KR20000074559A - Plasma Address Electroluminescence Display Apparatus and Driving Method thereof - Google Patents

Abstract

PURPOSE: A plasma address EL(electroluminescent) display device and a driving method thereof are provided to improve the brightness and the light emitting efficiency. CONSTITUTION: A plasma address EL comprises an EL panel(60) and a plasma channel unit(62). The EL panel(60) comprises upper/lower insulating layers(50,54), a light emitting layer(52) and a transparent electrode(56). The upper/lower insulating layers(50,54) comprises a dielectric material. The light emitting layer(52) comprises ZnS and Mn and generates a visual ray according to a transparent material by exciting with an electron. A transparent electrode is used as a data electrode. The plasma channel unit(62) selects a scanning line by addressing the EL panel(60). The plasma channel unit(62) has a lower substrate(42) and a barrier rib(48). An anode and a cathode generate a plasma discharge in a line unit. The barrier rib arranges a discharge space and divides the discharge space in the line unit.

Description

Plasma Address Electroluminescence Display Apparatus and Driving Method

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a flat panel display, and more particularly, to a plasma address electroluminescent display and a driving method thereof for addressing an electroluminescence using discharge.

Recently, various flat panel displays have been developed to reduce weight and volume, which are disadvantages of cathode ray tubes. Such flat panel displays include liquid crystal displays (LCDs), field emission displays (FEDs), plasma display panels (PDPs), and plasma address liquid crystals (PLA) s. &Quot; PALC ") and electroluminescence (hereinafter referred to as “EL”). Among them, studies on ELs having no PALC and viewing angle dependence, which are advantageous for large area, have been actively conducted.

PALC is an active matrix display device that addresses liquid crystal pixels by using space charges generated by plasma discharge. PALC is largely composed of a plasma channel portion, a liquid crystal portion and a backlight (2) as shown in FIG. The plasma channel portion includes a lower substrate 4 to which the first polarization filter 16 is bonded, an anode 12 and a cathode 14 formed side by side on the lower substrate 4, a pair of anodes 12 and a cathode 14. And a partition wall 18 vertically formed on the lower substrate 4 with the gap therebetween and a dielectric glass thin film 20 formed on the partition wall 18. The pair of anodes 12 and 14 cause plasma discharge in units of lines. The partition 18 serves to distinguish the discharge space in line units while providing a discharge space. The dielectric glass thin film 20 serves to distinguish between the plasma channel portion and the liquid crystal portion, and also electrically shorts with the anode 12 during discharge to serve as a virtual electrode. The liquid crystal part includes an upper substrate 6 having a second polarization filter 24 and a red, green, and blue color filter 8 formed on the front and back surfaces thereof, and a transparent electrode 10 formed side by side on the color filter 8. And a liquid crystal layer 22 formed between the transparent electrode 10 and the dielectric glass thin film 20. The color filter 8 selectively transmits white light supplied through the liquid crystal layer 22 for each wavelength to generate red, green, and blue color signals. The liquid crystal layer 22 serves to block or transmit the white light incident to it by the potential difference between the dielectric glass thin film 20 and the transparent electrode 10. The transparent electrode 10 is a data electrode to which data is supplied.

When a high-voltage discharge driving voltage is applied to the anode 12 and the cathode 14, plasma discharge is generated in the plasma channel portion. When plasma discharge occurs, the potential in the discharge space becomes the anode potential in almost all spaces except the vicinity of the cathode 14. At this time, the dielectric glass thin film 20 is electrically shorted with the anode 12 by the charged particles and ionized gas generated by the discharge. When the data signal is supplied to the transparent electrode 10 while the dielectric glass thin film 20 maintains the anode potential, the liquid crystal of the liquid crystal layer 22 is rotated by an electric field between the transparent electrode 10 and the anode 12. And the arrangement direction is changed. At this time, the white light irradiated from the backlight 2 is adjusted by the liquid crystal and gray scale display is performed. On the other hand, if a voltage is not applied between the anode 12 and the cathode 14, since the discharge gas is not ionized, the state between the anode 12 and the dielectric glass thin film 20 is electrically open.

PALC is advantageous in large area, but has a narrow viewing angle, low luminance and low luminous efficiency peculiar to liquid crystal. PALC is difficult to light and short and short due to the back light used as a light source, power consumption is excessive, and a color filter for generating color signals and a polarization filter for converting polarization characteristics of light are required. In addition, the dielectric glass thin film and the polarizing filter of PALC have a problem in that the material and manufacturing process is difficult.

EL display devices are classified into inorganic ELs and organic ELs according to materials and structures, and are self-luminous devices that emit light by electrons, holes, etc. by exciting a fluorescent material. Referring to FIG. 2, the EL panel is formed on the upper and lower insulating layers 34 and 38, the light emitting layer 36 positioned between the upper and lower insulating layers 34 and 38, and the bottom electrode formed on the lower insulating layer 38. And a transparent electrode 40 formed between the upper insulating layer 34 and the substrate 41. The upper and lower insulating layers 34 and 38 are made of a dielectric material and have a predetermined capacitance value. The light emitting layer 36 is made of ZnS, Mn, or the like, and is excited by electrons to emit light to play visible light. The back electrode 32 is a scanning electrode made of a metal material such as Al. The transparent electrode 40 is used as a data electrode to which data is applied.

When a voltage is applied between the back electrode 32 and the transparent electrode 40, electrons in the light emitting layer 36 are accelerated by an electric field as shown in FIG. 3A. The accelerated electrons collide with the light emitting center made of the phosphor material to excite the light emitting center 36a. The light emitting center 36a emits light as it transitions to the ground state after being excited. When an AC pulse signal is applied to the back electrode 32 and the transparent electrode 40, the polarity of the electric field is reversed, and electrons excite the light emitting center 36A continuously.

EL has the advantage of wide viewing angle and fast response speed. In addition, the EL has a light emission temperature dependency and strong vibration and shock. On the other hand, EL has low luminance and luminous efficiency, and requires a switch element such as a thin film transistor (hereinafter referred to as TFT) to be driven in an active matrix manner.

Accordingly, it is an object of the present invention to provide a plasma address EL which increases the luminance and luminous efficiency.

1 is a perspective view schematically showing a conventional plasma address liquid crystal display device;

2 is a cross-sectional view showing an electroluminescent element.

3A and 3B are diagrams showing step-by-step light emission of the electroluminescent element shown in FIG.

4 is a cross-sectional view illustrating a plasma address electroluminescence display device according to an exemplary embodiment of the present invention.

FIG. 5 is a sectional view of the plasma address electroluminescence display shown in FIG. 4; FIG.

FIG. 6 is a plan view showing an electrode arrangement of the plasma address electroluminescence display shown in FIG. 4; FIG.

7 is an equivalent circuit diagram of the plasma address electroluminescence display shown in FIG. 4;

Fig. 8 is a voltage waveform diagram showing a driving method of the plasma address electroluminescence display according to the first embodiment of the present invention.

9 is a view showing a scanning sequence and a light emitting sequence according to the driving method shown in FIG.

10 is a view showing a scanning method different from the scanning method shown in FIG.

Fig. 11 is a block diagram showing a driving device of the plasma address electroluminescence display according to the embodiment of the present invention.

12 is a voltage waveform diagram illustrating a method of driving a plasma address electroluminescence display according to a second embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

2: Backlight 4,42: Lower substrate

6,58: upper substrate 8: color filter

10,40,56: transparent electrode 12,44: anode

14,46 cathode 16,24 polarization filter

18,48 bulkhead 20 dielectric glass thin film

22 liquid crystal layer 32 back electrode

34,38,50,54 Upper insulating layer 36,52 Light emitting layer

60 EL panel 62 plasma channel portion

64: pixel 70: PAEL panel

72: timing controller 74: cathode drive unit

76: anode driver 78A, 78B: data driver

In order to achieve the above object, the plasma address EL display device according to the present invention is provided with an electroluminescence element which generates light by electric collision itself, and a discharge switch element which addresses the electroluminescence element by discharge. do.

The plasma address EL display device according to the present invention includes an electroluminescence element for generating light by an electric collision, a discharge switch element for addressing the electroluminescence element by discharge, and an electroluminescence element. And data driving means for supplying the power supply means, and discharging driving means for driving the discharge switch element.

The driving method of the plasma address EL display device according to the present invention includes the step of addressing the electroluminescence element by discharge.

The driving method of the plasma address EL display device according to the present invention includes the steps of addressing the electroluminescence element by discharge, and the step of emitting the electroluminescence element.

Other objects and advantages of the present invention in addition to the above objects will become apparent from the description of the embodiments with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 4 to 12.

4 and 5, the plasma address EL according to the present invention is composed of an EL panel 60 and a plasma channel portion 62. As shown in FIG. The EL panel 60 has a light emitting layer 52 positioned between the upper and lower insulating layers 50 and 54 and an upper insulating layer 50 and the upper substrate 58 between the upper and lower insulating layers 50 and 54. A transparent electrode 56 is formed. The upper and lower insulating layers 50 and 54 are made of a dielectric material and have a predetermined capacitance value. The light emitting layer 52 is made of ZnS, Mn, and the like, and is excited by electrons to emit light to play visible light. The light emitting layer 52 generates visible light of any one of red, green, and blue colors depending on the fluorescent material. The transparent electrode 40 is used as a data electrode to which data is applied. The plasma channel portion 62 serves to select the scanning line by addressing the EL panel 60. The plasma channel portion 62 includes a lower substrate 42 on which the cathode 44 and the anode 46 are formed, and a partition 48 formed vertically on the lower substrate 4. The pair of anodes 12 and 14 cause plasma discharge in units of lines. The partition 18 serves to distinguish the discharge space in line units while providing a discharge space.

In the plasma address EL according to the present invention, m × n pixels 64 are arranged in a matrix form as shown in FIG. Each of the m × n pixels 64 includes a cathode 44, an anode 46, and a data electrode 56. The m cathode lines K1, K2, ..., Km and the anode lines A1, A2, ..., Km are orthogonal to the n data lines D1, D2, ..., Dn.

One pixel of the plasma address EL can be represented as shown in FIG. In FIG. 7, Cdie1 and Cdie2 represent capacitance values of the upper insulating layer 50 and the lower insulating layer 50, respectively, and Cel represents a capacitance value of the light emitting layer 52. SW represents a switch virtually existing between the anode 46 and the lower insulating layer 54. This switch SW is turned on / off according to whether or not plasma discharge is generated to address the scanning line of the EL panel 60.

8 shows a driving method of the plasma address EL according to the first embodiment of the present invention.

In the plasma address EL according to the present invention, one horizontal line of data is written and held in one horizontal period (H). 1 The horizontal period (H) is an initial period (INT) for addressing the corresponding scanning line of the EL panel by generating a discharge, a data capture period (DC) in which data is written, and a sustain for maintaining light emission. ) Period DS. First, when a scanning pulse of about -350 V is applied to the first cathode line K1 during the initial period INT, the corresponding voltage of the plasma channel portion is determined by the voltage difference between the first cathode line K1 and the first anode line A1. Plasma discharge is generated in the discharge channel. Then, the anode lines A1, A2,..., Am-1, Am in the discharge channel where the plasma discharge is generated and the lower insulation layer 54 are electrically shorted, so that the lower insulation layer 54 is connected to the anode line A1, A2, ..., Am-1, Am) During the data capture period DC, data of one horizontal line is supplied to n data lines D1, D2, ..., Dn-1, Dn simultaneously. At this time, the data supplied to the n data lines D1, D2, ..., Dn-1, Dn is pulse amplitude modulation (hereinafter referred to as "PAM") according to the gray scale value. Therefore, the data has its amplitude, that is, its magnitude, depending on the gray scale value, including the sustain level + gray scale level. When such data is supplied, an electric field is applied between the upper insulating layer 50 and the lower insulating layer 54 in the first horizontal line of the addressed EL panel 60. The magnitude of this electric field depends on the amplitude of the data. The electrons in the light emitting layer 52 are accelerated toward the light emitting center by the electric field to excite the light emitting center. The light emitting center excited by the electrons is excited and then emits light as it transitions to the ground state. At this time, since the light emission intensity of the light emitting layer 52 is changed according to the gray level of the data, the gray value is changed. During the sustain period DC, light emission is caused by a sustain pulse applied to the anode lines A1, A2, ..., Am-1, Am and the data lines D1, D2, ..., Dn-1, Dn. maintain. The sustain pulse compensates the amount of decay of the potentials of the anode lines A1, A2, ..., Am-1, Am due to the plasma discharge after the initial period INT, and thus the anode lines A1, A2, ... The potential difference between, Am-1, Am and the data lines D1, D2, ..., Dn-1, Dn is maintained at the minimum level at which light emission can be maintained, that is, the sustain level. That is, the sustain pulse is applied to the anode lines A1, A2, ..., Am-1, Am and the data lines D1, D2, ..., Dn-1, Dn with the inverted polarity, so The polarity of the electric field applied to the insulating layers 50 and 54 is continuously inverted to maintain light emission of the light emitting layer 52 at a low voltage level due to the polarization effect.

FIG. 9 shows the lines scanned and the light emission sequence by the driving method of the plasma address EL shown in FIG. In Fig. 9, the horizontal axis represents the time axis and the vertical axis represents the scan line. After the first horizontal line is scanned during the first horizontal period H1, the scanning pulse is sequentially applied to the second to mth cathode lines K2, K3, ..., Km-1, Km as shown in FIG. When supplied, the corresponding horizontal lines of the EL panel 60 are sequentially scanned.

On the other hand, the scanning and light emission in the reverse order to the sequentially scanned and emitted from the first horizontal line to the m-th horizontal line in this way. That is, as shown in FIG. 10, scanning pulses are applied in the order of the mth cathode line Km to the first cathode line K1 to apply the scanning pulses from the mth horizontal line to the first horizontal line, and the data line ( Data signals are applied to D1, D2, Dn-1, and Dn to emit light, and then data lines D1, D2, Dn-1, Dn and anode lines A1, A2 ... A sustain pulse is applied to Am-1, Am) to maintain light emission. Alternatively, one screen may be divided into two or more blocks, and scanning and emission of each block may be separately controlled.

FIG. 11 shows a driving apparatus for implementing the driving method of the plasma address EL as shown in FIG.

Referring to Fig. 11, the driving apparatus of the plasma address EL according to the present invention includes a plasma address EL panel (hereinafter referred to as " PAEL panel ") 70 consisting of an EL panel 60 and a plasma channel portion 62, and a PAEL. Cathode drive portion 74 connected to cathode lines K1, K2, ..., Km-1, Km of panel 70 and anode lines A1, A2, ..., Am of PAEL panel 70. A positive driving unit 76 connected to -1, Am, and a first data driving unit connected to the odd-numbered data lines D1, D3, ..., Dn-3, Dn-1 of the PAEL panel 70 ( 78A), second data driver 78B connected to even-numbered data lines D2, D4, ..., Dn-2, Dn of PAEL panel 70, and first and second data driver 78A. And a data controller 80 commonly connected to the 78B, and a timing controller 72 connected to the cathode driver 74, the anode driver 74, and the data pulse generator 80 in common. Since the PAEL panel 70 is substantially the same as that shown in FIG. 4, a detailed description thereof will be omitted. The cathode driver 74 sequentially supplies scanning pulses to the first to mth cathode lines K1, K2,..., Km-1, Km during the initial period INT under the control of the timing controller 72. do. The anode driver 76 may cause a discharge to the scanning pulse in the first to mth anode lines A1, A2, ..., Am-1, Am during the initial period INT under the control of the timing controller 72. After supplying a common voltage of a possible voltage level, a sustain pulse having a different polarity from that supplied to the data lines D1, D2, ..., Dn-1, Dn is supplied during the sustain period DS. . The first and second data drivers 78A and 78B respectively include the odd-numbered data lines D1, D3, ..., Dn-3 and Dn-1 and the even-numbered data lines D2, during the data capture period DC. One horizontal line of data is supplied to D4, ..., Dn-2, Dn). The data pulse generator 80 generates a data pulse signal and supplies the data pulse signal to the first and second data drivers 78A and 78B. The timing controller 72 generates timing signals necessary for the cathode driver 74, the anode driver 76, and the data drivers 78A and 78B in response to the vertical and horizontal synchronization signals H included in the input signal.

12 shows a driving method of the plasma address EL according to the second embodiment of the present invention.

Data for one horizontal line is written and held in one horizontal period (H). One horizontal period H includes an initial period INT, a data capture period DC, and a sustain period DS. First, if a scanning pulse of about -350 V is applied to the first cathode line K1 during the initial period INT, the plasma channel portion may be formed by a voltage difference between the first cathode line K1 and the first anode line A1. Plasma discharge is generated in the discharge channel. Then, the anode lines A1, A2,..., Am-1, Am in the discharge channel where the plasma discharge is generated and the lower insulation layer 54 are electrically shorted, so that the lower insulation layer 54 is connected to the anode line A1, A2, ..., Am-1, Am) During the data capture period DC, data of one horizontal line is supplied to n data lines D1, D2, ..., Dn-1, Dn simultaneously. At this time, the data supplied to the n data lines D1, D2, ..., Dn-1, Dn is PAM modulated according to the gray scale value. When such data is supplied, an electric field whose intensity varies depending on the amplitude of the data is applied between the upper insulating layer 50 and the lower insulating layer 54 in the first horizontal line of the addressed EL panel 60. By this electric field, electrons in the light emitting layer 52 are accelerated toward the light emitting center to excite the light emitting center. The light emitting center excited by the electrons is excited and then emits light as it transitions to the ground state. At this time, the gradation value changes according to the gradation level of the data. During the sustain period DC, light is emitted by high frequency sustain pulses applied to the anode lines A1, A2, ..., Am-1, Am and the data lines D1, D2, ..., Dn-1, Dn. Is maintained. The high frequency sustain pulse emits a potential difference between the anode lines A1, A2, ..., Am-1, Am and the data lines D1, D2, ..., Dn-1, Dn after the initial period INT. This is kept at the minimum level that can be maintained, that is, the sustain level. The high frequency sustain pulse is applied to the anode lines A1, A2, ..., Am-1, Am and the data lines D1, D2, ..., Dn-1, Dn with the inverted polarity. The polarity of the electric field applied to the insulating layers 50 and 54 is continuously inverted to maintain light emission of the light emitting layer 52 at a low voltage level due to the polarization effect. The high frequency sustain pulse may have a constant pulse width, but may be pulse width modulated (PWM), initially set to a large pulse width, and then changed to a constant pulse width. While the high frequency sustain pulse is supplied, the first cathode line K1 is supplied with a stabilization pulse that maintains a high level for a period during which the high frequency sustain pulse is supplied. The stabilization pulse is applied to the upper insulating layer 50 by a high frequency sustain pulse applied to the data lines D1, D2, ..., Dn-1, Dn and the anode lines A1, A2, ... Am-1, Am. And the electric field between the lower insulating layer 54 is prevented from changing. In other words, the stabilization pulse minimizes the fluctuation of the electric field across the light emitting layer 52, thereby preventing the abnormal phenomenon in which the false discharge and discharge due to the high frequency sustain pulse are erased. After the first horizontal line is scanned during the first horizontal period H1 and the scanning pulse is sequentially supplied to the second to m-th cathode lines K2, K3, ..., Km-1, Km, the first horizontal line is scanned. Scanned sequentially from the line to the mth horizontal line.

As described above, the plasma address EL according to the present invention addresses the EL panel by plasma discharge and maintains light emission by supplying sustain pulses or high frequency sustain pulses to the anode line and the data line during the discharge attenuation period, thereby improving luminance and luminous efficiency. It can be improved. The present invention adopts an EL panel which is a self-light emitting element, so that the response speed is fast and the viewing angle is widened. Accordingly, the plasma address EL according to the present invention can solve the problems of the PALC represented by the liquid crystal. That is, the plasma address EL according to the present invention can realize a wide viewing angle, low power consumption, and fast response speed. In addition, the plasma address EL according to the present invention can be reduced in cost and thinned since the backlight, polarization filter, dielectric glass thin film, etc. required for PALC are removed. In addition, the present invention simplifies the process since the polarization filter, dielectric glass thin film, etc., which have a narrow selection of materials and high process difficulty, are removed. Furthermore, the plasma address EL according to the present invention can stabilize the switching characteristics and the discharge characteristics between the anode line and the cathode line by supplying a stabilizing pulse to the cathode line during the period in which the sustain pulse is supplied.

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 (24)

Electroluminescent element which generates light by electric collision by itself, And a discharge switch element for addressing the electroluminescence element by discharge. The method of claim 1, The electroluminescent device includes a data electrode, A light emitting layer emitting light by electric collision, A first insulating layer formed between the data electrode and the light emitting layer; And a second insulating layer formed between the light emitting layer and the discharge switch element. The method of claim 1, The discharge switch device includes a cathode and an anode which cause a discharge by a voltage difference; And a barrier rib formed vertically between the cathode and the anode. Electroluminescent element which generates light by electric collision by itself, A discharge switch element for addressing the electroluminescence element by discharge; Data driving means for supplying data to the electroluminescent element; And a discharge drive means for driving said discharge switch element. The method of claim 4, wherein The electroluminescent element includes a data electrode to which a data pulse is supplied from the data driving means; A light emitting layer emitting light by electric collision, A first insulating layer formed between the data electrode and the light emitting layer; And a second insulating layer formed between the light emitting layer and the discharge switch element. The method of claim 5, And the data driving means supplies one line of data in pulse form to the data electrode. The method of claim 4, wherein And said data driving means pulse-modulates said data so as to vary the amplitude of the data supplied to said electroluminescence element in accordance with a gray scale value. The method of claim 7, wherein And the data driving means supplies the data, and then supplies a sustain pulse to the data electrode to maintain light emission. The method of claim 8, And the data driving means pulse-modulates the sustain pulse to supply the data electrode to the data electrode. The method of claim 8, And the sustain pulse is a high frequency pulse. The method of claim 4, wherein The discharge switch element includes a cathode and an anode which cause a discharge by a signal supplied from the discharge drive means; And a barrier rib formed vertically between the cathode and the anode. The method of claim 11, The discharge driving means includes a cathode driving unit for supplying a scanning pulse to the cathode; And an anode driver for supplying a sustain pulse for maintaining light emission to the anode. The method of claim 12, The cathode driving unit supplies the stabilization pulse to the cathode after the supply of the scan pulse and to prevent the fluctuation of the electric field due to the sustain pulse during the supply period of the sustain pulse. Display. The method of claim 12, And the anode driving unit pulse-modulates the sustain pulse to supply the anode to the anode. The method of claim 12, And the sustain pulse is a high frequency pulse. A method of driving a plasma address electroluminescent display device comprising the step of addressing an electroluminescent element using discharge. Addressing the electroluminescent device using discharge; And emitting light of the electroluminescent device. The method of claim 17, The addressing may further include generating a discharge between the cathode and the anode by applying a scanning pulse to the cathode in the discharge cell in which the cathode and the anode are formed. Driving method. The method of claim 17, The emitting may include applying a data pulse to a data electrode formed on the electroluminescent device to emit light; And maintaining the light emission by applying a sustain pulse for maintaining the light emission to the anode and the data electrode in the discharge cell in which the cathode and the anode are formed. Way. The method of claim 19, And the data is pulse amplitude modulated according to the gray scale value. The method of claim 19, And the sustain pulse is pulse width modulated. The method of claim 19, And the sustain pulse is a high frequency pulse signal. The method of claim 19, And the sustain pulse is a high frequency pulse signal. The method of claim 19, And supplying a stabilization pulse to the cathode during the period in which the sustain pulse is supplied, thereby preventing a change in the electric field caused by the sustain pulse.