KR101174153B1 - Backlight driving device and Liquid Crystal Display device having the same - Google Patents

Abstract

Disclosed are a backlight driving device and a liquid crystal display device having the same, which can drive a lamp quickly by applying a predetermined pulse wave before driving the lamp in a dark condition.

According to the present invention, a backlight driving apparatus includes a plurality of lamps, a plurality of inverters connected to one side of each lamp to supply a predetermined voltage, and a predetermined wavelength connected to the other side of each lamp before the voltage is supplied to each inverter. It includes a plurality of switches for switching to be applied.

UV, pulse wave, CCFL, EEFL

Description

Backlight driving device and liquid crystal display device having same {Backlight driving device and Liquid Crystal Display device having the same}

1 is an exploded perspective view of a backlight of a conventional liquid crystal display device.

FIG. 2 is a schematic illustration of the lamp of FIG. 1; FIG.

3 is a view showing a backlight driving device for driving a plurality of lamps of FIG.

4 is a view showing a backlight driving apparatus according to an embodiment of the present invention.

5 shows the switch of FIG. 4 in detail;

6 is a view showing a backlight driving apparatus according to another embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

101 (1) to 101 (n): CCFL lamp 104a, 204a: first internal electrode

104b, 204b: second internal electrodes 109a, 209a: first lamp wire

109b, 209b: 2nd lamp wire 110 (1)-110 (n), 210: inverter

120, 220: switch part 120 (1) to 120 (n): switch

130, 230: control signal generator 132, 232: reference voltage (Vref) generator

134, 234: pulse wave generator 201 (1) to 201 (n): EEFL lamp

204a: first external electrode 204b: second external electrode

205a: first lamp fixing part 205b: second lamp fixing part

The present invention relates to a backlight, and more particularly, to a backlight driving device capable of driving a lamp quickly and a liquid crystal display device having the same.

In the liquid crystal display, two substrates on which electrodes are formed are disposed so that the surfaces on which the two electrodes are formed face each other, and liquid crystal is injected between the two substrates. A device expresses an image by varying light transmittance by shifting molecules of the liquid crystal by an electric field generated by applying a voltage to the two electrodes.

The liquid crystal display device has advantages of being able to drive by using low power and having a vivid color reproduction ability, whereas the liquid crystal panel of the liquid crystal display device is a non-light emitting device that does not directly generate light. A backlight for irradiating light is required.

Fluorescent lamp is used for the backlight device, mercury and inert gas are filled in the glass tube, phosphor is coated on the inner wall of the glass tube, and electrodes are provided on both sides of the glass tube. Is generated, and the higher the electric field is applied, the more the electrons accelerate in the glass tube.

The accelerated electrons ionize the mercury atoms in the glass tube, and the ionized mercury atoms emit ultraviolet rays to generate light.

1 is an exploded perspective view of a backlight of a conventional liquid crystal display.

As shown in FIG. 1, the backlight includes a plurality of lamps 1, an outer case 3 for fixing and supporting the plurality of lamps 1, the lamp 1 and a liquid crystal panel (not shown). ) And optical sheets 5a, 5b, and 5c disposed therebetween. It includes a plurality of diffusion sheets and the like provided between the liquid crystal panel to enhance the light scattering effect.

The inner surface of the outer case 3 is formed with a reflector 7 for reflecting the light generated by the lamp 1 to the display unit of the liquid crystal panel to increase the efficiency of the light.

2 is a view schematically showing the lamp of FIG.

As shown in FIG. 2, the lamp 1 is a cold cathode fluorescence lamp (CCFL), and the first and second internal electrodes 2a and 2b are disposed at both ends of the glass tube. Light is emitted by the power source 4 applied to the first and second internal electrodes 2a and 2b, and both ends of the lamp 1 are fitted in grooves formed on both sides of the outer case 3 of FIG. .

In addition, the first and second internal electrodes 2a and 2b are connected to first and second lamp wires 9a and 9b for transmitting power for driving the lamp 1. The second lamp wire 9b is electrically connected to the inverter 10, and the first lamp wire 9a is connected to the ground voltage GND.

3 is a view illustrating a backlight driving device for driving a plurality of lamps of FIG. 2.

As shown in FIG. 3, the lamp driving apparatus receives a plurality of lamps 1 (1) to 1 (n) and a DC voltage from a voltage source Vcc to convert the lamps into AC voltages. A plurality of inverters 10 (1) to 10 (n) respectively driving (1 (1) to 1 (n)) are provided. One end of the plurality of lamps 1 (1) to 1 (n) is connected to the ground voltage GND through a first lamp wire 9a, and the plurality of lamps 1 (1) to 1 (n). The other end of)) is connected to the inverters 10 (1) to 10 (n) through the second lamp wire 9b.

Each of the plurality of lamps 1 (1) to 1 (n) includes a glass tube, inert gases inside the glass tube, and a cathode and an anode installed at both ends of the glass tube. Inert gas containing argon (Ar), neon (Ne), and the like is filled in the glass tube, and phosphors are coated on the inner wall of the glass tube.

Each of the plurality of lamps 1 (1) to 1 (n) has a high-voltage AC voltage supplied from the inverters 10 (1) to 10 (n). When applied to an electrode positioned inside 1 (n)), electrons are emitted from the electrode and collide with inert gases in the glass tube to increase the amount of electrons exponentially.

As the current flows inside the glass tube by the increased electrons, ultraviolet rays are emitted while the inert gas is excited by the electrons. The ultraviolet rays collide with the luminescent phosphor applied to the inner wall of the glass tube to emit visible light.

The lamp 1 which drives such a drive does not normally drive in a dark state, i.e., no light exists in the surroundings and is in a low temperature state.

When voltage is supplied from the inverter 10 to the electrode 4 located inside the lamp 1, electrons must be emitted from the electrode 4 and collide with inert gases in the glass tube. A certain delay time is required for the inert gases to be excited (ionized).

As a result, when the lamp 1 is driven in a dark state, especially in a low temperature state, the lamp 1 does not generate light quickly but generates light with a predetermined delay time. As a result, when the lamp 1 is driven in the dark state, as the lamp 1 is turned on for a predetermined delay time, problems such as deterioration of display quality of an image are generated.

An object of the present invention is to provide a backlight driving device capable of driving a lamp quickly and a liquid crystal display device having the same.

A backlight driving apparatus according to an embodiment of the present invention for achieving the above object is a plurality of lamps, a plurality of inverters connected to one side of each lamp to supply a predetermined voltage, and connected to the other side of each lamp to each inverter It includes a plurality of switches for switching so that a predetermined wavelength is applied before the voltage is supplied.

A liquid crystal display according to an embodiment of the present invention for achieving the above object is a plurality of lamps, a plurality of inverters connected to one side of each lamp to supply a predetermined voltage, and connected to the other side of each lamp to each inverter A backlight driving device including a plurality of switches for switching a predetermined wavelength to be applied before a voltage is supplied, and a liquid crystal panel for displaying an image according to light emitted from each lamp.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention.

4 illustrates a backlight driving apparatus according to an embodiment of the present invention.

As shown in FIG. 4, the backlight driving apparatus includes a plurality of CCFL lamps 101 (1) to 101 (n) and a plurality of CCFL lamps 101 (1) to 101 (n). CCFL lamps 101 (1) to 101 (n) that supply power from a plurality of inverters 110 (1) to 110 (n) and the plurality of inverters 110 (1) to 110 (n). The first and second lamp wires 109a to 109b to be supplied to the control panel, a control signal generator 130 to generate control signals for controlling the plurality of inverters 110 (1 to 110 (n)), A reference voltage generator Vref for generating a reference voltage Vref, a pulse wave generator 134 for generating a pulse wave of 70 nm using the reference voltage, and a ground voltage GND connected to the pulse wave It includes a switching unit 120 is supplied.

First and second internal electrodes 104a and 104b are provided in the plurality of CCFL lamps 101 (1) to 101 (n), and the first internal electrode 104a is formed on the first lamp wire. It is electrically connected to 109a to receive a high voltage AC voltage generated by the inverters 110 (1) to 1109n.

In addition, the second internal electrode 104b receives a ground voltage GND or a pulse wave from the switch 120 that is electrically connected to the second lamp wire 109b.

The control signal generator 130 generates a predetermined control signal using a vertical / horizontal sync signal (Vsync / Hsync) and a data enable (DE) signal supplied from a system (not shown).

The switch unit 120, the reference voltage Vref generator 132, and the plurality of inverters 110 (1) to 110 (n) are controlled by the control signal generated by the control signal generator 130. .

When a high control signal is supplied to the reference voltage Vref generation unit 132 and the switch unit 120, a low control signal is supplied to the plurality of inverters 110 (1) to 110 (n). Is supplied. In addition, when a low control signal is supplied to the reference voltage (Vref) generation unit 132 and the switch unit 120, the plurality of inverters 110 (1) to 110 (n) are simultaneously high. The control signal is supplied.

As the high control signal is supplied to the reference voltage generator Vref, the reference voltage generator 134 generates a reference voltage Vref and supplies the generated reference voltage Vref to the pulse wave generator 134. .

The pulse wave generator 134 receives the reference voltage Vref to generate a pulse wave of 70 nm. The pulse of 70 nm means a wavelength corresponding to ultraviolet (UV).

The pulse wave generator 134 generates the 70 nm pulse for the following reason.

The CCFL lamp 101 includes an inert gas, internal electrodes 104a and 104b, and a phosphor. When a voltage is applied to the internal electrodes 104a and 104b, electrons are emitted from the internal electrodes 104a and 104b to collide with the inert gas and the inert gas is excited (ionized). In this process, the inert gas generates ultraviolet rays. The ultraviolet rays collide with the phosphor to generate visible light.

However, since the inert gas is not ionized when the CCFL lamp is in a low temperature state, the CCFL lamp does not collide with electrons, and thus no visible light is generated.

Therefore, the present invention generates a pulse wave corresponding to a wavelength of 70 nm ultraviolet ray (UV) in advance and drives the CCFL lamp 101 before the CCFL lamp 101 is driven, thereby deactivating the CCFL lamp 101. To get the gases to be excited in advance.

Inert gases of the CCFL lamp 101 include argon (Ar) and neon (Ne). In this case, since the argon (Ar) is ionized better than the neon (Ne), the argon (Ar) is ionized. The process of ionizing the argon (Ar) is well illustrated by the following equation.

As shown in the above equation, in order to ionize the argon (Ar), energy of 15.8 eV or more is required.

Using the above energy value, the wavelength value capable of ionizing the argon (Ar) is obtained as follows.

Therefore, the wavelength value at which argon (Ar) can be ionized is 70 nm.

Accordingly, the pulse wave generator 134 generates a pulse wave of 70 nm using the reference voltage Vref, and thus, the plurality of switches 120 (1) to 120 (n) positioned in the switch unit 120. To supply.

The plurality of switches 120 (1) to 120 (n) may transmit the 70 nm pulse wave to the plurality of CCFL lamps 101 (1) to 101 (n) according to a control signal supplied from the control signal generator 130. )) Through the second lamp wire 109b.

As shown in FIG. 5, the first switch 120 (1) is configured in series with an NMOS and a PMOS. The NMOS is connected to the pulse wave generator 134 and the PMOS is connected to the ground GND.

When a high level control signal is supplied to an input terminal of the first switch 120 (1), the NMOS is turned on and connected to the pulse wave generator 134. As a result, the 70 nm pulse wave is output from the output terminal of the first switch 120 (1).

In addition, when a low level control signal is supplied to an input terminal of the first switch 120 (1), the PMOS is turned on and connected to the ground voltage GND. As a result, the ground voltage GND is output from the output terminal of the first switch 120 (1).

As the 70 nm pulse wave is supplied to the plurality of CCFL lamps 101 (1) to 101 (n), argon (Ar) of inert gases of the CCFL lamps 101 (1) to 101 (n) is increased. It is ionized.

Subsequently, when the inert gas of the CCFL lamps 101 (1) to 101 (n) is ionized, the control signal generator 130 goes low to the reference voltage Vref generator 132 and the switch unit 120. (Low) Supply control signal. As the low control signal is supplied to the reference voltage Vref generator 132 and the switch 120, the pulse wave generator 134 does not generate the pulse wave of 70 nm.

As a result, no more than 70 nm pulse waves are supplied to the plurality of CCFL lamps 101 (1) to 101 (n).

The control signal generation unit 130 supplies a low control signal to the reference voltage (Vref) generation unit 132 and the switch unit 120 at the same time, the control signal generation unit 130 is the plurality of inverters The high control signal is supplied to (110 (1) to 110 (n)).

When a high control signal is supplied to the plurality of inverters 110 (1) to 110 (n), the plurality of inverters 110 (1) to 110 (n) generate an AC voltage having a high voltage to generate the first voltage. It is supplied to the first internal electrode 104a of the CCFL lamps 101 (1) to 101 (n) through the one lamp wire 109a.

The first internal electrode 104a emits electrons when the high-voltage alternating voltage is applied. The CCFL lamps 101 (1) to 101 (n) are already in an inert gas state and thus are discharged. It collides with the electrons to generate visible light.

That is, inert gas of the CCFL lamps 101 (1) to 101 (n) is ionized in advance in a state where no voltage is applied from the inverters 110 (1) to 110 (n). 1) to 101 (n)) to generate light because electrons generated by high voltage are directly reacted with the ionized inert gases.

Therefore, the backlight driving apparatus according to the present invention not only cools but also ionizes the inert gases of the CCFL lamps 101 (1) to 101 (n) in advance, thereby preventing the CCFL lamps 101 (1) to 101 (n). As the high voltage is supplied, electrons generated at the same time and the ionized inert gas react to generate light quickly.

As mentioned above, the backlight driving apparatus according to the present invention supplies a predetermined pulse wave to a CCFL lamp to ionize an inert gas of the CCFL lamp in advance, thereby generating electrons generated by applying a high voltage to the CCFL lamp and the ionized cells. The inert gas is collided to generate light quickly.

6 illustrates a backlight driving apparatus according to another embodiment of the present invention.

As shown in FIG. 6, the backlight driving device is configured to fix a plurality of EEFL lamps 201 (1) to 201 (n) and the plurality of EEFL lamps 201 (1 to 201 (n)). A first and second lamp fixing parts 205a and 205b, an inverter 210 for supplying a high-voltage alternating voltage to the plurality of EEFL lamps 201 (1) to 201 (n), and a reference voltage Vref. A reference voltage (Vref) generator 232 to generate, a pulse wave generator 234 to generate a pulse wave of 70 nm by using the reference voltage (Vref), the inverter 210 and the reference voltage (Vref) A plurality of EEFL lamps 201 (1) connected to a control signal generator 230 and a ground voltage GND for generating a control signal for controlling the switch 222 and the switch 222. 201 (n)).

The same description as described in the embodiment of the present invention will be omitted.

The plurality of EEFL lamps 201 (1) to 201 (n) include a glass tube, and the glass tube includes an inert gas composed of argon (Ar), neon (Ne), and the like. It is applied. In addition, first and second external electrodes 204a and 204b are formed at both ends of the glass tube. The first external electrode 204a is electrically connected to the inverter 210 through the first lamp wire 209a, and the second external electrode 204b is connected to the switch 220 and the second lamp wire ( Electrical connection via 209b).

The control signal generator 230 generates a predetermined control signal using a vertical / horizontal sync signal (Vsync / Hsync) and a data enable (DE) signal from a system (not shown). The control signal controls the inverter 210, the reference voltage Vref generator 232, and the switch 220.

When a high control signal is supplied from the control signal generator 230 to the reference voltage Vref generator 232 and the switch 220, a low control signal is supplied to the inverter 210. do. In addition, when a low control signal is supplied from the control signal generator 230 to the reference voltage Vref generator 232 and the switch 220, a high control signal is supplied to the inverter 210. Supplied.

When a high control signal is supplied from the control signal generator 230 to the reference voltage generator 232, the reference voltage generator 232 may have a DC voltage having a constant voltage level. To generate and supply the pulse wave generator 234. At this time, a low control signal is supplied to the inverter 210 so that the inverter 210 does not operate.

The pulse wave generator 234 generates a 70 nm pulse using the reference voltage Vref. The 70 nm pulse is supplied to the switch 220 and supplied to the second external electrode 204b of the plurality of EEFL lamps 201 (1) to 201 (n) through the second lamp wire 209b.

Description of the 70 nm pulse generated by the pulse wave generator 234 is the same as described above, and will be omitted.

Due to the 70 nm pulse supplied through the second external electrode 204b, argon (Ar) is ionized among inert gases provided in the EEFL lamps 201 (1) to 201 (n). When the argon is ionized, the control signal generator 230 supplies a low control signal to the reference voltage Vref generator 232 and the switch 220.

At the same time, the control signal generator 230 supplies a high control signal to the inverter 210 to drive the inverter 210. Accordingly, the reference voltage Vref generator 232 is not driven, and no more pulses of 70 nm are supplied to the EEFL lamps 201 (1) to 201 (n).

The inverter 210 generates an AC voltage having a high voltage according to the high control signal and supplies the alternating voltage to the EEFL lamps 201 (1) to 201 (n) through the first lamp wire 209 a. The switch 220 is connected to the ground voltage GND due to the low control signal to supply the ground voltage GND to the EEFL lamps 202 (1) to 201 (n).

The voltage and ground voltage GND supplied from the inverter 210 are applied to the first and second external electrodes 204a and 204b of the EEFL lamps 201 (1) to 201 (n), thereby providing the EEFL lamp. An electric field is formed inside the glass tube of 201 (1) to 201 (n) to emit electrons.

The emitted electrons collide with an inert gas that has been ionized in advance to form ultraviolet rays, and the ultraviolet rays react with the phosphor coated on the inner wall of the glass tube of the EEFL lamps 201 (1) to 201 (n) to generate visible light. Will occur.

That is, inert gas of the EEFL lamps 201 (1) to 201 (n) is ionized in advance in a state in which no voltage is applied from the inverter 210 to the EEFL lamps 201 (1 to 201 (n)). The electrons generated by supplying a high voltage to the external electrodes 204a and 204b of the light react directly with the ionized inert gases.

Accordingly, the backlight driving apparatus according to the present invention ionizes the inert gases of the EEFL lamps 201 (1) to 201 (n) as well as to a low temperature state, and thus, to the EEFL lamps 201 (1 to 201 (n)). The electrons generated at the same time the high voltage is supplied and the ionized inert gas reacts to generate light quickly.

As mentioned above, the backlight driving apparatus according to the present invention supplies predetermined pulse waves to an EEFL lamp to ionize an inert gas of the EEFL lamp in advance, thereby generating electrons generated by applying a high voltage to the EEFL lamp and the ionized lamp. The inert gas is collided to generate light quickly.

As described above, the backlight driving apparatus according to the present invention applies a predetermined pulse wave to the lamp to ionize the inert gases included in the lamp, so that the electrons generated when the voltage is supplied from the inverter collide with the ionized inert gas. Thus, visible light can be generated quickly. In addition, due to the backlight driving apparatus according to the present invention, as the lamp generates light rapidly, it is possible to overcome problems such as deterioration of image quality in the initial lighting section.

Claims (12)

A plurality of lamps; A plurality of inverters connected to one side of each lamp to supply an AC voltage; A reference voltage generator for generating a reference voltage; A pulse wave generator configured to generate a pulse wave using the reference voltage; A plurality of switches connected to the other side of each lamp to switch the pulse wave to be applied before a voltage is supplied to each inverter; A control unit generating a control signal using a vertical / horizontal synchronization signal and a data enable signal, and controlling the reference voltage generator, a plurality of switches, and a plurality of inverters using the control signal; The level of the control signal applied to the reference voltage generator and the plurality of switches is different from the level of the control signal applied to the plurality of inverters, The reference voltage generator generates a reference voltage based on a high level control signal and provides the generated reference voltage to the pulse wave generator. The plurality of switches are turned on by the high level control signal to provide the pulsed waves to the plurality of lamps, The plurality of inverters generate the AC voltage in response to the high level control signal to supply the AC voltage to the plurality of lamps. delete delete The method of claim 1, And the pulse wave is ultraviolet light. The method of claim 1, And the pulse wave is 70 nm or less. The method of claim 1, The lamp may be any one of a cold cathode fluorescent lamp (CCFL) and an external electrode fluorescent lamp (EEFL). A plurality of lamps; A plurality of inverters connected to one side of each lamp to supply an AC voltage; A reference voltage generator for generating a reference voltage; A pulse wave generator configured to generate a pulse wave using the reference voltage; A plurality of switches connected to the other side of each lamp to switch the pulse wave to be applied before a voltage is supplied to each inverter; A control unit generating a control signal using a vertical / horizontal synchronization signal and a data enable signal, and controlling the reference voltage generator, a plurality of switches, and a plurality of inverters using the control signal; And It includes; a liquid crystal panel for displaying an image in accordance with the light irradiated from each lamp, The level of the control signal applied to the reference voltage generator and the plurality of switches is different from the level of the control signal applied to the plurality of inverters, The reference voltage generator generates a reference voltage based on a high level control signal and provides the generated reference voltage to the pulse wave generator. The plurality of switches are turned on by the high level control signal to provide the pulsed waves to the plurality of lamps, And the plurality of inverters generate the AC voltage according to the high level control signal to supply the AC voltage to the plurality of lamps. delete delete 8. The method of claim 7, And the pulse wave is ultraviolet light. 8. The method of claim 7, And the pulse wave is 70 nm or less. 8. The method of claim 7, Wherein the lamp is one of a cold cathode fluorescent lamp (CCFL) and an external electrode fluorescent lamp (EEFL).

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