Projection display apparatus using color temperature correctors and liquid crystal shutters

Claim 2

A projection display apparatus for projecting light containing red, green and blue components emitted from a light source means onto a screen by projection lenses, said projection display apparatus comprising: color temperature correcting means for correcting a color temperature of an image on said screen, said color temperature correcting means being disposed close to said projection lenses in an optical path between said screen and said light source means to individually correct the amounts of the red, green and blue components contained within the light; wherein said color temperature correcting means comprises neutral density (ND) filters and wherein said neutral density (ND) filters are detachably coupled with said projection lenses.

Claim 3

A projection display apparatus as claimed in claim 1, wherein said neutral density filters are contained in a casing.

Claim 4

A projection display apparatus for projecting light containing red, green and blue components emitted from light source means on a screen by projection lenses, said projection display apparatus comprising: color temperature correcting means for correcting a color temperature of an image on said screen, said color temperature correcting means being disposed close to said projection lenses in an optical path between said screen and said light source means to individually correct the amounts of the red, green and blue components contained within the light; wherein said color temperature correcting means comprises color dividing means for dividing the light emitted from said light source means into red, green and blue components; three liquid-crystal shutters located in the optical paths of red, green and blue paths; and drive circuits for driving said liquid-crystal shutters.

Claim 5

A projection display apparatus for projecting light containing red, green and blue components emitted from light source means on a screen by projection lenses, said projection display apparatus comprising: color temperature correcting means for correcting a color temperature of an image on said screen, said color temperature correcting means being disposed close to said projection lenses in an optical path between said screen and said light source means to individually correct the amounts of the red, green and blue components contained within the light; wherein said color temperature correcting means comprises color dividing means for dividing the light emitted from said light source means into red, green and blue components; three liquid-crystal shutters located in the optical paths of red, green and blue paths; and drive circuits for driving said liquid-crystal shutters.

Claim 6

A projection display apparatus as claimed in claim 3, wherein said color dividing means comprises a couple of reflecting mirrors which reflect only the red component but allow the remaining color components to transmit therethrough, a couple of reflecting mirrors which reflect only the green component but allow the remaining color components to transmit therethrough, a couple of reflecting mirrors which reflect only the blue component but allow the remaining color components to transmit therethrough.

Claim 7

A projection display apparatus as claimed in claim 3, wherein said drive circuits comprises a driver for driving said liquid-crystal shutters and a pulse width controller for controlling the width of an electrical pulse input to said driver to change the liquid-crystal shutter speed.

Claim 8

A projection display apparatus for projecting light containing red, green and blue components emitted from light source means on a screen by projection lenses, said projection display apparatus comprising: color temperature correcting means for correcting a color temperature of an image on said screen, said color temperature correcting means being disposed close to said projection lenses in an optical path between said screen and said light source means to individually correct the amounts of the red, green and blue components contained within the light; wherein said color temperature correcting means comprises liquid-crystal shutters detachably coupled with said projection lens means and a drive circuit for driving said liquid-crystal shutters.

Claim 9

A projection display apparatus for projecting light containing red, green and blue components emitted from light source means on a screen by projection lenses, said projection display apparatus comprising: color temperature correcting means for correcting a color temperature of an image on said screen, said color temperature correcting means being disposed close to said projection lenses in an optical path between said screen and said light source means to individually correct the amounts of the red, green and blue components contained within the light; wherein said color temperature correcting means comprises liquid-crystal shutters detachably coupled with said projection lens means and a drive circuit for driving said liquid-crystal shutters.