LIGHT-EMITTING DEVICE

• US 20120194094A1
• Filed: 02/01/2011
• Published: 08/02/2012
• Est. Priority Date: 02/01/2011
• Status: Abandoned Application

• Current Assignee: Epistar Corporation
• Original Assignee: Epistar Corporation
• Inventors: Hsin-Mao, Liu, Kuang-Ping, Chao
• Application Number:
  US13/018,770
• Publication Number:
  US 20120194094A1
• Time in Patent Office: Days
• US Class Current: 315/291
• CPC Class Codes: H05B 45/37 Converter circuits
• CPC Class Codes: Y02B 20/30 Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]

Abstract

This disclosure discloses a light-emitting device adapted for receiving an alternating current signal from a power source. The light-emitting device comprises: a rectifying unit for receiving and regulating the alternating current signal into a first direct current signal; a first capacitor electrically connected in parallel with the rectifying unit and for receiving and regulating the first direct current signal to a second direct current signal; and a light-emitting unit electrically connected in parallel with the first capacitor and receiving the second direct current signal. The second direct current signal is a periodic signal, and the second direct current signal has a maximum voltage and a minimum voltage. The voltage difference between the maximum and minimum voltages is less than 5% of the maximum voltage in one cycle of the periodic signal.

Claims

1. A light-emitting device adapted for receiving an alternating current signal from a power source, the light-emitting device comprising:

a rectifying unit for receiving and regulating the alternating current signal into a first direct current signal;

a first capacitor electrically connected in parallel with the rectifying unit and for receiving and regulating the first direct current signal to a second direct current signal; and

a light-emitting unit electrically connected in parallel with the first capacitor and receiving the second direct current signal;

wherein the second direct current signal is a periodic signal, and the second direct current signal has a maximum voltage and a minimum voltage that the voltage difference between the maximum and minimum voltages is less than 5% of the maximum voltage in one cycle of the periodic signal.

2. The light-emitting device of claim 1, wherein the voltage difference between the maximum and minimum voltages is less than 2% of the maximum voltage.

3. The light-emitting device of claim 1, wherein the first capacitor has a capacitance value greater than 0.5 mF.

4. The light-emitting device of claim 1, wherein the first capacitor has a size small than 1.5 cm×

1.5 cm×

1.0 cm.

5. The light-emitting device of claim 1, further comprising a current-limiting unit electrically connected in series with and between the first capacitor and the light-emitting diodes.

6. The light-emitting device of claim 1, further comprising a resistor connected in parallel with and between the first capacitor and the light-emitting diodes.

7. The light-emitting device of claim 1, further comprising a current constant circuit electrically connected between the power source and the rectifying unit, wherein the current constant circuit comprises a second capacitor and a resistor electrically connected in parallel with the second capacitor.

8. The light-emitting device of claim 1, wherein the first capacitor comprises a first conductive plate, a second conductive plate, and a non-conductive layer between the first and second conductive plates, wherein each of the first and second conductive plates comprises magnetic materials.

9. The light-emitting device of claim 8, wherein the non-conductive layer is made of a dielectric material comprising hafnium silicate, zirconium silicate, hafnium dioxide, zirconium dioxide, titanium oxide, barium titanium oxide, silicon oxide, perovskite-oxide, or combinations thereof.