Patent Application
20080062505
The present invention can be fully understood from the following detailed description and preferred embodiment with reference to the accompanying drawings, in which:
The following detailed description is of the best presently contemplated modes of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating general principles of embodiments of the invention. The scope of the invention is best defined by the appended claims.
Referring to
The light-emitting device 2 includes a printed circuit board 22, and a light-emitting diode (LED) 21 is positioned at front end of the printed circuit board 22. Because the LED 21 has epoxy resin on its outer surface, the LED 21 is used to converge light beams. A reflective layer 24 is attached to the front end of the printed circuit board 22 so as to reflect light beams, and a conductive plate (not shown) is positioned at rear end of the printed circuit board 22. The printed circuit board 22 is positioned at a mounting frame 23, and the mounting frame 23 is positioned in vicinity of the front end of the housing 1 so that the light-emitting device 2 is positioned at the housing 1. The LED 21 is electrically connected with the power source (not shown) through the printed circuit board 22 and the conductive plate (not shown).
The collar 3 is cylindrical and the cap 4 is positioned in front of the collar 3. The convex lens 5 is positioned between the cap 4 and the collar 3, and the reflective plate 24 is positioned between the LED 21 and the convex lens 5. The convex lens 5 can be a single convex lens or a double convex lens. According to the embodiment of the present invention, a surface of the convex lens 5 confronting to the LED 21 is a flat plane, and the other surface of the convex lens is a concave surface. The convex lens 5 is positioned at optical pathway of light beams of the LED 21, and a longitudinal groove 31 is positioned at lower portion of the collar 3. A switch button 32 is adapted to be received at the longitudinal groove 31 and is L-shaped. The switch button 32 can be moved so that the switch button 32 is held by the first receiving groove 11 or the second receiving groove 12.
According to the second embodiment of the present invention (as shown in
According to the third embodiment of the present invention (as shown in
As shown in experiment data below, two convex lenses are used. Diameters of the two convex lenses are 38 mm and 22.8 mm respectively. When the distance between the object and the convex lens is 5 m, the image is focused at the other side of the convex lens and the diameter of the image is 35 cm if diameter of the convex lens is 38 mm, or the diameter of the image is 40 cm if the diameter of the convex lens is 22.8 mm. When the distance between the object and the convex lens is 30 m, then the image is focused at the other side of the convex lens and the diameter of the image is 1.1 m if the diameter of the convex is 38 mm, or the diameter of the image is 2 m if the diameter of the convex lens is 22.8 mm.
Experiment data:
The light beams are focused by the LED 21 so that beam angle is about 140°. The convex lens 5 is moved by a distance within two times of focal length of the convex lens 5. When the distance between the light source and the convex lens is changed, beam angle of light beams from the convex lens 5 ranges from 6° to 120°. In addition, because the diameters of the convex lens 5 are different, proper distance is within two times of focal length of the convex lens 5. It is more faster to change focus of the convex lens 5.
For example, the diameter of the convex lens is 22.8 mm. Light beams from the LED 21 are focused by an epoxy resin layer so the beam angle is about 140°. When the distance between the LED 21 and the convex lens 5 is 0 mm (the switch button 32 is held by the second receiving groove 12), beam angle is about 120° and the light beams are diverging beams after the light beams are refracted. The light beams are focused in front of the convex lens 5 by 3 m, and the diameter of the image is about 3 m. The collar 3 is pulled so that the distance between the LED 21 and the convex lens 5 is within two times of the focal length of the convex lens 5 (the switch button 32 is held by the first receiving groove 11). After the light beams are refracted by the convex lens 5, beam angle is about 60 and the light beams are focused in front of the convex lens 5 by 5 m. The diameter of the image is 40 m. If the light beams are focused in front of the convex lens by 30 m, then diameter of the image is about 2 m.
According to the present invention, light beams from the LED 21 are focused twice so that light beams are converged (the distance from the light source is within two times of the focal length of the convex lens 5) and diverged (the distance from the light source to the convex lens 5 is 0). The LED 21 is moved with respect to the convex lens 5 (the distance ranges from 0 to 32 mm), and beam angle is changed (ranging from 120° to 6°) so the brightness for long distance is increased and illumination scope for short distance is increased. The present invention does not need reflective cone and has a large range of light beams and quick to adjust the focal length of the lens.
Furthermore, when the switch button 32 is held by the first receiving groove 11 of the housing 1, the light beams are focused within two times of the focal length of the convex lens 5. That is, the distance between the LED 21 and the convex lens 5 is maximum and the beam angle is about 6°. And, the distance to change focus is 13 mm. When the switch button 32 is held by the second receiving groove 12 of the housing 1, the distance between the LED 21 and the convex lens 5 is 0 and the beam angle is about 120°. Due to change of distance from the light source to the convex lens, the beam angle ranges from 6° to 120°. When the distance between the light source and the convex lens is within two times of focal length of convex lens, the light beams are diverged. When the distance is changed, the light beams are becoming from diverging to converging or from converging to diverging.
According to the present invention, they produce optimal beams—no dark holes, rings, hot spots, or shadows when the lighting apparatus is in use so the present invention is widely used in flashlights, tactical light, table lamps, search lights, projection lights or exhibition lights. Changing focus depends on how far is the object. According to the present invention, the collars are movable with respect to the housing and the LEDs are not moveable. If the collars are not movable and the LEDs are movable, then distance between them are adjusted so as to change focus.
While the invention has been described with reference to the preferred embodiments, the description is not intended to be construed in a limiting sense. It is therefore contemplated that the appended claims will cover any such modifications or embodiments as may fall within the scope of the invention defined by the following claims and their equivalents.
