KR20000031112A - High brightness plasma address liquid crystal display and driving method thereof - Google Patents

Abstract

PURPOSE: A high brightness plasma address liquid crystal display is to improve a brightness and an optical efficiency. CONSTITUTION: A plasma address liquid crystal display comprises a side wall(64) for dividing a plasma unit into each discharging channel, a positive pole formed on lower portion of the side wall, and a pair of a negative poles formed on the discharging channel. The pair of negative pole are corresponded to two scan line. The positive pole is arranged so that it has the same pole at adjacent discharging channels. A method for driving the high brightness plasma address liquid crystal display comprises applying a driving voltage in sequence after dividing the pair of negative pole lines formed on the discharging channel into an add negative pole line and even negative pole line. The method comprises applying the driving voltage in sequence so that the add negative pole line and the even negative pole line have a predetermine difference in time.

Description

High Brightness Plasma Address Liquid Crystal Display and Driving Method Thereof

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flat panel display, and more particularly, to a high brightness plasma address liquid crystal display and a driving method thereof configured to improve brightness and light efficiency.

Recently, a liquid crystal display (hereinafter referred to as "LCD"), a field emission display (hereinafter referred to as "FED") and a plasma display panel (hereinafter referred to as "PDP") Such flat display devices are being actively developed. Among them, a plasma address liquid crystal display device (hereinafter referred to as " PALC ") and a PDP are attracting attention because they have excellent brightness and image quality and are advantageous for being larger than 40 inches.

Referring to FIG. 1, a PALC according to the related art includes a backlight unit, a plasma unit, and a liquid crystal unit. PALC uses plasma discharge like PDP, but differs from PDP in discharge conditions. The biggest difference is that the discharge area is different in size. For example, the discharge area of the PDP is the pixel area and the discharge area of the PALC is the scan line area. That is, it can be seen that the discharge area of the PALC is thousands of times larger than the discharge area of the PDP. As such, since PALCs generate discharges per scan line, it is very important to generate uniform and stable discharges. Detailed description thereof will be described later.

The backlight unit 10 supplies light beams to the plasma unit and the liquid crystal unit. In addition, the plasma unit may include a first polarizing plate 22 attached to the lower substrate 24 to face the backlight unit 10, an anode A and a cathode K formed side by side on the lower substrate 24, and A barrier rib 34 is formed vertically on the lower substrate 4 to separate respective discharge channels, and an insulating film 36 is formed on the barrier rib 34. In one discharge channel, a pair of anodes (A) and cathodes (K) are arranged and filled with discharge gases such as He and Ne. The plasma unit serves as a switch element for changing the arrangement of the liquid crystal using the virtual electrode formed by the plasma discharge. In other words, the plasma unit performs a function of a switch element that is the same as a thin film transistor (“TFT”) of an LCD. Meanwhile, the liquid crystal module includes a liquid crystal layer 26 formed on the insulating film 36, a transparent electrode (ITO) 38 formed on the liquid crystal layer 26, and a color filter formed on the transparent electrode 38. A color filter 28, an upper substrate 30 formed on the color filter 28, and a second polarizing plate 32 attached to the upper substrate 30. The first and second polarizers 22 and 32 change the horizontal or vertical polarization characteristics of the light beam. In addition, the liquid crystal layer 26 adjusts the transmission amount of the light beam corresponding to the image signal voltage level applied according to the capacitance partial pressure ratio of the insulating layer 36 and the liquid crystal layer 26. At this time, a color filter 28 of red (hereinafter referred to as "R"), green (hereinafter referred to as "G"), and blue (hereinafter referred to as "B") is disposed on the transparent electrode 38. ) Is formed to achieve the desired color.

Meanwhile, the operation principle of the PALC will be described in detail with reference to FIG. 2. As shown in FIG. 2, when 0 V is applied to the anode A disposed in the discharge channel and −350 V is applied to the cathode K, plasma discharge occurs. In this case, inside the discharge channel, the charged particles 42 formed by the plasma discharge have the anode potential except for the periphery of the cathode k. Accordingly, the plasma switch 44 is turned on to form a virtual electrode 40 in which the anode A is electrically shorted. That is, when plasma discharge occurs, the virtual electrode 40 is formed to have a short state with respect to the anode A. FIG. On the other hand, when the plasma discharge is completed, since the plasma switch 44 is turned off and the virtual electrode 40 is not formed, the plasma switch 44 is open to the anode. In addition, when an image signal is applied to the transparent electrode 38 during the discharge period (that is, when the virtual electrode is formed), the potential difference due to the capacitance partial ratio of the insulating layer 36 and the liquid crystal layer 26 is changed to the liquid crystal layer 26. To occur to change the arrangement of the liquid crystal to control the transmission amount of the light beam. As such, the plasma discharge inside the discharge channel performs a switching operation, and as a result, controls the light beam transmission amount of the liquid crystal unit. In other words, the plasma portion of the PALC performs the same function as the TFT of the LCD. In addition, since the state is maintained in the discharge channel even in the non-selection period after the discharge is completed, the state of the liquid crystal can be memorized. Accordingly, the PALC displays the screen corresponding to the image signal by changing the arrangement of the liquid crystal using the virtual electrode 40 formed by the plasma discharge.

On the other hand, since the liquid crystal is not a self-luminous element, the backlight unit 10 is used to supply external light. At this time, when the light beam is irradiated from the backlight unit 10, the light efficiency or luminance is changed by the position of the electrode and the structure of the discharge channel. Hereinafter, the electrode structure of the PALC according to the prior art will be described with reference to FIG. 3.

3, there is shown an electrode structure of a PALC according to the prior art. A plurality of discharge channels are provided between the first to n-th partition walls 34a to 34n formed vertically on the lower substrate 24. A pair of cathodes K and anodes A are disposed in the discharge channel. In this case, since the cathode K and the anode A are disposed above the lower substrate 24, the light beam is blocked at the portion where the cathode and the anode are provided. Accordingly, a problem of lowering the light efficiency and luminance level of the PALC has been derived. In addition, since the distance between the cathode K and the anode A disposed in the partition 34 is the same as that of the adjacent discharge channel, the problem that the adjacent cells cause mis-discharge during plasma discharge has been derived.

Accordingly, an object of the present invention is to provide a high brightness plasma address liquid crystal display and a driving method thereof configured to improve brightness and light efficiency.

1 is a perspective view showing the structure of a PALC according to the prior art.

2 is a view for explaining the operation principle of the PALC.

3 is a view showing the electrode configuration of FIG.

4 illustrates the structure of a PALC according to the present invention.

5 is a view showing the electrode configuration of FIG.

6 is a view illustrating a PALC driving method according to the present invention;

<Description of Symbols for Main Parts of Drawings>

10,70: backlight 22,32,52,62: polarization filter

24,54: lower substrate 26,66: liquid crystal

28,68: Color filter 30,60: Upper board

34,64 bulkhead 36,56 insulating film

38,58: transparent electrode 40: virtual electrode

42: charged particle 44: plasma switch

In order to achieve the above object, the plasma address liquid crystal display according to the present invention includes a partition for dividing the plasma unit into respective discharge channels, an anode formed under the partition wall, and a pair of cathodes formed in the discharge channel.

In addition, the driving method of the plasma address liquid crystal display according to the present invention is divided into odd-numbered cathode lines and even-numbered cathode lines, and then a driving voltage is sequentially applied.

Other objects and features of the present invention other than the above object will become apparent from the description of the embodiments with reference to the accompanying drawings.

A preferred embodiment of the present invention will be described with reference to FIGS. 4 to 6.

4, a plasma address liquid crystal display according to the present invention is shown. PALC according to the present invention includes a backlight unit, a plasma unit and a liquid crystal unit. Since the functions and operations of the backlight unit and the liquid crystal unit are sufficiently described in FIGS. 1 and 2, detailed descriptions thereof will be omitted. On the other hand, the plasma unit, the first polarizing plate 52 attached to the lower substrate 54 so as to face the backlight unit 70, a cathode (K ') pair formed in parallel on the upper portion of the lower substrate 54, and the lower substrate ( A partition 64 formed vertically on the upper portion of the upper surface 54, an anode A 'formed on the lower portion of the partition wall 64, and an insulating film 56 formed on the partition wall 64. The plasma part of the PALC according to the present invention has two plasma parts in one discharge channel, as shown in FIG. 5, compared to one anode A and one cathode K in one discharge channel. A cathode pair (eg, K2 ', K3') and one anode (eg, A2 ') corresponding to the scan line are provided. That is, two lines of channel space are formed in one discharge channel. Accordingly, the plasma portion of the PALC according to the present invention provides one anode and two cathodes in one discharge channel, thereby reducing the number of partition walls by 1/2 and reducing the number of anodes, thereby reducing the loss of light beams. Thus, the light efficiency is improved.

In addition, since the anode is formed under the partition wall 54, the anode is used as the same electrode in the adjacent discharge channel. For example, the second anode A2 ′ is formed under the second partition wall 54b to be used as the same electrode (that is, anode) for the third and fourth cathodes K3 ′ and K 4 ′. In this case, the first to nth anodes A1 'to An' are commonly connected to the ground voltage source GND. That is, the anode is formed under the partition 54 and used as an electrode having the same polarity in the adjacent discharge channels. Accordingly, the plasma portion of the PALC according to the present invention removes an unstable element of the discharge to the adjacent cell by disposing an electrode (ie, an anode) having the same polarity between the partition walls, thereby preventing the PALC from discharging and malfunctioning.

6, there is shown a diagram for explaining a PALC driving method according to the present invention. In order to drive the PALC according to the present invention, as shown in FIG. 5, the first to mth anodes A1 ′ to Am ′ are commonly connected to the base voltage source GND and fixed to 0V. On the other hand, the first to nth cathodes K1 'to Kn' apply a driving voltage having a negative voltage level. In this case, in order to prevent plasma discharge from occurring simultaneously in a pair of cathodes formed in one discharge channel, the driving voltage is applied after dividing into odd cathode lines Kn-1 'and even cathode lines Kn'. It causes a plasma discharge. To this end, it is preferable to predetermine a predetermined time difference so that discharge is performed once in a pair of cathode lines provided in each discharge channel. For example, as shown in (a) of FIG. 6, only odd lines are driven by sequentially applying a driving voltage to the odd cathode line Kn-1 by one vertical synchronous period 1H. Subsequently, as shown in (b) of FIG. 6, only even lines are driven by sequentially applying a driving voltage to the even cathode line Kn by one vertical synchronous period 1H. Accordingly, the first to nth cathode lines K1 'to Kn' are discharged. On the other hand, a discharge corresponding to two cathode lines occurs with a time difference in the same discharge channel, but a virtual switch (not shown) of a scan line corresponding to each line (that is, an odd cathode line or an even cathode line) by the plasma discharge. Not turned on) to charge the liquid crystal layer 66. In addition, when the virtual switch is turned off and the virtual switch is turned off, the discharge channel becomes a high impedance state so that the previous state is maintained as it is, and the current state is maintained until the sampling signal comes in the next cycle. In this case, the discharge channel serves as a sampling switch and the liquid crystal layer 68 serves as a holder for maintaining the current state. In this case, the discharge sequence of the discharge channel may be applied to the driving voltage so that the discharge is sequentially performed on even-numbered negative lines first and then sequentially on odd-numbered negative lines according to the designer's intention. Accordingly, in the PALC driving method according to the present invention, the driving voltage is applied to the odd cathode lines or the even cathode lines in a predetermined order so as to prevent erroneous discharge and malfunction of the PALC.

As described above, the high brightness plasma address liquid crystal display according to the present invention has the advantage that the number of partitions is reduced to 1/2 and the width of the anode is reduced to improve the light efficiency.

In addition, the high brightness plasma address liquid crystal display device according to the present invention has an advantage of preventing the discharge and malfunction of the plasma address liquid crystal display device by disposing an electrode having the same polarity (ie, an anode) under the partition wall.

In addition, the high-brightness plasma address liquid crystal display according to the present invention may prevent the discharge and malfunction of the plasma address liquid crystal display by applying a driving voltage to the odd cathode lines or even cathode lines in a predetermined order. There is an advantage.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (5)

A high brightness plasma address liquid crystal display device comprising a backlight unit, a plasma unit, and a liquid crystal unit, Partition walls for dividing the plasma unit into respective discharge channels; An anode formed under the partition wall; And a pair of cathodes formed in the discharge channel. The method of claim 1, And the pair of cathodes correspond to two scan lines. The method of claim 1, And the anode is disposed to have the same polarity in adjacent discharge channels. And dividing the pair of cathode lines formed in the discharge channel into odd-numbered cathode lines and even-numbered cathode lines, and then sequentially applying a driving voltage. The method of claim 4, wherein And applying the driving voltage to the odd-numbered cathode lines and the even-numbered cathode lines so as to have a predetermined time difference.