CN103871366A - Gray scale display driving method and device for LED display - Google Patents

Abstract

The invention discloses a gray scale display driving method and device for an LED display. The gray scale display driving method comprises the steps that all the n data bits of a gray scale datum are divided into m subframes, wherein n is an integer larger than or equal to 2, and m is an integer larger than or equal to 1; the preset weight C of each subframe is calculated; the weights of all the n data bits are established so that the combination of the weights can represent all gray scales; all the n data bits are combined into m subframes to enable the weight of each subframe is approximately equal to the preset weight of the corresponding subframe; the corresponding data bit of each subframe is displayed. The gray scale display driving method and device for the LED display can ensure uniformity of luminance on the premise that the refresh rate of a display system is increased, and then the display effect is improved.

Description

For gray scale display drive method and the device of light-emitting diode display

Technical field

The present invention relates to LED display technique, more specifically, relate to gray scale display drive method and device for light-emitting diode display.

Background technology

The pixel element using at light-emitting diode display is LED.Light-emitting diode display has the superiority of following aspect: high brightness, wide visible angle, abundant color and customizable screen shape.Therefore, light-emitting diode display is widely used in the every field such as industry, traffic, commercial advertisement, information issue, sports tournament.

In order to adapt to the characteristics of luminescence and the electrical characteristics of LED, vision signal is being provided to light-emitting diode display and must proofread and correct.The main non-linear correction method adopting is that γ (Gamma, gamma) proofreaies and correct at present.For example, gamma correction shows that to 8 of incoming video signal data DATA proofreaies and correct, and the gradation data after correction need be greater than 8, for example 12, the gray scale ability to express after proofreading and correct is significantly improved.The occasion of pursuing performance at some has started to adopt 16 gray scales even.

Take 12 gradation datas as example, gamma correction formula is as follows:

$y=4095*{\left(\frac{x}{255}\right)}^{\mathrm{\γ}}---\left(1\right)$

Wherein, x represents that 8 of input show data DATA, and y is 12 gradation datas after proofreading and correct, and γ is gamma value, and in light-emitting diode display application, codomain is generally 1 to 4.

In light-emitting diode display, can adopt electric current control method and ON time control method to realize multi-stage grey scale.In electric current control method, by regulating the size of current flowing through in LED to control its brightness.ON time control method is under the situation driving in constant current, recently controls the brightness of LED by changing duty.The ON time control method that has adopted widely timesharing by turn to show, shows multi-stage grey scale according to the gradation data after proofreading and correct.

In timesharing display packing by turn, for example, in order to show a two field picture, provide 12 gradation datas for each LED pixel.Each of gradation data is corresponding to effective displaying time of different weights, and its weight adopts 2 ⁿrepresent.From 12 gradation datas, extract by turn a bit data, be divided into 12 times and light/extinguish corresponding LED.Described LED lights effective time cumulative brightness effects as the gray level of this pixel.

Above-mentioned timesharing display packing by turn can realize 12 or higher gray level, but but causes the refresh rate that shows image to reduce.Due to the characteristics of luminescence of LED, if refresh rate is lower, may cause image flicker.Show in order further to improve the refresh rate that shows image, a two field picture can be divided into several subframes or further a subframe to be divided into several timeslices.But, because the weight of the bit data of gradation data adopts 2 ⁿrepresent, therefore the duration length of different subframes differs, and this can cause non-uniform light, thereby affects display effect.

Therefore, be desirably in LED display system in improving gray level, improve refresh rate and improve uniformity of luminance.

Summary of the invention

The object of this invention is to provide a kind of gray scale display drive method and device for light-emitting diode display, further to promote display effect.

According to an aspect of the present invention, provide a kind of gray scale display drive method for light-emitting diode display, comprising: whole n data bit of a gradation data are divided into m subframe, and wherein n is more than or equal to 2 integer, and m is more than or equal to 1 integer; Calculate the default weight C of a subframe; Build the weight of whole n data bit, make its combination can show whole gray levels; Whole n data bit patterns are become to m subframe, make the weight of each subframe be substantially equal to the default weight of described subframe; And carry out to subframe one by one the demonstration of corresponding data position.

Preferably, in described method, the numerical range of the weight of each data bit in described whole n data bit is to be more than or equal to 0 and be less than or equal to the arbitrary integer of maximum gray scale.

Preferably, in described method, in a described m subframe, the number p of the data bit of each subframe can be identical or different, and wherein p is more than or equal to 1 integer.

Preferably, in described method, the number p of the data bit of each subframe equals 2.

Preferably, in described method, in the step of weight that builds whole n data bit, the weights W (i) of any i data bit is met the following conditions:

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1.$

Preferably, in described method, the step of the default weight C of subframe of described calculating comprises: when in the set situation of LED display system refresh rate index, determine that according to following formula subframe presets weight

$C=\frac{T\_\mathrm{FRAM}}{T}$

Wherein:

T_FRAM represents the time of a subframe, and according to the refresh rate index of the requirement of display system or user's expectation, the parameters such as clock frequency, number of scans of coupling system calculates;

T represents the minimum response time of display system.

Preferably, in described method, the step of the default weight C of subframe of described calculating comprises: when in the set situation of LED display system gray level G, determine that according to following formula subframe presets weight

$C=\frac{G}{m}.$

Preferably, in described method, the step of the weight of the whole n of a described structure data bit comprises: a) set the 1st weights W (the 1)～W (m) to m data bit; And b) according to relational expression W (n+1-i)=C-W (i), calculate weights W (the m+1)～W (n) of m+1 data bit to a n data bit; Wherein, be enough to lower formula if the weight of calculating is discontented, adjust the value of W (1)～W (m), repeating step a) and b),

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1.$

Preferably, in described method, describedly become the step of m subframe to comprise whole n data bit patterns: respectively W (i) and W (n+1-i) are combined into subframe, wherein i is more than or equal to 1 arbitrary integer.

According to a further aspect in the invention, a kind of gray scale display drive apparatus for light-emitting diode display is provided, comprise: position weight data generating device, position weights W (the 1)～W (n) that is used for whole n the data bit of calculating or storing a gradation data, wherein n is more than or equal to 2 integer; Sub-frame data generation module, for whole n data bit patterns are become to m subframe, wherein m is more than or equal to 1 integer, and the demonstration data-switching in vision signal is become to the data bit numerical value one to one of m subframe; And subframe signal output module, drive signal for the ground of subframe one by one output gray level, with the LED pixel of driving LED display, wherein, sub-frame data generation module makes the weight of each subframe be substantially equal to the default weight C of an identical subframe.

Preferably, in described gray scale display drive apparatus, the numerical range of the weight of each data bit in described whole n data bit is to be more than or equal to 0 and be less than or equal to the arbitrary integer of maximum gray scale.

Preferably, in described gray scale display drive apparatus, in a described m subframe, the number p of the data bit of each subframe can be identical or different, and wherein p is more than or equal to 1 integer.

Preferably, in described gray scale display drive apparatus, institute's rheme weight data generating device comprises a weights memory, and institute's rheme weights memory is pre-stored in outside position weights W (the 1)～W (n) that calculates whole n data bit that obtain of light-emitting diode display.

Preferably, in described gray scale display drive apparatus, institute's rheme weight data generating device comprises: subframe is preset weight computation module, for obtaining the predetermined refresh rate of display system, then calculates the default weight of subframe according to described refresh rate; Position weight builds module, for building position weights W (the 1)～W (n) of whole n data bit; System gray level computing module, for position weights W (1)～W (n) summation to whole n data bit, to calculate system gray level G; And gamma correction gray count module, for obtaining the demonstration data of vision signal, and calculate the gradation data after correction.

Preferably, in described gray scale display drive apparatus, the default weight computation module of described subframe determines that according to following formula subframe presets weight

$C=\frac{T\_\mathrm{FRAM}}{T}$

Wherein:

T_FRAM represents the time of a subframe, and according to the refresh rate index of the requirement of display system or user's expectation, the parameters such as clock frequency, number of scans of coupling system calculates;

T represents the minimum response time of display system.

Preferably, in described gray scale display drive apparatus, institute's rheme weight builds module the weights W (i) of any i data bit is met the following conditions:

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1.$

Preferably, in described gray scale display drive apparatus, institute's rheme weight data generating device comprises: subframe is preset weight computation module, for obtaining the predetermined gray level G of display system, then calculates the default weight of subframe according to described gray level; And position weight structure module, for building position weights W (the 1)～W (n) of whole n data bit.

Preferably, in described gray scale display drive apparatus, the default weight computation module of described subframe determines that according to following formula subframe presets weight

$C=\frac{G}{m}.$

Preferably, in described gray scale display drive apparatus, institute's rheme weight builds module the weights W (i) of any i data bit is met the following conditions:

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1.$

The present invention proposes a kind of novel gray scale display drive method and device.This gray scale display drive method and device can guarantee that the time span of each subframe is basically identical, improve uniformity of luminance.Utilize the subframe scheme of breaing up of the present invention to promote display effect.

Accompanying drawing explanation

By the description to the embodiment of the present invention referring to accompanying drawing, above-mentioned and other objects of the present invention, feature and advantage will be more clear, in the accompanying drawings:

Fig. 1 is the schematic block diagram of conventional LED display system;

Fig. 2 is according to the indicative flowchart of the gray scale display drive method for light-emitting diode display of the first embodiment of the present invention;

Fig. 3 is according to the schematic block diagram of the gray scale display drive apparatus for light-emitting diode display of second embodiment of the invention;

Fig. 4 is according to the schematic block diagram of the gray scale display drive apparatus for light-emitting diode display of third embodiment of the invention; And

Fig. 5 is according to the schematic block diagram of the gray scale display drive apparatus for light-emitting diode display of fourth embodiment of the invention.

Embodiment

Hereinafter with reference to accompanying drawing, various embodiment of the present invention is described in more detail.In each accompanying drawing, identical element adopts same or similar Reference numeral to represent.For the sake of clarity, the various piece in accompanying drawing is not drawn in proportion.

Fig. 1 is the schematic block diagram of conventional LED display system.LED display system comprises LED cell board 1 to the LED cell board N of LED display controller and N serial connection, and wherein N is more than or equal to 1 integer.Each LED cell board comprises A LED drive circuit, and each LED drive circuit is used for driving B LED, and wherein A and B are more than or equal to 1 integer.Therefore, this LED display system can drive N*A*B LED altogether.

LED display controller provides data-signal DATA to LED cell board 1, and provides one group of control signal to LED cell board 1 to LED cell board N respectively, comprises clock signal clk, latch signal LAT and enable signal EN.The first LED drive circuit on the one LED cell board 1 receives data-signal DATA from LED display controller, and exports data-signal DATA to next LED drive circuit on this cell board.Each LED drive circuit produces output signal according to data-signal DATA, makes corresponding LED light or extinguish according to the mode that timesharing shows by turn.

In conventional LED display system, the weight of bit data is general adopts 2 ⁿrepresent.Take 12 gradation datas as example, gradation data is designated as to D[0:11].Suppose that the corresponding effectively weights W [0] of displaying time of gradation data lowest order is 1, each bit data D[n] the corresponding effectively weights W [n] of displaying time is 2 ^n-1, as shown in table 1:

Table 1, the not weight of coordination of 12 gradation datas

Due to 12 gradation data D[0:11] numerical value can change between FFFH at 000H, therefore can realize 4095 grades of gray scales.

Suppose that effective displaying time that gradation data lowest order is corresponding is t, according to the weight of bit data, effective displaying time that each gradation data is corresponding is as shown in table 2:

Table 2, not effective displaying time corresponding to coordination of 12 gradation datas

In order further to improve the refresh rate that shows image, a two field picture can be divided into several subframes, subframe shows one by one.The duration length of each subframe is shorter, and refresh rate index is higher, effective displaying time corresponding bit data of high weight can be distributed in different subframes and (break up).In table 3, illustrate for a kind of common subframe of 12 gradation datas and broken up scheme.

Table 3,12 a kind of common subframes of gradation data are broken up scheme

As shown in table 3, the time span of each two field picture is 4095t.Break up through subframe, the time span of the 1st subframe is 1058t, and the time span of the 2nd subframe is 1032t, and the time span of the 3rd subframe is 1041t, and the time span of the 4th subframe is 964t.As can be seen here, the time span difference of each subframe is little.Although subframe is broken up the refresh rate that can improve display system, but still think that the duration of each subframe is long.In suc scheme, the refresh rate index of display system is not high.

In order to make light-emitting diode display system there is higher refresh rate, above-mentioned subframe can be carried out again to subframe and break up, take the 1st subframe in table 3 as example, subframe is broken up and is 3 timeslices again, as shown in table 4:

The subframe again of table 4, the 1st subframe is broken up

As shown in table 4, the time span of the 1st subframe is 1058t.Break up through subframe again, the time span of timeslice 1 is reduced to 514t, and the time span of timeslice 2 is reduced to 288t, and the time span of timeslice 3 is reduced to 256t.As can be seen here, the time span of each timeslice significantly reduces, and therefore can obtain higher refresh rate.But the time phase difference between each timeslice is excessive.In suc scheme, subframe is again broken up and is caused non-uniform light, thereby will affect display effect.

Fig. 2 is according to the indicative flowchart of the gray scale display drive method for light-emitting diode display of first embodiment of the invention.

In gray scale display drive method of the present invention, in order to show a two field picture, for each LED pixel, adopt a gradation data to show its gray level.

The data bit of total n the different weights of this gradation data, wherein n is more than or equal to 2 integer.The weight of each data bit represents with W (i), and the weight of 12 data bit is respectively W(1) to W(12).Unlike the prior art, the weights W of each data bit (i) needn't equal W (i)=2 ^i-1, but can select any integer value.For the data bit that makes n different weights can be expressed

level gray scale, the weights W (i) of i data bit need to satisfy condition:

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1---\left(2\right).$

Whole n data bit of a gradation data are dispersed into m subframe, and wherein m is more than or equal to 1 integer.In a subframe, comprise p data bit, wherein p is more than or equal to 1 integer.The number p that it should be noted that the data bit of each subframe can be identical or different.

As previously mentioned, the weights W of each data bit (i) needn't equal W (i)=2 ^i-1.Alternatively, the numerical range of the weight of each data bit is to be more than or equal to 0 and be less than or equal to the arbitrary integer of maximum gray scale.Preset the weights W of each data bit (i).The weight of each subframe is steady state value substantially, and position weights W (mi) sum of whole p data bit in each subframe is substantially equal to the default weight C of a subframe,

${\mathrm{\Σ}}_{\mathrm{mi}=1}^{p}W\left(\mathrm{mi}\right)\≈C---\left(3\right).$

In an example, the number p of the data bit of each subframe equals 2, and each subframe comprises two data bit.Therefore, described gradation data has even number data bit, wherein n=2*m.The set of data bits of the data bit of highest weighting W (n) and minimal weight W (1) is combined into a subframe, and the set of data bits of the data bit of inferior high weights W (n-1) and time little weights W (2) is combined into a subframe.The like, combination obtains m subframe altogether.Weights W (i) and the W (n+1-i) of i data bit and n+1-i data bit are combined into subframe weight: W (i)+W (n+1-i).In the present invention, the weight of different subframes is approximately equalised steady state value substantially, i.e. default weight C,

W(i)+W(n+1-i)≈C (4)。

In this example, comprise following multiple step for the gray scale display drive method of light-emitting diode display, to meet above-mentioned condition (2) and (4).

In step S01, determine that subframe presets weight C;

A), when in the set situation of LED display system refresh rate index, determine that according to following formula subframe presets weight

$C=\frac{T\_\mathrm{FRAM}}{T}---\left(5\right)$

Wherein:

T_FRAM represents the time of a subframe, can be according to the refresh rate index of the requirement of display system or user's expectation, and the parameters such as clock frequency, number of scans of coupling system calculates;

T represents the minimum response time of display system;

B), when in the set situation of LED display system gray level G, because m subframe meets weight sum W (i)+W (n+1-i) ≈ C of each subframe, therefore C*m ≈ G, calculates the default weight of subframe accordingly

$C=\frac{G}{m}---\left(6\right)$

In step S02, according to formula (2) and (4), build position weights W (the 1)～W (n) of whole n data bit.

In this step, set the 1st weights W (the 1)～W (m) to m data bit, make it meet formula (2).Then,, according to relational expression W (the n+1-i)=C-W (i) of formula (4) acquisition, calculate weights W (the m+1)～W (n) of m+1 data bit to a n data bit.Whether weights W (the m+1)～W (n) that further, judges m+1 data bit to a n data bit meets formula (2).If do not met formula (2), adjust the value of W (1)～W (m), re-execute this step, until all position weights W (the 1)～W (n) of n data bit all meets formula (2) and (4).

At step S03, at weights W (the 1)～W (n) that builds whole n data bit afterwards, calculate system gray level $G={\mathrm{\Σ}}_{i=1}^{n}W\left(i\right).$

In step S04, the gradation data y by after gray level result of calculation substitution gamma correction formula calculation correction:

$y=G*{\left(\frac{x}{255}\right)}^{\mathrm{\γ}}---\left(7\right)$

Wherein x represents that 8 of input show data DATA, and y is the gradation data after proofreading and correct, and γ is gamma value, and in light-emitting diode display application, codomain is generally 1 to 4.

In step S05, according to the gradation data y after proofreading and correct, select a suitable n data bit, make wherein D(i) be the gray scale digital value of i data bit, this digital value can be 1 or 0.

In step S06, in the time showing, the set of data bits of the data bit of highest weighting W (n) and minimal weight W (1) is combined into a subframe, the set of data bits of the data bit of inferior high weights W (n-1) and time little weights W (2) is combined into a subframe.The like, whole n data bit patterns are become to m subframe.

In step S07, carry out to subframe one by one the demonstration of corresponding data position.

Fig. 3 is according to the schematic block diagram of the gray scale display drive apparatus 100 for light-emitting diode display of second embodiment of the invention.In this embodiment, each subframe comprises two data bit.This gray scale display drive apparatus 100 is for example a part for the LED display controller shown in Fig. 1, for the gray scale display drive method shown in execution graph 2, provides timesharing by turn to show required data-signal DATA and enable signal EN to LED cell board.

Gray scale display drive apparatus 100 comprises that subframe is preset weight computation module 101, position weight builds module 102, system gray level computing module 103, gamma correction gray count module 104, sub-frame data generation module 105 and subframe signal output module 106.

The default weight computation module 101 of subframe is obtained the predetermined refresh rate of display system, then calculates the default weight of subframe according to formula (5).The default weight computation module 101 of subframe will be preset weight C and offer a weight structure module 102.

According to above-mentioned formula (2) and (4), position weight structure module 102 builds position weights W (the 1)～W (n) of whole n data bit.Position weight builds module 102 the data bit weight of its structure is offered to system gray level computing module 103.

Set the 1st weights W (the 1)～W (m) to m data bit, make it meet formula (2).Then,, according to relational expression W (the n+1-i)=C-W (i) of formula (4) acquisition, calculate weights W (the m+1)～W (n) of m+1 data bit to a n data bit.Whether weights W (the m+1)～W (n) that further, judges m+1 data bit to a n data bit meets formula (2).If do not met formula (2), adjust the value of W (1)～W (m), re-execute this step, until all position weights W (the 1)～W (n) of n data bit all meets formula (2) and (4).

In system gray level computing module 103, to position weights W (1)～W (n) summation of whole n data bit, to calculate system gray level G.Then, system gray level G is offered gamma correction gray count module 104 by system gray level computing module 103.

In gamma correction gray count module 104, obtain the demonstration data in vision signal, calculate the gradation data y after correction according to above-mentioned formula (7).Then, the gradation data y after proofreading and correct is offered sub-frame data generation module 105 by gamma correction gray count module 104.

In sub-frame data generation module 105, the set of data bits of the data bit of highest weighting W (n) and minimal weight W (1) is combined into a subframe, and the set of data bits of the data bit of inferior high weights W (n-1) and time little weights W (2) is combined into a subframe.The like, whole n data bit patterns are become

individual subframe.Sub-frame data generation module 105 also becomes the demonstration data-switching in vision signal the data bit numerical value one to one with m subframe.Then, the data of each subframe are offered subframe signal output module 106 by sub-frame data generation module 105.

In subframe signal output module 106, subframe ground output gray level drives signal one by one, with the LED on driving LED unit.This gray scale drives signal for example to comprise subframe gradation data DATA and the enable signal EN of corresponding subframe.For every bit data, the corresponding high level lasting time of enable signal EN and the weight of this bit data are proportional.

Fig. 4 is according to the schematic block diagram of the gray scale display drive apparatus 200 for light-emitting diode display of third embodiment of the invention.In this embodiment, each subframe comprises two data bit.This gray scale display drive apparatus 200 is for example a part for the LED display controller shown in Fig. 1, for the gray scale display drive method shown in execution graph 2, provides timesharing by turn to show required data-signal DATA and enable signal EN to LED cell board.

Gray scale display drive apparatus 200 comprises that subframe is preset weight computation module 201, position weight builds module 202, sub-frame data generation module 205 and subframe signal output module 206.

The default weight computation module 201 of subframe is obtained the predetermined gray level of display system (for example 4096 gray levels), then calculates the default weight of subframe according to formula (6).The default weight computation module 201 of subframe will be preset weight C and offer a weight structure module 202.

According to above-mentioned formula (2) and (4), position weight structure module 202 builds position weights W (the 1)～W (n) of whole n data bit.Position weight builds module 202 the data bit weight of its structure is offered to sub-frame data generation module 205.

In sub-frame data generation module 205, the set of data bits of the data bit of highest weighting W (n) and minimal weight W (1) is combined into a subframe, and the set of data bits of the data bit of inferior high weights W (n-1) and time little weights W (2) is combined into a subframe.The like, whole n data bit patterns are become

individual subframe.Sub-frame data generation module 205 also obtains the demonstration data in vision signal, converts thereof into the data bit numerical value one to one with m subframe.Then, the data of each subframe are offered subframe signal output module 206 by sub-frame data generation module 205.

In subframe signal output module 206, subframe ground output gray level drives signal one by one, with the LED on driving LED unit.This gray scale drives signal for example to comprise subframe gradation data DATA and the enable signal EN of corresponding subframe.For every bit data, the corresponding high level lasting time of enable signal EN and the weight of this bit data are proportional.

Fig. 5 is according to the schematic block diagram of the gray scale display drive apparatus 300 for light-emitting diode display of fourth embodiment of the invention.In this embodiment, each subframe comprises two data bit.This gray scale display drive apparatus 300 is for example a part for the LED display controller shown in Fig. 1, for the gray scale display drive method shown in execution graph 2, provides timesharing by turn to show required data-signal DATA and enable signal EN to LED cell board.

Gray scale display drive apparatus 300 comprises a weights memory 307, sub-frame data generation module 305 and subframe signal output module 306.

In weights memory 307 in place, the data of position weights W (the 1)～W (n) of whole n the data bit that storage builds in advance.For example, can obtain the predetermined refresh rate of display system, calculate the default weight of subframe according to formula (5).Or, alternatively, can obtain the predetermined gray level of display system (for example 4096 gray levels), calculate the default weight of subframe according to formula (6).Then, build position weights W (the 1)～W (n) of whole n data bit according to formula (2) and (4).At position weights W (the 1)～W (n) that builds whole n data bit afterwards, be stored in the position weights memory 307 of gray scale display drive apparatus 300.Can, in the calculation element of outside display, carry out the operation of the data of position weights W (the 1)～W (n) of whole n data bit that build in advance, then these data be stored in weights memory 307 in place.Therefore, the part using position weights memory 307 as gray scale display drive apparatus 300 only.

In sub-frame data generation module 305, the set of data bits of the data bit of highest weighting W (n) and minimal weight W (1) is combined into a subframe, and the set of data bits of the data bit of inferior high weights W (n-1) and time little weights W (2) is combined into a subframe.The like, whole n data bit patterns are become

individual subframe.Sub-frame data generation module 305 also obtains the demonstration data in vision signal, converts thereof into the data bit numerical value one to one with m subframe.Then, the data of each subframe are offered subframe signal output module 306 by sub-frame data generation module 305.

In subframe signal output module 306, subframe ground output gray level drives signal one by one, with the LED on driving LED unit.This gray scale drives signal for example to comprise subframe gradation data DATA and the enable signal EN of corresponding subframe.For every bit data, the corresponding high level lasting time of enable signal EN and the weight of this bit data are proportional.

Although described gray scale display drive apparatus in the second to the 4th above-mentioned embodiment, whole n data bit of a gradation data are dispersed into m subframe, and comprise two data bit in a subframe.But, the invention is not restricted to this, the number of the data bit of each subframe can be identical or different, and can be to be more than or equal to 1 arbitrary integer.Even under the different situation of the number of the data bit of each subframe, also can build according to above-mentioned formula (2) and (3) position weights W (the 1)～W (n) of whole n data bit.

Gray scale display drive method and the drive unit of above-described embodiment, both the performance index such as refresh rate, gray level that LED display system improves be day by day well positioned to meet, the time span that guarantees again each subframe is basically identical, has promoted system display performance and display effect.

According to embodiments of the invention as described above, these embodiment do not have all details of detailed descriptionthe, and also not limiting this invention is only described specific embodiment.Obviously, according to above description, can make many modifications and variations, for example, change the weight number in each subframe.These embodiment are chosen and specifically described to this instructions, is in order to explain better principle of the present invention and practical application, thereby under making, technical field technician can utilize the present invention and the modification on basis of the present invention to use well.Protection scope of the present invention should be as the criterion with the scope that the claims in the present invention were defined.

Claims (19)

1. for a gray scale display drive method for light-emitting diode display, comprising:

Whole n data bit of a gradation data are divided into m subframe, and wherein n is more than or equal to 2 integer, and m is more than or equal to 1 integer;

Calculate the default weight C of a subframe;

Build the weight of whole n data bit, make its combination can show whole gray levels;

Whole n data bit patterns are become to m subframe, make the weight of each subframe be substantially equal to the default weight of described subframe; And

Carry out to subframe one by one the demonstration of corresponding data position.

2. gray scale display drive method according to claim 1, wherein, the numerical range of the weight of each data bit in described whole n data bit is to be more than or equal to 0 and be less than or equal to the arbitrary integer of maximum gray scale.

3. gray scale display drive method according to claim 1, wherein, in a described m subframe, the number p of the data bit of each subframe can be identical or different, and wherein p is more than or equal to 1 integer.

4. gray scale display drive method according to claim 3, wherein, the number p of the data bit of each subframe equals 2.

5. according to the gray scale display drive method described in any one in claim 1 to 4, wherein, in the step of weight that builds whole n data bit, the weights W (i) of any i data bit is met the following conditions:

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1.$

6. according to the gray scale display drive method described in any one in claim 1 to 4, wherein, the step of the default weight C of subframe of described calculating comprises:

When in the set situation of LED display system refresh rate index, determine that according to following formula subframe presets weight

$C=\frac{T\_\mathrm{FRAM}}{T}$

Wherein:

T_FRAM represents the time of a subframe, and according to the refresh rate index of the requirement of display system or user's expectation, the parameters such as clock frequency, number of scans of coupling system calculates;

T represents the minimum response time of display system.

7. according to the gray scale display drive method described in any one in claim 1 to 4, wherein, the step of the default weight C of subframe of described calculating comprises:

When in the set situation of LED display system gray level G, determine that according to following formula subframe presets weight

$C=\frac{G}{m}.$

8. gray scale display drive method according to claim 4, wherein, the step of the weight of the whole n of a described structure data bit comprises:

A) set the 1st weights W (the 1)～W (m) to m data bit; And

B), according to relational expression W (n+1-i)=C-W (i), calculate weights W (the m+1)～W (n) of m+1 data bit to a n data bit;

Wherein, be enough to lower formula if the weight of calculating is discontented, adjust the value of W (1)～W (m), repeating step a) and b)

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1.$

9. gray scale display drive method according to claim 7, wherein, describedly becomes the step of m subframe to comprise whole n data bit patterns:

Respectively W (i) and W (n+1-i) are combined into subframe, wherein i is more than or equal to 1 arbitrary integer.

10. for a gray scale display drive apparatus for light-emitting diode display, comprising:

Position weight data generating device, for calculating or store position weights W (the 1)～W (n) of whole n data bit of a gradation data, wherein n is more than or equal to 2 integer;

Sub-frame data generation module, for whole n data bit patterns are become to m subframe, wherein m is more than or equal to 1 integer, and the demonstration data-switching in vision signal is become to the data bit numerical value one to one of m subframe; And

Subframe signal output module, drives signal for the ground of subframe one by one output gray level, with the LED pixel of driving LED display,

Wherein, sub-frame data generation module makes the weight of each subframe be substantially equal to the default weight C of an identical subframe.

11. gray scale display drive apparatus according to claim 10, wherein, the numerical range of the weight of each data bit in described whole n data bit is to be more than or equal to 0 and be less than or equal to the arbitrary integer of maximum gray scale.

12. gray scale display drive apparatus according to claim 10, wherein, in a described m subframe, the number p of the data bit of each subframe can be identical or different, and wherein p is more than or equal to 1 integer.

13. according to claim 10 to the gray scale display drive apparatus described in any one in 12, wherein said position weight data generating device comprises a weights memory, and institute's rheme weights memory is pre-stored in outside position weights W (the 1)～W (n) that calculates whole n data bit that obtain of light-emitting diode display.

14. according to claim 10 to the gray scale display drive apparatus described in any one in 12, and wherein said position weight data generating device comprises:

Subframe is preset weight computation module, for obtaining the predetermined refresh rate of display system, then calculates the default weight of subframe according to described refresh rate;

Position weight builds module, for building position weights W (the 1)～W (n) of whole n data bit;

System gray level computing module, for position weights W (1)～W (n) summation to whole n data bit, to calculate system gray level G; And

Gamma correction gray count module, for obtaining the demonstration data of vision signal, and calculates the gradation data after correction.

15. gray scale display drive apparatus according to claim 14, the default weight computation module of wherein said subframe determines that according to following formula subframe presets weight

$C=\frac{T\_\mathrm{FRAM}}{T}$

Wherein:

T_FRAM represents the time of a subframe, and according to the refresh rate index of the requirement of display system or user's expectation, the parameters such as clock frequency, number of scans of coupling system calculates;

T represents the minimum response time of display system.

16. gray scale display drive apparatus according to claim 14, wherein said position weight builds module the weights W (i) of any i data bit is met the following conditions:

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1.$

17. according to claim 10 to the gray scale display drive apparatus described in any one in 12, and wherein said position weight data generating device comprises:

Subframe is preset weight computation module, for obtaining the predetermined gray level G of display system, then calculates the default weight of subframe according to described gray level; And

Position weight builds module, for building position weights W (the 1)～W (n) of whole n data bit.

18. gray scale display drive apparatus according to claim 17, the default weight computation module of wherein said subframe determines that according to following formula subframe presets weight

$C=\frac{G}{m}.$

19. gray scale display drive apparatus according to claim 17, wherein said position weight builds module the weights W (i) of any i data bit is met the following conditions:

$W\left(i\right)\≤{\mathrm{\Σ}}_{j=1}^{i-1}W\left(j\right)+1.$

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