Patent ID: 12216294

DESCRIPTION OF EXEMPLARY EMBODIMENTS

First Embodiment

A first embodiment of the present disclosure will be described below with reference to the drawings.

In the present specification, the primary component means the most abundant component among the components of a composition.

Exterior Configuration of Projector

FIG.1is a side view showing how a projector1according to the present embodiment is used.FIG.2is a perspective view showing the external appearance of the projector1.

The projector1according to the present embodiment is an image display apparatus that forms an image according to image information and projects the formed image onto a projection receiving surface PS, such as a screen, as shown inFIG.1. For example, the projector1is used with the projector1installed on a floor, a stand, or any other installation surface or with the projector1suspended from, for example, a ceiling or a wall. The projector1includes an exterior enclosure2, which forms the exterior of the projector1, as shown inFIGS.1and2.

Configuration of Exterior Enclosure

The exterior enclosure2includes a top surface section21, a bottom surface section22, a front surface section23, a rear surface section24, a left side surface section25, and a right side surface section26and is formed in a substantially rectangular parallelepiped shape, as shown inFIG.2.

The top surface section21and the bottom surface section22are surfaces of the exterior enclosure2that are opposite from each other.

The front surface section23, the rear surface section24, the left side surface section25, and the right side surface section26are side surface sections that intersect with the top surface section21and the bottom surface section22. The front surface section23and the rear surface section24are surfaces opposite from each other, and the left side surface section25and the right side surface section26are surfaces opposite from each other.

In the state shown inFIG.1, in which the projector1is used, the projector1is so installed that the top surface section21faces upward and the rear surface section24faces the projection receiving surface PS.

It is assumed in the following description that three directions perpendicular to one another are called directions +X, +Y, and +Z. It is assumed in the present embodiment that the direction +X is the direction from the left side surface section25toward the right side surface section26, the direction +Y is the direction from the bottom surface section22toward the top surface section21, and the direction +Z is the direction from the front surface section23toward the rear surface section24. That is, in the present embodiment, the directions +X, +Y, and +Z are perpendicular to one another. Although not illustrated, the direction opposite the direction +X is called a direction −X, the direction opposite the direction +Y is called a direction −Y, and the direction opposite the direction +Z is called a direction −Z.

The top surface section21has a first inclining section211, a second inclining section212, a recess213, and an image opening214.

The first inclining section211and the second inclining section212face each other in the direction +Z. The first inclining section211is located in a position facing in the direction −Z or on the side facing the front surface section23, and the second inclining section212is located in a position facing in the direction +Z or on the side facing the rear surface section24.

In detail, the first inclining section211inclines toward the negative side of the direction Y, which is the side facing the bottom surface section22, in the direction from a portion of the top surface section21, a portion facing the front surface section23, toward the positive side of the direction Z, which is the side facing the rear surface section24.

The second inclining section212inclines toward the positive side of the direction Y, which is the direction away from the bottom surface section22, in the direction from the +Z-direction end of the first inclining section211toward the positive side of the direction Z.

The recess213is provided in the first inclining section211. The recess213is formed so as to incline toward the negative sides of the directions Z and Y.

The image opening214is an opening through which image light outputted from a projection optical apparatus4passes. The reason why the second inclining section212is provided continuously with the first inclining section211, where the image aperture214is located, is to prevent the light having exited via the image aperture214from being blocked by the structure of the top surface section21.

Internal Configuration of Projector

FIG.3is a diagrammatic view showing the configuration of an image projection apparatus3.

In addition to the exterior enclosure2, the projector1includes the image projection apparatus3accommodated in the exterior enclosure2, as shown inFIG.3. The projector1further includes, although not shown, a power supply, a cooler, and a controller accommodated in the exterior enclosure2in addition to the image projection apparatus3. The power supply supplies electronic parts that form the projector1with electric power. The cooler cools cooling targets that form the projector1. The controller controls the operation of the projector1.

Configuration of Image Projection Apparatus

The image projection apparatus3projects image light that forms an image according to image information inputted from the controller. The image projection apparatus3includes a light source31, an image generator32, and a projection optical apparatus4.

Configuration of Light Source

The light source31outputs light to a homogenizer33of the image generator32. The configuration of the light source31may, for example, include a solid-state light source that outputs blue light that is excitation light and a wavelength converter that converts in terms of wavelength part of the blue light outputted from the solid-state light source into fluorescence containing green light and red light. The configuration of the light source31may instead, for example, include a light source lamp, such as an ultrahigh pressure mercury lamp, as the light source and may still instead include solid-state light sources that individually output blue light, green light, and red light.

Configuration of Image Generator

The image generator32modulates the light outputted from the light source31to generate image light according to the image information inputted from the controller. The image generator32includes the homogenizer33, a color separator34, a relay section35, and an image formation section36.

The homogenizer33homogenizes the light outputted from the light source31. The homogenized light travels via the color separator34and the relay section35and illuminates a modulation region of each light modulator363, which will be described later. The homogenizer33includes two lens arrays331and332, a polarization converter333, and a superimposing lens334.

The color separator34separates the light incident from the homogenizer33into the red light, the green light, and the blue light. The color separator34includes two dichroic mirrors341and342and a reflection mirror343, which reflects the blue light separated by the dichroic mirror341.

The relay section35is provided in the optical path of the red light, which is longer than the optical paths of the green light and the blue light, and suppresses loss of the red light. The relay section35includes a light-incident-side lens351, relay lenses353, reflection mirrors352and354. In the present embodiment, the relay section35is provided in the optical path of the red light, but not necessarily. For example, the blue light may be configured to have an optical path longer than those of the red light and the green light, and the relay section35may be provided in the optical path of the blue light.

The image formation section36modulates the red light, the green light, and the blue light incident thereon and combines the modulated red light, green light, and blue light with one another to form image light. The image formation section36includes three field lenses361, three light-incident-side polarizers362, three light modulators363, three viewing angle compensators364, and three light-exiting-side polarizers365, which are provided in accordance with the incident red light, green light, and blue light, and one light combiner366.

The light modulators363modulate the light outputted from the light source31. The three light modulators363include a light modulator363R, which modulates the red light, a light modulator363G, which modulates the green light, and a light modulator363B, which modulates the blue light. The light modulators363are each formed of a transmissive liquid crystal panel, and the light-incident-side polarizers362, the light modulators363, and the light-exiting-side polarizers365form liquid crystal light valves.

The light combiner366combines the blue light modulated by the light modulator363B, the green light modulated by363G, and the red light modulated by363R with one another to form image light and outputs the formed image light to the projection optical apparatus4. In the present embodiment, the light combiner366is formed of a cross dichroic prism and can instead be formed, for example, of a plurality of dichroic mirrors.

Configuration of Projection Optical Apparatus

The projection optical apparatus4is a projection lens that projects the image light generated by the image generator32onto the projection receiving surface PS. That is, the projection optical apparatus4projects the light modulated by the light modulators363. The projection optical apparatus4reflects the image light incident in the direction −Z from the image generator32in the directions +Z and +Y and widens the angle of the image light.

The light modulators363are disposed in the demagnifying-side image formation plane of the projection optical apparatus4.

The projection receiving surface PS is disposed in the magnifying-side image formation plane of the projection optical apparatus4. The final image is projected on the projection receiving surface PS.

FIG.4is a diagrammatic view showing the configuration of the projection optical apparatus4. In other words,FIG.4is a beam diagram showing beams passing through the projection optical apparatus4.

The projection optical apparatus4includes a first optical system41, a second optical system42, and an aperture43, as shown inFIG.4.

A first optical axis N1of the first optical system41and a second optical axis N2of a reflection surface52of the second optical system42extend in the direction +Z. The light modulators363form a projection image in a position shifted in the direction +Y from the first optical axis N1of the first optical system41. The projection receiving surface PS is installed in a position shifted in the direction +Y from the first optical axis N1of the first optical system41.

Configuration of First Optical System

The first optical system41is a refractive optical system including a plurality of lenses L1, L2, L3, L4, L5, L6, L7, L8, L9, and L10.

The lenses L1to L10are arranged in the presented order from the demagnifying side toward the magnifying side. In the present embodiment, the lens L2is a joined lens formed of a lens L21and a lens L22joined to each other. The lens L3is a joined lens formed of a lens L31and a lens L32joined to each other. The lens L4is a joined lens formed of a lens L41and a lens L42joined to each other. The lens L7is a joined lens formed of a lens L71and a lens L72joined to each other. The lens L8is a joined lens formed of a lens L81and a lens L82joined to each other. The aperture43is disposed between the lens L4and the lens L5.

In the first optical system41, the lens L10, which is located in a position closest to the magnifying side, has aspheric surfaces both on the magnifying and demagnifying sides. In the first optical system41, the lens L9, which is the second lens next to the lens closest to the magnifying side, also has aspheric surfaces both on the magnifying and demagnifying sides.

In the first optical system41, the lens L9has positive power. The first optical system41as a whole has positive power. Therefore, between the first optical system41and the second optical system42, the distance between the chief rays decreases as they approach the second optical system42.

Configuration of the Second Optical System

The second optical system42reflects and magnifies the image light incident from the first optical system41. In the present embodiment, the second optical system42is formed of one optical element5A. That is, the projection optical apparatus4includes the optical element5A.

The optical element5A is disposed on the first optical axis N1of the first optical system41. The optical element5A has a first transmission surface51, a reflection surface52, and a second transmission surface53sequentially arranged from the demagnifying side toward the magnifying side.

In the optical element5A, the second optical axis N2of the reflection surface52coincides with the first optical axis N1.

The first transmission surface51is a −Y-direction region of a surface of the optical element5A, the surface facing the first optical system41. The first transmission surface51is a convexly curved surface protruding toward the demagnifying side. The first transmission surface51transmits the image light incident from the first optical system41into the optical element5A. In other words, the first transmission surface51is a light incident surface of the optical element5A, the surface on which the image light is incident from the first optical system41.

The reflection surface52is a reflection coating layer provided on a surface of the optical element5A, the surface opposite from the first transmission surface51. The reflection surface52is provided on a convex portion of the optical element5A, the portion protruding in the direction −Z from the surface opposite from the first optical system41, and has a concavely curved shape. The reflection surface52magnifies the image light having entered the optical element5A via the first transmission surface51while reflecting the image light in the directions +Y and +Z.

The second transmission surface53is a +Y-direction region of a surface of the optical element5A, the surface facing the first optical system41. That is, the second transmission surface53is a convexly curved surface protruding toward the magnifying side. The second transmission surface53transmits the image light reflected off the reflection surface52and traveling through the interior of the optical element5A and causes the image light to exit out of the optical element5A. In other words, the second transmission surface53is a light exiting surface via which the optical element5A outputs the image light. In the present embodiment, the first transmission surface51and the second transmission surface53are formed at the same surface of the optical element5A. That is, the first transmission surface51and the second transmission surface53are formed at a surface of the optical element5A, the surface facing the first optical system41.

The optical element5A is designed by using the second optical axis N2of the reflection surface52as the axis in the design stage. In other words, the second optical axis N2is the design-stage optical axis of the first transmission surface51, the reflection surface52, and the second transmission surface53.

The first transmission surface51and the reflection surface52are disposed in positions shifted in the direction −Y from the second optical axis N2, and the second transmission surface53is disposed in a position shifted in the direction +Y from the second optical axis N2.

In the present disclosure, the first transmission surface51, the reflection surface52, and the second transmission surface53of the optical element5A each have a rotationally symmetric shape around the second optical axis N2. The first transmission surface51, the reflection surface52, and the second transmission surface53are each provided within an angular range of 180° around the second optical axis N2.

The first transmission surface51, the reflection surface52, and the second transmission surface53are each an aspheric surface. The first transmission surface51, the reflection surface52, and the second transmission surface53may instead each be a free-form surface. The free-form surface is one form of the shape of an aspheric surface. In this case, the free-form surface is designed by using the second optical axis N2as the design-stage axis. Therefore, also in the case where one of the first transmission surface51, the reflection surface52, and the second transmission surface53is a free-form surface in the projection optical apparatus4, the second optical axis N2of the reflection surface52is called the optical axis of the optical element5A.

Members that Form Optical Element

FIG.5is an enlarged diagrammatic view showing the optical element5A.

The optical element5A includes a first light-transmissive member61, a second light-transmissive member62, and a third light-transmissive member63. In addition, although not shown inFIG.5, the optical element5A includes a first joining member64, a second joining member65, and a spacer66(seeFIG.6). The first joining member64, the second joining member65, and the spacer66are provided between the first light-transmissive member61and the second light-transmissive member62. The optical element5A further includes a third joining member67, a fourth joining member68, and a spacer69(seeFIG.7).

Configuration of First Light-Transmissive Member

The first light-transmissive member61is disposed in the optical element5A on the side opposite from the first optical system41with the second light-transmissive member and the third light-transmissive member63interposed therebetween. That is, the first light-transmissive member61is disposed in the optical element5A in a position closest to the negative side of the direction Z. In other words, the first light-transmissive member61is disposed on the magnifying side of the second light-transmissive member62and the third light-transmissive member63.

The first light-transmissive member61is a light-transmissive member made of a first resin and is a lens in the present embodiment. The first resin is a resin material containing a cycloolefin polymer as the primary component, but not necessarily. The first resin may instead be another transparent optical resin material. Other examples of the transparent optical resin material may include a resin material containing an acrylic resin, such as polycarbonate and polymethylmethacrylate.

The first light-transmissive member61has a first surface611, which faces in the direction −Z, and a second surface612, which is provided on the side opposite from the first surface611. That is, the first surface611of the first light-transmissive member61is disposed on the magnifying side, and the second surface612of the first light-transmissive member61is disposed on the demagnifying side.

The first surface611is a convexly curved surface protruding in the direction −Z and has an aspherical shape. A reflection layer is formed at the first surface611, and the first surface611thus forms the reflection surface52of the optical element5A. The reflection surface52widens the angle of the image light incident thereon while reflecting the image light in the directions +Y and +Z. In this process, the image light reflected off the reflection surface52is focused at a predetermined focused light section PT in the optical element5A and then travels in the directions +Y and +Z with the angle of the image light widened. In the present embodiment, the focused light section PT is provided in the second light-transmissive member62. That is, the first surface611of the first light-transmissive member61focuses the light incident thereon in the second light-transmissive member62.

The second surface612corresponds to a first joint surface. The second surface612is a surface facing a first surface621of the second light-transmissive member62and is a spherical, concavely curved surface facing in the direction +Z. The second surface612is joined to the first surface621of the second light-transmissive member62via the first joining member64and the second joining member65(seeFIG.6).

Configuration of Second Light-Transmissive Member

The second light-transmissive member62is a lens disposed in a position shifted in the direction +Z from the first light-transmissive member61. In other words, the second light-transmissive member62is disposed between the first light-transmissive member61and the third light-transmissive member63in the direction +Z. That is, the second light-transmissive member62is disposed on the demagnifying side of the first light-transmissive member61and on the magnifying side of the third light-transmissive member63. The outer diameter of the second light-transmissive member62is greater than the outer diameter of the first light-transmissive member61. The second light-transmissive member62has the first surface621facing in the direction −Z and a second surface622provided on the side opposite from the first surface621. That is, the first surface621of the second light-transmissive member62is disposed on the magnifying side, and the second surface622of the second light-transmissive member62is disposed on the demagnifying side.

The first surface621corresponds to a second joint surface. The first surface621is a surface facing the second surface612of the first light-transmissive member61and is a spherical, convexly curved surface protruding in the direction −Z. The first surface621is joined to the second surface612via the first joining member64and the second joining member65(seeFIG.6).

The second surface622corresponds to a fourth joint surface. The second surface622is a spherical, convexly curved surface protruding in the direction +Z, as the second surface612. The second surface622is joined to a first surface631of the third light-transmissive member63via the third joining member67and the fourth joining member68(seeFIG.7).

As described above, the focused light section PT, where the image light reflected off the reflection surface52is focused is provided in the second light-transmissive member62. In the focused light section PT, where the optical density is high, the temperature tends to be high and the optical characteristics are likely to change.

In contrast, the second light-transmissive member62is made of a material different from that of the first light-transmissive member61. In detail, the second light-transmissive member62is made of a material that is less likely to deteriorate by light and heat than the material of which the first light-transmissive member61is made. That is, the heat resistance of the second light-transmissive member is higher than the heat resistance of the first light-transmissive member61. Furthermore, the optical transmittance of the second light-transmissive member62is higher than the optical transmittance of the first light-transmissive member61. Specifically, the second light-transmissive member62is made of glass. The thus formed second light-transmissive member62can suppress changes in the optical characteristics thereof and in turn changes in the optical characteristics of the optical element5A due to the deformation or transformation of the second light-transmissive member62. The heat resistance of the second light-transmissive member62is higher than the heat resistance of the third light-transmissive member63, which will be described later. Furthermore, the optical transmittance of the second light-transmissive member62is higher than the optical transmittance of the third light-transmissive member63.

Configuration of Third Light-Transmissive Member

The third light-transmissive member63is a lens disposed in the optical element5A in a position closest to the first optical system41. That is, the third light-transmissive member63is disposed on the side opposite from the first light-transmissive member61with the second light-transmissive member62interposed therebetween. In other words, the third light-transmissive member63is disposed on the demagnifying side of the first light-transmissive member61and the second light-transmissive member62. The outer diameter of the third light-transmissive member63is substantially equal to the outer diameter of the second light-transmissive member62. The third light-transmissive member63has the first surface631, which faces in the direction −Z, and a second surface632, which is provided on the side opposite from the first surface631. That is, the first surface631of the third light-transmissive member63is disposed on the magnifying side, and the second surface632of the third light-transmissive member63is disposed on the demagnifying side.

The first surface631corresponds to a third joint surface. The first surface631is a spherical, concavely curved surface facing in the direction −Z. The first surface631is joined to the second surface622of the second light-transmissive member62via the third joining member67and the fourth joining member68(seeFIG.7).

The second surface632is a convexly curved surface protruding in the direction +Z. The −Y-direction region of the second surface632is the first transmission surface51, and the +Y-direction region of the second surface632is the second transmission surface53. The second surface632has an aspheric shape as described above.

The third light-transmissive member63is made of a second resin. The second resin may be made of the same resin material as that of the first resin or a different resin material from that of the first resin.

Configuration of First Joining Member

FIG.6is a diagrammatic view of the first joining member64, the second joining member65, and the spacer66provided at the second surface612of the first light-transmissive member61and viewed in the direction −Z.

The first joining member64joins the second surface612of the first light-transmissive member61as the first joint surface to the first surface621of the second light-transmissive member62as the second joint surface.

The first joining member64joins the second surface612and the first surface621to each other over an entire light passage region AR1, where the light passes through the second surface612and the first surface621, as shown inFIG.6. That is, the first joining member64covers the entire light passage region AR1, where the light passes through the first surface621, when viewed in the direction −Z. Although not illustrated, the first joining member64covers the entire light passage region AR1, where the light passes through the second surface612, when viewed in the direction +Z. In detail, the first joining member64is disposed in the smaller one of an effective diameter region of the first light-transmissive member61and the effective diameter region of the second light-transmissive member62. In the present embodiment, the effective diameter region of the first light-transmissive member61is smaller than the effective diameter region of the second light-transmissive member62, so that the first joining member64is disposed in an effective diameter region LR1of the first light-transmissive member61, as shown inFIG.6. That is, the first joining member64is disposed so as to cover the entire effective diameter region LR1of the first light-transmissive member61when viewed in the direction +Z.

The first joining member64is made of a silicone adhesive (first adhesive). The silicone adhesive of which the first joining member64is made is an adhesive containing a dimethyl-based silicone adhesive as the primary component, but not necessarily. The first joining member64may instead be made of another silicone adhesive, for example, an adhesive containing a phenyl-based silicone adhesive as the primary component.

The light resistance and heat resistance of a silicone adhesive are higher than those of other adhesives, such as ene-thiol-based adhesives. That is, a silicone adhesive is less likely to deteriorate due to light and heat than other adhesives.

The first joining member64made of a silicone adhesive and provided in accordance with the light passage region AR1is therefore unlikely to deteriorate due to light. The first light-transmissive member61and the second light-transmissive member62can thus be stably joined to each other.

Furthermore, the refractive index of a silicone adhesive is close to the refractive index of the cycloolefin polymer contained in the first light-transmissive member61and the refractive index of the glass contained in the second light-transmissive member62. A situation in which the joining member between the first light-transmissive member61and the second light-transmissive member62has a refractive index greatly different from the refractive indices of the first light-transmissive member61and the second light-transmissive member62can therefore be avoided. Changes in the optical characteristics of the optical element5A due to the first joining member64can thus be suppressed, whereby deterioration of the imaging performance of the projection optical apparatus4can be suppressed.

A dimethyl-based silicone adhesive tends to maintain the short-wavelength-light transmittance as compared with a phenyl-based silicone adhesive when the adhesives absorb moisture in the air. The first joining member64containing a dimethyl-based silicone adhesive as the primary component can therefore suppress deterioration of the optical element5A.

Configuration of Second Joining Member

The second joining member65, along with the first joining member64, joins the second surface612of the first light-transmissive member61as the first joint surface to the first surface621of the second light-transmissive member62as the second joint surface. The second joining member65is disposed outside the smaller one of the effective diameter region of the first light-transmissive member61and the effective diameter region of the second light-transmissive member62. In detail, the second joining member65is disposed outside the first joining member64when viewed in the direction +Z. That is, the second joining member65is disposed outside the first joining member64and outside the effective diameter region LR1of the first light-transmissive member61when viewed in the direction +Z. The image light having entered the optical element5A is therefore not incident on the second joining member65.

The second joining member65is provided along the outer circumferential edge of the effective diameter region LR1. That is, the second joining member65is provided in an annular shape around the second optical axis N2when viewed in the direction +Z.

The second joining member65is made of an adhesive (second adhesive) having adhesiveness higher than the adhesiveness of the silicone adhesive of which the first joining member64is made. An epoxy-based adhesive is used as the second adhesive by way of example.

Configuration of Spacer

The spacer66corresponds to the first spacer in the present disclosure. The spacer66is disposed between the first light-transmissive member61and the second light-transmissive member62and maintains the distance between the first light-transmissive member61and the second light-transmissive member62substantially constant. Specifically, the spacer66is provided between the second surface612and the first surface621when the second surface612and the first surface621are joined to each other by the first joining member64and the second joining member65and maintains the distance between the second surface612and the first surface621substantially constant. That is, the spacer66is in contact with the second surface612and the first surface621.

By providing the thus configured spacer66, an increase in the dimension of at least one of the first light-transmissive member61and the second light-transmissive member62that expands due to heat can be ensured between the second surface612and the first surface621. The spacer66can further suppress changes in the optical characteristics of the optical element5A due to variation in the film thickness of the first joining member64and the film thickness of the second joining member65.

In the present embodiment, the planar size of the first light-transmissive member61when viewed in the direction +Z is smaller than the planar size of the second light-transmissive member62when viewed in the direction −Z. The spacer66is therefore provided in accordance with the outer circumferential edge of the second surface612of the first light-transmissive member61. That is, the spacer66is provided outside the light passage region AR1, where the light passes through the first surface621and the second surface612, and outside the effective diameter region LR1of the first light-transmissive member61. Furthermore, the spacer66is made of metal, formed in an annular shape, and disposed outside the second joining member65when viewed in the direction +Z. That is, the spacer66is disposed outside the first joining member64when viewed in the direction +Z.

The spacer66may be an adhesive containing particles made of resin or metal. The spacer66may be provided between the first joining member64and the second joining member65or may be partially provided along the outer circumferential edge of the second surface612.

Configuration of Third Joining Member

FIG.7is a diagrammatic view of the third joining member67, the fourth joining member68, and the spacer69provided at the second surface622of the second light-transmissive member62when viewed in the direction +Z.

The third joining member67joins the second surface622of the second light-transmissive member62as the fourth joint surface to the first surface631of the third light-transmissive member63as the third joint surface.

The third joining member67joins the second surface622and the first surface631to each other over an entire light passage region AR2, where the light passes through the second surface622and the first surface631, as shown inFIG.7. That is, the third joining member67covers the entire light passage region AR2, where the light passes through the second surface622when viewed in the direction +Z. Although not illustrated, the third joining member67covers the entire light passage region AR2, where the light passes through the first surface631when viewed in the direction −Z. In detail, the third joining member67is disposed in the smaller one of the effective diameter region of the second light-transmissive member62and the effective diameter region of the third light-transmissive member63. In the present embodiment, the effective diameter region of the second light-transmissive member62and the effective diameter region of the third light-transmissive member63have substantially the same size, so that either of the effective diameter region of the second light-transmissive member62or the effective diameter region of the third light-transmissive member63may be the smaller one. The third joining member67is therefore disposed, for example, in the effective diameter region LR2of the second light-transmissive member62. That is, the third joining member67is disposed so as to cover the entire effective diameter region LR2of the second light-transmissive member62when viewed in the direction +Z.

The third joining member67is made of a silicone adhesive, as the first joining member64. The thus configured third joining member67joins the second light-transmissive member62made of glass and the third light-transmissive member63made of the first resin containing a cycloolefin polymer, whereby changes in the optical characteristics of the optical element5A can be suppressed. Deterioration of the imaging performance of the projection optical apparatus4can therefore be suppressed.

The silicone adhesive of which the third joining member67is made is an adhesive containing a dimethyl-based silicone adhesive as the primary component. The thus formed third joining member67is likely to maintain the transmittance at which short-wavelength light in the visible wavelength range passes through the optical element5A, whereby deterioration of the optical element5A can be effectively suppressed. The second joining member65may, however, not necessarily be made of the adhesive described above and may instead be made of another silicone adhesive, for example, an adhesive containing a phenyl-based silicone adhesive as the primary component. The composition of the first joining member64and the composition of the third joining member67may be the same or differ from each other.

Configuration of Fourth Joining Member

The fourth joining member68, along with the third joining member67, joins the second surface622of the second light-transmissive member62as the fourth joint surface to the first surface631of the third light-transmissive member63as the third joint surface. The fourth joining member68is disposed outside the smaller one of the effective diameter region of the second light-transmissive member62and the effective diameter region of the third light-transmissive member63. In detail, the fourth joining member68is disposed outside the third joining member67when viewed in the direction +Z. That is, the fourth joining member68is disposed outside the effective diameter region LR2of the second light-transmissive member62and outside the third light joining member67when viewed in the direction +Z. The image light having entered the optical element5A is therefore not incident on the fourth joining member68.

The fourth joining member68is provided along the outer circumferential edge of the effective diameter region LR2. That is, the fourth joining member68is provided in an annular shape around the second optical axis N2when viewed in the direction +Z.

The fourth joining member68is made of the second adhesive having adhesiveness higher than the adhesiveness of the silicone adhesive of which the third joining member67is made. An epoxy-based adhesive is used as the second adhesive by way of example, as described above.

Configuration of Spacer

The spacer69is disposed between the second light-transmissive member62and the third light-transmissive member63and maintains the distance between the second light-transmissive member62and the third light-transmissive member63substantially constant. Specifically, the spacer69is provided between the second surface622and the first surface631when the second surface622and the first surface631are joined to each other by the third joining member67and the fourth joining member68and maintains the distance between the second surface622and the first surface631substantially constant. That is, the spacer69is in contact with the second surface622and the first surface631.

By providing the thus configured spacer69, an increase in the dimension of at least one of the second light-transmissive member62and the third light-transmissive member63that expands due to heat can be ensured between the second surface622and the first surface631. The spacer69can further suppress changes in the optical characteristics of the optical element5A due to variation in the film thickness of the third joining member67and the film thickness of the fourth joining member68.

In the present embodiment, the spacer69is provided in accordance with the outer circumferential edge of the second surface622or the outer circumferential edge of the first surface631. That is, the spacer69is provided outside the light passage region AR2, where the light passes through the second surface622and the first surface631, and outside the effective diameter region LR2of the second light-transmissive member62. Furthermore, the spacer69is made of metal, formed in an annular shape, and disposed outside the fourth joining member68when viewed in the direction +Z.

The spacer69may be an adhesive containing particles made of resin or metal. The spacer69may be provided between the third joining member67and the fourth joining member68or may be partially provided along the outer circumferential edge of the second surface622.

Effects of First Embodiment

The projector1according to the present embodiment described above provides the following effects.

The projector1includes the light source31, the light modulators363, which modulate the light outputted from the light source31, and the projection optical apparatus4, which projects the light modulated by the light modulators363. The projection optical apparatus4projects the light incident thereon. The projection optical apparatus4includes the optical element5A.

The optical element5A includes the first light-transmissive member61, the second light-transmissive member62, the first joining member64, and the second joining member65. The first light-transmissive member61has the first surface611having an aspheric shape and the second surface612provided on the side opposite from the first surface611and is made of the first resin. The second surface612corresponds to the first joint surface. The second light-transmissive member62has the first surface621and is made of a material different from that of the first light-transmissive member61. The first surface621corresponds to the second joint surface. The first joining member64and the second joining member65join the second surface612and the first surface621to each other. The first joining member64is made of a silicone adhesive and disposed in the effective diameter region LR1, which is the smaller one of the effective diameter region of the first light-transmissive member61and the effective diameter region of the second light-transmissive member62. The second joining member65is made of an adhesive having adhesiveness higher than the adhesiveness of a silicone adhesive. The second joining member65is disposed outside the first joining member64and outside the effective diameter region LR1.

Silicone adhesives have higher light resistance and heat resistance than other adhesives. That is, silicone adhesives are unlikely to deteriorate due to light and heat. Furthermore, silicone adhesives cure and shrink by smaller amounts than other adhesives and absorb short-wavelength light in the visible wavelength range by smaller amounts than other adhesives.

Therefore, even when the light is incident on the first joining member64, deformation, transformation, and other types of deterioration of the first joining member64can be suppressed.

The second joining member65is made of the second adhesive having adhesiveness higher than the adhesiveness of the first adhesive of which the first joining member64is made. The first light-transmissive member61and the second light-transmissive member62can therefore be joined to each other at increased joining strength. In addition, the second joining member65is disposed outside the effective diameter region LR1of the first light-transmissive member61. Entry of the light into the second joining member65can thus be suppressed, whereby deterioration of the second joining member65due to the light can be suppressed.

Therefore, the first light-transmissive member61and the second light-transmissive member62can be stably joined to each other, and changes in the optical characteristics of the optical element5A can be suppressed. Furthermore, the amount of light passing through the optical element5A can be increased. Deterioration of the imaging performance of the projection optical apparatus4can thus be suppressed, whereby a projector1capable of stably projecting an image can be achieved.

The optical element5A includes the spacer66disposed between the second surface612and the first surface621. The spacer66corresponds to the first spacer.

According to the configuration described above, even when at least one of the first light-transmissive member61and the second light-transmissive member62expands due to heat, the dimension corresponding to the expansion of the at least one of the light-transmissive members can be ensured between the second surface612and first surface and621.

Furthermore, since the thickness of the first joining member64can be maintained substantially constant, changes in the optical characteristics of the optical element5A due, for example, to variations in the thickness of the first joining member64can be suppressed.

In the optical element5A, the spacer66is disposed outside the first joining member64. That is, the spacer66is disposed outside the light passage region AR1, where the light passes through the second surface612and the first surface621.

According to the configuration described above, a situation in which the spacer66blocks the image light passing through the second surface612and the first surface621can be avoided.

In the optical element5A, the second light-transmissive member62is made of glass.

The refractive index of silicone resin is close to the refractive index of glass. The situation in which the joining member between the first light-transmissive member61and the second light-transmissive member62has a refractive index greatly different from the refractive indices of the first light-transmissive member61and the second light-transmissive member62can therefore be avoided. Changes in the optical characteristics of the optical element5A can therefore be suppressed.

Furthermore, since the second light-transmissive member62is made of glass, deterioration of the second light-transmissive member62can be suppressed even when the second light-transmissive member62has a region having a relatively high optical density.

In the optical element5A, the first surface611of the first light-transmissive member61focuses the light incident thereon in the second light-transmissive member62.

According to the configuration described above, the first light-transmissive member61focuses the image light in the second light-transmissive member62, so that a region where the optical density is locally high is created in the second light-transmissive member62. Even in the case described above, since the second light-transmissive member62is made of glass, deterioration of the high optical density region in the second light-transmissive member62can be suppressed, whereby changes in the optical characteristics of the second light-transmissive member62and in turn the optical characteristics of the optical element5A can be suppressed.

In the optical element5A, the first resin of which the first light-transmissive member61is made is a resin material containing a cycloolefin polymer as the primary component.

The refractive index of silicone resin is close to the refractive index of cycloolefin polymer.

According to the configuration described above, the situation in which the joining member between the first light-transmissive member61and the second light-transmissive member62has a refractive index greatly different from the refractive indices of the first light-transmissive member61and the second light-transmissive member62can be avoided. Changes in the optical characteristics of the optical element5A can therefore be suppressed.

In the optical element5A, the silicone adhesive contained in the first joining member64contains a dimethyl-based silicone adhesive as the primary component.

A dimethyl-based silicone adhesive, even when having absorbed moisture in the ambient environment, absorbs only a small amount of short-wavelength light in the visible wavelength range and can therefore maintain high short-wavelength light transmittance. A decrease in the amount of light passing through the optical element5A can therefore be suppressed.

The optical element5A includes the third light-transmissive member63and the third joining member67. The third light-transmissive member63has the first surface631. The first surface631corresponds to the third joint surface. The third light-transmissive member63is made of the second resin and disposed on the side opposite from the first light-transmissive member61with the second light-transmissive member62interposed therebetween. The third joining member67joins the second light-transmissive member62and the third light-transmissive member63to each other. The second light-transmissive member62has the second surface622, which is disposed on the side opposite from the first surface621and joined to the first surface631by the third joining member67. The second surface622corresponds to the fourth joint surface. The third joining member67is made of a silicone adhesive of which the first joining member64is made. The third joining member67is disposed in the smaller one of the effective diameter region of the second light-transmissive member62and the effective diameter region of the third light-transmissive member63and joins the first surface631and the second surface622to each other.

The configuration described above allows the second light-transmissive member62and the third light-transmissive member63to be stably joined to each other. In addition, changes in the optical characteristics of the optical element5A can be suppressed. Furthermore, the amount of light passing through the optical element5A can be increased. Moreover, since the third light-transmissive member63is made of the second resin, the weight of the optical element5A can be reduced as compared with a case where the third light-transmissive member63is made of glass.

Second Embodiment

A second embodiment of the present disclosure will next be described.

The projector according to the present embodiment has the same configuration as that of the projector1according to the first embodiment but differs therefrom in terms of the arrangement of the second joining member65. In the following description, portions that are the same or substantially the same as the portions having been already described have the same reference characters and will not be described.

Schematic Configuration of Projector

FIG.8is a diagrammatic view, viewed in the direction −Z, of the first joining member64, a second joining member65B, and the spacer66provided at the second surface612of the first light-transmissive member61of an optical element5B provided in the projector according to the present embodiment.

The projector according to the present embodiment has the same configuration and function as those of the projector1according to the first embodiment except that the optical element5A according to the first embodiment is replaced with the optical element5B shown inFIG.8. That is, the projection optical device4according to the present embodiment includes the optical element5B shown inFIG.8in place of the optical element5A according to the first embodiment.

Configuration of Optical Element

The optical element5B has the same configuration and function as those of the optical element5A according to the first embodiment except that the second joining member65according to the first embodiment is replaced with the second joining member65B. That is, the optical element5B includes the first light-transmissive member61, the second light-transmissive member62, the third light-transmissive member63, the first joining member64, the second joining member65B, the spacer66, and the third joining member67, the fourth joining member68, and the spacer69.

The second joining member65B joins the second surface612of the first light-transmissive member61to the first surface621of the second light-transmissive member62as the second joint surface, as the second joining member65does. The second surface612corresponds to the first joint surface, and the first surface621corresponds to the second joint surface, as described above. The second joining member65B is disposed outside the first joining member64and outside the effective diameter region LR1of the first light-transmissive member61when viewed in the direction +Z. The image light having entered the optical element5A is therefore not incident on the second joining member65B.

The second joining member65B is formed of a plurality of second joining members65B provided along the outer circumferential edge of the effective diameter region LR1. Specifically, three second joining members65B are provided at equal intervals along the circumferential direction around the second optical axis N2when viewed in the direction +Z, but not necessarily. The number of second joining members65B can be changed as appropriate. The second joining members65B are made of the second adhesive, as the second joining member65.

The projector including the projection optical device4including the thus configured optical element5B can provide the same effects as those provided by the projector1according to the first embodiment.

Out of the third joining member67and the fourth joining member68, which join the second light-transmissive member62and the third light-transmissive member63to each other, the fourth joining member68may be provided in the same manner in which the second joining members65B are provided.

Third Embodiment

A third embodiment of the present disclosure will next be described.

The projector according to the present embodiment has the same configuration as that of the projector1according to the first embodiment but differs therefrom in that the optical element provided in the projection optical apparatus has a groove. In the following description, portions that are the same or substantially the same as the portions having been already described have the same reference characters and will not be described.

Schematic Configuration of Projector

FIG.9is a diagrammatic view showing a groove70provided in the second surface612of the first light-transmissive member61of an optical element5C provided in the projector according to the present embodiment.

The projector according to the present embodiment has the same configuration and function as those of the projector1according to the first embodiment except that the optical element5A according to the first embodiment is replaced with the optical element5C shown inFIG.9. That is, the projection optical apparatus4according to the present embodiment includes the optical element5C shown inFIG.9in place of the optical element5A according to the first embodiment.

Configuration of Optical Element

The optical element5C has the same configuration and function as those of the optical element5A according to the first embodiment except that the optical element5C further has the groove70. That is, the optical element5C includes the first light-transmissive member61, the second light-transmissive member62, the third light-transmissive member63, the first joining member64, the second joining member65, the spacer66, and the third joining member67, the fourth joining member68, the spacer69, and the groove70.

The groove70is provided between the first joining member64and the second joining member65and surrounds the first joining member64. In detail, the groove70is formed in an annular shape surrounding the first joining member64with the second optical axis N2as the center of the annular shape when viewed in the direction +Z.

In the present embodiment, the groove70is provided in the second surface612out of the second surface612and the first surface621. That is, the second surface612as the first joint surface has the groove70provided between the first joining member64and the second joining member65, and the groove70surrounds the first joining member64, but not necessarily. The first surface621may have the groove70, or the second surface612and the first surface621may each have the groove70. The second surface612corresponds to the first joint surface, and the first surface621corresponds to the second joint surface.

A groove surrounding the third joining member67when viewed in the direction +Z may be provided in at least one of the second surface622of the second light-transmissive member62and the first surface631of the third light-transmissive member63, as the groove70is. The second surface622corresponds to the fourth joint surface, and the first surface631corresponds to the third joint surface, as described above.

It has been assumed that the groove70is provided in an annular shape around the second optical axis N2, but not necessarily. The groove70may be formed of a plurality of grooves divided along the circumferential direction around the second optical axis N2. That is, the groove70may not be continuous along the circumferential direction around the second optical axis N2.

Furthermore, the optical element5C may include the second joining members65B presented in the second embodiment in place of the second joining member65and may further include the fourth joining member68provided in the same manner in which the second joining members65B are provided.

Effects of Third Embodiment

The projector according to the present embodiment described above provides the effects below as well as the same effects provided by the projector1according to the first embodiment.

In the optical element5C, at least one of the second surface612and the first surface621has the groove70provided between the first joining member64and the second joining member65, and the groove70surrounds the first joining member64.

The configuration described above can suppress mixture of the silicone adhesive of which the first joining member64is made and the adhesive of which the second joining member65is made in the effective diameter region LR1.

Fourth Embodiment

A fourth embodiment of the present disclosure will next be described.

The projector according to the present embodiment has the same configuration as that of the projector according to the second embodiment but differs therefrom in that grooves surrounding the second joining members65B are provided. In the following description, portions that are the same or substantially the same as the portions having been already described have the same reference characters and will not be described.

Schematic Configuration of Projector

FIG.10is a diagrammatic view showing grooves71provided in the second surface612of the first light-transmissive member61of an optical element5D provided in the projector according to the present embodiment.

The projector according to the present embodiment has the same configuration and function as those of the projector1according to the first embodiment except that the optical element5A according to the first embodiment is replaced with the optical element5D shown inFIG.10. That is, the projection optical apparatus4according to the present embodiment includes the optical element5D shown inFIG.10in place of the optical element5A according to the first embodiment.

Configuration of Optical Element

The optical element5D has the same configuration and function as those of the optical element5B according to the second embodiment except that the optical element5D further has the grooves71. That is, the optical element5D includes the first light-transmissive member61, the second light-transmissive member62, the third light-transmissive member63, the first joining member64, the second joining members65B, the spacer66, and the third joining member67, the fourth joining member68, the spacer69, and the grooves71.

The grooves71are provided outside the first joining member64and surround the second joining members65B. In detail, the grooves71are formed in an annular shape surrounding the second joining members65B when viewed in the direction +Z.

In the present embodiment, the grooves71are provided in the second surface612out of the second surface612and the first surface621. That is, the second surface612as the first joint surface has the grooves71provided outside the first joining member64, and the grooves71surround the second joining members65B, but not necessarily. The first surface621may have the grooves71, or the second surface612and the first surface621may each have the grooves71. The second surface612corresponds to the first joint surface, and the first surface621corresponds to the second joint surface.

Out of the third joining member67and the fourth joining member68, which join the second surface622of the second light-transmissive member62and the first surface631of the third light-transmissive member63, the fourth joining member68may be provided in the same manner in which the second joining members65B are provided, and the grooves71surrounding the fourth joining members68may be provided in at least one of the second surface622and the first surface631. The second surface622corresponds to the fourth joint surface, and the first surface631corresponds to the third joint surface, as described above.

The projector including the projection optical apparatus4including the thus configured optical element5D provides the same effects as those provided by the projector including the projection optical apparatus4including the optical element5C according to the third embodiment.

Fifth Embodiment

A fifth embodiment of the present disclosure will next be described.

The projector according to the present embodiment has the same configuration as that of the projector1according to the first embodiment but differs therefrom in that two spacers are provided between the first light-transmissive member61and the second light-transmissive member62. In the following description, portions that are the same or substantially the same as the portions having been already described have the same reference characters and will not be described.

Schematic Configuration of Projector

FIG.11is a diagrammatic view showing two spacers66and72provided between the first light-transmissive member61and the second light-transmissive member62of an optical element5E provided in the projector according to the present embodiment.

The projector according to the present embodiment has the same configuration and function as those of the projector1according to the first embodiment except that the optical element5A according to the first embodiment is replaced with the optical element5E shown inFIG.11. That is, the projection optical apparatus4according to the present embodiment includes the optical element5E shown inFIG.11in place of the optical element5A according to the first embodiment.

Configuration of Optical Element

The optical element5E has the same configuration and function as those of the optical element5A according to the first embodiment except that the spacer72is further provided. That is, the optical element5E includes the first light-transmissive member61, the second light-transmissive member62, the third light-transmissive member63, the first joining member64, the second joining member65, the spacer66, the third joining member67, the fourth joining member68, the spacer69, and the spacer72.

In the optical element5E, the spacer66corresponds to the first spacer in the present disclosure. In the present embodiment, unlike the spacer66in the optical element5A according to the first embodiment, the spacer66is provided outside the effective diameter region LR1of the first light-transmissive member61and between the first joining member64and the second joining member65. That is, the spacer66surrounds the first joining member64when viewed in the direction +Z.

The spacer72corresponds to a second spacer in the present disclosure. The spacer72is disposed between the second surface612and the first surface621. That is, the spacer72is in contact with the second surface612and the first surface621. The second surface612corresponds to the first joint surface, and the first surface621corresponds to the second joint surface.

The spacer72is provided on the side facing the outer circumferential edge of the second surface612with respect to the second joining member65. In detail, the spacer72is provided in an annular shape along the circumferential direction around the second optical axis N2and extends along the outer circumferential edge of the second surface612. That is, the spacer72is disposed in an annular shape outside the second joining member65when viewed in the direction +Z. In the present embodiment, the spacer72is made of metal, as the spacer66is, and may instead be made of resin.

Furthermore, two spacers similar to the spacers66and72may be disposed between the second surface622of the second light-transmissive member62and the first surface631of the third light-transmissive member63in place of the spacer69.

Effects of Fifth Embodiment

The projector according to the present embodiment described above provides the effects below as well as the same effects as those provided by the projector1according to the first embodiment.

The optical element5E includes the spacer66and the spacer72disposed between the second surface612and the first surface621. The spacer66corresponds to the first spacer and is provided between the first joining member64and the second joining member65. The spacer72corresponds to the second spacer and is provided on the side facing the outer circumferential edge of the second surface612with respect to the second joining member65. The second surface612corresponds to the first joint surface.

According to the configuration described above, in which the spacers66and72are disposed between the second surface612and the first surface621, the dimension between the second surface612and the first surface621can be stably maintained.

In addition, providing the spacer66between the first joining member64and the second joining member65can prevent the second adhesive of which the second joining member65is made from leaking through the spacer66so that the first adhesive of which the first joining member64is made and the second adhesive of which the second joining member65is made are mixed with each other in the effective diameter region LR1.

Sixth Embodiment

A sixth embodiment of the present disclosure will next be described.

The projector according to the present embodiment has the same configuration as that of the projector1according to the fifth embodiment and differs therefrom in that the spacer disposed on the inner side out of the two spacers provided in the optical element is provided with cutouts. In the following description, portions that are the same or substantially the same as the portions having been already described have the same reference characters and will not be described.

Schematic Configuration of Projector

FIG.12is a diagrammatic view showing two spacers66F and72provided between the first light-transmissive member61and the second light-transmissive member62of an optical element5F provided in the projector according to the present embodiment.

The projector according to the present embodiment has the same configuration and function as those of the projector according to the fifth embodiment except that the optical element5E according to the fifth embodiment is replaced with the optical element5F shown inFIG.12. That is, the projection optical apparatus4according to the present embodiment includes the optical element5F shown inFIG.12in place of the optical element5E according to the fifth embodiment.

Configuration of Optical Element

The optical element5F has the same configuration and function as those of the optical element5E according to the fifth embodiment except that the spacer66according to the fifth embodiment is replaced with the spacer66F. That is, the optical element5F includes the first light-transmissive member61, the second light-transmissive member62, the third light-transmissive member63, the first joining member64, the second joining member65, the spacer66F, the third joining member67, the fourth joining member68, the spacer69, and the spacer72.

The spacer66F corresponds to the first spacer in the present disclosure. The spacer66F is disposed outside the effective diameter region LR1of the first light-transmissive member61and between the first light-transmissive member61and the second light-transmissive member62and maintains the distance between the first light-transmissive member61and the second light-transmissive member62substantially constant. Specifically, the spacer66F is provided between the second surface612and the first surface621when the second surface612and the first surface621are joined to each other by the first joining member64and the second joining member65and maintains the distance between the second surface612and the first surface621substantially constant. That is, the spacer66F is in contact with the second surface612and the first surface621.

The spacer66F is provided between the first joining member64and the second joining member65and disposed in an annular shape surrounding the first joining member64when viewed in the direction +Z. In the present embodiment, the spacer66F is made of metal, as the spacer66is, and may instead be made of resin.

The spacer66F has a plurality of cutouts66F1provided at equal intervals in the circumferential direction around the second optical axis N2. In the present embodiment, the spacer66F has three cutouts66F1.

The cutouts66F1causes the region inside the spacer66F to communicates with the region outside the spacer66F. The cutouts66F1allow the silicone adhesive of which the first joining member64is made and which is provided in the spacer66F to spread outward in the radial direction around the second optical axis N2by the pressing force for joining the second surface612, which is a concavely curved surface, and the first surface621, which is a convexly curved surface, to each other via the first joining member64and the second joining member65. That is, the cutouts66F1cause an excess portion of the silicone adhesive of which the first joining member64is made to be released out of the spacer66F. The number of cutouts66F1provided in the spacer66F is not limited to three and can be changed as appropriate.

A spacer similar to the spacer66F may be provided between the second surface622of the second light-transmissive member62and the first surface631of the third light-transmissive member63.

Effects of Sixth Embodiment

The projector according to the present embodiment described above provides the effects below as well as the same effects as those provided by the projector according to the fifth embodiment.

In the optical element5F, the spacer66F has the cutouts66F1, which cause the region inside the spacer66F to communicates with the region outside the spacer66F. The spacer66F corresponds to the first spacer.

According to the configuration described above, when the first light-transmissive member61and the second light-transmissive member62are joined to each other, the excess silicone adhesive can be released out of the spacer66F. Variation in the dimension between the second surface612and the first surface621that occurs when the excess silicone adhesive is present can therefore be suppressed.

Variations of Embodiments

The present disclosure is not limited to the embodiments described above, and variations, improvements, and other modifications to the extent that the advantage of the present disclosure is achieved fall within the scope of the present disclosure.

For example, the configurations shown in the embodiments described above may be combined with each other.

It has been assumed in each of the embodiments described above that the second surface612of the first light-transmissive member61and the first surface621of the second light-transmissive member62are each a curved surface. It has also been assumed that the second surface622of the second light-transmissive member62and the first surface631of the third light-transmissive member63are each a curved surface. The second surface612corresponds to the first joint surface, the first surface621corresponds to the second joint surface, the second surface622corresponds to the fourth joint surface, and the first surface631corresponds to the third joint surface. The assumptions described above are not necessarily made, and the surfaces612,621,622, and631may each not be a curved surface. For example, the second surface612and the first surface621may each be a flat surface, and the second surface622and the first surface631may each be a flat surface.

In the embodiments described above, the reflection surface52of each of the optical elements5A to5F reflects in the directions +Y and +Z the image light incident in the direction −Z via the first transmission surface51and causes the reflected image light to exit via the second transmission surface53, but not necessarily. An optical element in the present disclosure may transmit light in one direction. That is, the optical element may not have a reflection surface. For example, an optical element in which the second light-transmissive member62and the third light-transmissive member63are joined to each other is also an optical element according to the present disclosure. In this case, the second light-transmissive member62corresponds to a second light-transmissive member, the third light-transmissive member63corresponds to a first light-transmissive member, and the third joining member67corresponds to a first joining member, and the fourth joining member68corresponds to a second joining member. Out of the third joining member67and the fourth joining member68, which join the second light-transmissive member62and the third light-transmissive member63to each other, one of the joining members may be omitted.

It has been assumed in each of the embodiments described above that the first joining member64is disposed in the effective diameter region LR1of the first light-transmissive member61, which is the smaller one of the effective diameter region of the first light-transmissive member61and the effective diameter region of the second light-transmissive member62, and disposed so as to extend outward from the effective diameter region LR1. It has similarly been assumed that the third joining member67is disposed in the effective diameter region LR2of the second light-transmissive member62, which is the smaller one of the effective diameter region of the second light-transmissive member62and the effective diameter region of the third light-transmissive member63, and disposed so as to extend outward from the effective diameter region LR2. The assumptions described above are, however, not necessarily made, and at least part of the first joining member64may be disposed in the effective diameter region LR1, and at least part of the third joining member67may be disposed in the effective diameter region LR2. That is, the first joining member64may be provided in accordance with the light passage region AR1, where the light passes through the second surface612and the first surface621, and the third joining member67may be provided in accordance with the light passage region AR2, where the light passes through the second surface622and the first surface631.

It has been assumed in the embodiments described above that at least one spacer, such as the spacer66,66F, or72, is provided between the second surface612of the first light-transmissive member61and the first surface621of the second light-transmissive member62. It has further been assumed that at least one spacer, such as the spacer69, is provided between the second surface622of the second light-transmissive member62and the first surface631of the third light-transmissive member63. The assumptions described above are, however, not necessarily made, and an optical element according to the present disclosure may not include a spacer.

It has been assumed in the embodiments described above that the spacers66and66F are each disposed outside the first joining member64, but not necessarily. The spacers66and66F are each not necessarily disposed outside the first joining member64, as in the case shown in the sixth embodiment where the first adhesive leaks out of the spacer66F via the cutouts66F1of the spacer66F.

It has been assumed in the sixth embodiment described above that the optical element5F includes the spacer72as the second spacer, but not necessarily. The spacer72may be omitted.

It has been assumed in each of the embodiments described above that the second light-transmissive member62is made of glass. The glass material of which the second light-transmissive member62is made may contain a substance other than glass. The second light-transmissive member62may instead be made of a material other than a glass material. That is, the composition of the second light-transmissive member62is not limited to the composition described above and may not contain glass.

It has been assumed in each of the embodiments described above that the first light-transmissive member61, specifically, the first surface611, which forms the reflection surface52, focuses the incident light in the second light-transmissive member62, but not necessarily. The first surface611may reflect the incident light without focusing the light or may diffuse the incident light.

It has been assumed in each of the embodiments described above that the first resin of which the first light-transmissive member61is made is a resin material containing a cycloolefin polymer as the primary component. It has also been assumed that the first resin may be a transparent optical resin material containing an acrylic resin, such as polycarbonate and polymethylmethacrylate, but not necessarily. The composition of the first resin is not limited to the composition described above. The same applies to the second resin of which the third light-transmissive member63is made.

It has been assumed in each of the embodiments described above that the first joining member64and the second joining member65are each made of a silicone adhesive, but not necessarily. The first joining member64and the third joining member67may each contain another adhesive in addition to the silicone adhesive, and the other adhesive may be any adhesive. That is, the first joining member64and the third joining member67may each be made of a plurality of adhesives including a silicone adhesive.

It has also been assumed that the silicone adhesives of which the first joining member64and the third joining member67are made contains a dimethyl-based silicone adhesive as the primary component, but not necessarily. The silicone adhesive may instead contain a silicone adhesive other than a dimethyl-based silicone adhesive as the primary component.

It has further been assumed that an epoxy-based adhesive is presented by way of example as the adhesive of which the second joining members65and65B and the fourth joining member68are made, but not necessarily. The adhesive of which the second joining member and the fourth joining member are made may be any other adhesive having adhesiveness higher than the adhesiveness of the adhesive of which the first joining member and the third joining member are made.

It has been assumed in each of the embodiments described above that the first joining member64joins the second surface612and the first surface621to each other over the entire light passage region AR1, where the light passes through the second surface612and the first surface621. The second surface612corresponds to the first joint surface, and the first surface621corresponds to the second joint surface. The assumption described above is not necessarily made, and the first joining member64may not form part of the light passage region AR1and may be provided outside the light passage region AR1as long as the first joining member64is provided in the small one of the effective diameter region of the first light-transmissive member61and the effective diameter region of the second light-transmissive member62. Similarly, the third joining member67may not form part of the light passage region AR2and may be provided outside the light passage region AR2as long as the third joining member67is provided in the small one of the effective diameter region of the second light-transmissive member62and the effective diameter region of the third light-transmissive member63.

It has been assumed in the embodiments described above that in the optical elements5A to5F, the third joining member67, the fourth joining member68, and the spacer69are disposed between the second light-transmissive member62and the third light-transmissive member63, but not necessarily. The third light-transmissive member63, the third joining member67, the fourth joining member68, and the spacer69may be omitted. In this case, for example, the third light-transmissive member63may be integrated with the second light-transmissive member62. That is, the second light-transmissive member62and the third light-transmissive member63may be made of a single material different from that of the first light-transmissive member61, for example, a glass material and integrated with each other.

It has been assumed in the embodiments described above that the first light-transmissive member61, the second light-transmissive member62, and the third light-transmissive member63are each a lens, but not necessarily. At least one of the first, second, and third light-transmissive members may not be a lens.

Furthermore, the present disclosure is applicable to a joined lens formed by joining at least two optical parts to each other. For example, the present disclosure may be applied to at least one of the lenses L2, L3, L4, L7, and L8.

It has been assumed in each of the embodiments described above that the projector1includes the three light modulators363, but not necessarily. The present disclosure is also applicable to a projector including two or lessor four or more light modulators.

It has been assumed in each of the embodiments described above that the image generator32includes the optical parts and has the layout shown inFIG.3, but not necessarily. The optical parts provided in the image generator32and the layout thereof are not limited to the those described above.

It has been assumed in each of the embodiments described above that the projection optical apparatus4includes the plurality of lenses L1to L10shown inFIG.4and one of the optical elements5A to5F, but not necessarily. The optical parts provided in the projection optical apparatus4and the layout thereof are not limited to the those described above.

It has been assumed in each of the embodiments described above that the light modulators363are each formed of a transmissive liquid crystal panel having a light incident surface and a light exiting surface different from each other. The light modulators363may instead each be formed of a reflective liquid crystal panel having a surface that serves both as the light incident surface and the light exiting surface. Furthermore, a light modulator using any component other than a liquid-crystal-based component and capable of modulating an incident luminous flux to form an image according to image information, such as a device using micromirrors, for example, a digital micromirror device (DMD), may be employed.

The aforementioned embodiments have been described with reference to the case where one of the optical elements5A,5B,5C,5D,5E, and5F is used in the projection optical apparatus4, which projects the light incident thereon, and the case where the projection optical apparatus4is used in the projector1, but not necessarily. An optical element according to the present disclosure may be used in an optical apparatus other than a projection optical apparatus, and an optical apparatus similar to the projection optical apparatus according to the present disclosure may be used in an electronic instrument other than a projector, for example, an imaging apparatus.

Overview of Present Disclosure

The present disclosure will be summarized below as additional remarks.

An optical element according to a first aspect of the present disclosure includes a first light-transmissive member made of a first resin and having a first surface having an aspheric shape and a first joint surface provided on the side opposite from the first surface, a second light-transmissive member made of a material different from the material of the first light-transmissive member and having a second joint surface, and a first joining member and a second joining member that join the first joint surface and the second joint surface to each other. The first joining member is made of a silicone adhesive and disposed in the smaller one of an effective diameter region of the first light-transmissive member and the effective diameter region of the second light-transmissive member. The second joining member is made of an adhesive having adhesiveness higher than the adhesiveness of the silicone adhesive and is disposed outside the first joining member and outside the smaller effective diameter region.

Silicone adhesives have higher light resistance and heat resistance than other adhesives. That is, silicone adhesives are unlikely to deteriorate due to light and heat. Furthermore, silicone adhesives cure and shrink by smaller amounts than other adhesives and absorb short-wavelength light in the visible wavelength range by smaller amounts than other adhesives.

Therefore, according to the configuration described above, even when the light is incident on the first joining member, deformation, transformation, and other types of deterioration of the first joining member can be suppressed.

The second joining member is made of a second adhesive having adhesiveness higher than the adhesiveness of a first adhesive of which the first joining member is made. The first light-transmissive member and the second light-transmissive member can therefore be joined to each other at increased joining strength. In addition, the second joining member is disposed outside the smaller one of the effective diameter region of the first light-transmissive member and the effective diameter region of the second light-transmissive member. Entry of the light into the second joining member can thus be suppressed, whereby deterioration of the second joining member due to the light can be suppressed.

Therefore, the first light-transmissive member and the second light-transmissive member can be stably joined to each other, and changes in the optical characteristics of the optical element can be suppressed. Furthermore, the amount of light passing through the optical element can be increased.

In the first aspect described above, a first spacer disposed between the first joint surface and the second joint surface may be provided.

According to the configuration described above, even when at least one of the first light-transmissive member and the second light-transmissive member expands due to heat, the dimension corresponding to the expansion of the at least one of the light-transmissive members can be ensured between the first joint surface and the second joint surface.

Furthermore, since the thickness of the first joining member can be maintained substantially constant, changes in the optical characteristics of the optical element due, for example, to variations in the thickness of the first joining member can be suppressed.

In the first aspect described above, the first spacer may be disposed outside the first joining member. That is, the first spacer may be disposed outside a light passage region where the light passes through the first joint surface and the second joint surface.

According to the configuration described above, the situation in which the first spacer blocks the light passing through the first joint surface and the second joint surface can be suppressed.

In the first aspect described above, the optical element may include a second spacer disposed between the first joint surface and the second joint surface. The first spacer may be provided between the first joining member and the second joining member. The second spacer may be provided on the side facing the outer circumferential edge of the first joint surface with respect to the second joining member.

According to the configuration described above, in which the first and second spacers are disposed between the first joint surface and the second joint surface, the dimension between the first joint surface and the second joint surface can be stably maintained.

In addition, providing the first spacer between the first joining member and the second joining member can prevent the second adhesive, of which the second joining member is made, from leaking through the first spacer so that the first adhesive, of which the first joining member is made, and the second adhesive, of which the second joining member is made, are mixed with each other in the effective diameter region.

In the first aspect described above, the first spacer may have a cutout that causes the region inside the first spacer to communicate with the region outside the first spacer.

According to the configuration described above, when the first light-transmissive member and the second light-transmissive member are joined to each other, an excess portion of the silicone adhesive can be released out of the first spacer. Variation in the dimension between the first joint surface and the second joint surface that occurs when the excess silicone adhesive is present can therefore be suppressed.

In the first aspect described above, at least one of the first joint surface and the second joint surface may have a groove provided between the first joining member and the second joining member, and the groove may surround the first joining member.

The configuration described above can suppress a situation in which the first adhesive of which the first joining member is made and the second adhesive of which the second joining member is made are mixed with each other in the effective diameter region described above.

In the first aspect described above, at least one of the first joint surface and the second joint surface may have a groove provided outside the first joining member, and the groove may surround the second joining member.

The configuration described above can suppress a situation in which the first adhesive of which the first joining member is made and the second adhesive of which the second joining member is made are mixed with each other in the effective diameter region described above.

In the first aspect described above, the second light-transmissive member may be made of glass.

The refractive index of silicone resin is close to the refractive index of glass. The situation in which the joining member between the first light-transmissive member and the second light-transmissive member has a refractive index greatly different from the refractive indices of the first light-transmissive member and the second light-transmissive member can therefore be avoided. Changes in the optical characteristics of the optical element can therefore be suppressed.

Furthermore, since the second light-transmissive member is made of glass, deterioration of the second light-transmissive member can be suppressed even when the second light-transmissive member has a region having a relatively high optical density.

In the first aspect described above, the first surface of the first light-transmissive member may focus light incident thereon in the second light-transmissive member.

According to the configuration described above, the first light-transmissive member focuses the light in the second light-transmissive member, so that a region where the optical density is locally high is created in the second light-transmissive member. Even in the case described above, since the second light-transmissive member is made of glass, deterioration of the high optical density region in the second light-transmissive member can be suppressed, whereby changes in the optical characteristics of the second light-transmissive member and in turn the optical characteristics of the optical element can be suppressed.

In the first aspect described above, the first resin may be a resin material containing a cycloolefin polymer as the primary component.

The refractive index of silicone resin is close to the refractive index of cycloolefin polymer.

According to the configuration described above, the situation in which the joining member between the first light-transmissive member and the second light-transmissive member has a refractive index greatly different from the refractive indices of the first light-transmissive member and the second light-transmissive member can be avoided. Changes in the optical characteristics of the optical element can therefore be suppressed.

In the first aspect described above, the silicone adhesive may contain a dimethyl-based silicone adhesive as the primary component.

A dimethyl-based silicone adhesive, even when having absorbed moisture in the ambient environment, absorbs only a small amount of short-wavelength light in the visible wavelength range and can therefore maintain high short-wavelength light transmittance. According to the configuration described above, a decrease in the amount of light passing through the optical element can be suppressed.

In the first aspect described above, the optical element may include a third light-transmissive member having a third joint surface, made of a second resin, and disposed on the side opposite from the first light-transmissive member with the second light-transmissive member interposed therebetween and a third joining member that joins the second light-transmissive member and the third light-transmissive member to each other. The second light-transmissive member may have a fourth joint surface disposed on the side opposite from the second joint surface and joined to the third joint surface by the third joining member. The third joining member may be made of the silicone adhesive, disposed in the smaller one of the effective diameter region of the second light-transmissive member and the effective diameter region of the third light-transmissive member, and join the third joint surface and the fourth joint surface to each other.

The configuration described above allows the second light-transmissive member and the third light-transmissive member to be stably joined to each other. In addition, changes in the optical characteristics of the optical element can be suppressed. Furthermore, the amount of light passing through the optical element can be increased. Moreover, since the third light-transmissive member is made of the second resin, the weight of the optical element can be reduced as compared with a case where the third light-transmissive member is made of glass.

A projection optical apparatus according to a second aspect of the present disclosure is a projection optical apparatus that projects light incident thereon and includes the optical element according to the first aspect described above.

The configuration described above can provide the same effects as those provided by the optical element according to the first aspect described above. Furthermore, changes in the optical characteristics of the optical element can be suppressed, whereby deterioration of the imaging performance of the projection optical apparatus can be suppressed.

A projector according to a third aspect of the present disclosure includes a light source, a light modulator that modulates light outputted from the light source, and the projection optical apparatus according to the second aspect described above, which projects the light modulated by the light modulator.

The configuration described above can provide the same effects as those provided by the projection optical apparatus according to the second aspect described above. A projector capable of stably projecting an image can thus be achieved.