Sideway-emission light emitting diode

A sideway-emission light emitting diode includes a light emitting diode package comprised of a light emitting diode dice that gives off light and a lens that is positioned in front of a front end face of the package for receiving the light and redirecting the received light toward a circumference of the package and a light guide comprised of a board defining a cavity to receive and retain the light emitting diode package therein. The board has opposite sides each forming a cut-off delimited by opposite inclined edges, a refraction section extending from each inclined edge, and a projection section formed between opposite refraction sections, whereby light transmitting into the light guide is directed, by means of the reflection/refraction by the inclined edges, the refraction sections and the projection sections, toward and projected from the projection sections in sideway directions.

FIELD OF THE INVENTION

The present invention generally relates to a sideway-emission light emitting diode (LED), and in particular to an LED lighting construction comprising an LED dice, a lens, and a light guide in combination to redirect light emitted from the LED dice with the aid of the lens into the light guide that guides and projects the light from projection sections on opposite sides whereby perfect sideway emission of light can be realized for better utilization in different environments, such as shopping malls, advertisement boards, and backlight devices.

BACKGROUND OF THE INVENTION

A conventional light emitting diode (LED), such as U.S. patent application Ser. No. 09/849,042 filed on May 4, 2001, which is particularly shown inFIGS. 1aand1bof the attached drawings, comprises an LED package1having a front end face and an opposite rear end face. An LED dice2is embedded in the package1and gives off light in a first direction that is substantially normal to the front end face. A lens3is positioned in front of the front end face and receives the light emitted from the LED dice2. The lens3receives almost all the components of the light from the LED dice2, including the component of the light that travels substantially in the first direction, and redirects the light in directions that are substantially parallel to the front end face of the package1. Although the light from the LED dice2can be effectively redirected by the lens3to travel in directions that are substantially parallel to the front end face, such light is randomly distributed along the whole circumference of 360 degrees of the lens. There is no way for such a conventional LED package to concentrate the light on a particular sideway direction.

SUMMARY OF THE INVENTION

Thus, a primary objective of the present invention is to provide a sideway-emission light emitting diode (LED), comprising an LED dice, a lens, and a light guide that are combined together to have all components of the light from the LED dice redirected by the lens into the light guide, which in turn guides and projects the light from projection sections on opposite sides to realize effective sideway emission/projection of light and thus enhancing practical applications of the light emitting diodes.

To achieve the above objective, in accordance with the present invention, a sideway-emission light emitting diode is provided, comprising a light emitting diode package comprising a light emitting diode dice that gives off light and a lens that is positioned in front of a front end face of the package for receiving the light and redirecting the received light toward a circumference of the package and a light guide comprising a board defining a cavity to receive and retain the light emitting diode package therein. The board has opposite sides each forming a cut-off delimited by opposite inclined edges, a refraction section extending from each inclined edge, and a projection section formed between opposite refraction sections, whereby light transmitting into the light guide is directed, by means of the reflection/refraction by the inclined edges, the refraction sections and the projection sections, toward and projected from the projection sections in sideway directions.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

With reference to the drawings and in particular toFIGS. 2–4, a sideway-emission light emitting diode (LED) assembly constructed in accordance with the present invention comprises at least one LED package10comprised of an LED dice11and a lens12. The lens12is positioned in front of a front end face of the LED package10to receive light emitted from the LED dice11. The lens12is constructed to redirect substantially all the components of the light from the LED dice11toward a circumference of the LED package10.

A light guide20, preferably in the form of a board, defines a cavity21inside which the LED packages10are received and fixed. The light guide20has opposite sides in each of which an angled cut-off22is formed, which is delimited by two inclined edges having an included angle θ therebetween. The included angle is smaller than 95 degrees to properly guide the light from the LED dice11. A refraction section23extends from each inclined edge of the angled cut-off22in opposite directions and a projection section24is formed between remote ends of the refraction sections23on the opposite lateral sides of the light guide20for projecting the light therefrom in sideway directions.

A circuit board30is mounted to a bottom of the light guide20and is in electrical connection with the LED dice11.

By properly arranging and combining the LED dice11, the lens12, and the light guide20together, all the components of the light emitted from the LED dice11are redirected by the lens12to transmit through a lateral circumference of the LED package10. All the light components that transmit through the lateral circumference of the LED package10travel into the light guide12and are guided by the light guide12by being reflected/refracted by the inclined edges of the cut-offs22, the refraction sections23, and the projection sections24, to project from the projection sections24in the sideway directions. This enhances the practical applications of the LEDs.

Also referring toFIG. 5, in a practical application of the LED in backlight devices, a number of LED packages10are mounted to the light guide20first. The circuit board30is then connected to the LED packages10. The assembly is mounted to a backlight board40of the backlight device whereby light emitted from the LED packages10is redirected and guided to project from the projection sections24into the backlight board40. Perfect sideway emission can be realized.