KR20060109728A - Light-emitting diode union capacitor for preventing electrostatic discharge - Google Patents

Abstract

A light emitting diode structure is provided to prevent the damage of the light emitting diode and to mount effectively the light emitting diode on a PCB by discharging the static electricity abruptly applied to the light emitting diode using a static electricity preventing capacitor. A light emitting diode structure comprises a light emitting diode(12), an electrode pad at both electrodes of the light emitting diode, and a static electricity preventing capacitor. The static electricity preventing capacitor is bonded to the electrode pad. The static electricity preventing capacitor is installed between the electrode pad and the ground in order to discharge the static electricity applied to the electrode of the light emitting diode through the ground.

Description

Light-emitting diode union capacitor for preventing electrostatic discharge

1 and 2 illustrate an embodiment in which static electricity is applied to both electrodes of a general light emitting diode,

3 and 4 illustrate an embodiment in which a general light emitting diode and a power shunt device are installed together.

5 to 9 illustrate an embodiment of a light emitting diode to which an antistatic capacitor is bonded according to the present invention.

10 to 12 illustrate another embodiment of a light emitting diode in which an antistatic capacitor is bonded according to the present invention.

※ Explanation of code for main part of drawing

10: power supply unit 11: resistance

12,30: light emitting diode 13: IC

31: power supply shunt element 32, 33: pad

50, 51: capacitor 60, 61: variable capacitor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode in which an antistatic capacitor is bonded. For example, a surface mount device (LED) type LED mounted on a surface of a printed circuit board (PCB) is a static electricity. The present invention relates to a light emitting diode in which an antistatic capacitor is bonded to prevent damage thereof.

1 and 2 illustrate an embodiment in which static electricity is applied to both electrodes of a general light emitting diode. For example, as shown in FIG. 1, an anode of the light emitting diode 12 has a resistance. A power supply unit 10 (VCC) is connected through 11, and an IC 13 for controlling the light emission time interval is connected and connected to a cathode of the light emitting diode.

On the other hand, the resistor 11 connected to the anode electrode to control the current flow of the light emitting diode (Current) and to control the light intensity (Intensity), as shown in Figure 2, the printed circuit board ( When static electricity is instantaneously applied to both electrodes of the light emitting diode mounted on the surface of the PCB), there is a problem that the light emitting diode is damaged due to the static electricity.

For example, the light emitting diodes must maintain the maximum electrical allowable range of the diodes for each color of the light emitting diodes, and the static electricity is instantaneously caused by excessive voltage and current at the anode or the cathode of the light emitting diodes. Delivered.

When static electricity is applied to the anode electrode of the light emitting diode (LED), the moment when the maximum allowable electrical range of the light emitting diode is exceeded, excessive current flows inside the light emitting diode to depletion layer between the anode and the cathode. As the resistance increases, it breaks down and the current flows off, causing the light emitting diode (LED) to break.

In addition, when static electricity is applied to the cathode of the light emitting diode (LED), an excessive current flows inside the light emitting diode as soon as the maximum allowable reverse electric current range of the light emitting diode is exceeded, and a resistance value is formed in the depletion layer between the anode and the cathode. As it grows larger, the current flows off and the LED breaks.

On the other hand, in order to protect the light emitting diode (LED) from excessive electrostatic or electrical phenomena applied to the light emitting diode, the LED current resistor 11 for limiting the magnitude of the current is used. When introduced from a power source (VCC), which is likely to flow from an electric circuit, it has an effect of limiting low frequency voltage and current among electrical components of static electricity.

In addition, in the case of an actual terminal product, the position where the light emitting diode (LED) is disposed is located under the front keypad where the human finger touches, and the portion where the inflow of static electricity (ESD) from the keypad is inevitable. This is a terminal navigation key area with a metal material

And, the static electricity (ESD) accumulated in the human body is introduced into the navigation key (Navigation Key) through the finger, the electrostatic discharge (ESD) is transmitted to the direction button because the metal direction button is disconnected from other conductivity Electrostatic discharge (ESD) is located directly under the key pad (Key Pad) and is second-delivered to the anode (Anode, Cathode) electrode of the light emitting diode (LED) bonded to the printed circuit board, to solve this problem There is a need for a method for protecting both electrodes (Anode, Cathode) of the light emitting diode.

3 and 4 illustrate an embodiment in which a general light emitting diode and a power supply shunt element are installed together. For example, as a conventional method proposed for preventing static electricity, as shown in FIG. 3, a light emitting diode (LED) is shown. (30) and a light emitting diode package including a power shunting device (PSD) has been proposed.

On the other hand, the light emitting diode 30 and the power supply shunt element 31 are flip-chips having terminals on the surface, and these terminals are respectively positive electrode pads 32 and negative electrode pads 33. The use of flip chip bonding of both the light emitting diode 30 and the power supply shunt element 31 allows direct removal of the wire bonding from the assembly.

In addition, the bonding may be bonding by ultrasonic bonding, adhesive bonding, or soldering, such a flip chip light emitting diode comprising a transparent substrate on which various active layers are grown or deposited. And electrical contact is formed on the grown or deposited layer to make electrical contact with the n and p type layers of the light emitting diode.

In addition, the substrate of the light emitting diode is mounted so as to be a primary window for light emission. FIG. 4 is an electrical structural diagram of the light emitting diode 30 and the power supply shunt element 31. In the event that the applied voltage exceeds a predetermined threshold voltage, back-to-back Zener diodes 46,47 cause the voltage across LED 30 to clamp to a predetermined voltage. do.

In addition, since the current flows from the LED 30 to another place, the power supply shunt element 31 protects the LED from electrical overstress such as generated by an electrostatic discharge. Shunt element 31, a transient voltage suppressor diode (Transient Voltage Suppressor Diode) may be used, it is preferable to be located outside the lens in order to increase the Optical Efficiency (Optical Efficiency).

However, the light emitting diode (LED) assembly structure has a large component size due to an assembly structure for integrating with a power supply shunt element, and thus cannot be used for a product having a limited height and area, such as a terminal.

In addition, for the power shunt element, an increase in assembly size due to the use of a back-to-back zener diode causes difficulty in reducing the size of the component, and the cost of the back-to-back zener diode used in the power shunt element provides ESD protection. There is a disadvantage that the price is higher than the components for.

In addition, when the component height of the back-to-back zener diode used in the power supply shunt element is larger than other ESD protection components, and the electrostatic discharge is applied to the anode electrode of the LED, Since the electric shock is transmitted to the cathode electrode of the light emitting diode through the back-to-back zener diode without passing through the light emitting diode (LED) when the threshold range of the light emitting diode is exceeded, the cathode electrode of the light emitting diode (LED) is grounded ( If not connected to the ground and connected to the IC input that controls the light emitting time interval of the LED, excessive electric shock may be applied to the IC input, resulting in damage to the IC.

Conversely, when electrostatic discharge (ESD) is applied to the cathode of the light emitting diode (LED), excessive electrical shock may damage electronic components connected to the power supply connected to the anode electrode of the light emitting diode (LED) via the back-to-back control diode. Because of this, there are various problems in the practical application.

Accordingly, the present invention has been created to solve the above problems, for example, an anode (anode) electrode and a cathode (SMD) provided in the SMD type light emitting diode mounted on the surface of the printed circuit board (PCB) ( Cathode) In order to prevent breakage of the light emitting diode and to efficiently mount the light emitting diode on the surface of the printed circuit board even when static electricity is applied to at least one of the electrode pads at the moment. SUMMARY OF THE INVENTION An object of the present invention is to provide a light emitting diode bonded with an antistatic capacitor.

The light emitting diode to which the antistatic capacitor is bonded according to the present invention for achieving the above object is characterized in that the antistatic capacitor is bonded to one or more electrode pads of both electrodes of the light emitting diode which is a surface mount component. ,

In addition, the antistatic capacitor is installed between the one or more electrode pads and the ground to discharge the static electricity applied to the electrode through the ground, it characterized in that a fixed capacitor or a variable capacitor is used.

Hereinafter, with reference to the accompanying drawings, a preferred embodiment of a light emitting diode bonded to the antistatic capacitor according to the present invention will be described in detail.

5 to 9 illustrate an embodiment of a light emitting diode in which an antistatic capacitor is bonded according to the present invention. For example, an anode of a light emitting diode (LED) using an epoxy lens is illustrated. Capacitors 50 and 51 are connected to and bonded to the electrode and the cathode to protect the light emitting diode LED from being damaged by the electrostatic discharge.

In addition, the electronic component connected to both electrodes of the light emitting diode is protected from static electricity as well as other electric shocks. In particular, a protection circuit against high frequency noise included in the electrostatic (ESD) component The capacitors 50 and 51 play the role of.

For example, a software failure, which is a major problem of most ESD generated in a terminal, can be solved using an electrostatic protection light emitting diode (LED) to which the present invention is applied. As illustrated in FIG. 6, an epoxy lens emits light used in a light emitting diode (LED).

In addition, when the light emitting diode is used in a small chip mount LED, an anode electrode and a cathode electrode of the light emitting diode are connected to an anode electrode pad and a cathode electrode pad of the capacitor, and the connection method thereof is It is treated with Flip Chip Bonding.

In addition, the capacitors 50 and 51 connected to both electrodes of the light emitting diode (LED) are positioned on the rear surface of the light emitting diode, so that the area occupied by the structure connected to the light emitting diode is minimized. The ground (GND) electrode is disposed separately between the two electrodes to bond the printed circuit board (PCB).

On the other hand, when the electrostatic discharge (ESD) is applied to both electrodes of the light emitting diode (LED), the electric shock with excessive current and voltage, the value corresponding to the component of the electrostatic discharge (ESD), that is, the magnitude component of the current, voltage, frequency As a result, induction discharge is performed to the ground GND through capacitors connected to both electrodes of the light emitting diode.

That is, the range of application of the conventional light emitting diodes (LEDs) described above with reference to FIGS. 3 and 4 could be seen only when the cathode electrode is connected to the ground, but in the present invention, the light emission applied to the terminal It can be applied to all light emitting diodes (LEDs) connected to ICs that can control the light emitting time intervals, such as diodes (LEDs).

Therefore, the anode electrode, the cathode electrode, and the ground (GND) electrode of the light emitting diode (LED) require surface treatment that can be bonded to the printed circuit board, and the back surface of the light emitting diode (LED) The capacitor to be deposited may be deposited by using a discrete component type component or by reducing the thickness of the capacitor by a multi-layer process.

In addition, the size of the electrode pad, which is a connection portion between the anode electrode, the cathode electrode, and the both electrodes of the capacitor, of the light emitting diode (LED) according to the present invention, plays a necessary role for bonding with the PCB. The shape of the anode electrode and the cathode electrode is made vertically due to the bonding of the lens, the anode electrode, and the cathode electrode, so that the anode electrode and the cathode electrode are manufactured so as not to be exposed to the outside surface, thereby effectively preventing external static electricity from being applied.

Meanwhile, FIGS. 10 to 12 show another embodiment of a light emitting diode to which an antistatic capacitor is bonded according to the present invention. The capacitor for discharging the static electricity is illustrated in FIGS. 10 to 12 in addition to the fixed capacitor. As one can use a variable capacitor.

Or more, preferred embodiments of the present invention described above, for the purpose of illustration, those skilled in the art, within the technical spirit and the technical scope of the present invention disclosed in the appended claims below, to further improve various other embodiments Changes, substitutions or additions will be possible.

The light emitting diode to which the antistatic capacitor according to the present invention constructed and operated as described above is bonded, for example, an anode provided in an SMD type light emitting diode mounted on a surface of a printed circuit board (PCB). ) By bonding an antistatic capacitor to at least one of the electrode pads and at least one of the electrode pads, even if static electricity is momentarily applied to the light emitting diode, the ground (GND) is prevented through the antistatic capacitor. Discharge) to prevent the breakage of the light emitting diode due to static electricity, as well as a very useful invention that can be more efficiently mounted on the surface of the printed circuit board.

Claims (3)

An antistatic capacitor is bonded to an electrode pad of at least one of both electrodes of a light emitting diode which is a surface mount component. The method of claim 1, The antistatic capacitor is provided between the at least one electrode pad and the ground, the light emitting diode bonded to the antistatic capacitor, characterized in that to discharge the static electricity applied to the electrode through the ground. The method of claim 1, The antistatic capacitor is a light emitting diode bonded to the antistatic capacitor, characterized in that a fixed capacitor or a variable capacitor is used.

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