CONDENSING ELEMENT AND FORMING METHOD THEREFOR AND CONDENSING ELEMENT-CARRYING LED LAMP AND LINEAR LIGHT EMITTING DEVICE USING LED LAMP AS LIGHT SOURCE

摘要

This invention proposes a beam-condensing element comprising a beam-condensing portion having a translucent concave end face, which is the same curvature as a translucent convex face of a LED lamp comprising a LED chip and a substantially hemispherical translucent convex face enveloping the LED chip, and extending from a peripheral edge of the translucent concave end face in a shape of a parabolic rotating body, in which when viewing at a cross section including a rotation axis of the beam-condensing portion, an inclination of tangent drawn to the beam-condensing portion at a peripheral edge position of the translucent concave end face with respect to the rotation axis is set up so that an incidence efficiency of light beams emitted from the LED lamp to the beam-condensing portion is not less than a given value.