Patent Application
20120169781
This application claims all benefits accruing under 35 U.S.C. §119 from China Patent Application No. 201010614865.9, filed on Dec. 30, 2010 in the China Intellectual Property Office, disclosure of which is incorporated herein by reference.
1. Technical Field
The present disclosure relates to a field emission display and a drive method for the same.
2. Description of Related Art
Field emission displays (FEDs) are a novel, rapidly developing flat panel display technology. Compared to conventional displays, such as cathode-ray tube and liquid crystal display, FEDs are superior in providing a wider viewing angle, lower energy consumption, smaller size, and higher quality.
A conventional FED generally includes a number of pixels and a getter. The pixels and the getter are sealed in a vacuum environment. Each of the pixels includes an anode with a surface, a cathode, an emitter electrically connecting to the cathode, and a fluorescent layer disposed on the surface of the anode. When the field emission display is in operation, the cathode provides an electrical potential to the emitter. The emitter emits electrons according to the electrical potential. The anode also provides an electrical potential to accelerate the emitted electrons to bombard the fluorescent layer for luminance. When the fluorescent layer of each of the pixels is bombarded by the electrons, gas is generated. The getter removes the gas to maintain a vacuum environment.
However, when the conventional FED operates to display an image, the pixels corresponding to the objective image will illuminate. The fluorescent layer of each of the pixels corresponding to the objective image also generates gas, thus increasing the amount of gas of the conventional FED.
What is needed, therefore, is to provide a FED and a drive method that can reduce the amount of gas generated from pixels.
Many aspects of the disclosure can be better understood with reference to the drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the present disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views.
The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one.
According to one embodiment, a field emission display 10 as illustrated in
As shown in the
The pixel units 102 of the panel 100 can be arranged in a matrix. In one embodiment shown in
When receiving a signal 101 from an objective image 106, the computing circuit 104a processes the signal 101 of the objective image 106 and sends a command 108 to the drive circuit 104b. The drive circuit 104b receives and processes the command 108 from the computing circuit 104a and then drives the panel 100 to display the objective image 106.
More specifically, the computing circuit 104a selects a part of the pixel units 102. A number of the pixel units 102 that correspond to the objective image 106 are selected by the computing circuit 104a. The objective image 106 can be a character, a frame, or a number of frames. The number of the pixel units 102 to which the objective image 106 corresponds, is relative to the number of the pixels of the panel 100. The more the pixel units in the panel 100, the more the pixel units 102 can correspond to the objective image 106.
For example, in
Furthermore, the computing circuit 104a selects and divides the pixel units 102 into a number of pixel unit groups. If the objective image 106 has a smaller number of pixel units 102, each of the pixel unit groups may only include one pixel unit 102. If the objective image 106 has a greater number of pixel units 102, each of the pixel unit groups can include a number of pixel units 102.
In detail, when each of the pixel unit groups includes more than one pixel unit 102, the pixel units 102 can be disposed in an interlaced pattern or contiguously in one direction. The computing circuit 104a further selects and computes the illumination of each of the pixel units 102, and then divides the pixel units 102 into the pixel unit groups according to the illumination of each of the pixel units 102. Thus, illumination of each of the pixel unit groups can be the same.
In one embodiment, each of the pixel unit groups includes a pixel unit 102. Thus, there are fifteen pixel unit groups corresponding to the objective image 106. The drive circuit 104b scans the pixel unit groups to make the pixel unit groups sequentially work to satisfy an equation T<=t1+t2, wherein T is a total working time period of the pixel unit groups, t1 is an afterglow period of the fluorescent layer 102e of the pixel unit 102 of each of the pixel unit groups, and t2 is a time period of persistence of vision. When the pixel unit groups sequentially work according to the equation T<=t1+t2, the last pixel unit group will illuminate along with the afterglow of the first pixel unit group. Thus, the panel 100 can display the objective image 106.
The afterglow period t1 of the fluorescent layer 102e of each of the pixel units 102 can be in a range from about 1 millisecond to about 100 milliseconds. The time period of persistence of vision t2 can be in a range from about 0.1 seconds to about 0.4 seconds. In one embodiment, the afterglow period t1 of the fluorescent layer 102e of each of the pixel units 102 is about 0.05 seconds, and the time period of persistence of vision t2 is about 0.1 seconds. Thus, the time period T is about 0.15 seconds.
As shown in
wherein N is the number of the pixel unit groups, and t0 is the time period between two adjacent working pixel unit groups. In one embodiment, T is about 0.15 seconds, and N is 15. Thus, the time period t0 between two adjacent working pixel unit groups is about 0.01 seconds.
Specifically, if the objective image 106 has a frame, the pixel unit groups P1-P15 will continuously sequentially work so that the panel 100 displays the static objective image 106 having the frame. An interval between every two pixel unit groups P1-P15 is less than a formula,
In one embodiment, t1 is about 0.05 seconds, t2 is about 0.1 seconds, and N is 15. Thus, the interval between every two pixel unit groups P1-P15 is about 0.01 seconds.
If the objective image 106 has a number of frames, the pixel unit groups P1-P15 sequentially work to satisfy an equation
such that the panel 100 displays the dynamic objective image 106 having the frames. In other words, the panel 100 displays the dynamic objective image 106 having the frames at a rate of about 24 frame per second. In one embodiment, a time period between two adjacent working pixel unit groups corresponding to the Mth frame of the dynamic objective image 106 is less than a formula
wherein M is a positive integer, and Nm is the number of the pixel unit groups corresponding to the Mth frame of the dynamic objective image 106.
According to one embodiment, a drive method of the field emission display 10 as illustrated in
S11: receiving an objective image 106;
S12: selecting a part of the pixel units 102 that correspond to the objective image 106;
S13: dividing the selected pixel units 102 into a number of pixel unit groups;
S14: scanning the pixel unit groups to make the pixel unit groups sequentially work to satisfy an equation T<=t1+t2; and
S15: scanning the pixel unit groups to make the pixel unit groups continuously and sequentially so that the panel 100 displays the static objective image 106.
According to another embodiment, another drive method of the field emission display 10 as illustrated in
S21: receiving an objective image 106;
S22: selecting a part of the pixel units 102 that correspond to the objective image 106;
S23: dividing the selected pixel units 102 into a number of pixel unit groups;
S24: scanning the pixel unit groups to make the pixel unit groups sequentially work to satisfy an equation T<=t1+t2; and
S25: scanning the pixel unit groups to make the pixel unit groups sequentially work at a rate of about 24 frame per second such that the panel 100 displays the dynamic objective image 106.
Accordingly, the present disclosure is capable of providing a FED, which scans a number of pixel unit groups to sequentially work to display an image. The pixel unit groups can sequentially work for luminance such that there is only one pixel unit group enabled at one time so the amount of gas generated by the pixel units of the field emission display can be efficiently decreased. Thus, the field emission display can have a long service life and high display performance
It is to be understood that the above-described embodiments are intended to illustrate rather than limit the disclosure. Any elements described in accordance with any embodiments is understood that they can be used in addition or substituted in other embodiments. Embodiments can also be used together. Variations may be made to the embodiments without departing from the spirit of the disclosure. The above-described embodiments illustrate the scope of the disclosure but do not restrict the scope of the disclosure.
It is also to be understood that above description and the claims drawn to a method may include some indication in reference to certain steps. However, the indication used is only to be viewed for identification purposes and not as a suggestion as to an order for the steps.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201010614865.9 | Dec 2010 | CN | national |
