Light deflector and rear-projection screen
View Patent ↗The presented invention relates to a light deflector. The light deflector defining a light-incident side and a light-exiting side, the deflector comprising a plurality of reflector( 42 ) arranged side-by-side in a predetermined orientation, each reflector having, a first reflection face( 42 A), provided on the deflector light-incident side, for reflecting incident light so as to focus the light, and a second reflection face ( 42 B), provided on the deflector light-exiting side, for reflecting light reflected by the first reflection face of an adjacent reflection means( 42 ). In accordance with the present invention, light utilization efficiency can be raised.
1. A light deflector in a rear-projection screen defining a light-incident side and a light-exiting side, the deflector comprising:
a plurality of reflectors arranged side-by-side in a predetermined orientation along a length of said rear-projection screen, each reflector having
a first reflection face, provided on the deflector light-incident side, for reflecting incident light so as to focus the light, and
a second reflection face, provided on the deflector light-exiting side, for reflecting light reflected by the first reflection face of an adjacent reflector,
the plurality of reflectors being arranged so that incident light reflected by the first reflection face of one of the plurality of reflectors is reflected by the second reflection face of another reflector adjacent to the one of the reflectors.
2. A light deflector as recited in claim 1 , wherein in each reflector a component on which the first reflection face is provided and a component on which the second reflection face is provided are integrally composed.
3. A light deflector as recited in claim 2 , wherein the first reflection face and the second reflection face on each reflector are in a front/back relationship.
4. A light deflector as recited in claims 1 , wherein:
a shape of each first reflection face, in a cross-section through the deflector along the predetermined orientation is a portion of a quadratic curve having a focal point, and
a peak of the quadratic curve is directed towards the light-exiting side.
5. A rear-projection screen comprising:
a light deflector as recited in claim 1 ; and
a light transmitter, having a face that is approximately perpendicular to an optical axis of incident light, for selectively transmitting the incident light through the face.
6. A rear-projection screen comprising:
a plurality of light deflectors as recited in claim 1 , in which plurality of the reflectors are present extending along a direction perpendicular to the predetermined orientation, wherein:
the light deflectors in the plurality are adjacently arranged so that the light-exiting side of one light deflector and the light-incident side of another light deflector face onto each other, and
the one light deflector is arranged in such a way that a focal line defined by focal points of the first or second reflection faces of each reflector in that light deflector is rotated relative to the focal line of the other light deflector by a predetermined angle around an axis parallel to the orientation in which light-exiting and light-incident sides face on each other.
7. A rear-projection screen as recited in claim 6 , wherein said plurality of light deflectors numbers two, and the predetermined angle is 90 degrees.
8. A rear-projection screen as recited in claim 6 , wherein the rear-projection screen has,
on the incident-light side of the one light deflector, a face approximately perpendicular to the optical axis of light incident into every point on the screen, and
a light transmitter selectively transmitting the incident light through the face.
9. A light deflector defining a light-incident side and a light-exiting side, the deflector comprising:
a plurality of reflectors arranged side-by-side in a predetermined orientation, each reflector having
a first reflection face, provided on the deflector light-incident side, for reflecting incident light so as to focus the light, and
a second reflection face, provided on the deflector light-exiting side, for reflecting light reflected by the first reflection face of an adjacent reflector, the plurality of reflectors being arranged so that incident light reflected by the first reflection face of one of the plural reflector is reflected by the second reflection face of another reflector adjacent to the one of the reflector wherein,
a shape of each first reflection face, in a cross-section through the deflector along the predetermined orientation is a portion of a first quadratic curve having a focal point, wherein the shape of each second reflection face, in a cross-section through the deflector along the predetermined orientation is a portion of a second quadratic curve having a focal point, and
a peak of the second quadratic curve is directed towards the light-exiting side, wherein the peak of the first quadratic curve is directed towards the light-incident side, and the focal point of the second quadratic curve lies at the same point as the focal point of the quadratic curve corresponding to its adjacent first reflection face.
10. A light deflector as recited in claim 9 , wherein the cross-sectional shape that the first reflection face has, or the cross-sectional shape that the second reflection face has is a portion of a parabolic curve.
11. A light deflector as recited in claim 9 , wherein the cross-sectional shape that the first reflection face has, or the cross-sectional shape that the second reflection face has is a portion of an elliptic curve.