CN100409290C - Digitally driven type display device - Google Patents
Digitally driven type display device Download PDFInfo
- Publication number
- CN100409290C CN100409290C CNB028249569A CN02824956A CN100409290C CN 100409290 C CN100409290 C CN 100409290C CN B028249569 A CNB028249569 A CN B028249569A CN 02824956 A CN02824956 A CN 02824956A CN 100409290 C CN100409290 C CN 100409290C
- Authority
- CN
- China
- Prior art keywords
- voltage
- transistor
- value
- pixel
- display device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Abstract
A digitally driven type organic EL display device equipped with a display panel comprising pixels 51. Each pixel 51 comprises an organic EL element 50, a driving transistor TR2 for switching on/off power supply to the organic EL element 50 in response to the input of an on/off control signal, writing transistor TR1 which turns on by the impressing of a scanning voltage from a scanning driver, capacitor C on which a data voltage is impressed from a data driver under the on-state of the write transistor TR1, and comparator 9 that compares a predetermined lamp voltage with the output voltage of the capacitor C and supplies the result to the drive transistor TR2 as an on/off control signal.
Description
Technical field
The present invention relates to have the display device of the display screen that a plurality of pixels are constituted with rectangular arrangement such as organic el display etc.
Background technology
In recent years, just carrying out exploitation to organic electroluminescence display (below, be called OLED display), and to for example in portable telephone, adopting OLED display to study.
As Figure 33 and shown in Figure 34, OLED display (1) clips organic luminous layer (14) and disposes organic hole transporting layer (15) and organic electronic transfer layer (16) and form organic layer (13) on glass substrate (11), simultaneously at the both sides of this organic layer (13) configuration anode (12) and negative electrode (17), and, make organic luminous layer (14) luminous by between anode (12) and negative electrode (17), applying predetermined voltage.
(indium tin oxide: indium tin oxide) be material, negative electrode (17) is a material with the Al-Li alloy for example to anode (12), forms with strip respectively and be configured to matrix on the direction that crosses one another with transparent ITO.In addition, anode (12) uses as data electrode, negative electrode (17) uses as scan electrode, by a selecteed state of scan electrode to extend in the horizontal direction, apply the voltage corresponding on each data electrode of Yan Shening in vertical direction with importing data, make organic layer (13) luminous in the point of crossing of this scan electrode and each data electrode, thereby carry out the demonstration of a line.Then, by scan electrode is switched to vertical direction successively, scan in vertical direction, thereby carry out the demonstration of a frame.
As the type of drive of such OLED display, known to carry out passive matrix that timesharing drives just like above-mentioned use scan electrode and data electrode driving and keep the luminous active matrix drive-type of each pixel in a vertical-scan period.As shown in Figure 4, in the OLED display of active matrix drive-type, each pixel (52) has disposed the organic EL (50) that the part by organic layer constitutes; Control is to the driving transistor T R2 of the energising of organic EL (50); Applying of scanning voltage SCAN on the responding scanning electrode and become writing of conducting state and use transistor T R1; And write with transistor T R1 by this and to become that conducting state is applied in from the data voltage DATA of data electrode and the capacity cell C of stored charge, the output voltage of this capacity cell C is applied on the grid that drives with transistor T R2.
At first, apply voltage successively, make a plurality of the first transistor TR1 that are connected with same scan electrode become conducting state, and apply data voltage (input signal) to each data electrode with this scan-synchronized ground to each scan electrode.At this moment, the first transistor TR1 is a conducting state, so this data voltage is stored among the capacity cell C.
Then, determine the duty of transistor seconds TR2 according to the quantity of electric charge of the data voltage of being stored among this capacity cell C.For example, when transistor seconds TR2 conducting, the electric current of corresponding size with data voltage is supplied with to organic EL (50) through this transistor seconds TR2.This organic EL (50) is lighted with the brightness corresponding with data voltage as a result.This illuminating state keeps a vertical-scan period.
As mentioned above, for supplying with corresponding big or small electric current to organic EL (50) and making the OLED display of this organic EL (50), proposed to show the digitally driven type OLED display (for example the Japanese patent gazette spy opens flat 10-312173 number) of many gray scales here by the pulse current that has the dutycycle corresponding to organic EL (50) supply with data voltage in the analog-driven mode lighted with the data voltage corresponding brightness with data voltage.
Shown in Fig. 6 (a), in the digitally driven type OLED display, display cycle of a picture promptly is divided into a plurality of (N) subdomain (perhaps subframe) SF in a territory (perhaps frame), each subdomain SF is by constituting between scan period and light emission period.Here, all scan periods that the territory comprised have identical length, but between light emission period with 2 n power (n=0,1,2 ... length variations N-1).In illustrated example (N=4), be set to 8,4,2,1 length between four light emission periods respectively, can show 16 gray scales by the conduction and cut-off between each light emission period.
In above-mentioned subdomain drives, in the scan period of each subdomain SF, writing with transistor T R1 of each pixel (53) applies scanning voltage to constituting as shown in Figure 5, write the binary data of this subdomain to capacity cell C, between light emission period thereafter, by driving with transistor T R2 according to binary data to organic EL (50) supplying electric current.And, in subdomain drives, by on the line of driving that constitutes each pixel (53) as shown in Figure 5, on/off switch SW being set, can make the EL element (50) of each pixel and the luminous zero hour and luminous finish time in each subdomain keep synchronous with transistor T R2 supplying electric current.
But, having adopted above-mentioned subdomain to drive in the OLED display of method, in a territory, comprise in each subdomain of a plurality of subdomains, need scan all horizontal scanning lines, therefore there is following problem:, profile takes place perhaps to intend along with many gray processings need carry out scanning at a high speed.
Therefore the objective of the invention is to, provide a kind of and need not, and do not intend the digitally driven type display device of profile to many gray processings carry out scanning at a high speed.
Summary of the invention
Relevant organic EL display of the present invention connects scanner driver on the display screen that constitutes with a plurality of pixels of rectangular arrangement and data driver constitutes.Wherein, each pixel of display screen is provided with:
Accept the supply and the luminous display element of curtage;
Be applied in from the scanning voltage of scanner driver and become the write element of conducting state;
Become conducting state by write element and be applied in data voltage, and keep the voltage keeping part spare of this voltage from data driver; And
Only with the voltage swing time corresponding that remains in the described voltage keeping part spare in, to the driver part of described display element supplying electric current or voltage.
Specifically, described driver part relatively has the ramp voltage of predetermined change curve and the output voltage of described voltage keeping part spare, and according to this result to described display element supplying electric current or voltage.For example, described driver part can be made of following element:
According to the input of on signal, on/off is to the driving element of the energising of described display element; And
Relatively have the ramp voltage of predetermined change curve and the output voltage of described voltage keeping part spare, and will represent that its result's output signal supplies with the comparing element of described driving element as the on signal.
In the digitally driven type display device of the invention described above, in scan period in the display cycle of a picture, the scanning voltage of the driver of self-scanning in the future is applied on the write element that constitutes each pixel, make write element become conducting state, thereby on voltage keeping part spare, apply data voltage, keep this voltage from data driver.
On the other hand, between the light emission period in the display cycle of a picture in, the ramp voltage with predetermined change curve is applied on the comparing element, the output voltage (data voltage) of more described ramp voltage of this comparing element and voltage keeping part spare.Here, ramp voltage changes with predetermined change curve, therefore, is being inverted with the big or small moment corresponding ramp voltage of data voltage and the magnitude relationship of data voltage.Therefore, the output signal of comparing element only during corresponding with data voltage, is got the arbitrary value in high level or the low level.That is to say, data voltage is carried out pulse-length modulation, thereby generate on signal driving element.By this on signal, driving element is switched on/disconnects control, thereby on/off is to the energising of display element.
Specifically, display element is an organic EL, is provided with in the display cycle of a picture between a scan period and light emission period; In scan period, by scanner driver the write element of each pixel is applied scanning voltage, in the voltage keeping part spare of each pixel, keep data voltage; Between light emission period, by the output voltage of more described ramp voltage of comparing element and voltage keeping part spare, on/off is to the energising of the organic EL of each pixel.
In concrete structure, ramp voltage can irrespectively make between the output signal of first value that driving element often connects and comparing element and second value that data voltage irrespectively makes driving element often disconnect at the output signal of comparing element and data voltage and change, in the display cycle of a picture, keep second value in scan period, in between the light emission period beyond scan period, between first value and second value, change.Therefore, in scan period, driving element disconnects, and the energising of organic EL is often disconnected.In between the light emission period beyond scan period, driving element is only connected during corresponding with data voltage, connects the energising to organic EL.
For example, ramp voltage has the change curve of increasing or decreasing between described first value and second value, is the occasion of straight line at this change curve, can be only with time that is in proportion of data voltage in make organic EL luminous.If change curve is arbitrary curve, then can adjust the fluorescent lifetime with the big or small corresponding organic EL of data voltage arbitrarily, if adopt the change curve of for example having considered the γ correction, then need not to be provided with in addition checking gamma circuit, can carry out required γ correction.
In addition, be back to the change curve of a described value again through another value if adopt in first value and second value from a value, then can be in the display cycle of a picture, the middle body between scan period light emission period in addition makes organic EL luminous.
In addition, can adopt following structure: in a plurality of levels or perpendicular line that constitute a picture, the ramp voltage that is arranged in the pixel on the odd number line is had the change curve that a value from described first value and second value is changed to another value, the ramp voltage that is arranged in the pixel on the even number line is had the change curve that is changed to a described value from described another value.According to this structure, be arranged in the organic EL of the pixel on the odd number line luminous during and be arranged in the organic EL of the pixel on the even number line luminous during skew mutually, therefore, the total amount of the electric current that flows through a plurality of organic ELs that constitute a picture is disperseed in time.
In addition, can adopt following structure: in a plurality of levels or perpendicular line that constitute a picture, the ramp voltage that is arranged in the pixel on a kind of color line in the three primary colors is had the change curve that a value from described first value and second value is changed to another value, the ramp voltage that is arranged in the pixel on other two kinds of color lines is had the change curve that is changed to a described value from described another value.According to this structure, be arranged in the organic EL of the pixel on described a kind of color line luminous during and be arranged in the organic EL of the pixel on described other two kinds of color lines luminous during skew mutually, therefore, the total amount of the electric current that flows through a plurality of organic ELs that constitute a picture is disperseed in time.
In addition, can adopt following structure: in a plurality of levels or perpendicular line that constitute a picture, be arranged in the pixel on the odd number line and be arranged between the pixel on the even number line, scan period and the order between light emission period in the display cycle of a picture are alternate with each other.According to this structure, be arranged in the organic EL of the pixel on the odd number line luminous during and be arranged in the organic EL of the pixel on the even number line luminous during during the demonstration of a picture first-half period and be offset between latter half, therefore, the total amount of the electric current that flows through a plurality of organic ELs that constitute a picture is disperseed in time.
In addition, can adopt following structure: in constituting a plurality of levels or perpendicular line of a picture, to rate of change (inclinations) difference on each color of the ramp voltage that is arranged in the pixel on the shades of colour line in the three primary colors.According to this structure, in constituting a plurality of levels or perpendicular line of a picture,, can make rate of change between the light emission period corresponding by every kind of color with data voltage for the pixel on the shades of colour line that is arranged in the three primary colors, therefore can adjust white balance.
As mentioned above, according to relevant digitally driven type display device of the present invention,, can carry out many gray scale performances by in the display cycle of a picture, all horizontal scanning lines being carried out single pass, therefore, need not to carry out scanning at a high speed and can not intend profile.
The simple declaration of accompanying drawing
Fig. 1 is the block diagram of the structure of the relevant organic EL display of the present invention of expression.
Fig. 2 is the block diagram of another structure of the relevant organic EL display of the present invention of expression.
Fig. 3 is the circuit diagram of each pixel that constitutes the display screen of organic EL display of the present invention.
Fig. 4 is the circuit diagram that constitutes each pixel of traditional active matrix drive-type OLED display.
Fig. 5 is the circuit diagram that constitutes each pixel of the OLED display that adopts subdomain to drive method.
Fig. 6 is scan period among expression tradition and the present invention and the timing between light emission period, and the figure of the various waveform examples of the ramp voltage among the present invention.
Fig. 7 is the scan period of expression among the present invention and the figure of another waveform example of timing between light emission period and ramp voltage.
Fig. 8 be expression among the present invention scan period and the figure of another waveform example of timing between light emission period and ramp voltage.
Fig. 9 be expression among the present invention scan period and the figure of another waveform example of timing between light emission period and ramp voltage.
Figure 10 is the circuit diagram of the concrete structure of expression comparer.
Figure 11 is the oscillogram of the action of this comparer of expression.
Figure 12 is the circuit diagram of another concrete structure of expression comparer.
Figure 13 is the circuit diagram of another concrete structure of expression comparer.
Figure 14 is the circuit diagram of another concrete structure of expression comparer.
Figure 15 is the circuit diagram of another concrete structure of expression comparer.
Figure 16 is the circuit diagram of another concrete structure of expression comparer.
Figure 17 is the circuit diagram of another concrete structure of expression comparer.
Figure 18 is the circuit diagram of another concrete structure of expression comparer.
Figure 19 is the oscillogram of the action of this comparer of expression.
Figure 20 is the circuit diagram of another concrete structure of expression comparer.
Figure 21 is the oscillogram of the action of this comparer of expression.
Figure 22 is the figure that expression is built in the concrete structure of the slope voltage generating circuit in the pixel.
Figure 23 is the oscillogram of the action of this slope voltage generating circuit of expression.
Figure 24 is the figure that expression is built in another concrete structure of the slope voltage generating circuit in the pixel.
Figure 25 is the oscillogram of the action of this slope voltage generating circuit of expression.
Figure 26 is the figure that expression is built in another concrete structure of the slope voltage generating circuit in the pixel.
Figure 27 is the oscillogram of the action of this slope voltage generating circuit of expression.
Figure 28 is the circuit diagram that makes the pixel that the level of ramp voltage changes according to data voltage.
Figure 29 is the oscillogram of the action of this circuit of expression.
Figure 30 is the block diagram of structure of the organic EL display of the expression phase deviation that makes ramp voltage by each horizontal line.
Figure 31 is the oscillogram of the action of this organic EL display of expression.
Figure 32 is the scan period of expression among the present invention and the figure of another waveform example of timing between light emission period and ramp voltage.
Figure 33 is the figure of the stepped construction of expression passive matrix drive organic EL display.
Figure 34 is the biopsy cavity marker devices skeleton view of passive matrix drive organic EL display.
Preferred forms of the present invention
Below, with reference to the accompanying drawings, just implemented organic EL display of the present invention and be described in detail.As shown in Figure 1, relevant organic EL display of the present invention connects scanner driver (3) and data driver (4) and constitutes on the display screen (5) that constitutes with a plurality of pixels of rectangular arrangement.From the vision signal supplying video signal processing circuit (6) that video source such as TV receiver are supplied with, to carry out image and show required signal Processing, the RGB three primary colors vision signal that obtains is thus supplied with the data driver (4) of OLED display (2).
In addition, the horizontal-drive signal H sync and the vertical synchronizing signal V sync that obtain from video processing circuit (6) supply with timing signal generation circuit (7), and the timing signal that obtains is thus supplied with scanner driver (3) and data driver (4).In addition, supply with slope voltage generating circuit (8) from the timing signal that timing signal generation circuit (7) obtains, generate the ramp voltage that is used for OLED display (2) driving as described later thus, this ramp voltage is supplied with each pixel of display screen (5).And, on each circuit shown in Fig. 1, each driver and OLED display, connected power circuit (diagram is omitted).
Display screen (5) constitutes with the pixel (51) of circuit structure shown in the rectangular Pareto diagram 3.Each pixel (51) is provided with the organic EL (50) that is made of organic layer; According to the input to the on signal of grid, on/off is to the driving transistor T R2 of the energising of organic EL (50); Be applied on the grid and become writing of conducting state from the scanning voltage of described scanner driver and use transistor T R1; Become conducting state with transistor T R1 and be applied in capacity cell C by writing from the data voltage of described data driver; And the ramp voltage of supplying with from described slope voltage generating circuit and the output voltage of capacity cell C supply with positive and negative pair of input terminals, and the comparer (9) of two voltages relatively, and the output signal of comparer (9) is supplied with the grid that drives with transistor T R2.
The source electrode that drives with transistor T R2 is connected with electric current supplying wire (54), and the drain electrode that drives with transistor T R2 is connected with organic EL (50).An electrode (for example source electrode) that writes with transistor T R1 is connected with described data driver, and another electrode (for example drain electrode) that writes with transistor T R1 is connected with the end of capacity cell C, is connected with the reversed input terminal of comparer (9) simultaneously.Non-inverting input of comparer (9) is connected with the lead-out terminal of described slope voltage generating circuit (8).
Shown in Fig. 6 (b), in above-mentioned OLED display (2), before being divided into during territory between half scan period and later half light emission period.In scan period, for each horizontal line, constitute each pixel (51) write with transistor T R1 on apply scanning voltage from scanner driver, write with transistor T R1 and become conducting state, thus, apply the data voltage from data driver on the capacity cell C, this voltage is as charge storage.As a result, the data of a territory share all pixels that constitute OLED display (2) have been set.
In addition, shown in Fig. 6 (c), ramp voltage takes place in slope voltage generating circuit (8) during each territory, and this ramp voltage is kept high-voltage value in preceding half scan period, is changed to high-voltage value from the low voltage value straight line between later half light emission period.In preceding half scan period, be applied to non-inverting input of comparer (9) by high voltage from slope voltage generating circuit (8), shown in Fig. 6 (d), irrelevant with the input voltage of reversed input terminal, the output of comparer (9) is always high level.
In addition, in between later half light emission period, be applied to non-inverting input of comparer (9) from the ramp voltage of slope voltage generating circuit (8), the output voltage (data voltage) of capacity cell C is applied to the reversed input terminal of comparer (9) simultaneously, shown in Fig. 6 (d), the output of comparer (9) is got low level and these two values of high level according to the comparative result of two voltages thus.That is to say, ramp voltage be below the data voltage during, the output of comparer becomes low level, during ramp voltage exceeded data voltage, the output of comparer became high level.Here, comparer be output as low level during length, with being in proportion of data voltage.
Like this, the output of comparer (9) only with data voltage be in proportion during in become low level, thereby drive only conducting in during this period with transistor T R2, and connected energising to organic EL (50).As a result, constitute the organic EL (50) of each pixel (51) of display screen (5), only during a territory in to the data voltage of each pixel (51) be in proportion during in luminous, thereby realized that many gray scales show.
As mentioned above, according to relevant organic EL display of the present invention,, therefore, need not to carry out scanning at a high speed, and can not intend profile (quasi-contours) owing to only can carry out many gray scales performances by carrying out single pass in during a territory.In addition,, therefore, be difficult to be driven characteristic deviation influence with transistor T R2 because relevant organic EL display of the present invention has adopted the digital drive mode, and, can realize the low consumption electrification by the reduction of supply voltage.
Moreover in the above-described embodiments, the change curve of ramp voltage is the straight line of augment direction, but also can at random adjust fluorescent lifetime with the big or small corresponding organic EL (50) of data voltage by adopting curve arbitrarily.For example among Fig. 6 (e) 1. shown in, if adopt the change curve considered that γ proofreaies and correct, then need not to be provided with in addition checking gamma circuit, can carry out necessary γ and proofread and correct.
In addition, as among Fig. 6 (e) 2. shown in, the inclination negate by with the change curve of ramp voltage can be provided with between light emission period at the latter half during the slope.In addition, in the occasions that make two of comparer (9) the positive and negative counter-rotatings of input, in Fig. 6 (e) 3. or 4., the positive and negative counter-rotating of ramp voltage is got final product.In addition, as among Fig. 6 (e) 5. shown in, again be back to low level triangle wavy change curve from low level through high level if the change curve of ramp voltage adopts, then can make the middle body of organic EL (50) during the slope luminous.
In addition, as Fig. 7 (a) (b) shown in, in the level or perpendicular line during a territory, change by making with the positive and negative opposite change curve of rate of change to the ramp voltage that is arranged in the pixel on the odd number line with to the ramp voltage that is arranged in the pixel on the even number line, can with the organic EL that is arranged in the pixel on the odd number line luminous during and be arranged in the organic EL of the pixel on the even number line luminous during skew mutually.Therefore, the total amount of the electric current that flows through a plurality of organic ELs that constitute a picture is disperseed in time.
In addition, shown in Fig. 7 (c), change by making with the positive and negative opposite change curve of rate of change, the total amount of the electric current that flows through a plurality of organic ELs that constitute a picture is disperseed in time to the ramp voltage of the pixel on the line that is arranged in a kind of color (for example G) in the RGB three primary colors with to the ramp voltage of the pixel on the line that is arranged in other two kinds of colors (for example R and B).
In addition, as Fig. 8 (a) (b) shown in, in a plurality of levels or perpendicular line that constitute a picture, by making, can make between the light emission period that is arranged in the pixel on the odd number line and to only being offset for two/one-period mutually between the light emission period that is arranged in the pixel on the even number line to during the territory that is arranged in the pixel on the odd number line and to only being offset for two/one-period mutually during the territory that is arranged in the pixel on the even number line.Thus, the total amount of the electric current that flows through a plurality of organic ELs that constitute a picture is disperseed in time.In addition, sweep velocity is descended.
In addition, as Figure 32 (a) (b) shown in, can make between the scan period of each RGB and light emission period to be offset, therefore, the magnitude of current is disperseed, change ramp voltage by each RGB simultaneously.
In addition, as Fig. 9 (a) (b) shown in, for the pixel that is arranged on the trichromatic shades of colour line of RGB, by by the rate of change (inclination) of every kind of color change ramp voltage, can make rate of change between the light emission period corresponding by every kind of color, therefore can adjust white balance with data voltage.In this occasion, as shown in Figure 2,, R slope voltage generating circuit (81), G slope voltage generating circuit (82) and B slope voltage generating circuit (83) are set at trichromatic shades of colour line.
Figure 10 represents the concrete structure of comparer (9).As shown in the figure, comparer (9) is made of a plurality of transistor T R3～TR7.Apply constant voltage at the grid of transistor T R3, constitute constant current source from supplied with constant voltage line CONST.On the grid of transistor T R4, apply the output voltage (data voltage) of capacitor C, on the grid of transistor T R5, apply ramp voltage.Transistor T R6 and TR7 bring into play the function as resistance respectively.Exceed in the state of ramp voltage at data voltage, flow through electric current among the transistor T R4, comparer output becomes high level, exceeds in the state of data voltage at ramp voltage, flows through electric current among the transistor T R5, and comparer output becomes low level.
In above-mentioned comparer (9), as shown in figure 11, after data voltage changed in scan period, the value of ramp voltage rises between light emission period gradually, ramp voltage exceeds data voltage, thereby comparer output converts low level to from high level, drive the conducting with transistor T R2, organic EL flows through electric current in (50).
Comparer shown in Figure 12 (9) has omitted the transistor T R6 as resistance components shown in Figure 10.Same ramp voltage exceeds data voltage by this comparer (9), thereby comparer output converts low level to from high level, drives the conducting with transistor T R2, and organic EL flows through electric current in (50).
Comparer shown in Figure 13 (9) changes to the wiring state of the pair of transistor TR6 as resistance components shown in Figure 10, TR7 as shown in the figure.Also can access identical functions by this comparer (9).
Comparer shown in Figure 14 (9) will become the transistor T R of the constant current source shown in Figure 10 and as the positive and negative counter-rotating of configuration of pair of transistor TR6, the TR7 of resistance components, be configured as the transistor T R3 ' of constant current source at side of the positive electrode, at transistor T R6 ', the TR7 ' of negative side configuration as resistance components.Meanwhile, a pair of voltage ratio is with transistor T R4 ', TR5 ' employing p channel-type, as transistor T R6 ', the TR7 ' employing n channel-type of resistance components.
Comparer shown in Figure 15 (9) has omitted the transistor T R2 of the driving shown in Figure 14, connect organic EL (50) in the drain electrode with a transistor T R5 ' among transistor T R4 ', the TR5 ' in a pair of voltage ratio, by the electric current that flows through in this transistor T R5 ' on/off organic EL (50).
Comparer shown in Figure 16 (9) will be configured in side of the positive electrode as the transistor T R3 of the constant current source shown in Figure 10, meanwhile adopt p channel transistor TR3 '.In the comparer shown in Figure 17 (9), a pair of transistor T R6, TR7 as resistance components adopts depletion mode transistor.
Comparer shown in Figure 18 (9) is provided with a pair of luminous conduction and cut-off with transistor T R8, TR9 with as the depletion mode transistor TR10 of resistance components.On the grid of luminous conducting, apply data voltage, on source electrode, apply ramp voltage, in drain electrode, be connected with voltage source Vcc through transistor T R10 with transistor T R8.In addition, press DC, on source electrode, apply ramp voltage, in drain electrode, apply data voltage in the luminous constant DC that on grid, applies with transistor T R9.
As shown in figure 19, after scan period data voltage (A point voltage) changes, between light emission period, ramp voltage descend and and the difference between the data voltage (A point voltage) increase, exceed luminous conducting with the threshold level Vth between grid-source electrode of transistor T R8, then this transistor T R8 conducting if increase to, the gate voltage (B point voltage) that drives with transistor T R2 descends, thereby drive conducting, in organic EL (50), flow through electric current, begin luminous with transistor T R2.
Then, ramp voltage further descend and and the difference between the DC voltage DC increase, exceed luminous threshold level Vth between grid-source electrode of using transistor T R9 if increase to, then this transistor T R9 conducting makes luminous conducting descend with the potential difference (PD) between grid-source electrode of transistor T R8.So this transistor T R8 ends, the gate voltage (B point voltage) that drives with transistor T R2 rises.As a result, drive and end, stop the energising in the organic EL (50), and finish luminous with transistor T R2.
In above-mentioned comparer (9), use transistor T R9 owing to adopted luminous conducting with transistor T R8 and luminous ending, therefore, there is deviation even suppose the threshold level Vth between the grid-source electrode of two transistor between the pixel, if the threshold level Vth unanimity of two transistor in pixel, then luminous as shown in Figure 19 conducting period and luminously be offset equally by period, thus can not produce deviation between light emission period.
Comparer shown in Figure 20 (9) is provided with a pair of gate voltage conduction and cut-off transistor T R11, TR12 at the point of the B shown in Figure 18 and between driving with transistor T R2.In addition, the positive and negative counter-rotating of DC voltage DC and ramp voltage and Figure 18, meanwhile transistor T R8 ', TR9 ', TR10 ' employing p channel transistor.If B point current potential exceeds threshold value, then gate voltage conducting transistor T R11 conducting, C point current potential becomes low level, and below threshold value, then gate voltage is by using transistor T R12 conducting as if B point current potential, and C point current potential becomes high level.
Therefore, as shown in figure 21, after scan period data voltage (A point voltage) changes, between light emission period, ramp voltage rise and and the difference between the data voltage (A point voltage) increase, if increase to the threshold level Vth between the grid-source electrode that exceeds luminous conducting usefulness transistor T R8 ', then this transistor T R8 ' conducting.Therefore, the B point voltage rises, gate voltage conducting transistor T R11 conducting, and C point current potential becomes low level.As a result, drive conducting, in organic EL (50), flow through electric current, begin luminous with transistor T R2.
Then, ramp voltage further rise and and the difference between the DC voltage DC increase, exceed luminous threshold level Vth between grid-source electrode of using transistor T R9 ' if increase to, then this transistor T R9 ' conducting makes luminous conducting descend with the potential difference (PD) between grid-source electrode of transistor T R8 '.So this transistor T R8 ' ends, the B point voltage descends, and gate voltage is by using transistor T R12 conducting, and C point current potential becomes high level.As a result, drive and end, stop the energising in the organic EL (50), and finish luminous with transistor T R2.
In above-mentioned comparer (9), use transistor T R9 ' owing to adopted luminous conducting with transistor T R8 ' and luminous ending, therefore, there is deviation even suppose the threshold level Vth between the grid-source electrode of two transistor between the pixel, if the threshold level Vth unanimity of two transistor in pixel can not produce deviation in then as shown in Figure 21 between light emission period.And, drive and between light emission period, keep steady state value with the gate voltage (C point voltage) of transistor T R2, therefore, the action that drives with transistor T R2 can access height reliability.
In each above-mentioned embodiment, accept the ramp voltage supply from being arranged on the outside slope voltage generating circuit (8) of OLED display (2), but also can ramp voltage take place in the inside of each pixel that constitutes OLED display (2).For example the slope voltage generating circuit shown in Figure 22 (80) is provided with and accepts switching pulse SW and the transistor T R13 of conduction and cut-off, capacitor C1 that is recharged by this transistor T R13 conducting and the depletion mode transistor TR14 that works with resistance as discharge, the voltage when capacitor C1 is discharged as ramp voltage be applied to comparer+terminal.
As shown in figure 23, switching pulse SW converts low level to from high level between light emission period, is between high period at switching pulse SW, described transistor T R13 conducting, capacitor C1 is recharged, and is between low period at switching pulse SW, described transistor T R13 ends, capacitor C1 discharge.Along with capacitor C1 discharge, its voltage descends gradually, and as shown in figure 23, the voltage that is applied to comparer (9)+terminal becomes ramp voltage.
Slope voltage generating circuit shown in Figure 24 (80) is set to the negative electricity source with the transistor T R13 shown in Figure 22 from the positive supply sidesway, the voltage when discharging with capacitor C1 as ramp voltage be applied to comparer+terminal.As shown in figure 25, switching pulse SW converts low level to from high level between light emission period, is between high period at switching pulse SW, described transistor T R13 conducting, capacitor C1 is recharged, and is between low period at switching pulse SW, described transistor T R13 ends, capacitor C1 discharge.Along with capacitor C1 discharge, its voltage rises gradually, and as shown in figure 25, the voltage that is applied to comparer (9)+terminal becomes ramp voltage.
Slope voltage generating circuit shown in Figure 26 (80) the transistor T R15 that is connected in series on the depletion mode transistor TR14 shown in Figure 22 supplies with second switch pulse SW2 on the grid of this transistor T R15.As shown in figure 27, the first switching pulse SW1 becomes high level from low transition in scan period, at this switching pulse SW1 is between high period, described transistor T R13 conducting, capacitor C1 is recharged, at this switching pulse SW1 is between low period, and described transistor T R13 ends, capacitor C1 discharge.
In addition, second switch pulse SW2 becomes high level from low transition between light emission period, is between low period at this switching pulse SW2, and transistor T R15 ends, thereby stops the electric current that flows to as the transistor T R14 of resistive element.At this switching pulse SW2 is between high period, transistor T R15 conducting, and allowable current flows to the transistor T R14 as resistive element.Like this and since scan period electric current can not flow to transistor T R14, therefore reduced power consumption.
In each above-mentioned embodiment, comparer (9)+terminal applied ramp voltage, but also can by this+apply constant voltage on the terminal, according to data voltage the level of ramp voltage is changed on the other hand, and with this ramp voltage be applied to comparer (9)-terminal on, thereby control light emission period between.
For example shown in Figure 28, can adopt following structure: on the output terminal of capacitor C,, connected depletion mode transistor TR17 as resistive element through be switched on/disconnect the transistor T R16 of control by switching pulse SW.In this structure, switching pulse SW is low level in scan period, is high level that during this switching pulse SW was low level, transistor T R16 ended between light emission period, and capacitor C is recharged.In addition, be between high period at this switching pulse SW, transistor T R16 conducting, by the transistor T R17 as resistive element, capacitor C discharges.
Therefore, as shown in Figure 29, scan period comparer (9)-voltage that applies on the terminal, its level changes according to data voltage, becomes high level from low transition and the process that capacitor C discharges, this data voltage descends gradually at switching pulse SW.
Voltage at-terminal exceeds+state of the voltage of terminal in, comparer (9) is output as low level, drives the conducting with transistor T R2, organic EL flows through electric current in (50).Then, the voltage of-terminal is when the voltage of+terminal is following, and comparer (9) is output as high level, drives to end with transistor T R2, and the electric current that flows through organic EL (50) is disconnected.As a result, between the light emission period of organic EL (50) according to the size variation of data voltage.
In the embodiment shown in Fig. 6 or Fig. 7, to constituting all pixels of OLED display (2), in preceding half scan period, write data after, between later half light emission period, carry out light emitting control according to data, therefore, need scanning at a high speed in a way.In addition, in the embodiment shown in Fig. 8, during odd lines and even lines alternate sweep and between light emission period, so sweep velocity decline, but on sweep velocity, exist when limiting, just there is shortcoming short between light emission period.
Therefore, in the embodiment shown in Figure 30 and Figure 31,, after each horizontal line has just been write data, and then carry out horizontal luminous to each by each horizontal line being made the phase deviation of ramp voltage.As shown in figure 30, from the ramp voltage as digital signal of slope voltage generating circuit (8) output, supply with each horizontal each pixel by delayed circuit of each horizontal line (84) and DA converter (85).Therefore, as shown in figure 31, supply with each horizontal ramp voltage, its phase place from first line to the final stage line at every turn with certain time delay of skew.And writing of the data of supplying with from data driver (4) carried out before each horizontal ramp voltage rises.
Therefore, to each horizontal ramp voltage have as shown in figure 31 change to the mild degree of tilt of high level (perhaps from the high level to the low level) in an image duration from low level, can with whole image duration almost as between light emission period.
In addition, can carry out a whole image duration with almost all horizontal scannings, so sweep velocity can be slow.In addition, because the luminous moment of each pixel disperses, therefore, alleviated the influence of the voltage drop of the power lead in the display screen.
Moreover the structure of each one of the present invention is not limited in the foregoing description, and can carry out various changes in the technical scope of being put down in writing in the claims.For example, in the above-described embodiments, adopted organic EL, but be not limited in this, also can adopt other various display elements as the supply of accepting electric current and luminous element, thereby constitute display device of the present invention as display element.
In addition, if comparer (9) has enough current driving abilities, then can adopt to omit to drive and use transistor T R2, with the direct structure that is connected with organic EL (50) of the lead-out terminal of comparer (9).In this occasion, if adopt the ramp voltage of Fig. 6 (e) shown in 3., perhaps make the ramp voltage shown in Fig. 6 (c) do the time spent, need non-inverting input of the comparer shown in Fig. 3 (9) is anti-phase with being connected of reversed input terminal.According to this structure, can adopt the voltage driven type element as display element.
In addition, in the comparer shown in Figure 10, can adopt by voltage to be set on the source potential of transistor T R3, thereby in scan period comparer (9), not flow through the structure of electric current supplied with constant voltage line CONST.Therefore can reduce power consumption.
Claims (16)
1. digitally driven type display device, this device connect scanner driver on the display screen that constitutes with a plurality of pixels of rectangular arrangement and data driver constitutes, and wherein each pixel of display screen is provided with:
Accept the supply and the luminous display element of curtage;
Be applied in from the scanning voltage of scanner driver and become the write element of conducting state;
Become conducting state by write element and be applied in data voltage, and keep the voltage keeping part spare of this voltage from data driver; And
Only with the voltage swing time corresponding that remains in the described voltage keeping part spare in, to the driver part of described display element supplying electric current or voltage,
Described driver part is provided with:
According to the input of on signal, on/off is to the driving element of the energising of described display element; And
Relatively have the ramp voltage of predetermined change curve and the output voltage of described voltage keeping part spare, and the output signal that will represent its result supplies with the comparing element of described driving element as the on signal,
In the display cycle of a picture, be provided with between a scan period and light emission period; In scan period, by scanner driver the write element of each pixel is applied scanning voltage, in the voltage keeping part spare of each pixel, keep data voltage; Between light emission period,, control the display element on/off of each pixel by the output voltage of more described ramp voltage of described driver part and voltage keeping part spare; Ramp voltage can irrespectively make between the output signal of first value that driving element often connects and comparing element and second value that data voltage irrespectively makes driving element often disconnect at the output signal of comparing element and data voltage and change, in the display cycle of a picture, keep second value in scan period, in between the light emission period beyond scan period, between first value and second value, change.
2. digitally driven type display device as claimed in claim 1 is characterized in that:
Ramp voltage has the change curve of increasing or decreasing between described first value and second value.
3. digitally driven type display device as claimed in claim 1 is characterized in that:
Ramp voltage has the change curve of having considered that between described first value and second value γ proofreaies and correct.
4. digitally driven type display device as claimed in claim 1 is characterized in that:
Ramp voltage has the change curve that is back to a described value in described first value and second value from a value through another value again.
5. digitally driven type display device as claimed in claim 1 is characterized in that:
In a plurality of levels or perpendicular line that constitute a picture, the ramp voltage that is arranged in the pixel on the odd number line is had the change curve that a value from described first value and second value is changed to another value, the ramp voltage that is arranged in the pixel on the even number line is had the change curve that is changed to a described value from described another value.
6. digitally driven type display device as claimed in claim 1 is characterized in that:
In a plurality of levels or perpendicular line that constitute a picture, the ramp voltage that is arranged in the pixel on a kind of color line in the three primary colors is had the change curve that a value from described first value and second value is changed to another value, the ramp voltage that is arranged in the pixel on other two kinds of color lines is had the change curve that is changed to a described value from described another value.
7. digitally driven type display device as claimed in claim 1 is characterized in that:
In constituting a plurality of levels or perpendicular line of a picture, be arranged in the pixel on the odd number line with the pixel that is arranged on the even number line between, interior scan period and the order between light emission period of the display cycle of a picture is alternate with each other.
8. digitally driven type display device as claimed in claim 1 is characterized in that:
In a plurality of levels or perpendicular line that constitute a picture, to being arranged in the ramp voltage of the pixel on the shades of colour line in the three primary colors, the rate of change between its described first value and second value is different on each color.
9. as each described digitally driven type display device in the claim 1 to 8, it is characterized in that:
Described driving element comes on/off that the driving of the energising of display element is constituted with transistor by accept the on signal at grid; The said write element becomes writing with transistor of conducting state by accepting scanning voltage at grid and constitutes; Described voltage keeping part spare is by the capacity cell of data voltage as charge storage constituted; Comparing element is made of comparer, this comparer is accepted from the ramp voltage of slope voltage generating circuit supply and the output voltage of described capacity cell in positive and negative pair of input terminals, and will represent that the high level/low level signal of comparative result outputs to the transistorized grid of described driving from lead-out terminal.
10. digitally driven type display device as claimed in claim 9 is characterized in that:
Comparer is provided with a pair of voltage ratio of the output voltage that applies the ramp voltage supplied with from slope voltage generating circuit and described capacity cell on grid separately and uses transistor, to two voltage ratios with the current source of transistor supplying electric current, and as flowing to two voltage ratios with the resistive element of the resistance of transistorized electric current; Will the point of change in voltage take place as lead-out terminal in any voltage ratio than flowing through electric current with transistor.
11. digitally driven type display device as claimed in claim 10 is characterized in that:
Any voltage ratio is used transistor with transistor as driving, and on/off is to the energising of display element.
12. digitally driven type display device as claimed in claim 9 is characterized in that:
Comparer is provided with a pair of luminous conduction and cut-off transistor, conducting when luminous conducting surpasses predetermined threshold value with the difference of transistor between the output voltage of ramp voltage and capacity cell, make to drive and use transistor turns, luminous by with transistor in the conducting during of the difference between ramp voltage and the predetermined DC voltage above predetermined threshold value, driving is ended with transistor.
13. digitally driven type display device as claimed in claim 9 is characterized in that:
Slope voltage generating circuit is located at the outside of display screen.
14. digitally driven type display device as claimed in claim 9 is characterized in that:
Slope voltage generating circuit is located on each pixel of display screen, accepts the supply of the switching pulse supplied with from the outside of display screen, and capacitor by charge or discharge ramp voltage takes place between the high level of this pulse or low period.
15. digitally driven type display device as claimed in claim 14 is characterized in that:
Slope voltage generating circuit is provided with the transistor of the electric current that disconnection flows through along with the charging of described capacitor in scan period.
16., it is characterized in that as each described digitally driven type display device in the claim 1～8:
Display element is an organic electroluminescent device.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001381240 | 2001-12-14 | ||
| JP381240/2001 | 2001-12-14 | ||
| JP095425/2002 | 2002-03-29 | ||
| JP95425/2002 | 2002-03-29 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1698084A CN1698084A (en) | 2005-11-16 |
| CN100409290C true CN100409290C (en) | 2008-08-06 |
Family
ID=34746791
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB028249569A Expired - Fee Related CN100409290C (en) | 2001-12-14 | 2002-12-09 | Digitally driven type display device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN100409290C (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107481662A (en) * | 2017-07-20 | 2017-12-15 | 友达光电股份有限公司 | Display panel and driving method of pixels thereof |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2015004945A (en) * | 2013-02-04 | 2015-01-08 | ソニー株式会社 | Display device, drive method thereof and control pulse generation device |
| JP6157178B2 (en) * | 2013-04-01 | 2017-07-05 | ソニーセミコンダクタソリューションズ株式会社 | Display device |
| JP6333523B2 (en) | 2013-06-12 | 2018-05-30 | ソニーセミコンダクタソリューションズ株式会社 | Display device |
| JPWO2018164105A1 (en) * | 2017-03-06 | 2019-12-26 | ソニーセミコンダクタソリューションズ株式会社 | Drive device and display device |
| CN109817164B (en) * | 2017-11-20 | 2020-10-27 | 上海视涯技术有限公司 | AMOLED display panel and image display device |
| TWI798308B (en) * | 2017-12-25 | 2023-04-11 | 日商半導體能源研究所股份有限公司 | Display and electronic device including the display |
| CN109272940B (en) * | 2018-11-15 | 2020-08-07 | 京东方科技集团股份有限公司 | Pixel driving circuit, driving method thereof and display substrate |
| CN111402782B (en) | 2018-12-14 | 2021-09-03 | 成都辰显光电有限公司 | Digital driving pixel circuit and method for digitally driving pixel |
| CN109741707A (en) * | 2019-03-14 | 2019-05-10 | 昆山工研院新型平板显示技术中心有限公司 | A kind of pixel circuit and display panel |
| CN109872686B (en) * | 2019-04-19 | 2020-05-29 | 京东方科技集团股份有限公司 | Drive circuit, display panel and manufacturing method of display panel |
| CN110782831B (en) | 2019-11-05 | 2021-02-26 | 京东方科技集团股份有限公司 | Pixel driving circuit, display device, and pixel driving circuit driving method |
| CN114333704A (en) * | 2021-12-31 | 2022-04-12 | 厦门天马微电子有限公司 | Pixel driving circuit, driving method thereof and display panel |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05328269A (en) * | 1992-05-26 | 1993-12-10 | Citizen Watch Co Ltd | Liquid crystal display device |
| US5302966A (en) * | 1992-06-02 | 1994-04-12 | David Sarnoff Research Center, Inc. | Active matrix electroluminescent display and method of operation |
| JPH09243994A (en) * | 1996-03-07 | 1997-09-19 | Toshiba Corp | Liquid crystal display device |
| JPH11237606A (en) * | 1998-02-24 | 1999-08-31 | Nec Corp | Driving method of liquid crystal display device and liquid crystal display device using the method |
| WO2000019401A1 (en) * | 1998-09-29 | 2000-04-06 | Sarnoff Corporation | Analog active matrix emissive display |
| JP2000235370A (en) * | 1999-02-16 | 2000-08-29 | Nec Corp | Drive assembly for organic electroluminescent element |
| JP2001022315A (en) * | 1999-07-12 | 2001-01-26 | Seiko Epson Corp | Opto-electronic device, driving method and electronic device therefor |
| US6329974B1 (en) * | 1998-04-30 | 2001-12-11 | Agilent Technologies, Inc. | Electro-optical material-based display device having analog pixel drivers |
-
2002
- 2002-12-09 CN CNB028249569A patent/CN100409290C/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH05328269A (en) * | 1992-05-26 | 1993-12-10 | Citizen Watch Co Ltd | Liquid crystal display device |
| US5302966A (en) * | 1992-06-02 | 1994-04-12 | David Sarnoff Research Center, Inc. | Active matrix electroluminescent display and method of operation |
| JPH09243994A (en) * | 1996-03-07 | 1997-09-19 | Toshiba Corp | Liquid crystal display device |
| JPH11237606A (en) * | 1998-02-24 | 1999-08-31 | Nec Corp | Driving method of liquid crystal display device and liquid crystal display device using the method |
| US6329974B1 (en) * | 1998-04-30 | 2001-12-11 | Agilent Technologies, Inc. | Electro-optical material-based display device having analog pixel drivers |
| WO2000019401A1 (en) * | 1998-09-29 | 2000-04-06 | Sarnoff Corporation | Analog active matrix emissive display |
| JP2000235370A (en) * | 1999-02-16 | 2000-08-29 | Nec Corp | Drive assembly for organic electroluminescent element |
| JP2001022315A (en) * | 1999-07-12 | 2001-01-26 | Seiko Epson Corp | Opto-electronic device, driving method and electronic device therefor |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107481662A (en) * | 2017-07-20 | 2017-12-15 | 友达光电股份有限公司 | Display panel and driving method of pixels thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1698084A (en) | 2005-11-16 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP3973471B2 (en) | Digital drive display device | |
| US7212195B2 (en) | Drive circuit, display apparatus, and information display apparatus | |
| US7050028B2 (en) | Reference voltage generation circuit, display drive circuit, display device and reference voltage generation method | |
| US7106321B2 (en) | Reference voltage generation circuit, display drive circuit, display device and reference voltage generation method | |
| US7764260B2 (en) | Liquid crystal panel driving device | |
| US6304241B1 (en) | Driver for a liquid-crystal display panel | |
| CN101978415B (en) | Display panel with matrix form pixels | |
| US7123220B2 (en) | Self-luminous display device | |
| US6014122A (en) | Liquid crystal driving circuit for driving a liquid crystal display panel | |
| CN100409290C (en) | Digitally driven type display device | |
| JP3428380B2 (en) | Semiconductor device for drive control of liquid crystal display device and liquid crystal display device | |
| US7030840B2 (en) | Display device having a plurality of pixels having different luminosity characteristics | |
| US7196568B2 (en) | Input circuit, display device and information display apparatus | |
| US7375707B1 (en) | Apparatus and method for compensating gamma voltage of liquid crystal display | |
| JPH10260664A (en) | Liquid crystal driving circuit and liquid crystal device using the same | |
| US7414601B2 (en) | Driving circuit for liquid crystal display device and method of driving the same | |
| US7471269B2 (en) | Method for driving electroluminescence display panel with selective preliminary charging | |
| CN100437701C (en) | Current source circuit, a signal line driver circuit and a driving method thereof and a light emitting device | |
| US7250929B2 (en) | Active matrix display device and digital-to-analog converter | |
| KR960016720B1 (en) | Alternating current thin film electro luminescence used inter-voltage level | |
| JP2003345307A (en) | Display device and its driving method | |
| CN100507993C (en) | Light emitting system, and electronic equipment | |
| US20060125762A1 (en) | Electro-optical device and electronic apparatus | |
| JP3968925B2 (en) | Display drive device | |
| JP2849034B2 (en) | Display drive |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20080806 Termination date: 20100111 |