. The material, shape, dimensions, and other factors of the first lens unit enclosure63are not limited to specific ones.

The lens barrel630is a portion that houses the lens group61, and the mirror holder631is a portion that holds the first reflection mirror62. Although not shown, the lens barrel630includes supports that support the individual lenses that constitute the lens group61. In the present embodiment, the mirror holder631includes supports631a, which support the first reflection mirror62. The first reflection mirror62is attached to the supports631aof the mirror holder631with the aid of screw members64.

The light incident section632captures the image light IL having exited out of the body section20into the projection optical apparatus6. The light exiting section633causes the image light IL reflected off the first reflection mirror62out of the projection optical apparatus6. The light incident section632and the light exiting section633are each formed, for example, of a light transmissive window member. In the present embodiment, the light incident section632, for example, has a lens shape, which allows efficient capture of the image light IL.

The first lens unit enclosure63has a first opening63a. In the present embodiment, the first opening63ais provided at the mirror holder631of the first lens unit enclosure63.

The first opening63acauses the interior space of the first lens unit enclosure63to communicate with the exterior thereof. The lens group61and the first reflection mirror62are detachable from and attachable to the interior of the first lens unit enclosure63via the first opening63a. The first cover member634is detachable from and attachable to the first lens unit enclosure63to block the first opening63a.

The first cover member634hermetically seals the interior space of the first lens unit enclosure63. That is, the first lens unit enclosure63in the present embodiment has a sealing structure that seals a housing space S, which houses the lens group61and the first reflection mirror62. The thus configured first lens unit enclosure63, which suppresses entry of dust into the inner housing space S, can suppress deterioration in the optical characteristics of the lens group61and the first reflection mirror62due to dust that adheres thereto, and deformation of and damage to the lens group61and the first reflection mirror62due to the dust when caused to burn.

In a short-focal-distance projector, in general, by employing a configuration in which image light is so reflected off a reflection mirror that the image light is enlarged and projected onto a screen, the light density of the image light becomes uneven on the reflection mirror, causing the illuminance distribution formed on the reflection mirror to undesirably have locally high illuminance regions.

Also in the projection optical apparatus6according to the present embodiment, the illuminance distribution formed on the first reflection mirror62by the image light IL having exited out of the body section20has locally high illuminance regions.

FIG.3shows the illuminance distribution formed on the first reflection mirror62in the present embodiment. Specifically,FIG.3shows the illuminance distribution of the image light IL formed on a reflection layer621and further shows the maximum illuminance of the image light IL (black) and the minimum illuminance of the image light IL (white).

On the first reflection mirror62in the present embodiment, the image light IL at a lower portion (portion facing negative end of the direction Z shown inFIG.2) of the reflection surface62ahas locally high illuminance, as shown inFIG.3. An illuminance distribution SP of the image light IL has a first region SP1, where the illuminance is higher than a predetermined value. That is, the first region SP1means a region of the reflection surface62awhere the illuminance of the image light IL is locally high.

The predetermined value that defines the first region SP1is preferably greater than or equal to 50% of the maximum illuminance, more preferably, greater than or equal to 60% thereof, and most preferably, greater than or equal to 70% thereof.

In the projection optical apparatus6according to the present embodiment, the heat dissipation capability of the first reflection mirror62is enhanced to lower the temperature of the first reflection mirror62to suppress local deformation of the first reflection mirror62, so that a partial shift of the pixels of the projected image caused by the heat is suppressed.

The configurations of key parts of the projection optical apparatus6according to the present embodiment will be described below.

In the projection optical apparatus6according to the present embodiment, the first reflection mirror62includes a base620, the reflection layer621, and a first heat dissipation member622. The base620has an inner surface (first surface)620a, on which the image light is incident, and an outer surface (second surface)620b, which is opposite from the inner surface620a. The inner surface620aof the base620has a concave shape. Specifically, the inner surface620ahas, for example, a spherical shape, an aspherical shape, or a free-form surface shape.

In the present embodiment, the base620is made of a plastic material. Since plastic is more workable than glass, the inner surface620acan be readily and precisely formed into a desired shape. On the other hand, plastic tends to change in shape due to heat, and when the temperature of the reflection layer621becomes too high, the base620may be deformed.

The first reflection mirror62in the present embodiment, which includes the reflection layer621, the heat dissipation capability of which is improved by the first heat dissipation member622, as will be described later, allows suppression of the change in the shape of the base620due to heat. The first reflection mirror62thus has excellent workability and suppressed deformation due to heat.

The reflection layer621is formed along the inner surface620a. A surface621aof the reflection layer621therefore has a concave shape that conforms to the inner surface620a. In the present embodiment, the surface621aof the reflection layer621corresponds to the reflection surface62aof the first reflection mirror62.

The reflection layer621in the present embodiment is formed of a metallic or dielectric film. The metallic film that constitutes the reflection layer621is made, for example, of aluminum or silver. The dielectric film that constitutes the reflection layer621is, for example, a film that reflects visible light having wavelengths ranging from 400 nm to 700 nm. In the present embodiment, the reflection layer621is formed by using vapor deposition. That is, the reflection layer621is formed integrally with the inner surface620aof the base620.

It is assumed that the thickness of the reflection layer621is set, for example, at a value smaller than or equal to 1 μm, and that the surface621aof the reflection layer621is a quasi-mirror-finish or mirror-finish surface. Specifically, the inner surface620aof the base620is so formed that the surface roughness (Rz) of the surface621aof the reflection layer621is smaller than or equal to 0.2 μm.

The first heat dissipation member622is in contact with the outer surface620bof the base620. The term “in contact with” means that the first heat dissipation member622and the outer surface of the base620may be in direct contact with each other, or that a heat conductive member626, such as heat-dissipating grease, may be interposed between the first heat dissipation member622and the base620. The heat conductive member626may be replaced with an adhesive containing heat conductive particles.

The first heat dissipation member622is provided at least at part of the outer surface620bof the base620.

In the present embodiment, the first heat dissipation member622is provided at least at a second region SP2of the outer surface620b, as shown inFIG.2. The second region SP2is the region corresponding to the first region SP1of the reflection layer621.

Specifically, the second region SP2corresponding to the first region SP1is a region of the outer surface620bthat overlaps with the outer shape of the first region SP1in the direction of the shortest thickness of the reflection layer621and the base620. The direction of the shortest thickness of the reflection layer621corresponds to the direction along a surface normal to the surface621aof the reflection layer621, and the direction of the shortest thickness of the base620corresponds to the direction along a surface normal to the surfaces of the base620(inner surface620aand outer surface620b).

The first region SP1of the reflection layer621is a region where the illuminance is locally high and is therefore the hottest region of the surface621aof the reflection layer621. That is, out of the outer surface620bof the base620, the second region SP2corresponding to the first region SP1is the region to which the heat of the first region SP1is likely to be transferred and is therefore the hottest region.

In the present embodiment, since the first heat dissipation member622is provided at least at the second region SP2of the outer surface620bas described above, the heat of the first region SP1, which is the hottest region of the surface621aof the reflection layer621, can be dissipated to the first heat dissipation member622. The temperature of the first region SP1can therefore be efficiently lowered, whereby the temperature of the first reflection mirror62can be efficiently lowered.

The first heat dissipation member622is preferably provided in an area greater than or equal to 80% of the entire outer surface620band including the second region SP2, more preferably, across the entire outer surface620b. The heat dissipation capability of the first reflection mirror62can thus be further enhanced.

In the projection optical apparatus6according to the present embodiment, the first lens unit enclosure63having the sealed structure tends to accumulate heat therein. In contrast, the first reflection mirror62having heat dissipation capability enhanced by the first heat dissipation member622is unlikely to be affected by the heat accumulated in the enclosure. The projection optical apparatus6according to the present embodiment therefore allows both improvement in dust resistance of the first lens unit enclosure63and cooling of the first reflection mirror62.

The first heat dissipation member622in the present embodiment includes a sheet metal member623provided along the outer surface620bof the base620, and a heat pipe624connected to the sheet metal member623and protruding from the outer surface620b. That is, the first heat dissipation member622in the present embodiment includes the heat pipe624as a protrusion protruding from the outer surface620b. The heat pipe624is fixed to the sheet metal member623with screw members or an adhesive. The heat pipe624extends toward the rear side of the outer surface620bof base620diagonally downward (toward positive end of the direction X and negative end of the direction Z). The sheet metal member623is fixed to mirror holder631along with the base620with the screw members64. The first heat dissipation member622is thus caused to come into contact with the outer surface620bof the base620. The first reflection mirror62is thus fixed to the supports631aof the mirror holder631with the screw members64.

The heat pipe624is formed of a refrigerant containing pipe. The heat pipe624has one end provided with heat receiving sections65and the other end provided with heat dissipating sections66. The heat pipe624has a configuration in which the heat receiving sections65are coupled to the sheet metal member623, and the heat dissipating sections66are exposed to the space outside the first lens unit enclosure63. The heat pipe624, in which the heat received by the heat receiving sections65evaporates the refrigerant into a gas and the heat dissipating sections66dissipate the heat of the gas to condense the gas into a liquid, can cool the sheet metal member623. The heat pipe624is formed of a pipe made of metal having excellent heat conductivity, such as silver, copper, gold, and aluminum.

Part of the heat pipe624is exposed to the space outside the first lens unit enclosure63. In the present embodiment, the heat dissipating sections66of the heat pipe624are exposed to the space outside the first lens unit enclosure63. More specifically, the heat dissipating sections66of the heat pipe624are exposed to the space outside the first lens unit enclosure63via first slits634aprovided in the first cover member634. The gaps between the heat dissipating sections66and the first slits634aare filled with sealing members68. The interior of the first lens unit enclosure63is thus hermetically sealed.

The heat pipe624has a configuration in which the heat dissipating sections66, which are the portions exposed to the space outside the first lens unit enclosure63, are provided with heat dissipating fins67. The heat pipe624thus has enhanced heat dissipation capability of the heat dissipating sections66with the aid of the heat dissipating fins67.

The heat dissipating fins67are made of metal having excellent heat conductivity, such as silver, copper, gold, and aluminum, as the heat pipe624is.

The step of assembling the projection optical apparatus6according to the present embodiment will be subsequently described.

First, the first heat dissipation member622is caused to come into contact with the outer surface620bof the base620, on which the reflection layer621has been deposited, via the heat conductive member626with the aid of the screw members64to assemble the second reflection mirror162.

The first cover member634is subsequently attached to the first lens unit enclosure63to block the first opening63a. At this point of time, the heat dissipating sections66of the heat pipe624are exposed to the space outside the first lens unit enclosure63via the first slits634aof the first cover member634.

The heat dissipating fins67are subsequently attached to the heat dissipating sections66of the heat pipe624, which are exposed to the space outside the first lens unit enclosure63.

Finally, the gaps between the first slits634aof the first cover member634and the heat pipe624are filled with the sealing members68. The assembly of the projection optical apparatus6is thus completed.

As described above, the projection optical apparatus6according to the present embodiment includes the lens group61, which the image light IL enters, the first reflection mirror62, which reflects the image light IL having exited out of the lens group61, and the first lens unit enclosure63, which houses the lens group61and at least part of the first reflection mirror62, and the first reflection mirror62includes the base620, which has the inner surface620a, on which the image light IL is incident, and the outer surface620bopposite from the inner surface620a, the reflection layer621, which is provided at the inner surface620aof the base620, and the first heat dissipation member622, which is provided at the outer surface620bof the base620and including the heat pipe624protruding from the outer surface620b.

In the projection optical apparatus6according to the present embodiment, the first reflection mirror62, which reflects the image light IL, includes the first heat dissipation member622opposite from the reflection layer621, and the heat pipe624dissipates the heat absorbed from the reflection layer621by the first heat dissipation member622, the temperature of the first reflection mirror62can be lowered.

Even when the image light IL having an uneven illuminance distribution containing locally high illuminance is incident on the reflection layer621, the temperature of the reflection layer621is satisfactorily lowered, whereby a situation in which local temperature unevenness occurs at the reflection layer621can also be suppressed.

The projection optical apparatus6according to the present embodiment, in which the reflection layer621of the first reflection mirror62is unlikely to become locally hot, therefore suppresses deformation of the hot portions of the first reflection mirror62. A high-quality image having a suppressed partial shift of the pixels of the projected image caused by the heat of the first reflection mirror62can therefore be projected.

The projector1according to the present embodiment includes the light source apparatus2, which outputs illumination light, the light modulators11R,11G, and11B, which modulate the illumination light from the light source apparatus2, and the projection optical apparatus6, which projects the light modulated by the light modulators11R,11G, and11B.

The projector1according to the present embodiment, which includes the projection optical apparatus6, which suppresses a partial shift of the pixels of the projected image caused by the heat of the first reflection mirror62, can be a single-focus projector that projects a high-quality image onto a screen over a short distance.

The projector1according to the present embodiment is, for example, optimum for an interactive projector having an interactive function of reflecting on-screen detected position information in the projected image.

An interactive projector in general projects infrared light in the form of a grid pattern on a screen via an optical system different from a projection optical apparatus, and acquires information on a position on a projected image to which a user's fingertip, the tip of a pen, or any other pointing object points based on the grid pattern. It is a prerequisite for an interactive projector that the coordinates in the projected image coincide with the coordinates in the grid pattern. Therefore, if the pixels of the projected image move, the coordinates in the projected image do not coincide with the coordinates in the grid pattern, so that the interactive function cannot be fully provided. In contrast, the projector1according to the present embodiment can suppress a shift of the pixels of the projected image caused by the heat of the first reflection mirror62, whereby the interactive function can be provided in a stable manner.

Second Embodiment

Another configuration of the projection optical apparatus will be subsequently described as a second embodiment of the present disclosure. The present embodiment and the first embodiment differ from each other in terms of the structure of the reflection mirror, and the configurations of the reflection mirror and therearound will therefore be primarily described below. In the present embodiment, configurations or members common to those in the first embodiment have the same reference characters and will not be described in detail.

FIG.4is a cross-sectional view showing a schematic configuration of the projection optical apparatus according to the present embodiment.

A projection optical apparatus106according to the present embodiment includes the lens group61, a second reflection mirror (reflector)162, and a second lens unit enclosure (enclosure)163, which houses the lens group61and the second reflection mirror162, as shown inFIG.4.

The second lens unit enclosure163in the present embodiment includes the lens barrel630, the mirror holder631, the light incident section632, the light exiting section633, and a second cover member635.

The mirror holder631of the second lens unit enclosure163has a second opening163a. The second opening163acauses the interior space of the second lens unit enclosure163to communicate with the exterior thereof. The lens group61is detachable from and attachable to the interior of the second lens unit enclosure163via the second opening163a. The second cover member635is detachable from and attachable to the second lens unit enclosure163to block part of the second opening163a. The second cover member635is made, for example, of a plastic material. The second cover member635may be formed of a single member or a plurality of members.

The second reflection mirror162in the present embodiment includes the base620having the inner surface620aon which the reflection layer621is formed, and a second heat dissipation member625. The second heat dissipation member625is provided at part of the outer surface620bof the base620. The second heat dissipation member625in the present embodiment also serves as a cover member that blocks part of the second opening163a. The second heat dissipation member625along with the second cover member635blocks the second opening163a. More specifically, the second heat dissipation member625blocks the portion of the second opening163athat is not blocked by the second cover member635. That is, in the present embodiment, the entire second heat dissipation member625of the second reflection mirror162is exposed to the space outside the second lens unit enclosure163.

The second heat dissipation member625and the second cover member635hermetically seal the interior space of the second lens unit enclosure163, and therefore suppress degradation in the optical characteristics of the lens group61and the reflection layer621housed in the second lens unit enclosure163due to dust that adheres thereto, and deformation of and damage to the lens group61and the reflection layer621due to the dust caused to burn.

The second heat dissipation member625in the present embodiment is bonded to the outer surface620bof the base620. In the present embodiment, the heat conductive member626, such as heat dissipation grease, is sandwiched between the second heat dissipation member625and the outer surface620bof the base620. The heat conductivity between the second heat dissipation member625and the base620can thus be improved.

The second heat dissipation member625is a heat sink including a base section625aand heat dissipating fins625bcoupled to the base section625a. The base section625ais a metal plate provided along the outer surface620b. The heat dissipating fins625bare formed of a plurality of fin-shaped members and correspond to the protrusion protruding from the outer surface620b. Out of the heat dissipating fins625b, those provided at the outer edge of the base section625afunction as a fixing portion that fixes the second heat dissipation member625to the second cover member635, as will be described later.

The second reflection mirror162in the present embodiment has a configuration in which the base620on which the reflection layer621is deposited is fixed to the supports631aof the mirror holder631with first screw members71. The second heat dissipation member625is fixed to the second lens unit enclosure163along with the second cover member635with second screw members72. The base620and the second heat dissipation member625are bonded to each other via the heat conductive member626.

The step of assembling the projection optical apparatus106according to the present embodiment will now be described.

First, the second heat dissipation member625is bonded to the outer surface620bof the base620, on which the reflection layer621has been deposited, via the heat conductive member626to assemble the second reflection mirror162.

Subsequently, the second reflection mirror162is placed in the second lens unit enclosure163via the second opening163a, and the second reflection mirror162is then fixed to the supports631aof the mirror holder631with the first screw members71. The second cover member635is then attached to the second lens unit enclosure163. The second opening163aof the second lens unit enclosure163is thus blocked with the second heat dissipation member625of the second reflection mirror162and the second cover member635.

Finally, the second heat dissipation member625of the second reflection mirror162and the second cover member635are fixed to the second lens unit enclosure163with the second screw members72.

The assembly of the projection optical apparatus106is thus completed.

The projection optical apparatus106according to the present embodiment, which includes the second reflection mirror162including the second heat dissipation member625provided at the side opposite from the reflection layer621, which reflects the image light IL, can lower the temperature of the second reflection mirror162through dissipation of the heat of the reflection layer621via the second heat dissipation member625. The projection optical apparatus106according to the present embodiment, which suppresses deformation of the second reflection mirror162due to a locally high temperature of the reflection layer621, can therefore project a high-quality image having a suppressed partial shift of the pixels of the projected image caused by the heat of the second reflection mirror162.

Third Embodiment

Another configuration of the projection optical apparatus will be subsequently described as a third embodiment of the present disclosure. The present embodiment and the first embodiment differ from each other in terms of the structure of the reflection mirror, and the configurations of the reflection mirror and therearound will therefore be primarily described below. In the present embodiment, configurations or members common to those in the first embodiment have the same reference characters and will not be described in detail.

FIG.5is a cross-sectional view showing a schematic configuration of the projection optical apparatus according to the present embodiment.

A projection optical apparatus206according to the present embodiment includes the lens group61, a third reflection mirror (reflector)262, and a third lens unit enclosure (enclosure)263, which houses the lens group61and the third reflection mirror262, as shown inFIG.5.

The third lens unit enclosure263in the present embodiment includes the lens barrel630, the mirror holder631, the light incident section632, the light exiting section633, and a third cover member636.

The mirror holder631of the third lens unit enclosure263has a third opening263a. The third opening263acauses the interior space of the third lens unit enclosure263to communicate with the exterior thereof. The lens group61and the third reflection mirror262are detachable from and attachable to the interior of the third lens unit enclosure263via the third opening263a. The third cover member636is detachable from and attachable to the third lens unit enclosure263to block the third opening263a. The third cover member636is made, for example, of a plastic material. The third cover member636may be formed of a single member or a plurality of members.

The third reflection mirror262in the present embodiment includes the base620having the inner surface620aon which the reflection layer621is formed, a third heat dissipation member627, and the heat conductive member626.

The third heat dissipation member627in the present embodiment includes the sheet metal member623provided along the outer surface620bof the base620, and the heat pipe624connected to the sheet-metal member623and protruding from the outer surface620b.

The third reflection mirror262in the present embodiment and the first reflection mirror62in the first embodiment differ from each other in terms of the direction in which the heat pipe extends. The heat pipe624in the first embodiment extends toward the rear side of the outer surface620bof base620diagonally downward (toward positive end of direction X and negative end of direction Z). In contrast, the heat pipe624in the present embodiment extends toward the rear side of the outer surface620bof base620diagonally upward (toward positive end of direction X and positive end of direction Z) with a small distance between the heat pipe624and the outer surface620b, and then extends upward (toward positive end of direction Z).

In the present embodiment, the heat dissipating section66of the heat pipe624is exposed to the space outside the third lens unit enclosure263via a third slit636aprovided in the third cover member636. The heat pipe624has a configuration in which the heat dissipating section66, which is exposed to the space outside the third lens unit enclosure263, is provided with the heat dissipating fins67. The gap between the heat dissipating section66and the third slit636ais filled with the sealing member68. The interior of the third lens unit enclosure263is thus hermetically sealed.

The third cover member636in the present embodiment includes a pipe holder636b, which holds part of the heat pipe624. The heat pipe624is thus held by the third lens unit enclosure263via the third cover member636, whereby the heat pipe624can be held in a stable manner. Therefore, rattling of the heat pipe624can be suppressed, and disconnection between the heat pipe624and the sheet metal member623and other problems can be avoided.

The step of assembling the projection optical apparatus206according to the present embodiment will now be described.

First, the third heat dissipation member627is caused to come into contact with the outer surface620bof the base620, on which the reflection layer621has been deposited, via the heat conductive member626with the aid of the screw members64to assemble the third reflection mirror262.

The third cover member636is subsequently attached to the third lens unit enclosure263to block the third opening263a. At this point of time, the heat dissipating section66of the heat pipe624is exposed to the space outside the third lens unit enclosure263via the third slit636aof the third cover member636.

The heat dissipating fins67are subsequently attached to the heat dissipating section66of the heat pipe624, which is exposed to the space outside the third lens unit enclosure263.

Finally, the gap between the third slit636aof the third cover member636and the heat pipe624is filled with the sealing member68. The assembly of the projection optical apparatus206is thus completed.

The projection optical apparatus206according to the present embodiment, which includes the third reflection mirror262including the third heat dissipation member627to suppress deformation of the third reflection mirror262due to a locally high temperature of the reflection layer621, can also project a high-quality image having a suppressed partial shift of the pixels of the projected image caused by the heat of the third reflection mirror262.

Fourth Embodiment

Another configuration of the projection optical apparatus will be subsequently described as a fourth embodiment of the present disclosure. The present embodiment and the first embodiment differ from each other in terms of the structure of the reflection mirror, and the configurations of the reflection mirror and therearound will therefore be primarily described below. In the present embodiment, configurations or members common to those in the first embodiment have the same reference characters and will not be described in detail.

FIG.6is a cross-sectional view showing a schematic configuration of the projection optical apparatus according to the present embodiment.FIG.6is a cross-sectional view of the projection optical apparatus taken along a plane parallel to the plane XY.

A projection optical apparatus306according to the present embodiment includes the lens group61, a fourth reflection mirror (reflector)362, and a fourth lens unit enclosure (enclosure)363, which houses the lens group61and the fourth reflection mirror362, as shown inFIG.6.

The fourth lens unit enclosure363in the present embodiment includes the lens barrel630, the mirror holder631, the light incident section632, the light exiting section633, and a fourth cover member637.

The mirror holder631of the fourth lens unit enclosure363has a fourth opening363a. The fourth opening363acauses the interior space of the fourth lens unit enclosure363to communicate with the exterior thereof. The lens group61and the fourth reflection mirror362are detachable from and attachable to the interior of the fourth lens unit enclosure363via the fourth opening363a. The fourth cover member637is detachable from and attachable to the fourth lens unit enclosure363to block the fourth opening363a. The fourth cover member637is made, for example, of a plastic material. The fourth cover member637may be formed of a single member or a plurality of members.

The fourth reflection mirror362in the present embodiment includes the base620having the inner surface620aon which the reflection layer621is formed, a fourth heat dissipation member628, and the heat conductive member626.

The fourth heat dissipation member628in the present embodiment includes the sheet metal member623provided along the outer surface620bof the base620, and the heat pipe624connected to the sheet metal member623and protruding from the outer surface620b.

The fourth reflection mirror362in the present embodiment and the third reflection mirror262in the third embodiment differ from each other in the direction in which the heat pipe extends. The heat pipe624in the third embodiment extends toward the rear side of the outer surface620bof base620diagonally upward (toward positive end of direction X and positive end of direction Z) with a small distance between the heat pipe624and the outer surface620b, and then extends upward (toward positive end of direction Z). In contrast, the heat pipe624in the present embodiment is provided along the rear surface of the outer surface620bof the base620and extends toward the opposite ends in the rightward-leftward direction (axis-Y direction).

The fourth cover member637in the present embodiment includes a pipe holder638, which holds the opposite ends of the heat pipe624in the rightward-leftward direction. The heat pipe624is thus held by the fourth lens unit enclosure363via the fourth cover member637, whereby the heat pipe624can be held in a stable manner. Therefore, rattling of the heat pipe624can be suppressed, and disconnection between the heat pipe624and the sheet metal member623and other problems can be avoided.

In the present embodiment, the heat dissipating sections66of the heat pipe624are exposed to the space outside the fourth lens unit enclosure363via fourth slits638aprovided in the pipe holder638of the fourth cover member637. The heat pipe624has a configuration in which the heat dissipating sections66, which are exposed to the space outside the fourth lens unit enclosure363, are provided with the heat dissipating fins67. The gaps between the heat dissipating sections66and the fourth slits638aare filled with the sealing members68. The interior of the fourth lens unit enclosure363is thus hermetically sealed.

The step of assembling the projection optical apparatus306according to the present embodiment will now be described.

First, the fourth heat dissipation member628is caused to come into contact with the outer surface620bof the base620, on which the reflection layer621has been deposited, via the heat conductive member626with the aid of the screw members64to assemble the fourth reflection mirror362.

The fourth cover member637is subsequently attached to the fourth lens unit enclosure363to block the fourth opening363a. At this point of time, the heat dissipating sections66of the heat pipe624are exposed to the space outside the fourth lens unit enclosure363via the fourth slits638aof the pipe holder638of the fourth cover member637.

The heat dissipating fins67are subsequently attached to the heat dissipating sections66of the heat pipe624, which are exposed to the space outside the fourth lens unit enclosure363.

Finally, the gaps between the fourth slits638aof the pipe holder638and the heat pipe624are filled with the sealing members68. The assembly of the projection optical apparatus306is thus completed.

The projection optical apparatus306according to the present embodiment, which includes the fourth reflection mirror362including the fourth heat dissipation member628to suppress deformation of the fourth reflection mirror362due to a locally high temperature of the reflection layer621, can also project a high-quality image having a suppressed partial shift of the pixels of the projected image caused by the heat of the fourth reflection mirror362.

The technical scope of the present disclosure is not limited to the embodiments described above, and a variety of changes can be made thereto to the extent that the changes do not depart from the intent of the present disclosure.

In addition to the above, the number, arrangement, shape, material, and other specific configurations of the variety of components that constitute the projection optical apparatus are not limited to those in the embodiments described above and can be changed as appropriate.

For example, the aforementioned embodiments have been described with reference to the case where the first reflection mirror62is a mirror having the concave reflection surface62a, and the present disclosure is also applicable to a projection optical apparatus using a reflection mirror having a convex or planar reflection surface.

The aforementioned embodiments have been described with reference to the case where the protrusion, which is part of the heat dissipation member, protrudes outward from the lens unit enclosure, and the entire heat dissipation member may instead be housed in the lens unit enclosure. The thus configured projection optical apparatus, in which providing the heat dissipation member improves the heat dissipation capability of the reflection mirror, can also project a high-quality image having a suppressed partial shift of the pixels of the projected image due to the heat of the reflection mirror.

The aforementioned embodiments have been described with reference to the projection optical apparatus6used in the projector1, which projects visible light as the image light onto the screen. Visible light is therefore used as the light projected by the projection optical apparatus6. Depending on the type and application of the light source of the projector, however, a film that reflects near-infrared or infrared light may be used as the dielectric film that constitutes the reflection layer621.

The light modulators11R,11G, and11B are each not limited to a transmissive liquid crystal panel. The light modulators11R,11G, and11B may instead each be a reflective light modulator, such as a reflective liquid crystal panel. Still instead, for example, a digital micromirror device that includes micromirrors as pixels and controls the direction in which light incident thereon exits on a micromirror basis to modulate the light emitted from the light source21may be employed. Furthermore, the configuration in which a light modulator is provided for each of a plurality of color luminous fluxes is not necessarily employed, and a single light modulator may modulate the plurality of color luminous fluxes in a time division manner.

In the embodiments described above, the light source apparatus according to the present disclosure is used in a projector by way of example, but not necessarily. The light source apparatus according to the present disclosure may be used as a lighting apparatus, such as a headlight of an automobile.

The present disclosure will be summarized below as additional remarks.

Additional Remark 1

A projection optical apparatus including an optical system that image light enters, a reflector that reflects the light that exits out of the optical system, and an enclosure that houses the optical system and at least part of the reflector, the reflector including a base having a first surface on which the image light is incident and a second surface opposite from the first surface, a reflection layer provided at the first surface of the base, and a heat dissipation member provided at the second surface of the base and including a protrusion protruding from the second surface.

The projection optical apparatus according to the configuration described above, in which the reflector, which reflects light, includes the heat dissipation member opposite from the reflection layer, and the heat dissipation member dissipates heat absorbed from the reflection layer via the protrusion, can lower the temperature of the reflector.

Even when light having an uneven illuminance distribution containing locally high illuminance is incident on the reflection layer, the temperature of the reflection layer is satisfactorily lowered, whereby the situation in which local temperature unevenness occurs at the reflection layer can be suppressed.

The projection optical apparatus having the configuration described above, in which the reflection layer of the reflector is unlikely to become locally hot, therefore suppresses deformation of the hot portions of the reflector. A high-quality image having a suppressed partial shift of the projected image light caused by the heat of the reflector can therefore be projected.

Additional Remark 2

The projection optical apparatus described in the additional remark 1, in which an illuminance distribution formed by the light at the reflection layer has a first region where the illuminance is higher than a predetermined value, and the heat dissipation member is provided at the second surface at least at a second region thereof corresponding to the first region.

According to the configuration described above, in which a heat conductive layer is provided at least at the second region of the second surface as described above, the heat can be efficiently dissipated from the first region, which is the hottest region of the surface of the reflection layer, toward the heat conductive layer. The temperature of the first region, which is the hottest region, is therefore efficiently lowered, whereby the temperature of the reflector can be efficiently lowered.

Additional Remark 3

The projection optical apparatus described in the additional remark 1 or 2, in which the heat dissipation member is a heat sink including a heat dissipating fin as the protrusion, and at least part of the heat dissipating fin is exposed to a space outside the enclosure.

According to the configuration described above, the heat absorbed by the heat sink from the reflection layer can be efficiently dissipated from the portion exposed to the space outside the enclosure. The cooling performance of the reflector can thus be improved. Furthermore, since the heat sink does not release the heat inside the enclosure, an increase in the temperature of the interior of the enclosure can be suppressed.

Additional Remark 4

The projection optical apparatus described in the additional remark 1 or 2, in which the heat dissipation member includes a heat pipe as the protrusion, and at least part of the heat pipe is exposed to a space outside the enclosure.

According to the configuration described above, the heat absorbed by the heat pipe from the reflection layer can be efficiently dissipated from the portion exposed to the space outside the enclosure. The cooling performance of the reflector can thus be improved. Furthermore, since the heat pipe does not release the heat inside the enclosure, an increase in the temperature of the interior of the enclosure can be suppressed.

Additional Remark 5

The projection optical apparatus described in the additional remark 4, in which a heat dissipating fin is provided at a portion of the heat pipe that is exposed to the space outside the enclosure.

According to the configuration described above, the heat dissipation capability of the heat pipe is improved by the heat dissipating fin, whereby the cooling performance of the reflector can be further enhanced.

Additional Remark 6

The projection optical apparatus described in any one of the additional remarks 1 to 5, in which the enclosure has a hermetically sealed structure that seals a housing space that houses the optical system and the reflector.

The configuration described above, which suppresses entry of dust into the housing space in the enclosure, suppresses deterioration in the optical characteristics of the optical system and the reflector due to dust that adheres thereto, and deformation of and damage to the optical system and the reflector due to the dust caused to burn.

Additional Remark 7

The projection optical apparatus described in any one of the additional remarks 1 to 6, in which the base is made of a plastic material.

The configuration described above can improve the workability of the reflector. The reflector can therefore be readily processed into a desired shape.

Additional Remark 8

The projection optical apparatus described in any one of the additional remarks 1 to 7, in which the reflection layer has a concave shape.

According to the configuration described above, in which the reflector including the concave reflection layer is provided, a single-focus projection optical apparatus can be provided.

Additional Remark 9

The projection optical apparatus described in any one of the additional remarks 1 to 8, in which the heat dissipation member also serves as a cover member that blocks an opening provided in the enclosure.

According to the configuration described above, in which the heat dissipation member also serves as a cover member that blocks the opening of the enclosure, the number of parts that constitute the projection optical apparatus can be reduced. The cost of the projection optical apparatus can thus to be reduced.

Additional Remark 10

The projection optical apparatus described in any one of the additional remarks 1 to 9, in which the image light that exits via a reduction-side conjugate plane enters the optical system, and the reflector reflects and projects the image light into an enlargement-side conjugate plane.

According to the configuration described above, a single-focus projection optical apparatus that projects a display image in the reduction-side conjugate plane into the enlargement-side conjugate plane to generate projected image light can be provided.

Additional Remark 11

A projector including a light source apparatus that outputs light, a light modulator that modulates the light from the light source apparatus, and the projection optical apparatus described in any one of additional remarks 1 to 10 that projects modulated image light from the light modulator.

The thus configured projector, which includes the projection optical apparatus, which suppresses a partial shift of the projected image light caused by the heat of the reflector, can be a single-focus projector that projects a high-quality image onto a screen over a short distance.

The projector having the configuration described above, which can suppress a partial shift of the image light projected onto the screen, is optimum for a projector having an interactive function of reflecting on-screen detected position information in the projected image.