KR20050098032A - White-light led and method for regulating the generated light color of the white-light led - Google Patents

Abstract

The present invention discloses a white light emitting diode (LED) and a method of adjusting the color of light generated from the LED. Here, the LED has at least one InGaN chip 30 and at least one AlGaInP chip 20. When forward bias voltages are applied to the InGaN chip 30 or AlGaInP chip 20, blue light and yellow green light are generated, and when these are mixed, white light is generated. By adjusting the forward bias voltages by adjusting an external impedance value applied to the LED, clean white light may be generated based on the intensity of the adjusted luminance of the blue light and the yellow green light.

Description

White light LED and a method for adjusting the color of light generated from the white light LED {WHITE-LIGHT LED AND METHOD FOR REGULATING THE GENERATED LIGHT COLOR OF THE WHITE-LIGHT LED}

The present invention relates to a white light emitting diode (LED) and a method for adjusting the color of light generated from the LED, and more particularly, the color of light generated from the LED can be determined by adjusting an external impedance value applied to the LED. Is there.

Development and manufacture of conventional light emitting diodes have brightness and color tone issues, although they are of low power consumption and long service life. However, with improvements in manufacturing technology to obtain higher luminance, LEDs capable of generating white light have recently been developed and applied to the construction of illuminance devices.

Some known techniques for generating white light LEDs are listed below.

1. White light is generated by mixing the blue light emitted by the InGaN chip and the yellow light generated by the YAG phosphor powder.

2. The InGaN chip is used to excite phosphor powders of R, G and B colors to generate white light.

3. The ultraviolet light is used to excite the phosphor powders of the R, G, and B colors to generate white light.

4. White light is generated by mixing the blue light supplied by the InGaN chip and the yellow light generated by the GaP chip.

As one common feature of the first to third techniques described above, it should be noted that the phosphor powder is adopted as an essential raw material for producing white light. However, slight aberrations in the thickness of the phosphor powder coated on the LED or a percentage error of the composite results in color aberration of the generated light. Thus, the generated light may be light yellow or blue. Even for batches of the same LED products, the color of light emitted from each LED may be different. Therefore, it is difficult to obtain a consistent and clean white light. Another problem is that the drive voltage to activate these LEDs must be higher than 3 volts.

For the fourth technique, the manufacturing cost of the LEDs is much higher than the cost of the previous three techniques because of the GaP chip. In addition, the luminance performance is lower than that of the three kinds of techniques described above.

In view of this, the main object of the present invention to improve the deficiencies of the conventional techniques presented above for generating white light LEDs is to achieve the effect of increasing the brightness performance, reducing the manufacturing cost, etc. It is to provide a "white light emitting diode (LED)".

It is an object of the present invention to provide a method for adjusting the color of a white light emitting diode (LED) and light generated from the LED, the generated light being controlled by an external impedance applied to the LED.

White light LED of the present invention to achieve the above object,

A supporting base formed by a cathode terminal and at least two anode terminals, wherein a supporting platform on which the cavity is defined is formed on an upper end of the cathode terminal;

An AlGaInP chip mounted in the cavity of the support platform, wherein a cathode node of the AlGaInP chip is electrically connected to the cathode terminal, and an anode node is connected to one of the at least two anode terminals;

At least one InGaN chip mounted in the cavity, wherein a cathode node of the at least one InGaN chip is electrically connected to the cathode terminal, and an anode of the InGaN chip is connected to another one of the at least two anode terminals. Become;

A light pervious body formed to comprehensively seal the two chips on the support base; And

And at least one resistor, the first end of which is selectively connected to the AlGaInP chip or the at least one InGaN chip and the second end of which is connected to a positive voltage.

Other objects, advantages and inventive features of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.

Referring to FIG. 1, the white light emitting diode (LED) according to the first embodiment mainly includes a metal support base 10, an aluminum-gallium-indium phosphide (AlGaInP) chip 20, and an indium-gallium nitride (InGaN) chip ( 30 and a light transmitting body 14.

The support base 10 is formed by a cathode terminal 11 and two anode terminals 12, 13. On the upper end of the cathode terminal 11 is formed a support platform 111 in which a cavity 112 is defined.

The AlGaInP chip 20 is mounted to the cavity 112 of the support platform 111, where a cathode node of the AlGaInP chip 20 is connected to the cathode terminal 11 through a bonding wire. An anode node is correspondingly connected to a first anode terminal of the anode terminals.

The InGaN chip 30 is also firmly mounted to the cavity 112 via epoxy or other similar materials, where, via another bonding wire, the cathode terminal 11 is connected to the InGaN chip 30. A cathode node is also connected, and an anode of the InGaN chip 30 is connected to the second anode terminal 13.

The light transmitting body 14 is formed on the support base 10 to comprehensively seal the two chips 20, 30 and the bonding wire.

Referring to FIG. 2, an equivalent circuit of the LED of FIG. 1 is shown. In the first embodiment, an external resistor 15 is provided to connect between the positive voltage source V + and the anode terminal 12 electrically connected to the AlGaInP chip 20. By appropriately adjusting the resistance value of the external resistor 15 to change the forward bias voltage level beyond the AlGaInP chip 20, the yellow green light having the desired luminance generated by the AlGaInP chip 20 is converted into the InGaN chip ( It can be mixed with the blue light emitted from 30) to generate clean white light. Alternatively, the brightness of the InGaN chip 30 can also be changed by adjusting its forward bias using an external resistor.

3 and 4, a second embodiment of the LED of the present invention has a metal support base 40 having a cathode terminal 41 and three anode terminals 42, 43, and 44, Here, a platform 411 is integrally formed on top of the cathode terminal 41, and a cavity 412 is defined in the platform 411.

Two AlGaInP chips 21 and 22 are mounted in the cavity 412, and a cathode of each AlGaInP chip 21 and 22 is electrically connected to the cathode terminal 41 through a bonding wire. The anodes of the AlGaInP chips 21 and 22 are electrically connected to the anode terminals 42 and 44.

One InGaN chip 31 mounted in the cavity 412 and between the two AlGaInP chips 21, 22 is a cathode node connected to the cathode terminal 41 and the anode terminal 43, respectively. And an anode.

A light transmitting body 45 is formed on the support base 10 to comprehensively seal the three chips 21, 22, 31 and the bonding wire.

Referring to FIG. 5, an equivalent circuit of the LED of FIG. 3 is shown. A first external resistor 46 is connected between a positive voltage source V + and a common node to which the anode nodes of the two AlGaInP chips 21 and 22 are connected together, so that the two chips 21 and 22 are connected. Adjust the forward bias voltage level above. A second external resistor 47 is connected between the positive voltage source V + and the anode terminal 43 to control the brightness of the InGaN chip 31.

Referring to FIG. 6, DC power of 2.7 volts is applied to the chips 21, 22, and 31, and a preferable value of the first external resistor 46 is 8.5Ω and the second external resistor is 20Ω. By simultaneously adjusting the luminance of each chip 21, 22, 31, clean white light can be generated.

As shown in FIGS. 3 and 4, the three chips 21, 22, 31 are arranged linearly, but the mounting positions within the cavity 412 can be changed to any desired form. It should be noted that the amount of chips in the cavity 412 is also variable. For example, four AlGaInP chips can be placed in a rectangle, and one InGaN chip is mounted at the central position of these AlGaInP chips.

As discussed above, the present invention uses blue light and yellow green light generated by the InGaN chip and the AlGaInP chip, respectively, to obtain clean light by appropriately mixing the two colors. Since the AlGaInP chip is much cheaper than the GaP chip, the white light LED of the present invention is well suited for mass production. The external resistors are only applied to generate white light, but can also be used to adjust the LED to generate the desired white-yellow light or white-blue light if necessary. In addition, only a low operating voltage is employed to adjust the brightness of the chips.

However, although a number of features and advantages of the invention have been defined in the foregoing description, along with the details of the structure and function of the invention, this disclosure is merely exemplary and is the term set forth in the appended claims. Changes may be made in matters of shape, size and configuration of the parts within the principles of the invention in its broadest sense.

Compared with the conventional white light emitting diode manufacturing techniques through the above description, the present invention has the effect of reducing the manufacturing cost and can produce a diode having better brightness performance. In conclusion, it is clear that the present invention has various advantages as described above, and has a relatively remarkably improved effect compared to the conventional white light emitting diode manufacturing techniques presented above.

1 is a plan view of a white light emitting diode (LED) according to a first embodiment of the present invention;

2 is an equivalent circuit diagram of the LED of FIG. 1;

3 is a cross-sectional view of a white light emitting diode (LED) according to a second embodiment of the present invention;

4 is a top plan view of the LED of FIG. 3;

5 is an equivalent circuit diagram of a white light emitting diode (LED) according to a third embodiment of the present invention; And

FIG. 6 is a circuit diagram illustrating a DC voltage applied to the LED of FIG. 5.

<Description of the symbols for the main parts in the drawing>

10 metal support base 11 cathode terminal

12, 13 anode terminals 14 light transmitting body

20: AlGaInP chip 30: InGaN chip

111: support platform 112: cavity

Claims (3)

The support base formed by the cathode terminal 11 and the at least two anode terminals 12, 13, wherein on the upper end of the cathode terminal 11 a support platform 111 on which a cavity 112 is defined Formed; At least one AlGaInP chip 20 mounted in the cavity 112 of the support platform 111, wherein the cathode terminal of the at least one AlGaInP chip 20 is electrically connected to the cathode terminal 11. An anode node is connected to a first anode terminal 12 of the at least two anode terminals; An InGaN chip 30 mounted in the cavity 112 and a cathode node of the InGaN chip 30 are electrically connected to the cathode terminal 11, and a second anode terminal of the at least two anode terminals. An anode of the InGaN chip 30 is connected to (13); A light transmitting body (14) formed to comprehensively seal the two chips (20, 30) on the support base (10); And At least one resistor 15 having a first end selectively connected to the AlGaInP chip 20 or the at least one InGaN chip 30 and a second end connected to a positive voltage V +. White light emitting diode (LED). In a method of adjusting the light color of an LED having at least one AlGaInP chip 20 and at least one InGaN chip 30, Mixing blue light and yellow green light generated by the at least one AlGaInP chip (20) and the at least one InGaN chip (30), respectively; And By controlling an external impedance value to adjust the forward bias voltage of the at least one AlGaInP chip 20 or the at least one InGaN chip 30, the luminance of the blue light or the yellow green light is changed accordingly, and thus the color of the desired light. Generating a method. The method of claim 2, The control of the external impedance value is achieved by connecting a resistor 15 between the power supply V + and the at least one AlGaInP chip 20 or the at least one InGaN chip 30. .