Abstract: An optical unit that directs illumination light to a plurality of digital micromirror devices that produce projection light by modulating the illumination light on an image display surface according to an image signal, and that transmits and emits the projection light, the optical unit includes: a plurality of first prisms, wherein the projection light exits a first face of a most emergence-side first prism among the first prisms; and a second prism disposed next to the first prisms, wherein the second prism includes: a 2A-th face into which the projection light enters; and a 2B-th face disposed perpendicular to an optical axis of the projection light, the projection light exits the 2B-th face, the second prism is wedge-shaped with the 2A-th and 2B-th faces not being in parallel with each other.

Abstract: An illumination optical system includes a lens group, a diaphragm, and a prism unit including first to third prisms and a rotationally-asymmetrical curved reflective surface having a positive power and satisfying the conditional formula: PYa/PZa<PYb/PZb, where Pya, Pyb represent powers of the curved reflective surface at positions of points a, b, respectively within a reference plane formed in the prism unit by rays passing through centers of the lens group and the diaphragm, and PZa, PZb represent powers of the curved reflective surface at positions of points a, b, respectively, within a plane including normal lines of the reference plane and the curved reflective surface, points a and b representing where the principal ray of a beam illuminating the area nearest and farthest, respectively, to the lens group impinges on the curved reflective surface, along an intersection line between an image display surface and the reference plane.

Abstract: A prism unit includes a first prism and a second prism. The first prism includes a first optical surface that allows the illumination light to enter the prism, a second optical surface that reflects the illumination light that entered through the first optical surface, and a third optical surface that allows the illumination light reflected by the second optical surface to exit the prism. The second prism includes a fourth optical surface that forms a first air gap with the second optical surface and allows the illumination light that exited through the second optical surface to enter the prism, and a fifth optical surface that allows the illumination light that entered through the fourth optical surface to exit the prism.

Abstract: An optical unit that directs illumination light to a plurality of digital micromirror devices that produce projection light by modulating the illumination light on an image display surface according to an image signal, and that transmits and emits the projection light, the optical unit includes: a plurality of first prisms, wherein the projection light exits a first face of a most emergence-side first prism among the first prisms; and a second prism disposed next to the first prisms, wherein the second prism includes: a 2A-th face into which the projection light enters; and a 2B-th face disposed perpendicular to an optical axis of the projection light, the projection light exits the 2B-th face, the second prism is wedge-shaped with the 2A-th and 2B-th faces not being in parallel with each other.

Abstract: In an optical unit, illumination light is directed to a plurality of digital micromirror devices that produce projection light by modulating the illumination light on an image display surface according to an image signal. The optical unit emits the projection light produced by the digital micromirror devices. The optical unit includes: a reflector having an illumination light reflecting face on which the illumination light is reflected; and a prism unit composed of a plurality of first prisms. The reflected illumination light enters the prism unit via a first face of a most emergence-side first prism among the first prisms and the projection light exits via the first face.

Abstract: In an optical unit, illumination light is directed to a plurality of digital micromirror devices that produce projection light by modulating the illumination light on an image display surface according to an image signal. The optical unit emits the projection light produced by the digital micromirror devices. The optical unit includes: a reflector having an illumination light reflecting face on which the illumination light is reflected; and a prism unit composed of a plurality of first prisms. The reflected illumination light enters the prism unit via a first face of a most emergence-side first prism among the first prisms and the projection light exits via the first face.

Abstract: A projection lens included in a projector using laser beams as a light source is provided, the laser beams including as the light source, first blue laser light beams, second blue laser beams, first green laser beams, second green laser beams, first red laser beams, and second red laser beams, which are different in wavelength range. The projection lens has a relative maximum value of a transmittance on an optical axis between a wavelength not shorter than 645 nm and a wavelength not longer than 680 nm.

Abstract: An illumination optical system includes a lens group, a diaphragm, and a prism unit including first to third prisms and a rotationally-asymmetrical curved reflective surface having a positive power and satisfying the conditional formula: PYa/PZa<PYb/PZb, where Pya, Pyb represent powers of the curved reflective surface at positions of points a, b, respectively within a reference plane formed in the prism unit by rays passing through centers of the lens group and the diaphragm, and PZa, PZb represent powers of the curved reflective surface at positions of points a, b, respectively, within a plane including normal lines of the reference plane and the curved reflective surface, points a and b representing where the principal ray of a beam illuminating the area nearest and farthest, respectively, to the lens group impinges on the curved reflective surface, along an intersection line between an image display surface and the reference plane.

Abstract: In a reflection-type image display for use in an image projection apparatus, when normal vectors of a pixel reflection surface in image display and non-display states are VA and VB, respectively, a Y axis is set in a normal direction of an image display surface with the pixel center as an origin, an X axis is set in a direction perpendicular to the Y axis and the normal vector VA, and a projection of the vector VB onto an XY plane is vb, the projection vb is at a predetermined angle not parallel to the Y axis, and among projections of illumination light incident on the pixel reflection surfaces onto the XY plane, a projection forming a maximum angle with respect to the Y axis exists only on a side with respect to the Y axis where a region in which the projection vb exists lies.

Abstract: A prism unit includes a first prism and a second prism. The first prism includes a first optical surface that allows the illumination light to enter the prism, a second optical surface that reflects the illumination light that entered through the first optical surface, and a third optical surface that allows the illumination light reflected by the second optical surface to exit the prism. The second prism includes a fourth optical surface that forms a first air gap with the second optical surface and allows the illumination light that exited through the second optical surface to enter the prism, and a fifth optical surface that allows the illumination light that entered through the fourth optical surface to exit the prism.

Abstract: A color splitting/combining prism splits apart illumination light from a projector and combines together projection light from the projector. A part of the illumination light that is not used as the projection light passes through the color splitting/combining prism as OFF-light via an image display element in a direction different from the projection light. The color splitting/combining prism includes a dichroic film of which a cutoff wavelength, at which the dichroic film exhibits a transmittance of 50% when splitting two different colors between reflection and transmission, is provided in a wavelength range in which wavelength separation is possible for all of the illumination light, the projection light, and the OFF-light that are incident at different incidence angles respectively.

Abstract: A prism unit that combines light in the three primary colors of R, G, and B on the same optical axis includes: a G-reflecting dichroic coating that reflects G light and passes R and B light; and an RB dichroic coating that reflects one of R and B, and passes the other one of R and B, the prism unit satisfying the following conditional expression: ?rg??rb?0.67×?rg+0.33×?gb, where ?gb represents the wavelength at which the transmittance is 50% when the colors of G and B on the composite optical axis are combined, ?rg represents the wavelength at which the transmittance is 50% when the colors of R and G on the composite optical axis are combined, and ?rb represents the wavelength at which the transmittance is 50% when the colors of R and B on the composite optical axis are combined.

Abstract: A projection type image display apparatus (1) comprises a focus correction system (30). The system includes a temperature detection mechanism (16) for measuring temperature in the vicinity of a projection lens group (13), a correction amount calculation unit (18) for calculating a correction amount for correcting the focus shift caused by a temperature change, and a driving signal generation unit (19) for generating, based on the correction amount, a driving signal for driving a focus adjustment mechanism (15). If the user performs a focus adjustment using a focus operation input unit (23), a focus operation determination unit (21) determines that a focus adjustment has occurred independently of the focus correction system and changes a correction condition stored in a memory (20).

Abstract: In a reflection-type image display for use in an image projection apparatus, when normal vectors of a pixel reflection surface in image display and non-display states are VA and VB, respectively, a Y axis is set in a normal direction of an image display surface with the pixel center as an origin, an X axis is set in a direction perpendicular to the Y axis and the normal vector VA, and a projection of the vector VB onto an XY plane is vb, the projection vb is at a predetermined angle not parallel to the Y axis, and among projections of illumination light incident on the pixel reflection surfaces onto the XY plane, a projection forming a maximum angle with respect to the Y axis exists only on a side with respect to the Y axis where a region in which the projection vb exists lies.

Abstract: A color splitting/combining prism splits apart illumination light from a projector and combines together projection light from the projector. A part of the illumination light that is not used as the projection light passes through the color splitting/combining prism as OFF-light via an image display element in a direction different from the projection light. The color splitting/combining prism includes a dichroic film of which a cutoff wavelength, at which the dichroic film exhibits a transmittance of 50% when splitting two different colors between reflection and transmission, is provided in a wavelength range in which wavelength separation is possible for all of the illumination light, the projection light, and the OFF-light that are incident at different incidence angles respectively.

Abstract: A projection lens included in a projector using laser beams as a light source is provided, the laser beams including as the light source, first blue laser light beams, second blue laser beams, first green laser beams, second green laser beams, first red laser beams, and second red laser beams, which are different in wavelength range. The projection lens has a relative maximum value of a transmittance on an optical axis between a wavelength not shorter than 645 nm and a wavelength not longer than 680 nm.

Abstract: A prism unit that combines light in the three primary colors of R, G, and B on the same optical axis includes: a G-reflecting dichroic coating that reflects G light and passes R and B light; and an RB dichroic coating that reflects one of R and B, and passes the other one of R and B, the prism unit satisfying the following conditional expression: ?rg??rb?0.67×?rg+0.33×?gb, where ?gb represents the wavelength at which the transmittance is 50% when the colors of G and B on the composite optical axis are combined, ?rg represents the wavelength at which the transmittance is 50% when the colors of R and G on the composite optical axis are combined, and ?rb represents the wavelength at which the transmittance is 50% when the colors of R and B on the composite optical axis are combined.

Abstract: A projection type image display apparatus (1) comprises a focus correction system (30). The system includes a temperature detection mechanism (16) for measuring temperature in the vicinity of a projection lens group (13), a correction amount calculation unit (18) for calculating a correction amount for correcting the focus shift caused by a temperature change, and a driving signal generation unit (19) for generating, based on the correction amount, a driving signal for driving a focus adjustment mechanism (15). If the user performs a focus adjustment using a focus operation input unit (23), a focus operation determination unit (21) determines that a focus adjustment has occurred independently of the focus correction system and changes a correction condition stored in a memory (20).

Abstract: A projection type image display apparatus (1) comprises a focus correction system (30). The system includes a temperature detection mechanism (16) for measuring temperature in the vicinity of a projection lens group (13), a correction amount calculation unit (18) for calculating a correction amount for correcting the focus shift caused by a temperature change, and a driving signal generation unit (19) for generating, based on the correction amount, a driving signal for driving a focus adjustment mechanism (15). If the user performs a focus adjustment using a focus operation input unit (23), a focus operation determination unit (21) determines that a focus adjustment has occurred independently of the focus correction system and changes a correction condition stored in a memory (20).

Abstract: Assuming that a normal line of an image display surface of a DMD is a normal line Ax of the image display surface, that a direction in which a light beam specularly reflected by a mirror is outputted is a specular reflection direction R, and that an angle that the specular reflection direction R forms with respect to the normal line Ax of the image display surface is denoted by ?, an image projection apparatus satisfies the following conditional expression: ?(2·k?1)?2·???(2·k)??(2·k+1), where ?(2·k?1) and ?(2·k+1) represent a diffraction angle of an odd-order diffracted light, and ?(2·k) represents a diffraction angle of an even-order diffracted light.