KR101294842B1 - Backlight for liquid crystal display using carbon nano tube - Google Patents

Abstract

A backlight for a liquid crystal display device using carbon nanotubes is provided. The backlight comprises: an anode substrate comprising an anode metal thin film layer formed on the first insulating substrate and a phosphor layer formed on the anode metal thin film layer; A negative electrode substrate including a negative electrode metal thin film layer formed on a second insulating substrate, a carbon nanotube formed on the negative electrode metal thin film layer, and an insulating adhesive layer bonding the carbon nanotubes on the negative electrode metal thin film layer; And a spacer provided between the anode substrate and the cathode substrate.

Liquid Crystal Display, Backlight, Carbon Nanotube

Description

Backlight for liquid crystal display using carbon nano tube}

1 is a cross-sectional view of a backlight for a liquid crystal display device using a conventional carbon nanotube.

FIG. 2 is an electric field distribution diagram of the backlight for the liquid crystal display of FIG. 1.

3 is a cross-sectional view of a backlight for a liquid crystal display using a carbon nanotube according to an embodiment of the present invention.

4 is an electric field distribution diagram of the backlight for the liquid crystal display of FIG. 3.

5 is a graph illustrating field emission characteristics of a backlight for a liquid crystal display using a conventional carbon nanotube and field emission characteristics of a backlight for a liquid crystal display using a carbon nanotube according to an embodiment of the present invention.

 DESCRIPTION OF THE REFERENCE NUMERALS (S)

100: anode substrate 200: cathode substrate

500: spacer

The present invention relates to a backlight for a liquid crystal display (LCD) using carbon nanotubes, and more particularly, by using an insulating material to bond carbon nanotubes, it is possible to lower turn-on voltage and improve field emission characteristics. The present invention relates to a backlight for a liquid crystal display device using a carbon nanotube.

In today's information society, the role of electronic displays has become very important, and various electronic displays have been widely used in various industrial fields. In the electronic display device field, electronic display devices having new functions suitable for the demands of the information society, which have been continuously developed and diversified, are continuously being developed. In general, an electronic display device refers to a device that transmits various pieces of information to a human through vision. That is, an electronic display device refers to an electronic device that converts an electronic information signal output from various electronic devices into an optical information signal that can be recognized by a human eye, and is a device that plays a role of a bridge between humans and electronic devices. It can be said.

When the optical information signal is displayed by the light emitting phenomenon, it is referred to as a light emitting display device. When the optical information signal is displayed by light modulation due to reflection, scattering, interference, or the like, it is called a light receiving display device. Light emitting displays, also called active display devices, include cathode ray tubes (CRTs), plasma display panels (PDPs), organic electroluminescent displays (OELDs), light emitting diodes ( Light Emitting Diode (LED) etc. can be mentioned. The light receiving display device, which is called a passive display device, may include a liquid crystal display (LCD) and an electrophoretic image display (EPID).

Cathode ray tube display device, which is used for television and computer monitor, and has the longest history, has the highest market share in terms of economy, but has many disadvantages such as heavy weight, large volume and high power consumption. .

Due to the rapid development of semiconductor technology, the demand for flat panel display device as an electronic display device suitable for a new environment is rapidly increasing due to the low voltage and low power of various electronic devices, and the miniaturization, thinning, and lightening of electronic devices. have. Accordingly, flat panel display devices such as a liquid crystal display (LCD), a plasma display device (PDP), an organic EL display device (OELD), and the like have been developed, and among these flat panel display devices, it is easy to miniaturize, light weight, and thinner. In particular, liquid crystal display devices having low power consumption and low driving voltage are drawing attention.

The liquid crystal display device injects a liquid crystal material having anisotropic dielectric constant between a color filter substrate, which is an upper transparent insulating substrate, and an array substrate, which is an upper transparent insulating substrate, and adjusts the strength of an electric field formed in the liquid crystal material to adjust molecules of the liquid crystal material. A display device expresses a desired image by changing an arrangement and adjusting an amount of light transmitted through a transparent insulating substrate through the arrangement. Since the liquid crystal display cannot display an image by self-luminous, and can only display an image by receiving light from the rear, the backlight providing the rear light is an important component of the liquid crystal display. In recent years, backlights using carbon nanotubes have been developed as backlights for liquid crystal display devices in order to ensure uniformity of luminance of provided light and lower power consumption.

1 and 2, a backlight for a liquid crystal display device using a conventional carbon nanotube will be described.

Conventional backlights for liquid crystal displays using carbon nanotubes include an upper substrate 10, a lower substrate 80, and a spacer 50, as shown in FIG. 1.

The transparent conductive thin film layer 20 is coated on the upper substrate 10 used as the anode, and the phosphor layer 30 is coated on the transparent conductive thin film layer 20. A transparent conductive thin film layer 70 is coated on the lower substrate 80 used as a cathode, and a metal thin film layer 42 made of Ag having a particle size of about 1 μm is coated on the transparent conductive thin film layer 70. A carbon nanotube 60 is formed on the 42, and a fine metal particle layer 41 made of Ag having a particle size of about 0.5 μm is formed in the empty space between the carbon nanotubes 60. The conductive adhesive layer 40 including the metal thin film layer 42 and the fine metal particle layer 41 adheres the carbon nanotubes 60 onto the cathode. A spacer 50 is provided between the upper substrate 10 and the lower substrate 80, and the inside thereof is vacuumed through the vacuum exhaust glass tube 90 or filled with an inert gas. The metal thin film layer 42 and the fine metal particle layer 41 are for improving adhesion between the transparent conductive thin film layer 70 and the carbon nanotubes 60.

Such a backlight for a liquid crystal display device has a sufficient voltage applied between the transparent conductive thin film layer 20 of the upper substrate 10 and the transparent conductive thin film layer 70 of the lower substrate 80 as a driving voltage. The light is emitted by being emitted from the tip of the carbon nanotube 60 and colliding with the phosphor of the phosphor layer 30.

In the case of using the Ag metal thin film layer 42 and the Ag fine metal particle layer 41 to improve the adhesion between the transparent conductive thin film layer 70 and the carbon nanotube 60, the transparent conductive thin film layer of the upper substrate 10 ( When voltage is applied to the transparent conductive thin film layer 70 of the lower substrate 80 and 20, as shown in FIG. 2, the equipotential surface protrudes on the Ag metal thin film layer 42 and the Ag fine metal particle layer 41. It is formed only in the carbon nanotubes 60 to reduce the aspect ratio of the carbon nanotubes 60 to contribute to the field emission. As a result, the turn-on voltage of the backlight for the liquid crystal display device is increased, and the field emission characteristic of the carbon nanotube 60 is deteriorated.

An object of the present invention is to provide a backlight for a liquid crystal display device using carbon nanotubes that can lower the turn-on voltage and improve the field emission characteristics of the carbon nanotubes by using an insulating material to bond the carbon nanotubes. have.

The technical objects to be achieved by the present invention are not limited to the technical matters mentioned above, and other technical subjects which are not mentioned can be clearly understood by those skilled in the art from the following description. There will be.

A backlight for a liquid crystal display device of the present invention comprises: a positive electrode substrate having an anode metal thin film layer formed on a first insulating substrate and a phosphor layer formed on the anode metal thin film layer; A negative electrode substrate including a negative electrode metal thin film layer formed on a second insulating substrate, a carbon nanotube formed on the negative electrode metal thin film layer, and an insulating adhesive layer bonding the carbon nanotubes on the negative electrode metal thin film layer; And a spacer provided between the anode substrate and the cathode substrate.
The carbon nanotubes are embedded in the insulating adhesive layer, and an upper portion of the carbon nanotubes protrudes above the insulating adhesive layer. The thickness of the insulating adhesive layer is 1/10 to 8/10 of the length of the carbon nanotubes.
The insulating adhesive layer contains only an insulating material, and the specific resistance of the insulating adhesive layer is 1 * 10 ¹² Pa · m to 1 * 10 ¹⁸ Pa · m.

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The details of other embodiments are included in the detailed description and drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. Like reference numerals refer to like elements throughout.

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Hereinafter, a backlight for a liquid crystal display device using a carbon nanotube according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 3 to 5.

3 is a cross-sectional view of a backlight for a liquid crystal display using a carbon nanotube according to an embodiment of the present invention. 4 is an electric field distribution diagram of the backlight for the liquid crystal display of FIG. 3. 5 is a graph illustrating field emission characteristics of a backlight for a liquid crystal display using a conventional carbon nanotube and field emission characteristics of a backlight for a liquid crystal display using a carbon nanotube according to an embodiment of the present invention.

A backlight for a liquid crystal display device using a carbon nanotube according to an embodiment of the present invention includes a positive electrode substrate 100, a negative electrode substrate 200, and a spacer 500.

The anode substrate 100 includes an anode metal thin film layer 120 formed on the first insulating substrate 110 and a phosphor layer 130 formed on the anode metal thin film layer 120.

The first insulating substrate 110 may be a glass substrate, an alumina substrate, a quartz substrate, a plastic substrate, a silicon substrate, or the like. Do. The anode metal thin film layer 120 is formed of a transparent conductor material such as indium tin oxide (ITO) or indium zinc oxide (IZO) on the first insulating substrate 110.

The negative electrode substrate 200 is formed on the negative electrode metal thin film layer 220, the carbon nanotube 240 formed on the negative electrode metal thin film layer 220, and the negative electrode metal thin film layer 220 formed on the second insulating substrate 210. The insulating adhesive layer 230 is formed on the cathode metal thin film layer 220 to bond the carbon nanotubes 240. The insulating adhesive layer 230 is made of only an insulating material such as glass frit. The carbon nanotubes 240 are embedded in the insulating adhesive layer 230, and upper portions thereof protrude above the insulating adhesive layer 230.

Like the first insulating substrate 110, the second insulating substrate 210 may be a glass substrate, an alumina substrate, a quartz substrate, a plastic substrate, a silicon substrate, or the like, but considering the trend of large area of the liquid crystal display device, It is preferable to use a glass substrate. The cathode metal thin film layer 220 is a metal selected from Au, Pt, Al, Cu, Co, Ag or a transparent conductor material such as indium tin oxide (ITO) or indium zinc oxide (IZO) on the second insulating substrate 210. It is formed.

Is formed on the cathode metal thin film layer (220) diameter is 1 nm ~ 100 nm, a length (L) that is a single-layer carbon nanotube or a multi-layer carbon nanotubes 10 ㎛ ~ 20 ㎛ 1 * 10 3 gae / ㎣ ~ 1 * ¹⁰ 10 gae It is formed at a density of / ㎣.

Between the cathode metal thin film layer 220 and the carbon nanotubes 240, the insulating adhesive layer 230 is made of an insulating material such as glass frit to improve adhesion between the cathode metal thin film layer 220 and the carbon nanotubes 240. ) Is formed, and the specific resistance of the insulating adhesive layer 230 is 1 * 10 ¹² m · m to 1 * 10 ¹⁸ Ω · m, and the thickness D of the insulating adhesive layer 230 is the length of the carbon nanotubes 240. It is 1/10-8/10 of (L).

A spacer 500 is provided between the anode substrate 100 and the cathode substrate 200, and the inside of the space formed by the anode substrate 100, the cathode substrate 200, and the spacer 500 is a vacuum exhaust glass tube ( Through 300) or filled with an inert gas.

When a sufficient voltage is applied to the driving voltage between the anode metal thin film layer 120 of the anode substrate 100 and the cathode metal thin film layer 220 of the cathode substrate 200, electrons are released from the carbon nanotubes 240 by the field emission. The light is emitted by being emitted from the tip and colliding with the phosphor of the phosphor layer 130.

When the carbon nanotubes 240 are bonded to the cathode metal thin film layer 220 by using an insulating adhesive layer 230 such as glass frit, the anode metal thin film layer 120 of the anode substrate 100 and the cathode metal thin film layer of the cathode substrate 200 are formed. When a voltage is applied between the 220, as shown in FIG. 4, the equipotential surface is formed not only in the carbon nanotubes 240 protruding from the top of the insulating adhesive layer 230, but also in the insulating adhesive layer 230. As such, the aspect ratio of the carbon nanotubes 240 contributing to the field emission can be sufficiently increased. Therefore, the field emission effect of the carbon nanotubes 240 may be effectively improved.

As shown in FIG. 5, when comparing the conventional field emission characteristic curve T1 using the conductive adhesive layer with the field emission characteristic curve T2 of the present invention using the insulating adhesive layer 230, due to the insulating adhesive layer 230. It can be seen that the present invention provides a higher current density at a lower voltage than the prior art, and the turn-on voltage Von2 of the backlight for the liquid crystal display according to the exemplary embodiment of the present invention is that of the backlight for the conventional liquid crystal display. It can be seen that the lower than the turn-on voltage (Von1).

The backlight for a liquid crystal display device using the carbon nanotubes according to an embodiment of the present invention uses an insulating material such as glass frit to improve the adhesion of the carbon nanotubes 240, thereby lowering the turn-on voltage and reducing the carbon nanotubes ( The field emission effect of 240 can be effectively improved.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, You will understand.

It is to be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the invention, and are to be considered in all respects as illustrative and not restrictive, Are only defined by the scope of the claims.

As described above, the backlight for a liquid crystal display device using the carbon nanotube according to the exemplary embodiment of the present invention uses an insulating material such as glass frit to improve the adhesion of the carbon nanotube, thereby reducing the turn-on voltage and reducing the carbon nanotube. The field emission effect of the tube can be effectively improved.

Claims (4)

An anode substrate having an anode metal thin film layer formed on a first insulating substrate and a phosphor layer formed on the anode metal thin film layer; A negative electrode substrate including a negative electrode metal thin film layer formed on a second insulating substrate, a carbon nanotube formed on the negative electrode metal thin film layer, and an insulating adhesive layer bonding the carbon nanotubes on the negative electrode metal thin film layer; And A spacer provided between the anode substrate and the cathode substrate, The carbon nanotubes are embedded in the insulating adhesive layer, the upper portion of the carbon nanotubes protrude above the insulating adhesive layer, the thickness of the insulating adhesive layer is 1/10 to 8/10 of the length of the carbon nanotubes, The insulating adhesive layer includes only an insulating material, and the specific resistance of the insulating adhesive layer is 1 * 10 ¹² Pa · m to 1 * 10 ¹⁸ Pa · m, backlight for a liquid crystal display device using carbon nanotubes. delete The method of claim 1, The insulating material is a glass frit (glass frit), the backlight for a liquid crystal display device using a carbon nanotube. delete

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