Abstract:
An exemplary electrostatic discharge protection device includes: an electrostatic discharge part configured for discharging electrostatic when the electrostatic is larger than a threshold value; and a light emitting part configured for emitting light when electrostatic discharge happens.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to electrostatic discharge (ESD) protection devices, and more particularly to an ESD protection device with phosphors and a method of fabricating the ESD protection device. 
       GENERAL BACKGROUND 
       [0002]    Static electricity is likely to be generated in the processes of manufacturing, assembling, testing, storing, or transporting electronic components. Moreover, static electricity can also accumulate in the human body, testing instruments, storing devices, and even in the electronic components themselves. When a human body, a testing instrument, or a storing device contacts an electronic component, ESD is liable to occur. When this happens, it can seriously damage or even destroy the electronic component. Therefore, an ESD protection device needs to be installed in various electronic components. 
         [0003]      FIG. 3  is an abbreviated circuit diagram of a conventional liquid crystal display (LCD). The LCD  1  includes a plurality of ESD protection devices  10 , a first common electrode  141 , a second common electrode  142 , a third common electrode  143 , a plurality of scan lines  12  parallel to each other, a plurality of data lines  13  parallel to each other. The scan lines  12  are perpendicular to the data lines  13 . Each scan line  12  is connected to the first common electrode  141  via an ESD protection device  10 , and is also connected to the second common electrode  142  via another ESD protection device  10 . Each data line  13  is connected to the third common electrode  143  via an ESD protection device  10 . 
         [0004]      FIG. 4  is a circuit diagram of one of the ESD protection devices  10 . The ESD protection device  10  is connected between a first conductor line  101  and a second conductor line  102 . The first conductor line  101  may be one of the scan lines  12  when the second conductor line  102  is one of the first common electrode  141  and the second common electrode  142 . Alternatively, the first conductor line  101  may be one of the data lines  13  when the second conductor line  102  is the third common electrode  143 . The ESD protection device  10  includes a first transistor  110 , a second transistor  120 , and a third transistor  130 . A gate electrode of the first transistor  110  is connected to the first conductor line  101 , and a drain electrode of the first transistor  110  is connected to the first conductor line  101 . Further, a source electrode of the first transistor  110  is connected to a gate electrode of the third transistor  130 . A gate electrode of the second transistor  120  is connected to the second conductor line  102 , and a drain electrode of the second transistor  120  is connected to the second conductor line  102 . Further, a source electrode of the second transistor  120  is connected to the gate electrode of the third transistor  130 . A drain electrode of the third transistor  130  is connected to the second conductor line  102 , and a source electrode of the third transistor  130  is connected to the first conductor line  101 . 
         [0005]    When a voltage difference between the first conductor line  101  and the second conductor line  102  is larger than a setting voltage of the first transistor  110  or the second transistor  120 , the third transistor  130  is turned on. Accordingly, ESD occurs via the activated third transistor  130 . 
         [0006]    However, when the ESD protection device  10  discharges, users generally cannot perceive the occurrence of the discharge and cannot ascertain the time of discharge. The reason is that the ESD protection device  10  has no means for alerting or recording the occurrence of ESD. 
         [0007]    What is needed, therefore, is an ESD protection device and a method of fabricating the ESD protection device which can overcome the above-described deficiencies. 
       SUMMARY 
       [0008]    An electrostatic discharge protection device includes: an electrostatic discharge part configured for discharging electrostatic energy when the electrostatic energy is larger than a threshold value of the electrostatic discharge part; and a light emitting part configured for receiving the discharged electrostatic energy and converting the received energy into light emission. 
         [0009]    A liquid crystal display includes an electrostatic discharge protection system. The electrostatic discharge protection system includes an electrostatic discharge part configured for discharging electrostatic energy when the electrostatic energy is larger than a threshold value of the electrostatic discharge part; and a light emitting part configured for receiving the discharged electrostatic energy and converting the received energy into light emission. 
         [0010]    A method of fabricating an electrostatic discharge protection device includes: providing an electrostatic discharge part; providing a light emitting part capable of converting electrical energy into light energy; and attaching the light emitting part to the electrostatic discharge part. 
         [0011]    Other novel features and advantages will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a schematic, side cross-sectional view of an ESD protection device according to a first embodiment of the present invention. 
           [0013]      FIG. 2  is a schematic, side cross-sectional view of an ESD protection device according to a second embodiment of the present invention. 
           [0014]      FIG. 3  is an abbreviated circuit diagram of a conventional LCD, the LCD including a plurality of ESD protection devices. 
           [0015]      FIG. 4  is a circuit diagram of one of the ESD protection devices of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0016]    Reference will now be made to the drawings to describe preferred and exemplary embodiments of the present invention in detail. 
         [0017]      FIG. 1  is a schematic, side cross-sectional view of an ESD protection device  20  according to a first embodiment of the present invention. The ESD protection device  20  includes a silicon substrate  201 , an iron film  202 , a plurality of carbon nano-tubes  203 , and a transparent cover  204 . The silicon substrate  201  includes a first surface  21  and a second surface  22  at opposite sides thereof. The iron film  202  is formed on the first surface  21  of the silicon substrate  201 , and the plurality of carbon nano-tubes  203  is formed on the iron film  202 . An area of the iron film  202  is smaller than that of the first surface  21  of the silicon substrate  201 . The silicon substrate  201  is sealed with the transparent cover  204 . The transparent cover  204  and the silicon substrate  201  cooperatively form an accommodating space having the iron film  202  and the plurality of carbon nano-tubes  203  therein. An inner surface of the transparent cover  204  is spherical, and a portion of the inner surface of the transparent cover  204  above the iron film  202  is coated with phosphors  205 . 
         [0018]    Multiple ESD protection devices  20  can be used in LCDs, and also in the processes of manufacturing LCDs. The ESD protection devices  20  can be mounted on items such as machine arms, device shells, and circuit boards via surface mount technology. 
         [0019]    Static electricity generally accumulates on machine arms, device shells, and the circuit boards. When the static electricity accumulates to a certain extent, an instantaneous high voltage is correspondingly generated. The high voltage is transmitted to the iron film  202  of the ESD protection device  20  via the silicon substrate  201 , and electron beams are emitted from free ends of the carbon nano-tubes  203  when the high voltage is larger than a threshold voltage of the ESD protection device  20 . The phosphors  205  are bombarded by the electron beams and correspondingly emit visible light. That is, the energy of the electron beams is converted into light energy by the phosphors  205 , and thereby the energy of the electrostatic discharge is released. 
         [0020]    The moment when the phosphors  205  emit visible light is a discharging time of the ESD protection device  20 . The discharging time of one or more of the ESD protection devices  20  can be monitored and recorded by a computer (not shown) equipped with appropriate software. The cause of the ESD can be backtracked according to the discharging time or times, and suitable remedial and/or preventive measures can be correspondingly taken to protect the corresponding LCDs and/or manufacturing equipment such as machine arms. 
         [0021]      FIG. 2  is a schematic diagram of an ESD protection device  30  according to a second embodiment of the present invention. The ESD protection device  30  is similar to the ESD protection device  20 . However, a unique characteristic of the ESD protection device  30  is that the ESD protection device  30  further includes a donor doping layer  307  and an aluminum film  308 . The donor doping layer  307  is formed on a second surface  32  of a silicon substrate  301 , and the aluminum film  308  is formed on a bottom of the donor doping layer  307 . An area of the donor doping layer  307  is the same as that of the aluminum film  308 . The donor doping layer  307  and the aluminum film  308  can reduce a resistance of the silicon substrate  301 . Thus, a threshold voltage of the ESD protection device  30  is lower than that of the ESD protection device  20 . 
         [0022]    An exemplary method of fabricating the ESD protection device  20  includes the following steps: step 1, providing a silicon substrate  201 , the silicon substrate  201  including a first surface  21  and a second surface  22  at opposite sides thereof; step 2, forming an iron film  202  on the first surface  21  of the silicon substrate  201  via a physical vapor deposition method; step 3, etching the iron film  202  according to a pre-designed circuit pattern; step 4, forming a plurality of carbon nano-tubes  203  on the iron film  202 ; step 5, cutting the silicon substrate  201 ; step 6, providing a transparent cover  204 ; step 7, coating phosphors  205  on an inner surface of the transparent cover  204 ; and step 8, sealing the transparent cover  204  with the silicon substrate  201 . 
         [0023]    In step 4, firstly, methane gas (CH 4 ), hydrogen gas (H 2 ), and nitrogen gas (N 2 ) are provided above the iron film  202 . Then a chemical reaction occurs, and according to the following equation: CH 4 +H 2 ═C+3H 2 . In the chemical reaction, one of the products is carbon atoms, which accumulate on the iron film  202  and finally form a plurality of carbon nano-tubes  203 . Furthermore, in the chemical reaction, the nitrogen gas is used to accelerate the rate of reaction rate and facilitate good orientation of the carbon nano-tubes  203 . 
         [0024]    In step 6, the transparent cover  204  can be manufactured with a plastic extrusion method, or a glass heating and stamping method. An inner surface of the transparent cover  204  is spherical. 
         [0025]    A method of fabricating the ESD protection device  30  includes the following steps: step 1, providing a silicon substrate  301 , the silicon substrate  301  including a first surface  31  and a second surface  32  at opposite sides thereof; step 2, forming an iron film  302  on the first surface  31  of the silicon substrate  301  via a physical vapor deposition method; step 3, heavily depositing donor elements such as phosphorus and arsenic in the second surface  32  of the silicon substrate  301  to form a donor doping layer  307 ; step 4, forming an aluminum film  308  on the donor doping layer  307  via a physical vapor deposition method, the aluminum film  308  being in ohmic contact with the silicon substrate  301 ; step 5, etching the iron film  302  according to a pre-designed circuit pattern; step 6, forming a plurality of carbon nano-tubes  303  on the iron film  302 ; step 7, cutting the silicon substrate  301 ; step 8, providing a transparent cover  304 ; step 9, coating phosphors  305  on an inner surface of the transparent cover  304 ; and step 10, sealing the transparent cover  304  with the silicon substrate  301 . 
         [0026]    It is to be further understood that even though numerous characteristics and advantages of the present embodiments have been set out in the foregoing description, together with details of the structures and functions of the embodiments, the disclosure is illustrative only; and that changes may be made in detail, especially in matters of shape, size, and arrangement of parts within the principles of the invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.