Back lighting device for a panel
First Claim
1. A back lighting device for a liquid-crystal panel comprising:
- a light conducting plate made of alight-transmissive material;
a linear light source provided at an end portion of at least one side of said light conducting plate, at least a portion of said inner light source which is capable of uniform light emission being equal to or less than a length of said end portion, said linear light source being enclosed with a light diffusing reflector having a slit through which light emitted from said linear light source is admitted into one side of the light conducting plate and providing a clearance between an outer surface of the linear light source and an opposing surface of said reflector;
a coating of a light diffusing material having a refractive index greater than said light-transmissive material, said coating being provided in a dot pattern on one major surface of said light conducting plate such that an area of coverage (Y) of said coating satisfies the functional relationship Y=aXn or Y=ax or the approximate relationship thereof (where X or x represents the distance from the linear light source;
n=1.7-3.5; and
a is a constant determined by regression of a mathematical expression) and such that an area of coverage (Y'"'"')of said coating which is provided on said major surface of the light conducting plate in an increasing amount towards both ends of a line parallel to the axis of said linear light source satisfies the functional relationship Y'"'"'=a'"'"'X'"'"'n or Y'"'"'=a'"'"'x'"'"' or the approximate relationship thereof (where X'"'"' or x'"'"' represents the distance the coating departs from a line vertical to the center of the linear light source towards both ends thereof;
n=1.7-3.5; and
a'"'"' is a constant determined by regression of a mathematical expression) over the range from the area that is nearest to the linear light source and where X'"'"' is at maximum (each end of the light conducting plate) to the area where Y=Y'"'"' with Y'"'"' decreasing or increasing gradually, and is constant with increasing X along said both ends of the light conducting plate;
a specular or light diffusing/replacing plate for covering said coated surface; and
at least one light scattering plate provided on the other major and light emerging surface of said light conducting plate.
1 Assignment
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Accused Products
Abstract
An improved backlighting device for liquid-crystal display panels comprising a linear light source the length of which is equal to or less than the length of an end portion of a light conducting plate at which light is admitted from the linear light source placed adjacent to it, the linear light source being enclosed with a light diffusing reflector that has a slit formed in the surface through which incident light is admitted into the light conducting plate and which is provided in such a way as to form a clearance from the surface of the linear light source, one major surface of the light conducting plate being partially covered with a light diffusing material under specified conditions that has a higher refractive index than the material of which the light conducting plate is made, the major surface being further covered with a specular or light diffusing/reflecting plate, with a plurality of light diffusing plates being provided on the other major (light emerging) surface of the light conducting plate.
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Citations
13 Claims
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1. A back lighting device for a liquid-crystal panel comprising:
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a light conducting plate made of alight-transmissive material; a linear light source provided at an end portion of at least one side of said light conducting plate, at least a portion of said inner light source which is capable of uniform light emission being equal to or less than a length of said end portion, said linear light source being enclosed with a light diffusing reflector having a slit through which light emitted from said linear light source is admitted into one side of the light conducting plate and providing a clearance between an outer surface of the linear light source and an opposing surface of said reflector; a coating of a light diffusing material having a refractive index greater than said light-transmissive material, said coating being provided in a dot pattern on one major surface of said light conducting plate such that an area of coverage (Y) of said coating satisfies the functional relationship Y=aXn or Y=ax or the approximate relationship thereof (where X or x represents the distance from the linear light source;
n=1.7-3.5; and
a is a constant determined by regression of a mathematical expression) and such that an area of coverage (Y'"'"')of said coating which is provided on said major surface of the light conducting plate in an increasing amount towards both ends of a line parallel to the axis of said linear light source satisfies the functional relationship Y'"'"'=a'"'"'X'"'"'n or Y'"'"'=a'"'"'x'"'"' or the approximate relationship thereof (where X'"'"' or x'"'"' represents the distance the coating departs from a line vertical to the center of the linear light source towards both ends thereof;
n=1.7-3.5; and
a'"'"' is a constant determined by regression of a mathematical expression) over the range from the area that is nearest to the linear light source and where X'"'"' is at maximum (each end of the light conducting plate) to the area where Y=Y'"'"' with Y'"'"' decreasing or increasing gradually, and is constant with increasing X along said both ends of the light conducting plate;a specular or light diffusing/replacing plate for covering said coated surface; and at least one light scattering plate provided on the other major and light emerging surface of said light conducting plate. - View Dependent Claims (2)
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3. A back lighting device for a liquid-crystal panel comprising:
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a light conducting plate made of a light-transmissive material; a linear light source provided in close proximity to an end portion of at least one side of said light conducting plate; a coating of a light diffusing material having a refractive index greater than said light-transmissive material and is provided on one surface of said light conducting plate such that the coverage of said coating increases with the distance from the linear light source; a specular reflecting plate or a light diffusing/reflecting plate for covering said one surface; and a plurality of light scattering plates provided on the other and surface of said light conducting plate. - View Dependent Claims (4, 5, 6, 7)
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8. A back lighting device for a liquid-crystal panel comprising:
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a light conducting plate made of a light-transmissive material; a linear light source provided in close proximity to the end portion of one side of said light conducting plate; a first coating of alight diffusing material having a refractive index greater than said light-transmissive material and providing on one major surface of said light conducting plate such that a coverage of said first coating increases with the distance from an end portion of said one side of said light conducting plate which faces said linear light source; and a specular reflecting member for covering an end face of said light conducting plate which is farthest from said linear light source. - View Dependent Claims (9, 10, 11, 12, 13)
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Specification