LED lamp, in particular for internal lighting of an electric household appliance

• US 8,334,643 B2
• Filed: 12/03/2009
• Issued: 12/18/2012
• Est. Priority Date: 12/04/2008
• Status: Expired due to Fees

• Current Assignee: Illinois Tool Works Inc.
• Original Assignee: Illinois Tool Works Inc.
• Inventors: Giordano, Sergio, Pietrafesa, Domenico
• Primary Examiner(s): Mai, Anh
• Assistant Examiner(s): QUARTERMAN, KEVIN J
• Application Number:
  US13/132,577
• Publication Number:
  US 20110241517A1
• Time in Patent Office: 1,111 Days
• Field of Search: 313/498, 313500-502, 313/512, 313/113, 362/646, 362/227, 362/249.01, 362/249.02, 362/249.03
• US Class Current: 313/498
• CPC Class Codes: F21K 9/00 Light sources using semiconductor devices as light-generating elements, e.g. using light-emitting diodes [LED] or lasers
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]

Abstract

A lamp for internal lighting of an electric household appliance includes an LED, a printed circuit for supporting and powering the LED, and a supporting body made of an electrically non-conductive material and provided, at a first end thereof, with a reflecting/diffusing element for light emitted from the LED. The LED is carried on a flat face of the printed circuit, at a first end of the printed circuit. The supporting body has a tubular shape and the printed circuit being supported inside the supporting body, with the flat face arranged substantially coplanar with an optical axis of the reflecting/diffusing element and the first end of the printed circuit overhangingly protruding from the first end of the supporting body, so that the reflecting/diffusing element collects at least a part of the light emitted from the LED. The printed circuit extends over an entire length of the supporting body.

Claims

1. A lamp for internal lighting of an electric household appliance, comprising:

at least one first light source including a light emitting diode (LED);

a printed circuit for supporting and powering the at least one first light source; and

a supporting body for the printed circuit, the supporting body made of an electrically non-conductive material and provided, at a first end thereof, with a reflecting/diffusing element for light emitted from the at least one first light source, the reflecting/diffusing element defining an optical axis arranged substantially parallel to a longitudinal axis of the supporting body, wherein

the at least one first light source is carried on a first flat face of the printed circuit and is mounted at a first end of the printed circuit, with a light diffusion axis of the at least one first light source oriented substantially perpendicular to the first flat face,

the supporting body has a tubular shape and the printed circuit is supported inside the supporting body, with the first flat face arranged substantially coplanar with the optical axis of the reflecting/diffusing element and the first end of the printed circuit overhangingly protruding from the first end of the supporting body, within a concavity of the reflecting/diffusing element, so that the reflecting/diffusing element is arranged to collect at least a part of the light emitted from the at least one first light source, and

the printed circuit extends over an entire length of the supporting body, to a second end of the supporting body opposite to the first end of the supporting body.

2. A lamp according to claim 1, wherein

the printed circuit is provided, on at least the first flat face, with electrically and thermally conductive tracks connected to the at least one first light source, and

the tracks are exposed in use to a convective cooling motion of the environmental air through respective longitudinal slots made through at least one side wall of the supporting body, at a predetermined distance from the first end of the supporting body and towards the second end of the supporting body.

3. A lamp according to claim 2, wherein the slots are made both above and below the optical axis and parallelly to the optical axis, so that some of the slots are facing the first flat face of the printed circuit and other slots are facing a second flat face of the printed circuit opposite to the first flat face.

4. A lamp according to claim 3, wherein the second flat face of the printed circuit is also provided with respective electrically and thermally conductive tracks and supports, at the first end of the printed circuit, at least one second light source including an LED, the at least one second light source also having a light diffusion axis perpendicular to the printed circuit and arranged within the concavity of the reflecting/diffusing element.

5. A lamp according to claim 1, wherein

the LED is an RGB-type LED, and

the printed circuit carries onboard electronic control circuitry for the LED.

6. A lamp according to claim 1, further comprising a cup-shaped optical element fitted over the first end of the supporting body so as to accommodate, at a concave bottom wall of the cup-shaped optical element, the reflecting/diffusing element, wherein

at least one first portion of the concave bottom wall, facing the reflecting/diffusing element on a side of the at least one first light source is transparent to the light, and

at least one second portion of the concave bottom wall, opposite to the at least one first portion with respect to the optical axis, is at least partially reflecting, so as to intercept at least a part of the light emitted from the at least one first light source to reflect the part of the light towards the reflecting/diffusing element.

7. A lamp according to claim 6, wherein

the first and second portions of the concave bottom wall of the cup-shaped optical element are asymmetric, and

the second portion of the concave bottom wall is a flat surface obliquely arranged with respect to the optical axis.

8. A lamp according to claim 6, wherein the reflecting/diffusing element is shaped so as to collect the part of the light reflected by the second portion of the concave bottom wall of the cup-shaped optical element and at least one part of the light directly emitted from the at least one first light source for directing both parts of of the light towards the first portion of the concave bottom wall, so as to form a predominant lighting beam having an oblique axis and placed at a solid angle delimited by the optical axis and by the light diffusion axis of the at least one first light source.

9. A lamp according to claim 6, wherein

the reflecting/diffusing element is at least partially transparent to the light, and

the supporting body is provided, on a part of the second end of the supporting body, with a reflecting screen and with a corresponding connecting element for the cup-shaped optical element arranged at the reflecting screen, immediately adjacent to the reflecting screen on a side of the second end of the supporting body.

10. A lamp according to claim 1, wherein the reflecting/diffusing element is formed so as to completely overhangingly protrude, in a direction of the optical axis, from the first end of the supporting body, with which the reflecting/diffusing element is integrally formed in a synthetic plastic material, so that the reflecting/diffusing element makes a selectively variable opening angle, simply by replacing respective inserts of a mould for forming the supporting body.

11. A lamp according to claim 1, wherein a first end of the tubular body is internally filled with an electrically insulating resin in which a portion of the printed circuit close to the first end of the tubular body is embedded, so as to seal the first end of the supporting body in a substantially fluid-tight manner.

12. A lamp according to claim 1, wherein the printed circuit carries an electronic component selected from the group consisting of a dusk sensor, an evaporation freshener, a self-powered battery, a humidity sensor, a temperature sensor and combinations thereof.