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LIGHT-EMISSION LENS, LIGHT-EMITTING ELEMENT ASSEMBLY, SHEET-SHAPED LIGHT SOURCE DEVICE AND COLOR LIQUID CRYSTAL DISPLAY ASSEMBLY

  • US 20090273727A1
  • Filed: 12/02/2005
  • Published: 11/05/2009
  • Est. Priority Date: 12/03/2004
  • Status: Abandoned Application
First Claim
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1. A lens formed from circular bottom, lateral and top faces and having a surface light source of a finite size provided at the center of the bottom face thereof, whereinin an assumed cylindrical coordinate (r, φ

  • , z) of which the origin is the center of the bottom face and z-axis is a normal line passing through the center of the bottom face,the top face is an aspheric surface rotational symmetric with respect to the z-axis and which totally reflects a part of a component, whose polar angle is smaller than a polar angle Θ

    0 at the intersection between the lateral and top faces, of light emitted at a half of a whole solid angle from the surface light source, andthe lateral face is an aspheric surface rotational symmetric with respect to the z-axis and pervious to a component, whose polar angle is larger than the polar angle Θ

    0, and component, totally reflected at the top face, of light emitted at the half of the whole solid angle from the surface light source,a function r=fS(z) where z is a variable representing the aspheric lateral face increasing monotonously as the variable z decreases in a closed zone defined by 0≦

    z≦

    Z1 when the z-coordinate of the intersection between the lateral and top faces is z1, and having at least one point where an absolute value |d2r/dz2| of a second-order differential coefficient of the variable z takes a maximum value in the closed zone.

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