JP5071954B2 - Driving device and driving method of light emitting display panel - Google Patents

Description

  The present invention relates to a driving device and a driving method for a light emitting display panel in which a color display pixel is configured by a plurality of types of light emitting elements having different emission colors and arranged in a matrix, for example, to realize display of a color image. .

  For example, in a PDP (Plasma Display Panel) or the like, a PLE (Peak) that obtains an average luminance level (APL = Average Picture Level) of a video signal to be displayed and controls the display luminance of the video signal based on the average luminance level. Luminance enhancement) control means is employed.

  In the PLE control means, when the average luminance level is small even when the signals have the same luminance level (when the entire image is dark), a high luminance display is performed by setting the peak luminance level high. The On the other hand, when the average luminance level is large (when the whole image is bright), the peak luminance level is lowered to suppress the power consumption. By performing the PLE control in this manner, it is possible to realize low power consumption and display an image with good contrast.

As described above, a display device including a PLE control unit that obtains an average luminance level APL of a video signal to be displayed and controls display luminance by this APL is disclosed in Patent Documents 1 and 2 shown below. .
JP-A-9-281927 JP 2001-175220 A

  By the way, when the video signal is an R (red), G (green), or B (blue) signal, the video signal is converted into grayscale (luminance) data when the PLE control is performed. A value is calculated. In this case, when the color video signal is converted to grayscale, even if the values of the R, G, and B signals are the same, the brightness (apparent whiteness) on the grayscale differs for each color. . For example, in NTSC, the ratio of light emission luminance (R: G: B) for each color is about 3: 6: 1.

  Therefore, conventionally, when converting a color video signal to a grayscale signal, a means for calculating the APL by weighting according to the light emission luminance ratio of each color during grayscale display has been adopted.

  FIG. 1 is a diagram for explaining the basic configuration of APL calculation means in the case of handling a conventional color video signal. A block denoted by reference numeral 31 receives R, G, B video signals, and sets the luminance ratio of each color. The luminance ratio weighting means for performing weighting in response to this is shown, and the block denoted by reference numeral 32 represents averaging means for adding the weighted video signals and calculating the average value.

  The luminance ratio weighting means 31 and the averaging means 32 constitute an APL calculating means 33, and the peak luminance control means 34 is controlled by the APL output from the APL calculating means 33. Then, the peak luminance control means 34 controls the peak luminance of the composite video signal by the APL output, thereby realizing the PLE control. That is, the PLE control means 35 is constituted by the APL calculation means 33 and the peak luminance control means 34 described above.

  In the luminance ratio weighting means 31 described above, in order to simplify the explanation of the operation, the luminance ratio (luminance ratio) of each color pixel necessary for obtaining the same brightness on the gray scale is, for example, R: Assuming G: B = 3: 6: 1, 3 / (3 + 6 + 1) for the R video signal, 6 / (3 + 6 + 1) for the G video signal, and 3 / (3 + 6 + 1) for the B video signal. , 1 / (3 + 6 + 1), respectively, to be weighted.

The video signals weighted by the luminance ratio weighting unit 31 are added by the averaging unit 32 to calculate an average value. This average value is output from the APL calculation means 33 as APL (average brightness level) and supplied as a control signal to the peak brightness control means 34 described above. That is, the above-mentioned APL is obtained by the following equation 1.
APL = R × 3 / (3 + 6 + 1) + G × 6 / (3 + 6 + 1)
+ B × 1 / (3 + 6 + 1) (Formula 1)

  By the way, in recent years, display panels using organic EL (electroluminescence) elements that take advantage of the characteristic that they can be made thin and have high display quality and are self-luminous elements have been put into practical use. This is also due to the fact that the use of an organic compound that can be expected to have good light-emitting characteristics for the light-emitting functional layer of the device has led to higher efficiency and longer life that can withstand practical use.

  The organic EL element described above can be electrically represented by an equivalent circuit as shown in FIG. That is, the organic EL element can be replaced with a configuration of a diode component E as a light emitting element and a parasitic capacitance component Cp coupled in parallel to the diode component E. The organic EL element is a capacitive light emitting element. I can say that.

  In the organic EL element, when a light emission driving voltage is applied, first, a charge corresponding to the electric capacity of the element flows into the electrode as a displacement current and is accumulated. Subsequently, when a certain voltage specific to the element (light emission threshold voltage = Vth) is exceeded, a current starts to flow from one electrode (the anode side of the diode component E) to the organic layer constituting the light emitting layer, and is proportional to this current. It can be considered that light is emitted with intensity.

  FIG. 3 shows the light emission static characteristics of such an organic EL element. According to this, as shown in FIG. 3A, the organic EL element emits light with a luminance L substantially proportional to the drive current I, and the drive voltage V becomes the light emission threshold voltage as shown by the solid line in FIG. When Vth is equal to or higher than Vth, the current I suddenly flows to emit light.

  In other words, when the drive voltage is equal to or lower than the light emission threshold voltage Vth, almost no current flows through the EL element and no light is emitted. Therefore, as shown by a solid line in FIG. 3B, the luminance characteristics of the EL element are such that the emission luminance L increases as the value of the voltage V applied thereto increases in the light emission possible region that is higher than the threshold voltage Vth. It has the characteristic which becomes.

  Further, it is also known that the luminance characteristics of the organic EL element change depending on the temperature as shown by a broken line in FIG. That is, the EL element has a characteristic that, in a light emission possible region that is larger than the light emission threshold voltage, the light emission luminance L increases as the value of the voltage V applied thereto increases. The threshold voltage is reduced. Therefore, the EL element is in a state in which light can be emitted with a smaller applied voltage as the temperature becomes higher, and has a luminance temperature dependency such that it is brighter at high temperatures and darker at low temperatures even when the same applied voltage capable of emitting light is applied.

  Furthermore, the above-mentioned EL element has a problem that the light emission efficiency with respect to the driving voltage varies depending on the light emission color, and the light emission efficiency of the EL element that emits R, G, B, which can be put into practical use at present. As shown in FIG. 3C, the light emission efficiency of G is high and the light emission efficiency of R and B is low. Each of the EL elements that emit light of R, G, and B also has temperature dependency as shown in FIG.

  As described above, in the display device of the color display panel in which the color display pixel is configured by using the light emitting elements represented by the organic EL elements having different emission efficiency for each color as the sub-pixels, the above-described PLE control is realized. However, the following technical problems will occur.

  That is, since the luminous efficiency of the elements for each color is different, when luminance control (PLE control) is performed based on the APL value calculated only from the video signal and the luminance ratio as in the configuration shown in FIG. When the lighting rate (equivalent to the APL value described above) is high in a light emitting element with low luminous efficiency and low luminance ratio, it is determined that the screen is a “dark screen” despite the high lighting rate. An operation for increasing the peak luminance is executed.

  For example, as described above, the luminance ratio is R: G: B = 3: 6: 1, the light emission efficiency of the blue (B) light emitting element is the worst, and only the blue light emitting element is fully lit. Assuming that the APL output at this time is APL = B × 1 / (3 + 6 + 1) from Equation 1, it is determined that the screen is very “dark”. Therefore, although the blue light emission efficiency is the worst, control is performed such that the peak luminance is increased, and as a result, the power consumption increases, and the effect of the PLE described above that reduces the peak luminance and reduces the power consumption at a high lighting rate. The problem arises that damage is lost.

  The present invention has been made paying attention to the above technical problems, and is caused by a difference in luminous efficiency in a driving device of a color display panel configured using light emitting elements having different luminous efficiency for each color. Thus, it is an object of the present invention to provide a driving device and a driving method for a light-emitting display panel that can prevent an inappropriate APL value (lighting rate) from being calculated in terms of power consumption.

A preferred first basic form of the drive device for a light emitting display panel according to the present invention, which has been made to solve the above-mentioned problems, is that light emitting elements of a plurality of colors are arranged in a matrix, and each light emitting element is based on a video signal. A light emitting display panel driving device configured to selectively drive light emission, wherein APL calculating means for calculating an average luminance level (APL) from the video signal, and APL calculated by the APL calculating means are predetermined. When the value is smaller than the value, the peak luminance level is raised, and when the APL is larger than the predetermined value, the peak luminance level is lowered, so that the peak luminance in the video signal can be varied according to the APL. Peak luminance control means for controlling, and the APL calculation means for the gray scale for each color video signal. A first weighting means for performing weighting according to the emission current ratio of each color at the time of display for each color video signal, second weighting means for performing weighting according to each color light emission luminance ratio at the time of the gray scale display The weighting by the first weighting means is performed on the video signal of each color by the selection means for the user to select either the first weighting means or the second weighting means. or weighting means by said second weighting means is configured to be selected.

In a second preferred embodiment of the light emitting display panel driving device according to the present invention, the light emitting elements of a plurality of colors are arranged in a matrix, and the light emitting elements are selectively driven to emit light based on a video signal. A light emitting display panel driving device configured as described above, wherein an APL calculating means for calculating an average luminance level (APL) from the video signal and a peak when the APL calculated by the APL calculating means is smaller than a predetermined value. Peak luminance control means for variably controlling the peak luminance in the video signal according to the APL by increasing the luminance level and performing a control to decrease the peak luminance level when the APL is larger than the predetermined value The APL calculation means includes a light emission power for each color at the time of gray scale display for each color video signal. A first weighting means for performing weighting according to, for each color of the video signal, second weighting means for performing weighting according to each color light emission luminance ratio at the time of the gray scale display is further provided, said first The weighting means by the first weighting means or the second weighting means is applied to the video signals of the respective colors by the selection means for selecting one of the weighting means and the second weighting means. weighting is configured to be performed.

On the other hand, a preferred first basic aspect of the driving method of the light emitting display panel according to the present invention made to solve the above-described problem is that a plurality of color light emitting elements are arranged in a matrix, and each light emitting element is connected to a video signal. A light emitting display panel driving method configured to selectively drive light emission based on the image signal, wherein an average luminance level (APL) is calculated from the video signal by an APL calculating unit, and the peak luminance controlling unit By supplying the APL information calculated by the APL calculating means as a control signal, a peak luminance variable control operation for variably controlling the peak luminance in the video signal is executed. The APL calculating means When calculating the brightness level, the video signal of each color corresponds to the emission current ratio of each color during grayscale display. Characterized in that performing a weighting operation for weighted.

In a second preferred basic aspect of the light emitting display panel driving method according to the present invention, the light emitting elements of a plurality of colors are arranged in a matrix, and the light emitting elements are selectively driven to emit light based on the video signal. A light emitting display panel driving method configured as described above, wherein an APL calculation unit calculates an average luminance level (APL) from the video signal, and APL information calculated by the APL calculation unit with respect to a peak luminance control unit Is supplied as a control signal to execute a peak luminance variable control operation for variably controlling the peak luminance in the video signal, and the APL calculating means calculates the video of each color when calculating the average luminance level. Executes a weighting operation to weight the signal according to the emission power ratio of each color at the time of grayscale display That has a feature to the point.

According to a third preferred aspect of the driving method of the light emitting display panel according to the present invention, the light emitting elements of a plurality of colors are arranged in a matrix, and the light emitting elements are selectively driven to emit light based on the video signal. A light emitting display panel driving method configured as described above, wherein an APL calculation unit calculates an average luminance level (APL) from the video signal, and APL information calculated by the APL calculation unit with respect to a peak luminance control unit As a control signal, and when the calculated APL is smaller than a predetermined value, the peak luminance level is increased, and when the APL is larger than the predetermined value, the peak luminance level is decreased . The peak luminance variable control operation for variably controlling the peak luminance in the video signal is executed, and the APL calculating means When calculating the average luminance level, a first weighting operation for weighting the video signal of each color according to the light emission current ratio of each color at the time of grayscale display, or when calculating the average luminance level, each color The video signal is characterized in that one of the second weighting operations for performing weighting according to the emission luminance ratio of each color at the time of gray scale display is executed by the user's selection.

The fourth basic aspect of the light emitting display panel driving method according to the present invention is such that a plurality of light emitting elements are arranged in a matrix and each light emitting element is selectively driven to emit light based on a video signal. A light emitting display panel driving method configured as described above, wherein an APL calculation unit calculates an average luminance level (APL) from the video signal, and APL information calculated by the APL calculation unit with respect to a peak luminance control unit As a control signal, and when the calculated APL is smaller than a predetermined value, the peak luminance level is increased, and when the APL is larger than the predetermined value, the peak luminance level is decreased . The peak luminance variable control operation for variably controlling the peak luminance in the video signal is executed, and the APL calculating means When calculating the average luminance level, a first weighting operation for weighting the video signal of each color according to the light emission power ratio of each color at the time of grayscale display, or when calculating the average luminance level, each color The video signal is characterized in that one of the second weighting operations for performing weighting according to the emission luminance ratio of each color at the time of gray scale display is executed by the user's selection.

Furthermore, a fifth preferred aspect of the driving method of the light emitting display panel according to the present invention is such that the light emitting elements of a plurality of colors are arranged in a matrix, and each of the light emitting elements is selectively driven to emit light based on a video signal. A light emitting display panel driving method configured as described above, wherein an APL calculation unit calculates an average luminance level (APL) from the video signal, and APL information calculated by the APL calculation unit with respect to a peak luminance control unit Is supplied as a control signal to execute a peak luminance variable control operation for variably controlling the peak luminance in the video signal, and the APL calculating means calculates the video of each color when calculating the average luminance level. A first weighting operation for weighting the signal according to the light emission current ratio of each color at the time of gray scale display And when calculating the average luminance level for each color of the video signal, characterized in that performing a second weighting operation of performing weighting according to each color light emission luminance ratio at the time of the gray scale display.

Furthermore, a preferred sixth basic aspect of the driving method of the light emitting display panel according to the present invention is that the light emitting elements of a plurality of colors are arranged in a matrix, and each of the light emitting elements is selectively driven to emit light based on a video signal. A light emitting display panel driving method configured as described above, wherein an APL calculating unit calculates an average luminance level (APL) from the video signal and calculates an APL calculated by the APL calculating unit with respect to a peak luminance control unit. By supplying information as a control signal, a peak luminance variable control operation for variably controlling the peak luminance in the video signal is executed, and the APL calculating means calculates the average luminance level for each color. A first weighting that weights the video signal according to the emission power ratio of each color during grayscale display Operation, and when calculating the average luminance level for each color of the video signal, characterized in that performing a second weighting operation of performing weighting according to each color light emission luminance ratio at the time of the gray scale display.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS A light emitting display panel driving apparatus according to the present invention will be described below based on the embodiments shown in the drawings. FIG. 4 is a block diagram showing the overall configuration of a driving device including a light emitting display panel, which constitutes a driving device intended for an active matrix type display panel.

  The drive device has an analog / digital (A / D) conversion unit 2, a video memory 3 that can store video signals for at least one frame, and a video signal for a controller circuit 1 that generates various timing signals. A PLE control unit 4 is connected as a peak luminance control means capable of controlling the display luminance. In the embodiment shown in FIG. 4, an analog video signal is supplied to the controller circuit 1 and the A / D converter 2. The controller circuit 1 generates a clock signal CK for the A / D converter 2, a write signal W and a read signal R for the video memory 3 based on horizontal and vertical synchronization signals in the analog video signal.

  The A / D converter 2 samples the input analog signal based on the clock signal supplied from the controller circuit 1, converts the sampled analog signal into a video signal for each pixel, and supplies the video signal to the video memory 3. Act on. The video memory 3 operates so as to sequentially write video signals for each pixel supplied from the A / D converter 2 to the video memory 3 in accordance with the write signal W from the controller circuit 1.

  As described above, a frame memory is used as the video memory 3, and data for one screen is written on a display panel described later by the writing operation. The video signal written in the video memory 3 is read by a read signal R output from the controller circuit 1 and supplied to the PLE control unit 4.

  The PLE control unit 4 operates to control the display luminance of the video signal read from the video memory 3 for each frame period, for example. For this purpose, a synchronization signal synchronized with one frame period is supplied from the controller circuit 1 to the PLE control unit 4. The more specific configuration and operation of the PLE control unit 4 will be described later in detail. The video signal output from the PLE control unit 4 is supplied to an output processing unit 5, which converts the video signal into a signal form that can be driven by a data driver 7 described later and outputs the signal. .

  The controller circuit 1 generates a shift clock signal and a start pulse for the scanning driver 6 and the data driver 7 based on the horizontal and vertical synchronization signals in the video signal, and supplies them to the drivers 6 and 7. Is configured to do.

  Reference numeral 10 shown in FIG. 4 indicates a display panel in which a large number of display pixels each including a light emitting element are arranged in a matrix. In this display panel 10, as indicated by R, G, and B, color display pixels each having a set of sub-pixels including EL elements that emit red, green, and blue colors are arranged in a matrix in the vertical and horizontal directions. .

  In the display panel 10, scanning lines 11 and data lines 12 connected to the scanning driver 6 and the data driver 7 are arranged in directions orthogonal to each other, and the EL elements are arranged at intersections thereof. The included sub-pixels R, G, and B are arranged. Note that each of the sub-pixels is configured to be supplied with a pixel driving driving voltage from a power supply circuit 8 via a power supply line 13.

  FIG. 5 shows a circuit configuration corresponding to one sub-pixel R arranged in the display panel 10 described above, and this shows the most basic pixel configuration when an EL element is used as a light-emitting element. In FIG. 5, the circuit configuration of a pixel corresponding to R is shown as a representative sub-pixel, but the circuit configuration of this pixel is the same in the other G and B sub-pixels.

  In this pixel R, the data signal Vdata corresponding to the video signal from the data driver 7 is supplied to the control TFT, that is, the source of the data write transistor Tr1 through the data line 12 arranged in the display panel. It is configured.

  A scanning signal Select (hereinafter also referred to as a writing pulse) is supplied to the gate of the data writing transistor Tr1 through a scanning line 11 connected to a scanning driver 6. The drain of the data writing transistor Tr1 is connected to a lighting driving TFT, that is, a gate of the lighting driving transistor Tr2, and is connected to one terminal of the charge holding capacitor C1.

  Further, the source of the lighting drive transistor Tr2 is connected to the other terminal of the capacitor C1, and the drive voltage Vcc is supplied from the power supply circuit 8 through the power supply line 13. . The drain of the lighting drive transistor Tr2 is connected to an anode terminal of an organic EL element E1 as a light emitting element, and a cathode terminal of the organic EL element E1 is connected to a reference potential point (ground) of the display panel 10.

  In the circuit configuration of the pixel R shown in FIG. 5, the data write transistor Tr1 is configured by an n-channel TFT, and the drive transistor Tr2 is configured by a p-channel TFT. The pixels having the above-described configuration form color display pixels by combining R, G, and B sub-pixels, and a large number of the color display pixels are arranged in a matrix in the row and column directions as shown in FIG. A display panel 10 is configured.

  In the configuration of the pixel R shown in FIG. 5, a write pulse Select as a scanning signal is supplied from the scanning driver 6 to the gate of the control transistor Tr1 during the address period. At this time, when the data signal Vdata supplied from the data driver 7 is data for lighting the pixel, a current corresponding to the data signal Vdata flows to the capacitor C1 via the source / drain of the control transistor Tr1, and the capacitor C1 is charged.

  Then, the charging voltage is supplied to the gate of the driving transistor Tr2, and the transistor Tr2 supplies a current corresponding to the gate voltage and the driving voltage Vcc supplied to the drain to the EL element E1, whereby the EL element E1 emits light. To do.

  When application of the write pulse to the gate of the control transistor Tr1 is stopped, the transistor Tr1 becomes a so-called cutoff. However, the gate voltage of the drive transistor Tr2 is held by the electric charge accumulated in the capacitor C1, thereby maintaining the drive current to the EL element E1.

  In this embodiment, the pixels arranged on the display panel 10 are controlled to emit light based on the video signal whose luminance is controlled by the PLE control unit 4. In this case, as one means, the voltage of the data signal Vdata supplied from the data driver 7 to the source of the control transistor Tr1 through each data line 12, for example, based on the video signal whose luminance is controlled by the PLE control unit 4. By controlling the value, the luminance (gradation) of each sub-pixel can be controlled. Thereby, the control of the peak luminance of the pixel by the PLE described above can be realized. At this time, the display color in one color display pixel can be adjusted by individually controlling the gradation between the R, G, and B described above.

  As another means, one frame period is divided into a plurality of subframes, and the pixels are controlled to be lit or unlit in units of subframes. The luminance (gradation) of each pixel is determined by the total lighting time of the pixels in one frame period. Control) can be realized. By using such a subframe method, it is possible to realize control of the peak luminance of the pixel based on the PLE control described above. Also in this case, the display color of one color display pixel can be adjusted by controlling the gradation of each of the R, G, and B subpixels in units of subframes.

FIG. 6 is a block diagram showing a first embodiment that can be suitably employed for the PLE control unit 4 shown in FIG. In the configuration shown in FIG. 6, the video signal read from the video memory 3 is supplied to the color signal demodulating circuit 21 that constitutes the APL calculating means 20, and the video signals corresponding to the R, G, and B described above. Demodulated. That is, it is configured so as to be output as a video signal of a level corresponding to each of the R, G, and B luminances.

  The video signals corresponding to R, G, and B output from the circuit 21 are supplied to the weighting means 22A, and weighting is executed on the R, G, and B video signals. In this weighting means 22A, the ratio of the light emission currents required for the light emitting elements of the respective colors in order to obtain the same brightness when the image signals R, G, B of the respective colors are displayed in gray scale, that is, gray. Weighting is performed according to the emission current ratio of each color at the time of scale display. The weighting means 22A will be referred to as first weighting means for convenience.

  In order to simplify the description of the weighting action by the first weighting means 22A, the ratio of the light emission currents required for each R, G, B light emitting element to obtain the same brightness on the gray scale is, for example, R Assuming that G: B = 1: 1: 2, R video signal is 1 / (1 + 1 + 2), G video signal is 1 / (1 + 1 + 2), and B video signal. Is weighted by being multiplied by 2 / (1 + 1 + 2).

The video signal weighted by the first weighting means 22A is supplied to the averaging means 23 to calculate an average value, and this average value is output from the APL calculation means 20 as APL (average luminance level). The operation of calculating the average value in the averaging means 23 is as already described based on the configuration shown in FIG. 1, and the APL output at this time is obtained by the following equation 2.
APL = R × 1 / (1 + 1 + 2) + G × 1 / (1 + 1 + 2)
+ B × 2 / (1 + 1 + 2) (Formula 2)

  The APL output obtained by the APL calculating unit 20 is supplied to the peak luminance control unit 29 as a control signal. The peak luminance control means 29 is supplied with the composite video signal read from the video memory 3 as a controlled signal, and the peak luminance of the video signal is controlled by the APL output, thereby realizing PLE control. .

  The output from the peak luminance control means 29, that is, the output from the PLE control unit 4 is supplied to the output processing unit 5 as described above, and the output processing unit 5 converts the video signal into a signal form that can be driven by the data driver 7. And output.

  According to the APL calculation output using the weighting means 22A described above, weighting is performed according to the ratio of the light emission currents required for each light emitting element of each color in order to obtain the same brightness when displayed in grayscale. In the case where the PLE control described above is introduced into a display panel driving apparatus using a light emitting element represented by an organic EL element whose light emission luminance depends on a driving current, the determination of APL calculation can be appropriately performed. Therefore, regardless of the light emitting elements of R, G, and B, it is possible to realize PLE control that reduces power consumption by reducing peak luminance when the lighting rate is high.

Further, in the configuration shown in FIG. 6, the first weighting means 22A is necessary for each light emitting element of each color in order to obtain the same brightness when displaying in R, G, B video signals in gray scale. The weighting may be performed according to the ratio of the emitted light power, i.e., the emitted light power ratio of each color at the time of gray scale display. This arrangement, Ru der corresponds to the second embodiment can be suitably employed for PLE control unit 4 shown in FIG.

  That is, the weighting means 22A in the first form of the PLE control unit 4 described above performs the weighting according to the ratio of the light emission currents required for the light emitting elements of the respective colors. The weighting means 22A is different in that “weighting is performed according to the ratio of the light emission power required for each light emitting element of each color”.

  However, the light emission power P of the light emitting element can be expressed as P = Vf × If which is the product of the forward voltage Vf and the current If. That is, the light emission power P has a relationship proportional to the light emission current If and a relationship proportional to the forward voltage Vf. Therefore, the configuration for realizing the weighting means 22A in the second mode of the PLE control unit 4 can be shown as the configuration of the block diagram similar to the weighting unit 22A in the first mode shown in FIG.

  According to the PLE operation by the weighting operation by the second means and the APL output generated by the averaging means, the PLE operation by the APL output generated by the weighting operation by the first means and the averaging means already described. The same effect can be obtained.

Figure 7 is Ru der shows the third embodiment may be suitably used relative to PLE control unit 4 shown in FIG. 4 in block diagram. In FIG. 7, parts that perform the same functions as those shown in FIG. 6 already described are denoted by the same reference numerals. Therefore, the description is omitted as appropriate.

  In the configuration shown in FIG. 7, the first selection unit 26 and the second selection unit 27 are provided in the configuration shown in FIG. The video signals corresponding to G and B can be selectively supplied to the first weighting means 22A or the second weighting means 22B. The first weighting means 22A performs the same function as the first weighting means 22A shown in FIG.

  Also, the second weighting means 22B shown in FIG. 7 is a luminance required for each light emitting element of each color in order to obtain the same brightness when displaying in R, G, B color video signals in gray scale. The weighting is performed according to the ratio of light emission, that is, the light emission luminance ratio of each color at the time of gray scale display, and this performs the same function as the luminance ratio weighting means shown in FIG.

  The first weighting means 22A and the second weighting means 22B are connected to averaging means 23a and 23b, respectively, and the averaged output from the averaging means 23a and 23b is supplied to the second selection means 27. The averaged output selected by the second selection means 27 is supplied to the peak luminance control means 29. That is, the first and second selection means 26 and 27 are configured so that the averaged output by the first or second weighting means 22A and 22B can be selected alternatively.

  According to the configuration shown in FIG. 7, it is possible to select the function of weighting by the light emission current ratio by the first weighting means 22A and the function of weighting by the luminance ratio by the conventional second weighting means 22B. That is, when the weighting operation based on the light emission current ratio is selected by the selection unit, the energy saving mode can be set. On the other hand, when the weighting operation based on the luminance ratio is selected, the image quality is high (contrast-oriented). Can be set to mode.

  Further, as described in the second embodiment, the first weighting means 22A in the configuration shown in FIG. 7 is replaced with a weighting means that performs weighting according to the emission power ratio of each color during grayscale display. It can also be configured. Even in such a configuration, the above-described energy saving mode and contrast priority mode can be selected.

Figure 8 is Ru der shows the fourth embodiment may be suitably used relative to PLE control unit 4 shown in FIG. 4 in block diagram. In FIG. 8, the same reference numerals are used for the portions that perform the same functions as those shown in FIG. 6 and FIG.

  In the configuration shown in FIG. 8, the second weighting unit 22B further applies the luminance ratio to the R, G, B color video signals for which the first weighting unit 22A has performed the weighting operation based on the light emission current ratio. The APL output is obtained by averaging the video signals of the respective colors weighted by both by the averaging means 23. In the configuration shown in FIG. 8, the first weighting means 22A and the second weighting means 22B can obtain the same characteristics even if they are interchanged.

  According to the configuration shown in FIG. 8, it is possible to obtain the characteristics provided with the characteristics by the first and second weighting means 22A and 22B already described, and the first to third characteristics shown in FIGS. Compared to the embodiment, the calculated average luminance level can be relatively accurate.

  Further, as described in the second embodiment, the first weighting means 22A in the configuration shown in FIG. 8 is replaced with a weighting means that performs weighting according to the emission power ratio of each color during grayscale display. It can also be configured. Even in such a configuration, a relatively accurate average luminance level calculated in the same manner can be obtained.

It is a block diagram explaining the basic composition of the conventional APL calculation means in the case of handling a color video signal. It is an equivalent circuit diagram of an organic EL element. It is the static characteristic figure which showed the various characteristics of the organic EL element. It is the block diagram which showed the whole structure of the drive device containing a display panel. FIG. 5 is a circuit configuration diagram illustrating a configuration example of pixels arranged in the light emitting display panel illustrated in FIG. 4. FIG. 5 is a block diagram illustrating first and second embodiments that can be suitably employed in the PLE control unit shown in FIG. 4. It is a block diagram explaining a 3rd embodiment similarly. It is a block diagram explaining a 4th embodiment similarly.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Controller circuit 2 A / D conversion part 3 Video memory 4 PLE control part 5 Output processing part 6 Scan driver 7 Data driver 8 Power supply circuit 10 Display panel 11 Scan line 12 Data line 13 Power supply line 20 APL calculation means 21 Color signal Demodulation circuit 22A First weighting means 22B Second weighting means 23 Averaging means 24 Temperature detection means 25 Look-up tables 26, 27 Selection means 29 Peak luminance control means

Claims (4)

A drive device for a light-emitting display panel configured such that light-emitting elements of a plurality of colors are arranged in a matrix and each of the light-emitting elements is selectively driven to emit light based on a video signal,
APL calculating means for calculating an average luminance level (APL) from the video signal, and if the APL calculated by the APL calculating means is smaller than a predetermined value, the peak luminance level is increased, and the APL is higher than the predetermined value. Is also provided with a peak luminance control means for variably controlling the peak luminance in the video signal in accordance with the APL by performing control to lower the peak luminance level .
The said APL calculating unit, for each color video signal, a first weighting means for performing weighting according to the emission current ratio of each color at the gray scale display, for each color of the video signal, when a gray scale display A second weighting means for performing weighting according to the light emission luminance ratio of each color in
By the selecting means for the user to select one of said first weighting means and said second weighting means, the respective color video signals, weighted or said second by the first weighting means A drive device for a light-emitting display panel, characterized in that weighting by weighting means is performed. A drive device for a light-emitting display panel configured such that light-emitting elements of a plurality of colors are arranged in a matrix and each of the light-emitting elements is selectively driven to emit light based on a video signal,
APL calculating means for calculating an average luminance level (APL) from the video signal, and if the APL calculated by the APL calculating means is smaller than a predetermined value, the peak luminance level is increased, and the APL is higher than the predetermined value. Is also provided with a peak luminance control means for variably controlling the peak luminance in the video signal in accordance with the APL by performing control to lower the peak luminance level .
The said APL calculating unit, for each color video signal, a first weighting means for performing weighting according to the emission power ratio of each color at the gray scale display, for each color of the video signal, when a gray scale display A second weighting means for performing weighting according to the light emission luminance ratio of each color in
By the selecting means for the user to select one of said first weighting means and said second weighting means, the respective color video signals, weighted or said second by the first weighting means A drive device for a light-emitting display panel, characterized in that weighting by weighting means is performed. A driving method of a light-emitting display panel configured such that light emitting elements of a plurality of colors are arranged in a matrix and each light emitting element is selectively driven to emit light based on a video signal,
An average luminance level (APL) is calculated from the video signal by the APL calculating means, and the APL information calculated by the APL calculating means is supplied as a control signal to the peak luminance controlling means, and the calculated APL is predetermined. When the APL is larger than the predetermined value, the peak luminance level is increased, and when the APL is larger than the predetermined value, the peak luminance level is decreased . To perform variable control operations,
In calculating the average luminance level, the APL calculating means performs a first weighting operation for weighting the video signal of each color according to the light emission current ratio of each color at the time of gray scale display, or the average luminance level. A second weighting operation for weighting the video signal of each color according to the emission luminance ratio of each color at the time of grayscale display,
Any one of the above is executed by the user's selection. A driving method of a light-emitting display panel configured such that light emitting elements of a plurality of colors are arranged in a matrix and each light emitting element is selectively driven to emit light based on a video signal,
An average luminance level (APL) is calculated from the video signal by the APL calculating means, and the APL information calculated by the APL calculating means is supplied as a control signal to the peak luminance controlling means, and the calculated APL is predetermined. When the APL is larger than the predetermined value, the peak luminance level is increased, and when the APL is larger than the predetermined value, the peak luminance level is decreased . To perform variable control operations,
In calculating the average luminance level, the APL calculating means performs a first weighting operation for weighting the video signal of each color according to the emission power ratio of each color at the time of gray scale display, or the average luminance level. A second weighting operation for weighting the video signal of each color according to the emission luminance ratio of each color at the time of grayscale display,
Any one of the above is executed by the user's selection.

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