Abstract: A method for producing an optimum sound field of loudspeakers is revealed. Firstly enclose a surface of a human head with a first closed geometric shape. Then enclose the first closed geometric shape with at least one second closed geometric shape. Next set up reference points on the first and second closed geometric shapes respectively. Use signal strength of the reference point on the second closed geometric shape and a gradient of the corresponding reference points on the first and second closed geometric shapes to obtain a transfer function of each point between a virtual loudspeaker/a real loudspeaker and the sound field respectively. Then create a virtual sound field and a real sound field according to the above transfer functions. Finally, get an optimum signal of the real loudspeaker by minimizing an error between the virtual sound field and the real sound field with a boundary condition.

Abstract: A method for producing an optimum sound field of loudspeakers is revealed. Firstly enclose a surface of a human head with a first closed geometric shape. Then enclose the first closed geometric shape with at least one second closed geometric shape. Next set up reference points on the first and second closed geometric shapes respectively. Use signal strength of the reference point on the second closed geometric shape and a gradient of the corresponding reference points on the first and second closed geometric shapes to obtain a transfer function of each point between a virtual loudspeaker/a real loudspeaker and the sound field respectively. Then create a virtual sound field and a real sound field according to the above transfer functions. Finally, get an optimum signal of the real loudspeaker by minimizing an error between the virtual sound field and the real sound field with a boundary condition.

Abstract: A light-emitting diode (LED) structure includes a substrate, a plurality of LED chips, a first colloid, a second colloid, and a lens. The substrate is provided with at least one retaining section, and the LED chips are mounted on the substrate and covered by the first colloid. The second colloid is located to one side of the first colloid opposite to the substrate. The lens is provided with at least one catching section correspondingly engaged with the at least one retaining section, so that the lens is connected to the substrate to form a unitary body through engagement of the catching section with the retaining section and closes the LED chips, the first colloid and the second colloid in between the lens and the substrate. With these arrangements, the LED structure can have upgraded lighting efficiency and allows quick change of LED color temperature or LED beam angle.