TWI399714B - Driving apparatus and driving method for a bipolar field emission display - Google Patents

Description

Driving device of two-pole field emission display and driving method thereof

The present invention relates to a driving technique for a field emission display, and more particularly to a driving device for a two-pole field emission display and a driving method thereof.

With the advent of the digital era and the popularity of the Internet, the display technology of information images is becoming more and more important, and the peripheral products of flat-panel displays are increasingly valued by the industry. A new generation of field emission display (FED) was born.

Under the pressure of the development of mainstream liquid crystal displays, plasma displays, and organic laser displays, field emission display technology seems to be less mature. A field emission display is a new type of flat panel display that is similar in principle to a cathode ray tube. The "field" of field emission refers to an electric field. The principle is to apply a high electric field to the conductor material, so that the electrons in it pass through the potential barrier. As the voltage increases, the current it emits also increases. The emitted electrons collide with the fluorescent substance on the fluorescent screen, and then emit light to form an image.

The basic structure of the field emission display can be divided into a cathode plate (emitter base), an anode plate (fluorescent powder) and a vacuum sealing zone between the two plates. When an electron emitter on the cathode plate emits electrons and strikes phosphors of different colors, color development occurs.

Currently developed field emission display technology is mostly three-pole control, three-pole field emission display has anode, cathode and gate. The gate is used to control the magnitude of the current and direct electrons through the cathode to the anode. Since the control mode of the three-pole field emission display is quite complicated, it is also necessary to use a feedback circuit to control the uniformity of the current to avoid the brightness being too bright or too dark. Recently, the industry has begun to develop into a two-pole field emission display. Since the driving technology of the two-pole field emission display starts slowly, more breakthroughs are required in the driving technology, which is also a problem to be overcome by the present invention.

The present invention provides a driving method for a two-pole field emission display, in which a different voltage level is applied to an anode conductor and a cathode conductor corresponding to a pixel of a two-pole panel, and when the applied voltage difference is maximum, the pixel is turned on and emits light, otherwise The pixels are off and not lit.

The invention provides a driving device for a two-pole field emission display, wherein the driving device applies different voltage levels to an anode conductor and a cathode conductor corresponding to a pixel of the two-pole panel, and when the applied voltage difference is maximum, the pixel is turned on and emits light. Otherwise the pixels are off and not lit.

The invention provides a driving method for a two-pole field emission display, comprising: setting a voltage level value for determining a threshold value of turning on and off a pixel of a two-pole panel, when the voltage difference between the two ends of the pixel is lower than a voltage The level value is off state, and when the voltage difference between the two ends of the pixel is higher than the voltage level value is the on state; the first anode level is applied or the second anode is located at the anode conductor corresponding to the pixel, wherein the second anode is The potential difference between the bit and the first anode level is much greater than the voltage level value; the first cathode level is applied or the second cathode is located at the cathode conductor corresponding to the pixel, wherein the second anode level is greater than the second cathode level, And the second cathode level is greater than the first cathode level, and the absolute difference between the second cathode level and the first cathode level is equal to the voltage level value; and when the pressure difference between the two ends applied to the pixel is the second anode When the bit is reduced to the first cathode level, the pixel is turned on to emit light, and when the pressure difference between the two ends of the pixel is the second anode level minus the second cathode level, the pixel is turned off without emitting light.

In an embodiment of the present invention, the driving method of the above-described two-pole field emission display, wherein the step of applying the first anode level or the second anode to the anode conductor corresponding to the pixel of the two-pole panel comprises: A voltage switching element applies a first anode level or a second anode level to the anode conductor.

In an embodiment of the invention, the driving method of the above-described two-pole field emission display, wherein the first voltage switching element switches the first anode level or the second anode level according to the first control signal.

In an embodiment of the present invention, the driving method of the above-described two-pole field emission display, wherein the step of applying the first cathode level or the second cathode to the cathode conductor corresponding to the pixel comprises: passing the second voltage switching element A first cathode level or a second cathode level is applied to the cathode conductor.

In an embodiment of the invention, the driving method of the above-described two-pole field emission display, wherein the second voltage switching element switches the first cathode level or the second cathode level according to the second control signal.

In an embodiment of the invention, the driving method of the above-described two-pole field emission display, wherein the first anode level is a ground potential, and the first cathode level is a ground potential.

The invention provides a driving device for a two-pole field emission display, the driving device comprising a first voltage switching element, a second voltage switching element, and a signal controller. The first voltage switching element is configured to apply a first anode level or the second anode is located on an anode conductor corresponding to a pixel of the two-pole panel, wherein the second anode level is greater than the first anode level, and the second anode is The potential difference between the bit and the first anode level is much larger than the voltage level value, and the voltage level value is used to determine the threshold value of the pixel on and off. When the voltage difference between the two ends of the pixel is lower than the voltage level value The state is off, and when the voltage difference between the two ends of the pixel is higher than the voltage level, the value is on. The second voltage switching element is configured to apply a first cathode level or the second cathode is located at a cathode conductor corresponding to the pixel, wherein the second anode level is much larger than the second cathode level, and the second cathode level is greater than the first cathode The level is absolute, and the absolute difference between the second cathode level and the first cathode level is equal to the voltage level value. The signal controller is coupled to the first voltage switching component and the second voltage switching component, and the signal controller is configured to control switching of the first voltage switching component and the second voltage switching component, wherein when the second anode potential is applied to the anode conductor and applied When the first cathode level is to the cathode conductor, the pixel is turned on to emit light. When the second anode level is applied to the anode conductor and the second cathode level is applied to the cathode conductor, the pixel is turned off when the first anode level is applied to the anode. When the conductor is on, the pixel is turned off and does not emit light.

In an embodiment of the invention, the driving device of the above-described two-pole field emission display, wherein the signal controller sends the first control signal to the first voltage switching component, and the signal controller sends the second control signal to the second voltage switching component And used to control the level switching of the first voltage switching element and the second voltage switching element.

In an embodiment of the invention, the driving device of the above-mentioned two-pole field emission display, wherein the first anode level is a ground potential, and the first cathode level is a ground potential.

Based on the driving device of the above-described two-pole field emission display and the driving device thereof, in the embodiment of the present invention, the anode conductor and the cathode conductor corresponding to the pixels of the two-pole panel are applied with different voltages, and only the voltages on the anode conductor and the cathode conductor need to be controlled. When the applied voltage difference is maximum, the pixel is turned on to emit light. Since the driving method is simple, the driving device can be realized with fewer components, so that the driving device can be smaller in size. The panel controlled by the driving device can emit light uniformly and stably.

The above described features and advantages of the present invention will be more apparent from the following description.

Embodiments of the present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which FIG. However, the invention can be embodied in many different forms and should not be construed as limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and the scope of the invention is fully conveyed by those skilled in the art.

It will also be understood that when an element is referred to as "in", "connected" or "coupled" to another element, it can be directly connected, connected to or coupled to the other element. In contrast, when an element is referred to as being “directly connected,” “directly connected,”

First, the driving method of the two-pole field emission display is divided into a column control and a row control, the row control is for the anode portion, and the column control is for the cathode portion. When a voltage is applied to the anode or the cathode, a potential difference is generated between the anode and the cathode. When the potential difference is large enough, a large amount of electrons are emitted to strike the phosphor on the phosphor screen to brighten the pixel; When the pressure difference becomes small, the electric field pulling the fluorescent powder is insufficient, so the pixels do not illuminate.

1 is a flow chart of a driving method of a two-pole field emission display according to an embodiment of the invention. Referring to FIG. 1, the steps of the driving method include the following steps. In step S110, a voltage level value is set in advance. As for how to set this voltage level value, it will be explained in detail later. Since a pixel of a two-pole panel is turned off to turn on, the voltage difference between the pixels needs to be higher than a threshold value, that is, the anode conductor corresponding to the pixel must be applied. The high voltage level, and the cathode conductor corresponding to the pixel is additionally applied with a voltage level. If the voltage difference between the two ends of the pixel is lower than the voltage level, the state is off, and if the voltage difference between the two ends of the pixel is higher than this The voltage level value is on. Next, in step S120, the application of the first anode level or the second anode is located in the anode conductor corresponding to the pixel, wherein the potential difference between the second anode level and the first anode level is much greater than the voltage level value. Next, in step S130, the first cathode level or the second cathode is applied to the cathode conductor corresponding to the pixel, wherein the second anode level is greater than the second cathode level, and the second cathode level is greater than the first cathode level. And the absolute difference between the second cathode level and the first cathode level may be equal to the aforementioned voltage level value. Next, in step S140, when the pressure difference applied to the pixel is the second anode level minus the first cathode level, the pixel is turned on and emits light, and when the pressure difference between the two ends of the pixel is the second anode level, the second is reduced. At the cathode level, the pixels are turned off and no light is emitted.

The aforementioned driving method can cause the pixels to emit light. The principle used is that when the potential of the anode conductor is at a high potential (second anode level), the potential of the cathode conductor has a fast switching between a high potential (second cathode level) and a low potential (first cathode level). Therefore, when the potential of the cathode conductor is cut to a high potential (second cathode level), the potential difference between the two ends of the pixel becomes small, so that the pixel off does not light. When the potential of the cathode conductor is cut to a low potential (first cathode level), the potential difference between the two ends of the pixel is the largest, so that the pixel is turned on when it is turned on.

2 is a circuit block diagram of a voltage switching element in accordance with an embodiment of the present invention. Please refer to Figure 2. In order to implement switching of different voltage levels, the voltage switching component 200 can switch the first voltage level (low potential) V _Low or the second voltage level (high potential) V _High according to the control signal, and output the voltage to the outside. . Among other things, embodiments of the voltage switching component 200 can utilize semiconductor switching switches, such as CMOS or MOSFETs.

In another embodiment, the voltage switching element 200 can be applied to the anode, wherein V _High can be 100 volts, and V _Low can be 0 volts; in the same manner, the voltage switching element 200 can also be applied to the cathode, where V _High can be 50 V, V _Low can be 0 volts.

3 is a schematic diagram of a driving circuit of a two-pole field emission display according to an embodiment of the invention. Please refer to Figure 3. In order to perform a potential change across the pixel, the voltage switching element 300 can switch the potential of the first anode level VA1 or the second anode level VA2 according to the control signal Sa to become the output anode voltage Va. The first anode level VA1 or the second anode level VA2 can thus be applied to the anode conductor by the voltage switching element 300. The principle of the same switching voltage level, the voltage switching element 320 can switch the potential of the first cathode level VC1 or the second cathode level VC2 according to the control signal Sc to become the output cathode voltage Vc. The first cathode level VC1 or the second cathode level VC2 can thus be applied to the cathode conductor by the voltage switching element 320.

4 is a signal timing diagram of anode voltage and cathode voltage in accordance with the embodiment of FIG. 3 of the present invention. Please refer to Figure 4. The anode voltage Va is between the first anode level VA1 and the second anode level VA2. The cathode voltage Vc is between the first cathode level VC1 and the second cathode level VC2. The second anode level VA2 shown in FIG. 4 is greater than the first anode level VA1, and the second cathode level VC2 is greater than the first cathode level VC1. The second anode level VA2 is greater than the second cathode level VC2, and the absolute difference between the second cathode level VC2 and the first cathode level VC1 may be equal to a voltage level value Vth. This voltage level value Vth can be a threshold value for determining the on and off of pixels on the two-pole panel.

In another embodiment, the voltage level can be designed as follows: the first anode level VA1 is the ground potential (0 volts), the second anode level VA2 is 100 volts, and the first cathode level VC1 is the ground potential (0 volts). The second cathode level VC2 is 50 volts and the voltage level value Vth is 50 volts. Referring to FIG. 3 and FIG. 4 together, the principle of illumination is: when the voltage difference between the two ends of the pixel is ΔV1 and lower than the voltage level value Vth, the pixel is turned off and does not emit light; and when the voltage difference between the two ends of the pixel is △ V2 is higher than the voltage level value Vth, so the potential difference across the pixel is sufficiently large, and the pixel is turned on to emit light. That is, at the time T1 of the start timing, the anode voltage Va is 0 volt, and the pulse wave change of the cathode voltage Vc is not bright; the time T2 starts, the anode voltage Va is 100 volts, and the cathode voltage Vc rises to 50 volts due to The voltage difference ΔV1=50 volts, the pixel is off state and does not emit light; at time T3, the anode voltage Va is 100 volts, the cathode drops to 0 volts, and the voltage difference ΔV2=100 volts exceeds the voltage level value Vth, the pixel will Glowing. Similarly, the times T4 and T6 are the same as the time T2, and the time T5 is the same as the time T3. Those skilled in the art should understand that each voltage level can be designed according to the actual situation, and should not be limited to this embodiment.

5 is a circuit diagram of a two-pole field emission display in accordance with an embodiment of the present invention. Please refer to Figure 5. The driving device 500 is used to drive a two-pole field emission display panel 510 having m rows x n columns of pixels, where m and n are positive integers. The driving device 500 includes voltage switching elements 301, 302, 303, ..., 30m, voltage switching elements 321, 322, 323, ..., 32n, and a signal controller 502. The voltage switching elements 301, 302, 303, ..., 30m apply a first anode level VA1 or a second anode level VA2 to the anode conductors of the m columns of the two-pole panel. The voltage switching elements 321, 322, 323, ..., 32n apply a first cathode level VC1 or a second cathode level VC2 to the cathode conductors of the n rows of the two-pole panel. The voltage levels output by the respective voltage switching elements can be implemented with reference to the signal timing diagram of FIG. 4, and are not described herein.

The signal controller 502 is coupled to the voltage switching elements 301, 302, 303, ..., 30m and the voltage switching elements 321, 322, 323, ..., 32n. The signal controller 502 sends the row control signals Sa1, Sa2, Sa3, ..., Sam to the corresponding voltage switching elements 301, 302, 303, ..., 30m, and the signal controller 502 sends the column control signals Sc1, Sc2, Sc3, ..., Scn to the corresponding voltage switching elements 321, 322, 323, ..., 32n. The signal controller 502 is used to control the voltage level switching of the respective voltage switching elements. The detailed control mode of the signal controller 502: according to which rows of pixels or columns of pixels need to make it bright, through a timing to do the control of the voltage switching element, so that some of the pixels are lit, some are not lit. More specifically, the potential of the anode is at a high potential VA2, so that the potential difference between the pixels at a certain point is large enough ((ΔV2=VA2-VC1)>>Vth), and the potential at both ends of the pixel When the pressure difference becomes small ((ΔV1=VA2-VC2)<Vth), it will not light.

The working principle of the driving device 500: when the second anode level VA2 is applied to the anode conductor corresponding to a certain pixel and the first cathode level VC1 is applied to the cathode conductor corresponding to the pixel, the pixel is turned on and emits light, and When the second anode level VA2 is applied to the aforementioned anode conductor and the second cathode level VC2 is applied to the aforementioned cathode conductor, the pixel is turned off, and when the first anode level VA1 is applied to the aforementioned anode conductor, the pixel is turned off without Will shine.

In summary, the embodiment of the present invention applies a different voltage to the anode conductor and the cathode conductor corresponding to the pixels of the two-pole panel, and only needs to control the voltage on the anode conductor and the cathode conductor, and the voltage level applied to both ends of the pixel. When the difference is maximum, the pixel is turned on to emit light. The driving device of the above-described two-pole field emission display and the driving method thereof have at least the following advantages:

1. The driving method is simple;

2. The implementation of the driving device can use fewer components to illuminate the pixels on the two-pole panel, so the driving device can be smaller in size;

3. The panel controlled by the driving device can emit light uniformly and stably.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the invention, and any one of ordinary skill in the art can make some modifications and refinements without departing from the spirit and scope of the invention. The scope of the invention is defined by the scope of the appended claims.

200. . . Voltage switching element

300. . . Voltage switching element

301, 302, 303, ..., 30m. . . Voltage switching element

320. . . Voltage switching element

321, 322, 323, ..., 32n. . . Voltage switching element

500. . . Drive unit

502. . . Signal controller

S110～S140. . . Steps of the flowchart

Sa. . . control signal

Sa1, Sa2, Sa3, ..., Sam. . . Line control signal

Sc1, Sc2, Sc3, ..., Scn. . . Column control signal

T1 ~ T6. . . time

Va. . . Anode voltage

VA1. . . First anode level

VA2. . . Second anode level

Vc. . . Cathode voltage

VC1. . . First cathode level

VC2. . . Second cathode level

V _Low . . . First voltage level

V _High . . . Second voltage level

Vth. . . Voltage level value

△V1, △V2. . . Pressure difference

1 is a flow chart of a driving method of a two-pole field emission display according to an embodiment of the invention.

2 is a circuit block diagram of a voltage switching element in accordance with an embodiment of the present invention.

3 is a schematic diagram of a driving circuit of a two-pole field emission display according to an embodiment of the invention.

4 is a signal timing diagram of anode voltage and cathode voltage in accordance with the embodiment of FIG. 3 of the present invention.

5 is a circuit diagram of a two-pole field emission display in accordance with an embodiment of the present invention.

S110～S140. . . Steps of the flowchart

Claims (9)

A driving method for a two-pole field emission display, comprising: setting a voltage level value for determining a threshold value of turning on and off a pixel of a two-pole panel, when a pressure difference between the two ends of the pixel is lower than the The voltage level value is a closed state, and when the voltage difference between the two ends of the pixel is higher than the voltage level value is an on state; applying a first anode level or a second anode is located at an anode corresponding to the pixel a conductor, wherein a potential difference between the second anode level and the first anode level is much greater than the voltage level; applying a first cathode level or a second cathode is located at a cathode conductor corresponding to the pixel Wherein the second anode level is greater than the second cathode level, and the second cathode level is greater than the first cathode level, and the absolute difference between the second cathode level and the first cathode level is equal to The voltage level value; and when the pressure difference between the two ends applied to the pixel is the second anode level minus the first cathode level, the pixel is turned on to emit light, and when the pressure difference between the two ends of the pixel is The pixel is subtracted when the second anode level is lower than the second cathode level Closed not emit light. The method for driving a two-pole field emission display according to claim 1, wherein the step of applying the first anode level or the second anode is located at the anode conductor corresponding to the pixel includes: A voltage switching element applies the first anode level or the second anode level to the anode conductor. The driving method of the two-pole field emission display according to claim 2, wherein the first voltage switching element switches the first anode level or the second anode level according to a first control signal. The driving method of the two-pole field emission display according to claim 1, wherein the step of applying the first cathode level or the second cathode to the cathode conductor corresponding to the pixel comprises: The second voltage switching element applies the second variable voltage to the cathode conductor. The driving method of the two-pole field emission display according to claim 4, wherein the second voltage switching element switches the first cathode level or the second cathode level according to a second control signal. The driving method of the two-pole field emission display according to claim 1, wherein the first anode level is a ground potential, and the first cathode level is a ground potential. A driving device for a two-pole field emission display, comprising: a first voltage switching component for applying a first anode level or a second anode corresponding to an anode conductor corresponding to a pixel of a two-pole panel, Wherein the second anode level is greater than the first anode level, the potential difference between the second anode level and the first anode level is much greater than a voltage level value, and the voltage level value is used to determine the a threshold value of turning on and off the pixel, when the voltage difference between the two ends of the pixel is lower than the voltage level value is off state, and when the voltage difference between the two ends of the pixel is higher than the voltage level value is an on state; a second voltage switching element for applying a first cathode level or a second cathode corresponding to a cathode conductor corresponding to the pixel, wherein the second anode level is far greater than the second cathode level, and the The second cathode level is greater than the first cathode level, and the absolute difference between the second cathode level and the first cathode level is equal to the voltage level value; and a signal controller coupled to the first Voltage switching element and the second voltage switching element The signal controller is configured to control switching of the first voltage switching element and the second voltage switching element, wherein when the second anode level is applied to the anode conductor and the first cathode level is applied to the cathode conductor The pixel is turned on to emit light. When the second anode level is applied to the anode conductor and the second cathode level is applied to the cathode conductor, the pixel is turned off and does not emit light. When the first anode level is applied to the In the case of an anode conductor, the pixel is turned off without illuminating. The driving device of the two-pole field emission display according to claim 7, wherein the signal controller sends a first control signal to the first voltage switching component, and the signal controller sends a second control signal to the And a second voltage switching component to control the level switching of the first voltage switching component and the second voltage switching component. The driving device of the two-pole field emission display according to claim 7, wherein the first anode level is a ground potential, and the first cathode level is a ground potential.