TWI413056B - Method for driving field emission display - Google Patents

Abstract

The present invention relates to a method for driving field emission display. The method includes following steps of: providing a field emission display including a screen consisting of a plurality of pixel units and a controlling circuit electrically connected to the plurality of pixel units; computing number and position of pixel units of an objective image; dividing the pixel units of the objective image into a plurality of pixel unit groups, wherein each pixel units group includes at least one pixel unit; driving the plurality of pixel unit groups one by one through scanning which following a formula T < =t1+t2, wherein 'T' is time from the first pixel unit group working to the last pixel unit group working, 't1' is time afterglow of phosphor layer, 't2' is time of persistence of vision of the eyes.

Description

Field emission display driving method

The invention relates to a driving method of a display, in particular to a driving method of a field emission display.

Field emission displays are the next generation of emerging technologies with the most potential after cathode ray tube (CRT) displays and liquid crystal (LCD) displays. Compared with the previous display, the field emission display has the advantages of good display effect, large viewing angle, low power consumption and small volume, especially the field emission display based on carbon nanotubes, which has received more and more attention in recent years.

In general, prior art field emission displays typically include a plurality of pixel units and getters sealed in a vacuum environment. Each of the pixel units includes at least one cathode electrode, an electron emitter is electrically connected to the cathode electrode, an anode electrode is spaced apart from the cathode electrode, and a phosphor layer is disposed on the anode electrode surface. When the field emission display is in operation, electrons emitted by the electron emitter accelerate under the action of the anode electrode to bombard the phosphor layer to emit light. The getter can absorb the gas emitted by the phosphor layer to maintain the vacuum of the field emission display.

However, when the field emission display of the prior art operates, all of the pixel units that normally constitute the target picture are simultaneously illuminated to display the target picture. Since the phosphor layer of each pixel unit emits gas when it emits light, all of the pixel units constituting the target picture simultaneously emit light, which causes the amount of deflation of the phosphor layer to be higher when the field emission display operates.

In view of the above, it is necessary to provide a driving method of a field emission display which can reduce the amount of deflation of the phosphor powder layer during operation of the field emission display.

A method for driving a field emission display, comprising the steps of: providing a field emission display comprising a display screen composed of a plurality of pixel units, and a control circuit electrically connected to the plurality of pixel units, and each drawing The element unit includes at least one cathode electrode, an electron emitter is electrically connected to the cathode electrode, an anode electrode is spaced apart from the cathode electrode, and a phosphor layer is disposed on the surface of the anode electrode; the target screen and the calculation are calculated by the control circuit The number and location of the pixel units corresponding to the display screen; the pixel unit corresponding to the target picture is divided into a plurality of pixel unit groups by the control circuit, and each pixel unit group includes at least one pixel unit; The plurality of pixel units are scanned by the control circuit, so that the plurality of pixel units operate in sequence, and the following relationship is satisfied: T<=t1+t2, where T represents the operation from the first pixel unit group to The time required for the last pixel group to work, t1 represents the afterglow time of the phosphor layer of each pixel unit group, and t2 represents the visual persistence of the human eye. between.

A driving method of a field emission display, comprising the steps of: scanning a pixel unit corresponding to the target image by a control circuit according to a pre-displayed pattern, so that a pixel unit corresponding to the target image is sequentially operated, and satisfies The following relationship: T <= t1 + t2, where T represents the time required to work from the first pixel unit to the last pixel unit, and t1 represents the afterglow time of the phosphor layer of each pixel unit , t2 represents the visual persistence time of the human eye.

Compared with the prior art, since the plurality of pixel units are scanned by the control circuit, the plurality of pixel units are sequentially operated, so that only one pixel unit group emits light at the same time, thereby reducing the field emission display. The amount of deflation of the phosphor layer during operation.

The driving method of the field emission display provided by the embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Referring to FIG. 1, the present invention first introduces a field emission display 10 used in the following embodiments, which includes a display screen 100 composed of a plurality of pixel units 102, and a control circuit 104 and the plurality of pixel units 102. connection.

Each pixel unit 102 includes at least one cathode electrode (not shown), an electron emitter (not shown) is electrically connected to the cathode electrode, an anode electrode (not shown) is spaced apart from the cathode electrode, and a A phosphor layer (not shown) is disposed on the surface of the anode electrode. When the pixel unit 102 is in operation, the electron emitter corresponding to the pixel unit 102 emits electrons to illuminate the phosphor layer corresponding to the pixel unit 102 to emit light. It can be understood that when the field emission display 10 realizes color display, each pixel unit 102 should include three sub-pixel units of red, green, and blue, respectively.

The plurality of pixel units 102 of the field emission display 10 can be arranged in any manner. Preferably, the plurality of pixel units 102 are arranged in a matrix, and are controlled by an address circuit so that each pixel unit 102 can work independently. The field emission display 10 of the embodiment of the present invention includes 10 x 10 pixel units 102. In the embodiment of the present invention, the direction in which the pixel units 102 are laterally arranged is defined as the X direction, and the direction in which the pixel units 102 are vertically arranged is defined as the Y direction.

The control circuit 104 includes an arithmetic circuit (not shown) and a drive circuit (not shown). The arithmetic circuit can receive the signal of the target picture 106 input by the signal source, analyze and process the signal, and then issue an instruction to the driving circuit according to the processing result. The drive circuit accepts and executes an instruction issued by the arithmetic circuit to cause the field emission display 10 to display the target screen 106.

A first embodiment of the present invention provides a driving method of a field emission display 10, which specifically includes the following steps:

Step S11: The number and position of the pixel units 102 corresponding to the display screen 100 of the target screen 106 are calculated by the control circuit 104.

The target screen 106 can be a character or a picture or the like. The number of pixel units 102 corresponding to the display screen 100 and the number of pixels of the display screen 100 is related to the number of pixels of the display screen 100. The higher the number of pixels, the larger the number of pixel units 102 corresponding to the target screen 106. The position of the pixel unit 102 corresponding to the target screen 106 and the display screen 100 is related to the position and proportion of the target screen 106 on the display screen 100. In this embodiment, the target picture 106 is a "ten" character located at the center of the display screen 100, and the number of corresponding pixel units 102 is 15, wherein the eight pixel units 102 are arranged along the X direction. The eight pixel units 102 are arranged in the Y direction, and one pixel unit 102 is shared at the intersection. This step is done by the arithmetic circuit.

Step S12: The pixel unit 102 corresponding to the target screen 106 is divided into a plurality of pixel unit groups by the control circuit 104.

Each pixel unit group includes at least one pixel unit 102. When the number of pixel units 102 corresponding to the display screen 100 and the display screen 100 is small, each pixel unit group may include only one pixel unit 102. When the number of pixel units 102 corresponding to the target screen 106 and the display screen 100 is very large, each pixel unit group may include a plurality of pixel units 102 to reduce the sequential scanning of the control circuit in the subsequent steps. Difficulty. In this embodiment, each pixel unit group includes only one pixel unit 102. This step is done by the arithmetic circuit.

When the pixel unit group includes a plurality of pixel units 102, the number of pixel units of each pixel unit group may be the same or different, and the pixel units of each pixel unit group may be adjacent or spaced apart. Preferably, each of the corresponding pixel units 102 is first subjected to luminance calculation according to the target picture 106, and then the total luminance of each of the grouped pixel unit groups is the same according to the luminance grouping. It can be understood that the amount of deflation of the phosphor layer of each pixel unit 102 is related to the display brightness, and the higher the display brightness, the larger the amount of deflation. Since the total brightness of each pixel unit group is the same, the total amount of bleed of each pixel unit group is substantially the same in the subsequent sequential scanning of the plurality of pixel unit groups, thereby making the vacuum of the field emission display 10 The degree is stable.

Step S13: scanning a plurality of pixel units by the control circuit 104, so that the plurality of pixel units operate in sequence, and satisfy the following relationship: T<=t1+t2, where T represents the first pixel. The time required for the unit group working time to start until the last pixel unit group working time begins, t1 represents the afterglow time of the phosphor layer of each pixel unit group, and t2 represents the visual persistence time of the human eye.

The control circuit 104 scans a plurality of pixel units using a pulse voltage to sequentially operate a plurality of pixel units. Since the pulse time of the pulse voltage is very short, the working time of each pixel unit group may or may not be counted. When the control circuit 104 operates a certain pixel unit group, all of the pixel units 102 of the pixel unit group simultaneously operate to emit light. Since the phosphor layer has a afterglow effect, the human eye has a visual persistence effect, and a plurality of pixel units work in sequence to satisfy the relationship: T<=t1+t2, so when the last pixel unit group emits light The image of the first pixel unit group is also retained in the human brain, so that the human eye sees a complete target picture 106. Since the plurality of pixel units work in sequence, only one pixel unit group emits light at the same time, thereby reducing the amount of deflation of the phosphor layer during operation of the field emission display 10. This step is done by the drive circuit.

The afterglow time t1 of the phosphor layer of the field emission display 10 is typically from 1 millisecond to 100 milliseconds. The visual persistence time t2 of the human eye is usually 0.1 second to 0.4 seconds. In this embodiment, the afterglow time t1 of the phosphor layer of the field emission display 10 is 0.05 seconds. Calculated by the human eye's visual persistence time t2 of 0.1 second, the maximum time for the plurality of pixel units to work sequentially is T = 0.15 seconds. In this embodiment, the target picture 106 corresponds to 15 pixel unit groups, so the time interval t0 between two pixel unit groups working in sequence is T/(N-1)=0.15/14=0.01. Seconds, where t0 represents the time interval between two pixel cell groups operating in sequence, and N represents the number of the plurality of pixel cell groups. Referring to FIG. 2, the 15 pixel unit groups P1 to P15 corresponding to the target picture 106 are sequentially operated, and the maximum time for the 15 pixel unit groups to work sequentially is T, and the two pixel units work in sequence. The time interval between groups is t0.

Step S14: Perform repeated scans on the plurality of pixel unit groups to implement static display.

When the plurality of pixel units are repeatedly scanned, the interval between the end of each scan and the start of the next scan should be less than (t1+t2)/(N-1), so that the human eye sees a complete Target screen 106. It can be understood that since the interval between the end of each scan and the start of the next scan is less than (t1+t2)/(N-1), when the first pixel unit group P1 is illuminated for the second time, the human brain The image produced by the first work of the second pixel unit group P2 is also retained, so that the human eye can always see a complete and statically held target picture 106.

A second embodiment of the present invention provides a driving method of a field emission display 10, which specifically includes the following steps:

Step S21: The number and position of the pixel units 102 corresponding to the display screen 100 of the target screen 106 are calculated by the control circuit 104.

Step S22: The pixel unit 102 corresponding to the target screen 106 is divided into a plurality of pixel unit groups by the control circuit 104.

Step S23: scanning a plurality of pixel unit groups by the control circuit 104, so that the plurality of pixel unit groups work sequentially, and satisfy the following relationship: T<=1/24 seconds, wherein T represents the first picture. The time required for the working time of the prime unit group to start the working time of the last pixel unit group, t1 represents the afterglow time of the phosphor layer of each pixel unit group, and t2 represents the visual persistence time of the human eye. Since the speed of the output screen of the display should be greater than or equal to 24 frames per second, the human eye can perceive a continuous dynamic picture. Therefore, each target picture 106 needs to be displayed within 1/24 second. In this embodiment, the time interval in which the pixel unit groups corresponding to the Mth target picture 106 operate in sequence should be less than 1/24×(Nm−1), where M is a positive integer, and Nm represents the Mth target picture 106. The number of pixel units.

Step S24: The target screen 106 is replaced at a speed greater than or equal to 24 frames per second to achieve dynamic display.

Since the speed of the output screen of the display should be greater than or equal to 24 frames per second, the human eye can feel the dynamic picture. Therefore, the field emission display 10 should replace the target picture 106 at a speed of 24 frames per second or more, and for each target. The time when the pixel unit group corresponding to the screen 106 is sequentially operated once should be T<=1/24 seconds.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by persons skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

10‧‧‧ field emission display

100‧‧‧ display

102‧‧‧ pixel unit

104‧‧‧Control circuit

106‧‧‧ Target screen

FIG. 1 is a schematic structural diagram of a field emission display used in an embodiment of the present invention.

FIG. 2 is a schematic diagram showing the time relationship of the pixel unit groups corresponding to the target picture in the first embodiment of the present invention.

Claims (10)

A method of driving a field emission display, comprising the steps of:
An emission display is provided, comprising: a display screen composed of a plurality of pixel units, and a control circuit electrically connected to the plurality of pixel units, and each pixel unit includes at least one cathode electrode, an electron emitter and The cathode electrode is electrically connected, an anode electrode is spaced apart from the cathode electrode, and a phosphor layer is disposed on the anode electrode surface;
Calculating, by the control circuit, the number and location of the pixel units corresponding to the display screen of the target screen;
The pixel unit corresponding to the target picture is divided into a plurality of pixel units by a control circuit, and each pixel unit group includes at least one pixel unit; and the plurality of pixel units are scanned by the control circuit, The plurality of pixel units are sequentially operated, and the following relationship is satisfied: T<=t1+t2, where T represents the time required to work from the first pixel unit group to the last pixel unit group, t1 Indicates the afterglow time of the phosphor layer of each pixel unit group, and t2 represents the visual persistence time of the human eye. The method of driving a field emission display according to claim 1, wherein each of the pixel unit groups includes a plurality of pixel units. The driving method of the field emission display of claim 1, wherein the step of dividing the pixel unit corresponding to the target picture into a plurality of pixel units performs luminance calculation for each pixel unit. And grouping according to the brightness of the pixel units, so that the total brightness of each pixel unit group after grouping is the same. The method of driving a field emission display according to claim 1, wherein each of the pixel unit groups includes a plurality of pixel unit adjacent settings. The driving method of the field emission display of claim 1, wherein each of the pixel unit groups includes a plurality of pixel unit interval settings. The method of driving a field emission display according to claim 1, wherein when a certain pixel unit group is operated, all of the pixel units of the pixel unit group work simultaneously. The method for driving a field emission display according to claim 1, wherein the plurality of pixel unit groups are further repeatedly scanned to achieve static display, and each scan ends and is separated from the start of the next scan. The time is less than (t1 + t2) / (N-1), where N represents the number of the plurality of pixel cell groups. The method for driving a field emission display according to claim 1, wherein the plurality of pixel unit groups are sequentially operated to satisfy the following relationship: T<=1/24 seconds, and further equal to or greater than or equal to one second. The target frame is changed at a speed of 24 frames for dynamic display. The method for driving a field emission display according to claim 1, wherein the plurality of pixel units are arranged in a matrix, and each pixel unit is independently operated by an address circuit. A method of driving a field emission display, comprising the steps of:
The pixel units corresponding to the target picture are scanned by the control circuit according to the pre-displayed pattern, so that the pixel units corresponding to the target picture work sequentially, and the following relationship is satisfied: T<=t1+t2, where T represents the time required to work from the first pixel unit to the last pixel unit, t1 represents the afterglow time of the phosphor layer of each pixel unit, and t2 represents the visual persistence time of the human eye.