JP2014194578A - Organic el display device and driving method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL display device, capable of acquiring display with no unevenness of luminance at each pixel group when an images is displayed on the two pixel groups respectively, and a driving method thereof.SOLUTION: A driver IC 12 controls lighting time of each of organic EL pixels 13 and 14 so that a product of current density (=driving current/pixel area) flowing through the organic EL pixels 13 and 14 and the light time of the organic EL pixels 13 and 14 becomes constant. Thus, even when pixel area of the organic EL pixel 13 of a dot display unit 7 is different from pixel area of the organic EL pixel 14 of a segment display unit 8, display luminance of the organic EL pixels 13 and 14 is made uniform respectively, and display with no unevenness of luminance can be acquired at the dot display unit 7 and the segment display unit 8.

Description

  The present invention relates to an organic EL display device and a driving method thereof.

  Conventionally, for example, Patent Documents 1 to 4 have proposed display devices that display desired images in two display areas, respectively.

  Specifically, Patent Document 1 proposes an organic EL display device in which a dot matrix portion and a segment portion for displaying an image are mixed. This organic EL display device is provided with a dot matrix driver for controlling the dot matrix portion and a segment driver for controlling the segment portion. The dot matrix section and the dot matrix driver are electrically connected via a dedicated dot matrix wiring, and the segment section and the segment driver are also electrically connected via a segment dedicated wiring.

  Further, when performing dimming to reduce the luminance of the display, the organic EL display device controls the luminance by changing the current value for the dot matrix portion, and performs pulse width modulation (PWM) for the segment portion. By controlling the brightness.

  Patent Document 2 proposes a display device that includes a main panel, a sub panel, and a driver IC that drives the main panel and the sub panel. The sub panel is connected to the driver IC via the main panel. For this reason, the wiring for connecting the sub panel and the driver IC and the wiring for connecting the main panel and the driver IC are common.

  In the display device having such a configuration, the main panel and the sub panel are simultaneously driven by the same driver IC. In this case, the driving voltage of the main panel and the driving voltage of the sub panel are different from each other, and a part of the screen displayed on the main panel is not displayed on the sub panel.

  Patent Documents 3 and 4 propose a display device in which organic EL elements are arranged in a matrix at a plurality of intersections of drive line anode lines and scan line cathode lines. In this display device, the selected organic EL element emits light by selectively connecting the anode line to the drive source in synchronization with a scanning period in which the cathode line is periodically connected to the ground potential. Yes. In addition, a reset period for resetting all of the organic EL elements is provided during the scanning period.

  Then, at the time of dimming to reduce the luminance of the display device, the reverse bias voltage applied to the cathode lines that are not scanned is reduced. As a result, the luminance level in the scanning period is brought close to a constant level as compared with the case where a constant reverse bias voltage is always applied.

JP 2008-209833 A JP-A-2005-70121 Japanese Patent No. 3874390 Japanese Patent No. 3854182

  However, since Patent Document 1 uses two drivers, a dot matrix driver and a segment driver, two drivers are required, and a space for mounting these wirings and drivers on the panel is required. And there is a problem that the assembly and parts are costly.

  Further, in Patent Document 2, when different voltages are applied to the two panels of the main panel and the sub panel, the same voltage is applied to each panel. There is a problem that a uniform display without uneven brightness cannot be obtained. Further, in the case where driving of pixels having different areas and element characteristics such as a main panel and a sub panel is realized using an organic EL element, each element cannot emit light evenly by simply applying a constant current. Depending on the area and the element characteristics, there is a problem that the display has a lot of luminance unevenness.

  In Patent Documents 3 and 4, the luminance level in the scanning period is brought close to a constant level by lowering the reverse bias voltage when dimming. However, when the display device is provided with two display areas of the dot area and the segment area, it cannot be said that the luminance level of the two display areas approaches a certain level simply by reducing the reverse bias voltage. There may be uneven brightness.

  An object of the present invention is to provide an organic EL display device and a driving method thereof capable of obtaining a display with no luminance unevenness in each pixel group when displaying images on two pixel groups. .

  In order to achieve the above object, according to the first aspect of the present invention, a first pixel group (7) having a plurality of organic EL pixels (13) having a uniform pixel area with respect to one scanning line (10), and one scanning. A second pixel group (8) having one or more organic EL pixels (14) having a pixel area different from that of the organic EL pixel (13) of the first pixel group (7) with respect to the line (11); And drivers (5, 12) for driving the group (7) and the second pixel group (8), respectively. Then, the driver (5, 12) determines the current density flowing through the organic EL pixel (13, 14) and the lighting time of the organic EL pixel (13, 14) according to the pixel area of the organic EL pixel (13, 14). The lighting time is controlled so that the product of is constant.

  According to this, since the display luminance of the organic EL pixel (13, 14) is proportional to the product of the current density and the lighting time, the current density flowing through the organic EL pixel (13, 14) and the organic EL pixel (13, 14) The display brightness can be controlled by controlling the lighting time so that the product of the lighting time becomes constant. For this reason, display luminance can be made uniform in the organic EL pixels (13, 14) having different pixel areas. Therefore, a display with no luminance unevenness can be obtained in each pixel group (7, 8).

  On the other hand, in the invention described in claim 2, the current density of the driver (5, 12) flowing in the organic EL pixel (13, 14) according to the pixel area and the light emission efficiency characteristic of the organic EL pixel (13, 14). And the lighting time of the organic EL pixel (13, 14) and the lighting time of the organic EL pixel (13, 14) are controlled to be constant.

  According to this, since the display luminance of the organic EL pixel (13, 14) is proportional to the product of the current density, the relative luminous efficiency ratio and the lighting time, it is relative to the current density flowing through the organic EL pixel (13, 14). The display brightness can be controlled by controlling the lighting time so that the product of the typical luminous efficiency ratio and the lighting time is constant. For this reason, display luminance can be made uniform in each of the organic EL pixels (13, 14) having different pixel areas and light emission efficiency characteristics. Therefore, a display with no luminance unevenness can be obtained in each pixel group (7, 8).

  In the first and second aspects of the invention, the organic EL pixel (13, 14) is dimmed by PWM control, and the driver (5, 12) is dimming (hereinafter referred to as a dimming period). In the first selection period (45) in which an image is displayed on the first pixel group (7), the organic EL pixels (13, 14) are applied during the scanning period between the scanning period and the next scanning period. The reset driving for discharging the charge charged in the formed parasitic capacitance is performed, and the reset driving is stopped in the second selection period (46) in which an image is displayed on the second pixel group (8).

  According to this, at the time of reset release, it is possible to reduce the influence of the charge wraparound from the parasitic capacitance due to the reset driving, and thus the influence of the instantaneous light emission, that is, the overshoot due to the reverse bias voltage wraparound can be reduced. Therefore, it is possible to obtain a good display without luminance unevenness.

  As in the third aspect of the present invention, the area of the first pixel group (7) is S, the area of a pixel of the second pixel group (8) is Sx, and the driver (5, 12) has a scanning line. When the number is M and the number of scanning lines of the first pixel group (7) is m, a pixel in the second pixel group (8) may satisfy the relationship of Sx ≦ (M−m) × S. .

  In the present invention, the area of the first pixel group (7) is S, the area of a pixel in the second pixel group (8) is Sx, and the number of scanning lines of the driver (5, 12) is When M is M and the number of scanning lines of the first pixel group (7) is m, when the second pixel group (8) satisfies the relationship Sx> (M−m) × S, the second pixel group (8) In a certain pixel, the organic EL pixel (14) of the second pixel group (8) is divided so as to satisfy Sx ′ ≦ (M−m) × S.

  Thereby, even if the pixel area of one organic EL pixel (14) of the second pixel group (8) is large, the organic EL pixel (14) is divided. By driving the pixels, one large organic EL pixel (14) apparently can be driven.

  The invention according to claim 5 is characterized in that the organic EL pixels (14) of the second pixel group (8) are divided into a plurality of areas so as to have the same area. Thereby, since the current density of each divided pixel becomes the same, luminance unevenness in one organic EL pixel (14) can be suppressed.

  In the invention according to claim 6, the driver (5, 12) is configured such that the relative light emission efficiency ratio of the organic EL pixel (13, 14) depends on the light emission efficiency characteristic of the organic EL pixel (13, 14). The lighting time is controlled so that the product of the lighting time of the organic EL pixels (13, 14) becomes constant.

  According to this, since the display luminance of the organic EL pixel (13, 14) is proportional to the product of the current density and the lighting time, the relative luminous efficiency ratio of the organic EL pixel (13, 14) and the organic EL pixel (13 14), the display brightness can be controlled by controlling the lighting time so that the product of the lighting time with 14) is constant. For this reason, it is possible to make the display luminance uniform in the organic EL pixels (13, 14) having different relative luminous efficiency ratios. Therefore, a display with no luminance unevenness can be obtained in each pixel group (7, 8).

  According to the sixth aspect of the present invention, the reset driving for discharging the charge charged in the parasitic capacitance formed in the organic EL pixel (13, 14) during the scanning period between the scanning period and the next scanning period is performed. The driver (5, 12) performs a first selection period (45) for displaying an image on the first pixel group (7) and a second selection period for displaying an image on the second pixel group (8). In accordance with each period of (46), the reset drive state is set during the scanning period between the scanning period for emitting the selected one of the organic EL pixels (13, 14) and the next scanning period. It is characterized by changing.

  According to this, at the time of reset release, it is possible to reduce the influence of the charge wraparound from the parasitic capacitance due to the reset driving, and thus the influence of the instantaneous light emission, that is, the overshoot due to the reverse bias voltage wraparound can be reduced. Therefore, it is possible to obtain a good display without luminance unevenness.

  In the invention described in claim 6, the organic EL pixel (13, 14) is dimmed by PWM control, and the driver (5, 12) is used in the second selection period (46) during the dimming period. The reset driving is stopped.

  According to this, since reset driving is not performed during the dimming period, sneak charges from parasitic capacitance due to reset driving can be eliminated, and deterioration of luminance unevenness can be suppressed.

  The invention according to claim 7 is characterized in that the first pixel group (7) is a dot matrix display portion and the second pixel group (8) is a segment display portion. Thereby, the multi-information display by the dot matrix display part and the clear display by the segment display part can be made compatible in one image display area.

  In the invention described in claim 8, the emission color of the organic EL pixel (13) of the first pixel group (7) is different from the emission color of the organic EL pixel (14) of the second pixel group (8). And As a result, images with different emission colors can be displayed in a single image display device without uneven brightness.

  Although the organic EL display device has been described above, the same applies to the method of driving each organic EL pixel (13, 14) in the organic EL display device.

  That is, according to the ninth aspect of the invention, the current density flowing through the organic EL pixel (13, 14) and the organic EL pixel according to the pixel area of the organic EL pixel (13, 14) by the driver (5, 12). The lighting time is controlled so that the product of the lighting times of (13, 14) becomes constant.

  According to this, since the display luminance of the organic EL pixel (13, 14) is proportional to the product of the current density and the lighting time, the current density flowing through the organic EL pixel (13, 14) and the organic EL pixel (13, 14) The display brightness can be controlled by controlling the lighting time so that the product of the lighting time becomes constant. For this reason, display luminance can be made uniform in the organic EL pixels (13, 14) having different pixel areas. Therefore, a display with no luminance unevenness can be obtained in each pixel group (7, 8).

  On the other hand, in the invention according to claim 10, the relative luminous efficiency ratio of the organic EL pixel (13, 14) is determined by the driver (5, 12) according to the luminous efficiency characteristic of the organic EL pixel (13, 14). The lighting time is controlled so that the product of the lighting time of the organic EL pixels (13, 14) becomes constant.

  According to this, since the display luminance of the organic EL pixel (13, 14) is proportional to the product of the current density and the lighting time, the relative luminous efficiency ratio of the organic EL pixel (13, 14) and the organic EL pixel (13 14), the display brightness can be controlled by controlling the lighting time so that the product of the lighting time with 14) is constant. For this reason, it is possible to make the display luminance uniform in the organic EL pixels (13, 14) having different relative luminous efficiency ratios. Therefore, a display with no luminance unevenness can be obtained in each pixel group (7, 8).

  On the other hand, in the invention described in claim 11, the current density flowing through the organic EL pixel (13, 14) by the driver (5, 12) according to the pixel area and the light emission efficiency characteristic of the organic EL pixel (13, 14). And the lighting time of the organic EL pixel (13, 14) and the lighting time of the organic EL pixel (13, 14) are controlled to be constant.

  According to this, since the display luminance of the organic EL pixel (13, 14) is proportional to the product of the current density, the relative luminous efficiency ratio and the lighting time, it is relative to the current density flowing through the organic EL pixel (13, 14). The display brightness can be controlled by controlling the lighting time so that the product of the typical luminous efficiency ratio and the lighting time is constant. For this reason, display luminance can be made uniform in each of the organic EL pixels (13, 14) having different pixel areas and light emission efficiency characteristics. Therefore, a display with no luminance unevenness can be obtained in each pixel group (7, 8).

  According to the ninth, tenth and eleventh aspects of the present invention, in the first selection period (45) in which an image is displayed on the first pixel group (7) by the driver (5, 12), the scanning period and the next scanning period In the second period, reset driving is performed to discharge the charges charged in the parasitic capacitance formed in the organic EL pixels (13, 14) during the scanning period, and the second pixel group (8) displays an image. In the selection period (46), the reset driving is stopped.

  According to this, at the time of reset release, it is possible to reduce the influence of the charge wraparound from the parasitic capacitance due to the reset driving, and thus the influence of the instantaneous light emission, that is, the overshoot due to the reverse bias voltage wraparound can be reduced. Therefore, it is possible to obtain a good display without luminance unevenness.

  In the invention described in claim 12, the number of scanning lines of the driver (5, 12) is M, the number of scanning lines of the first pixel group (7) is m, and the driver (5, 12) can be controlled. When the characteristic number is n, the lighting time is controlled in the (M−m) × (n−1) stage by the driver (5, 12). Thereby, fine lighting time control can be performed, and a display without luminance unevenness can be obtained in each pixel group (7, 8).

  The invention described in claim 13 is characterized in that the driver (5, 12) drives the first pixel group (7) and the second pixel group (8) used in the vehicle display. According to this, it is possible to provide an easy-to-view display with no luminance unevenness for the passenger of the vehicle (15).

  In addition, the code | symbol in the bracket | parenthesis of each means described in this column and the claim shows the correspondence with the specific means as described in embodiment mentioned later.

1 is a configuration diagram of an organic EL display device according to a first embodiment of the present invention. It is the model which mounted the organic EL display apparatus in the vehicle. It is AB sectional drawing of FIG. It is a circuit diagram of a dot row voltage generation part. It is a circuit diagram of the COM signal generation circuit for segments. FIG. 2 is a partial circuit diagram of the organic EL display device shown in FIG. 1. It is a figure for demonstrating the drive method of driver IC. It is the figure which showed the relationship between instantaneous brightness | luminance and current density. It is the figure which showed the relationship between the shape of a pixel, an area, current density, and instantaneous luminance. It is a schematic diagram which controls display brightness with lighting time for pixels having different areas. (A) is the figure which showed an example which displays an image on an organic electroluminescent panel, (b) is the figure which showed the content of RAM corresponding to the display content of (a). It is the figure which showed the drive waveform of driver IC. FIG. 13 is a circuit diagram showing a circuit operation according to the drive waveform shown in FIG. 12. FIG. 14 is a circuit diagram illustrating a circuit operation following FIG. 13. In 2nd Embodiment, it is the figure which showed the content of RAM for displaying the same image as Fig.11 (a). In 2nd Embodiment, it is the figure which showed the drive waveform of driver IC. FIG. 17 is a circuit diagram showing a circuit operation according to the drive waveform shown in FIG. 16 in the second selection period. In 3rd Embodiment, it is the figure which showed the relationship between the instantaneous brightness | luminance and current density of an element from which the light emission efficiency characteristic differs. In 3rd Embodiment, it is the figure which showed the relationship between the shape of a pixel, an area, a current density, and instantaneous luminance. (A) is the figure which showed an example which displays an image on an organic electroluminescent panel in 3rd Embodiment, (b) is the figure which showed the content of RAM corresponding to the display content of (a). In 3rd Embodiment, it is the figure which showed the drive waveform of driver IC. FIG. 22 is a circuit diagram showing a circuit operation according to the drive waveform shown in FIG. 21 in the second selection period. In 4th Embodiment, it is the figure which showed the relationship between the instantaneous brightness | luminance and current density of an element from which a pixel area and luminous efficiency characteristic differ. In 4th Embodiment, it is the figure which showed the relationship between the shape of a pixel, an area, a current density, and instantaneous luminance. (A) is the figure which showed an example which displays an image on an organic electroluminescent panel in 4th Embodiment, (b) is the figure which showed the content of RAM corresponding to the display content of (a). In 4th Embodiment, it is the figure which showed the drive waveform of driver IC. FIG. 27 is a circuit diagram showing a circuit operation according to the drive waveform shown in FIG. 26 in the second selection period. FIG. 10 is a diagram illustrating a driving waveform of a driver IC in a fifth embodiment. It is a figure for demonstrating the parasitic capacitance of each organic EL pixel in the reset period before n row selection. It is a figure for demonstrating the parasitic capacitance of each organic EL pixel at the time of R1 row selection. It is a figure for demonstrating the parasitic capacitance of each organic EL pixel at the time of R4 row selection. In 5th Embodiment, it is the figure which showed the relationship between the forward voltage concerning a pixel, and a drive voltage. In 5th Embodiment, it is the figure which showed the optical waveform of a dot pixel and a segment pixel when a reverse bias voltage is changed. In 6th Embodiment, it is the figure which showed the drive waveform of driver IC. In 6th Embodiment, it is the figure which showed the optical waveform of the segment pixel in the case of stopping reset drive. It is the figure which showed the content of RAM which concerns on 7th Embodiment. FIG. 10 is a diagram illustrating a driving waveform of a driver IC in a seventh embodiment. FIG. 38 is a circuit diagram showing a part of the circuit operation according to the drive waveform shown in FIG. 37. In the eighth embodiment, it is a diagram showing the relationship between the pixel shape, area, current density, and instantaneous luminance. In the eighth embodiment, the column pulse width applied to the column wiring is shown for each gradation. (A) is the figure which showed an example which displays an image on an organic electroluminescent panel in 8th Embodiment, (b) is the figure which showed the content of RAM corresponding to the display content of (a). FIG. 20 is a diagram illustrating a driving waveform of a driver IC in an eighth embodiment. (A) is the figure which showed the content of RAM in 9th Embodiment, (b) is the figure which showed the drive waveform according to (a). In 10th Embodiment, it is the schematic diagram which divided | segmented the organic EL pixel of the segment display part. (A) is the figure which showed the relationship between each column wiring, the segment number, and the area ratio of the pixel area of the organic EL pixel of a dot display part, (b) showed the display data of RAM with respect to (a). FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, the same or equivalent parts are denoted by the same reference numerals in the drawings.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The organic EL display device according to the present embodiment is mounted on a vehicle, for example, and used as a vehicle display that displays predetermined information as an image.

  FIG. 1 is a configuration diagram of an organic EL display device according to the present embodiment. As shown in the figure, the organic EL display device 1 includes an organic EL panel 2, a panel connection unit 3, a drive voltage generation unit 4, a segment COM signal generation circuit 5, and a drive control unit 6. It is prepared for.

  The organic EL panel 2 is a display for displaying an image, and includes a dot display unit 7, a segment display unit 8, a column wiring 9, a dot row wiring 10, a segment COM wiring 11, a driver IC 12, and the like. , And is configured. In FIG. 1, as an example, the output of the driver IC 12 is shown as three on the column (data) side and six on the row (scan) side.

  The dot display unit 7 is a uniform pixel group in which the organic EL pixels 13 are arranged in a dot matrix. The organic EL pixel 13 of the dot display unit 7 is a pixel having a plurality of uniform pixel areas with respect to the dot row wiring 10 which is one scanning line. In FIG. 1, a 3 × 3 dot matrix is shown as an example.

  On the other hand, the segment display unit 8 is a non-uniform pixel group in which one or more organic EL pixels 14 are arranged to display a predetermined image. In the present embodiment, for example, three organic EL pixels 14 of “Δ”, “◯ (ellipse)”, and “☆” are provided in the segment display unit 8. The organic EL pixel 14 of the segment display unit 8 is a pixel having a pixel area different from that of the organic EL pixel 13 of the dot display unit 7 with respect to the segment COM wiring 11 that is one scanning line.

  As described above, the multi-information display by the dot display unit 7 and the predetermined clear image display by the segment display unit 8 can be performed in one organic EL panel 2.

  FIG. 2 is a schematic diagram in which the organic EL display device 1 is mounted on a vehicle. As shown in FIG. 2A, the organic EL display device 1 is mounted on a vehicle 15 as a multi-information display device for vehicle information and the like. In this case, as shown in FIG. 2 (b), the organic EL panel 2 is disposed, for example, in the central portion of the meter 16. The vehicle information is, for example, the total travel distance of the vehicle.

  The column wiring 9 is a data electrode driving wiring (anode) that connects the driver IC 12, the dot display unit 7, and the segment display unit 8 in series. That is, the column wiring 9 for the driver IC 12, the dot display unit 7, and the segment display unit 8 is shared. The column wiring 9 is a wiring for selecting which organic EL pixels 13 and 14 emit light, and a constant driving current is applied by the driver IC 12.

  The dot row wiring 10 is a wiring (cathode) for applying a voltage to each organic EL pixel 13 of the dot display unit 7. An organic EL pixel 13 is provided at a position where the column wiring 9 and the dot row wiring 10 intersect. In this embodiment, since the dot display unit 7 is a 3 × 3 dot matrix, there are three dot row wirings 10 which are scanning lines.

  The segment COM wiring 11 is a wiring (cathode) for applying a voltage to the organic EL pixel 14 of the segment display unit 8. The segment COM wiring 11 is a wiring common to the three organic EL pixels 14 provided in the segment display unit 8.

  The dot row wiring 10 and the segment COM wiring 11 are so-called scanning lines, and a predetermined voltage is applied by the driver IC 12 and the segment COM signal generation circuit 5.

  The driver IC 12 is an integrated circuit that drives the dot display unit 7 and the segment display unit 8 via the column wiring 9 and the dot row wiring 10, respectively. In the present embodiment, the driver IC 12 directly controls the drive current applied to the column wiring 9 and directly controls the voltage applied to the dot row wiring 10.

  The driver IC 12 controls a voltage application period applied to the segment COM wiring 11 via the segment COM signal generation circuit 5. Therefore, a synchronization signal is output to the segment COM signal generation circuit 5 so that the segment COM wiring 11 is scanned after the dot row wiring 10 is scanned.

  Further, the driver IC 12 includes a RAM 17 that stores the contents (display data) to be displayed as an image. Display data is sent from the drive control unit 6 to the RAM 17. The RAM 17 is commonly used by the dot display unit 7 and the segment display unit 8. For this reason, a part of the entire storage area of the RAM 17 is used as the image display area of the dot display unit 7, and the remaining storage area is used as the image display area of the segment display unit 8. Therefore, the RAM 17 is not required for each dot display unit 7 and segment display unit 8.

  Next, a cross-sectional structure of the organic EL panel 2 having the above configuration will be described. 3 is a cross-sectional view taken along the line AB of FIG. As shown in this figure, a transparent column wiring 9 such as ITO that functions as a hole injection electrode is formed on a substrate 18 such as glass. An organic layer 19 related to light emission is formed on the column wiring 9. The organic layer 19 is an organic film layer in which a hole injecting and transporting layer, a light emitting layer, an electron injecting and transporting layer, and the like are sequentially formed. A dot row wiring 10 such as a metal thin film that functions as an electron injection electrode and a segment COM wiring 11 are formed on the organic layer 19. The dot row wiring 10 and the segment COM wiring 11 are formed by being routed around the outer edge portion of the substrate 18.

  As described above, the organic layer 19 is sandwiched between the column wiring 9 and the dot row wiring 10, and the organic layer 19 is sandwiched between the column wiring 9 and the segment COM wiring 11. A cover 20 is mounted on the substrate 18 with an adhesive 21 so as to cover the laminated structure. Thereby, the organic layer 19 is sealed.

  A driver IC 12 electrically connected to the column wiring 9, the dot row wiring 10, and the segment COM wiring 11 is mounted on the substrate 18. Further, the driver IC 12 and the like are covered and protected by a sealing body 22 such as a resin. The organic EL panel 2 has the above structure.

  The panel connection unit 3 shown in FIG. 1 is a wiring unit for connecting the organic EL panel 2 to the drive voltage generation unit 4 and the segment COM signal generation circuit 5. As the panel connection unit 3, for example, an FPC (Flexible Printed Circuit; FPC) is employed.

  The drive voltage generation unit 4 is a circuit unit that generates a voltage for driving the organic EL panel 2, and generates a drive voltage from the voltage of the battery 23 of 12 V, for example. Such a drive voltage generation unit 4 includes a column voltage generation unit 24, a dot row voltage generation unit 25, and a segment COM voltage generation unit 26.

  The column voltage generator 24 is a booster circuit configured by a transformer, a capacitor, and the like for boosting the voltage of the battery 23. The column voltage generator 24 generates a voltage VddC from the voltage of the battery 23 and supplies the voltage VddC to the driver IC 12 via the panel connector 3. As a result, the driver IC 12 supplies the voltage VddC to each column wiring 9.

  The dot row voltage generator 25 is a step-down circuit that lowers the voltage boosted by the column voltage generator 24 to a predetermined voltage. The dot row voltage generation unit 25 generates a voltage VddR (dot) from the voltage VddC according to a voltage change signal input from the drive control unit 6 and supplies the voltage VddR (dot) to the driver IC 12 via the panel connection unit 3. As a result, the driver IC 12 supplies the voltage VddR (dot) to each dot row wiring 10.

  In the present embodiment, the voltage level of the voltage VddR (dot) is changed by the voltage change signal. FIG. 4 is a diagram illustrating an example of a circuit of the dot row voltage generation unit 25. As shown in this figure, a resistor 27 and a resistor 28 are connected in series between the voltage VddC and GND, and one of the resistors 29 is connected between the resistor 27 and the resistor 28. The other end of the resistor 29 is connected to the collector of an npn transistor 30. The emitter of the transistor 30 is connected to GND, and a voltage change signal is input to the base of the transistor 30. Further, a resistor 32 is connected between the base and emitter of the transistor 30.

  The resistor 27 is connected between the base and the collector of the npn transistor 31, and the voltage VddC is applied to the collector of the transistor 31, and the emitter voltage of the transistor 31 is set to the voltage VddR (dot).

  According to such a circuit configuration, when the voltage change signal is input to the transistor 30, the base voltage of the transistor 31 is adjusted. Since the voltage VddC that is the collector voltage of the transistor 31 is a fixed value, the voltage VddR (dot) increases as the base voltage of the transistor 31 increases, and the voltage VddR (dot) decreases as the base voltage of the transistor 31 decreases. In this way, the voltage VddC is stepped down to the voltage VddR (dot), and the voltage level of the voltage VddR (dot) is adjusted by the voltage change signal.

  The segment COM voltage generator 26 is a step-down circuit that lowers the voltage boosted by the column voltage generator 24 to a predetermined voltage. The segment COM voltage generator 26 generates a voltage VddR (seg) from the voltage VddC generated by the column voltage generator 24 and supplies the voltage VddR (seg) to the segment COM signal generator 5.

  The column voltage generator 24, the dot row voltage generator 25, and the segment COM voltage generator 26 can be said to be means for supplying power to the driver IC 12 and the segment COM signal generator 5.

  The segment COM signal generation circuit 5 is a circuit that supplies the voltage VddR (seg) generated by the segment COM voltage generation unit 26 to the segment COM wiring 11 in accordance with the synchronization signal input from the driver IC 12.

  FIG. 5 is a diagram showing an example of the segment COM signal generation circuit 5. As shown in this figure, the segment COM signal generation circuit 5 includes an XOR circuit 33, a D flip-flop 34, and a NOT circuit 35.

  The XOR circuit 33 is a logic circuit that performs so-called exclusive OR, and inputs the synchronization signal 1 (row output 3) and the synchronization signal 2 (row output 1) from the driver IC 12 to calculate the exclusive OR. Output.

  The D flip-flop 34 is a circuit that Q-outputs the state of reaching the D terminal before the clock pulse is input simultaneously with the fall of the clock pulse. The synchronization signal 1 is input to the D terminal, and the output of the XOR circuit 33 is input to the clock terminal as a clock pulse. The D flip-flop 34 outputs an inverted signal of Q.

  The NOT circuit 35 is a logic circuit that inverts and outputs the output of the D flip-flop 34. The output of the NOT circuit 35 is supplied to the segment COM wiring 11.

  According to such a configuration of the segment COM signal generation circuit 5, the voltage VddR (seg) or the GND voltage is applied to the segment COM wiring 11 in accordance with the combination of the synchronization signal 1 and the synchronization signal 2. Therefore, it can be said that the segment COM signal generation circuit 5 is a switch circuit.

  The drive control unit 6 is a microcomputer that includes a CPU or the like that inputs vehicle information from each device mounted on the vehicle 15 and performs processing for displaying them as images. Such a drive control unit 6 normally generates display data based on vehicle information input from the outside, and outputs the display data to the driver IC 12.

  In addition, the drive control unit 6 includes a dimming control unit that performs dimming control on the organic EL panel 2. The dimming control unit generates a voltage change signal for controlling a voltage applied to the dot row wiring 10 based on the selection period signal from the segment COM signal generation circuit 5 and the vehicle information, and generates a dot row voltage generation unit. To 25. Further, the dimming control unit generates a PWM signal and outputs the PWM signal to the driver IC 12 in order to cause the driver IC 12 to PWM the dimming when dimming the display brightness of the organic EL panel 2 is reduced based on the vehicle information. As a result, the driver IC 12 performs dimming of the organic EL pixels 13 and 14 by PWM control. That is, the driver IC 12 dims the organic EL pixels 13 and 14 by reducing the width of the voltage pulse applied to the column wiring 9.

  FIG. 6 shows an overall circuit diagram of the organic EL panel 2 in the organic EL display device 1 having the above configuration. As shown in this figure, a plurality of matrix-like multiples are respectively formed at intersections of a plurality of scanning lines (dot row wiring 10 and segment COM wiring 11) and a plurality of data lines (column wiring 9) drawn from the driver IC 12. Organic EL pixels 13 and 14 are arranged, respectively. As described above, as an arrangement example, the dot display unit 7 has the organic EL pixels 13 ((0, 0) to (2, 2)) arranged as a 3 × 3 matrix, and the segment display unit 8 has three organic EL elements. Pixels 14 ((3, 0) to (3, 2)) are arranged.

  The driver IC 12 includes data electrode selection switches 36 to 38 for applying a constant driving current to each column wiring 9. The drive current is generated based on the voltage VddC. Each of the data electrode selection switches 36 to 38 has a movable contact on each column wiring 9 side, and either a fixed contact connected to GND (0 V) or a fixed contact connected to the constant current source 39 to 41 is movable contact. Can be contacted.

  As described above, since the organic EL pixel 13 of the dot display unit 7 and the organic EL pixel 14 of the segment display unit 8 are connected to the common column wiring 9, each organic EL pixel 13 and 14 is driven to the same size. Current or GND voltage is supplied. This eliminates the need for a circuit for flowing a drive current for each of the organic EL pixels 13 and 14.

  The driver IC 12 also includes scan electrode selection switches 42 to 44 for applying a voltage VddR (dot) or a GND voltage to each dot row wiring 10. Each of the scanning electrode selection switches 42 to 44 has a movable contact on each dot row wiring 10 side, and either a fixed contact connected to GND (0 V) or a fixed contact to which voltage VddR (dot) is applied. The movable contact can be brought into contact.

  The driver IC 12 drives on / off of the data electrode selection switches 36 to 38 and the scan electrode selection switches 42 to 44. Specifically, the driver IC 12 processes the display data input from the drive control unit 6, causes the pixels selected as the light emitting pixels to emit light, and causes the other pixels to emit no light, thereby causing the data electrode selection switches 36 to 38 to emit light. Further, on / off of the scan electrode selection switches 42 to 44 is controlled.

  Further, the segment COM wiring 11 is connected to the segment COM signal generation circuit 5. As described above, the segment COM signal generation circuit 5 is connected to the segment COM wiring 11 so as to apply the voltage VddR (seg) or the GND voltage to the segment COM wiring 11 in accordance with the synchronization signal input from the driver IC 12. Has been. The above is the overall configuration of the organic EL display device 1 according to the present embodiment.

  Next, a method for driving the organic EL pixels 13 and 14 by the driver IC 12 will be described with reference to FIGS. In the present embodiment, the driver IC 12 drives and controls two display areas of the dot display unit 7 and the segment display unit 8.

  Specifically, as shown in FIG. 7, the driver IC 12 performs time-division driving that scans the segment display unit 8 (seg driving) after scanning the dot display unit 7 (dot driving). This is because, when the number of row lines (scanning lines) of the dot display unit 7 is smaller than the number of channels that can be driven by the driver IC 12, the number of row lines (number of scanning lines) of the dot display unit 7 is subtracted from the number of channels that can be driven by the driver IC12. This is possible by using the scan time of the remaining output.

  In the present embodiment, a period for performing dot driving, that is, a period for displaying an image on the dot display unit 7 is referred to as a first selection period 45, and a period for performing segment driving, that is, a period for displaying an image on the segment display unit 8 is second selected. It is called period 46.

  Therefore, the driver IC 12 drives the dot display unit 7 in the first selection period 45, and the driver IC 12 and the segment COM signal generation circuit 5 drive the segment display unit 8 in the second selection period 46.

  Further, the display luminance (instantaneous luminance) of the organic EL pixels 13 and 14 is proportional to the current density (= drive current / pixel area) as shown in FIG. For example, if the drive current applied to one pixel from the data electrode is 0.6 mA, the organic EL pixels 13 and 14 are classified as shown in FIG. That is, when the area of the dot (□) that is the organic EL pixel 13 of the dot display unit 7 is 0.001 cm 2, the current density is 600 mA / cm 2. Thus, the instantaneous luminance is 27000 cd / m 2 from FIG.

  On the other hand, as shown in FIG. 9, the organic EL pixel 14 of the segment display unit 8 has a current density of 300 mA / cm 2 when the areas of the seg A (☆) and the seg B (◯) are both 0.002 cm 2. . Further, from FIG. 8, the instantaneous luminance is 13500 cd / m 2. Further, when the area of the segment C (Δ) is 0.003 cm 2, the current density is 200 mA / cm 2, and the instantaneous luminance is 9000 cd / m 2 from FIG.

  Therefore, in order to make the instantaneous luminance of each of the organic EL pixels 13 and 14 shown in FIG. 9 the same, the unit time for lighting the seg B is set twice as long as the dot, and the unit time for lighting the seg C is set to 3 dots. Double it. In this way, the pixel areas of the organic EL pixels 13 and 14 are different, and the magnitudes of the drive currents applied from the data electrodes to the organic EL pixels 13 and 14 are the same. In order to display the pixels with the same display brightness, the display brightness of the pixels having different pixel areas can be made the same by controlling the lighting time to be longer as shown in FIG.

  For this reason, the driver IC 12 determines the current density (= drive current / pixel area) flowing through the organic EL pixels 13 and 14 and the lighting time of the organic EL pixels 13 and 14 according to the pixel areas of the organic EL pixels 13 and 14. The lighting time is controlled so that the product of becomes constant.

  Specifically, the driver IC 12 controls the lighting time as follows. First, FIG. 11A is a diagram illustrating an example of displaying an image on the organic EL panel 2. The organic EL pixels 13 (0, 0), (0, 1), (1, 2), (2, 0) in the matrix of the dot display unit 7 are caused to emit light, and “O” in the segment display unit 8 is displayed. It is assumed that the “Δ” organic EL pixel 14 emits light. The organic EL pixels 13 and 14 that emit light are hatched.

  When the area of the organic EL pixel 13 of the dot display unit 7 is S, the area of the “☆” organic EL pixel 14 of the segment display unit 8 is 2S, the area of the organic EL pixel 14 of “◯” is 2S, “ The area of the organic EL pixel 14 of “Δ” is assumed to be 3S. As described above, in order to make the product of the current density and the lighting time constant, the lighting time of the organic EL pixel 14 having the area 2S is twice the lighting time of the organic EL pixel 13 having the area S. What should I do? Similarly, the lighting time of the organic EL pixel 14 having an area of 3S may be set to three times the lighting time of the organic EL pixel 13 having an area S.

  FIG. 11B shows the contents of the RAM 17, that is, the display data when the organic EL pixels 13 and 14 emit light as shown in FIG. 11A. The area where the organic EL pixels 13 and 14 emit light is hatched. The C0 to C2 columns correspond to the column wiring 9, the R0 to R2 rows are areas assigned to the dot display unit 7, and the R3 to R5 rows are areas assigned to the segment display unit 8.

  FIG. 12 is a diagram illustrating a driving waveform of the driver IC 12. 13 and 14 are circuit diagrams showing circuit operations in accordance with the drive waveforms shown in FIG.

  First, the stage shown in FIGS. 13A to 13C is the first selection period 45 for driving the dot display section 7, and the stage shown in FIGS. 14A to 14C is the segment. This is a second selection period 46 for driving the display unit 8.

  When the R0 row shown in FIG. 13A is selected, the driver IC 12 uses the data selection switches 36 and 37 to drive the organic EL pixels 13 of (0, 0) and (0, 1) to emit constant current. 39 and 40 are selected, and the data selection switch 38 selects GND. As a result, as shown in FIG. 12, when the R0 row is selected on the scanning side (row), the driving current flows in the C0 column and the C1 column, and the signal on the data side (column) is driven in the C2 column. The signal does not flow.

  As shown in FIG. 13A, the driver IC 12 selects GND by the scan electrode selection switch 42 and the voltage VddR (dot) by the scan electrode selection switches 43 and 44 so that only the R0 row is selected. Select. Further, the driver IC 12 selects the voltage VddR (seg) by the segment COM signal generation circuit 5 by outputting a synchronization signal.

  Thus, the voltage applied to each dot row wiring 10 and segment COM wiring 11 by the driver IC 12 by the data electrode selection switches 36 to 38, the scan electrode selection switches 42 to 44, and the segment COM signal generation circuit 5 is determined. When selected, a drive current flows through the organic EL pixels 13 located at (0, 0) and (0, 1), and these emit light. On the other hand, the non-light-emitting organic EL pixels 13 and 14 are charged to the parasitic capacitance based on the applied potential difference.

  Here, the driver IC 12 emits the selected one of the organic EL pixels 13 and 14 between the scanning period (for example, when the R0 row is selected) and the next scanning period (for example, when the R1 row is selected). During the scanning period, reset driving is performed to discharge the charges charged in the parasitic capacitances formed in the non-light-emitting organic EL pixels 13 and 14. A period during which reset driving is performed is a reset period. In the following, reset driving is performed during each scanning period.

  Subsequently, at the time of selecting the R1 row shown in FIG. 13B, the driver IC 12 selects GND by the data selection switches 36 and 37 in order to cause the organic EL pixel 13 of (1, 2) to emit light, and the data selection switch. The constant current source 41 is selected by 38. Thus, as shown in FIG. 12, when the R1 row is selected, the signal on the data side (column) is a signal in which the drive current does not flow in the C0 column and the C1 column, but the drive current flows in the C2 column. .

  Also, as shown in FIG. 13B, the driver IC 12 selects GND by the scan electrode selection switch 43 and the voltage VddR (dot) by the scan electrode selection switches 42 and 44 so that only the R1 row is selected. Select. Further, the driver IC 12 selects the voltage VddR (seg) by the segment COM signal generation circuit 5 by outputting a synchronization signal.

  As a result, a current flows through the organic EL pixel 13 located at (1, 2) to emit light. On the other hand, the non-light-emitting organic EL pixels 13 and 14 are charged to the parasitic capacitance based on the applied potential difference. Then, the driver IC 12 performs reset driving.

  Thereafter, at the time of selecting the R2 row shown in FIG. 13C, the driver IC 12 selects GND by the data selection switches 37 and 38 in order to cause the (2, 0) organic EL pixel 13 to emit light, and the data selection switch. The constant current source 39 is selected by 36. Thus, as shown in FIG. 12, when the R2 row is selected, the signal on the data side (column) is a signal in which the drive current does not flow in the C0 column and the C1 column but the drive current flows in the C2 column. .

  As shown in FIG. 13C, the driver IC 12 selects GND by the scan electrode selection switch 44 and the voltage VddR (dot) by the scan electrode selection switches 42 and 43 so that only the R2 row is selected. Select. Further, the driver IC 12 selects the voltage VddR (seg) by the segment COM signal generation circuit 5 by outputting a synchronization signal.

  As a result, a current flows through the organic EL pixel 13 located at (2, 0) to emit light. On the other hand, the non-light-emitting organic EL pixels 13 and 14 are charged to the parasitic capacitance based on the applied potential difference. Then, the driver IC 12 performs reset driving. In this way, the driver IC 12 causes the organic EL pixels 13 of the dot display unit 7 to emit light in the first selection period 45.

  Next, when the R3 to R5 rows shown in FIGS. 14A to 14C are selected, the driver IC 12 causes the organic EL pixels 14 of “◯” and “Δ” to emit light. Here, rows R3 to R5 are portions not connected to the organic EL panel 2, and the above-described segment COM wiring 11 is connected instead. That is, when the rows R3 to R5 are selected, that is, in the second selection period 46, the driver IC 12 selects the voltage VddR (dot) by the scan electrode selection switches 42 to 44, and outputs the synchronization signal, thereby generating the segment COM signal generation circuit 5 Select GND. Therefore, as shown in FIG. 12, the drive waveform when the R3 to R5 rows are selected is a COM waveform, and the segment COM wiring 11 is set to the GND voltage while the R3 to R5 rows are selected.

  When the R3 and R4 rows shown in FIGS. 14 (a) and 14 (b) are selected, the driver IC 12 uses the data selection switch 36 to cause the light to emit the “O” and “Δ” organic EL pixels 14. The constant current sources 40 and 41 are selected by the data selection switches 37 and 38. Thus, as shown in FIG. 12, when the R3 row and the R4 row are selected, the driving current does not flow in the C0 column and the driving current flows in the C1 column and the C2 column in the data side (column) signal. Signal.

  Subsequently, when the R5 row shown in FIG. 14C is selected, the driver IC 12 selects GND by the data selection switches 36 and 37 and causes the data selection switch 38 to cause the “Δ” organic EL pixel 14 to emit light. The constant current source 41 is selected. Thus, as shown in FIG. 12, when the R5 row is selected, the signal on the data side (column) is a signal in which the drive current does not flow in the C0 column and the C1 column but the drive current flows in the C2 column. .

  As described above, the organic EL pixel 14 of “◯” is turned on when the R3 and R4 rows are selected, so that the lighting time is twice the lighting time of the organic EL pixel 13 of the dot display unit 7. The “Δ” organic EL pixels 14 are turned on when the R3 to R5 rows are selected, so that the lighting time is three times the lighting time of the organic EL pixels 13 of the dot display section 7. In this way, the lighting time of a pixel having a large area is lengthened. For this reason, even for the organic EL pixel 14 of the segment display unit 8 having a pixel area different from that of the organic EL pixel 13 of the dot display unit 7, the display luminance is uniformly controlled by making the current density × lighting time constant. it can.

  As described above, the driver IC 12 displays the display data stored in the RAM 17 on the organic EL panel 2.

  The driver IC 12 reduces the pulse width of the data electrode selection period (column side) of the scanning period in which the organic EL pixels 13 and 14 emit light by PWM control when the organic EL panel 2 is dimmed to display an image. To control dimming.

  As described above, in this embodiment, the driver IC 12 has a constant product of the current density (= drive current / pixel area) flowing through the organic EL pixels 13 and 14 and the lighting time of the organic EL pixels 13 and 14. Thus, the lighting time of each organic EL pixel 13 and 14 is controlled.

  Thereby, the display brightness | luminance of each organic EL pixel 13 and 14 from which a pixel area differs can be made the same, respectively. For this reason, even if the pixel area of the organic EL pixel 13 of the dot display unit 7 and the pixel area of the organic EL pixel 14 of the segment display unit 8 are different, the display luminance of each of the organic EL pixels 13 and 14 is made uniform. can do. Therefore, a display with no luminance unevenness can be obtained by the dot display unit 7 and the segment display unit 8.

  In particular, when the organic EL display device 1 is mounted on the vehicle 15, it is possible to make it easier for a passenger such as a driver to recognize an image because there is no luminance unevenness in the image display of the organic EL panel 2.

  Regarding the correspondence between the description of the present embodiment and the description of the scope of claims, the dot display section (dot matrix display section) 7 corresponds to the “first pixel group” of the scope of claims, and the segment display section 8 corresponds to the “second pixel group” in the claims. Further, the dot row wiring 10 related to the dot display portion 7 corresponds to “one scanning line related to the first pixel group” in the claims, and the segment COM wiring 11 related to the segment display portion 8 corresponds to the claims. The column wiring 9 corresponds to “data electrode driving wiring” in the claims. Further, the driver IC 12 and the segment COM signal generation circuit 5 correspond to a “driver” in the claims.

  Further, the column voltage generation unit 24, the dot row voltage generation unit 25, and the segment COM voltage generation unit 26 correspond to a “voltage generation unit” in the claims.

(Second Embodiment)
In the present embodiment, parts different from the first embodiment will be described. In the first embodiment, since “◯” of the segment display unit 8 is lit twice, the organic EL related to “◯” continuously in the R3 and R4 rows among the R3 to R5 rows on the scanning side (low). The pixel 14 was lit and not lit in the R5 row. As described above, since the lighting time related to “◯” only needs to be twice the lighting time of the organic EL pixel 13 of the dot display unit 7, the “lighting time” can be adjusted in the R3 to R5 rows. it can.

  Therefore, in this embodiment, the contents of the RAM 17 are set as shown in FIG. Specifically, the timing at which “◯” is emitted in the C1 column is set to twice in the R3 row and the R5 row. As a result, the drive waveform of the driver IC 12 becomes the waveform shown in FIG.

  That is, at the time of selecting the R3 row shown in FIG. 17A, the driver IC 12 selects GND by the data selection switch 36 and causes the data selection switch 37 to emit the “O” and “Δ” organic EL pixels 14. 38, constant current sources 40, 41 are selected. Thus, as shown in FIG. 16, when the R3 row and the R4 row are selected, the drive current does not flow in the C0 column and the drive current flows in the C1 column and the C2 column in the data side (column) signal. Signal. That is, “◯” and “Δ” organic EL pixels 14 emit light.

  Subsequently, when the R4 row shown in FIG. 17B is selected, the driver IC 12 selects GND by the data selection switches 36 and 37 and causes the data selection switch 38 to cause the organic EL pixel 14 of “Δ” to emit light. The constant current source 41 is selected. Thus, as shown in FIG. 16, when the R4 row is selected, the signal on the data side (column) is a signal in which the drive current does not flow in the C0 column and the C1 column but the drive current flows in the C2 column. . That is, only the “Δ” organic EL pixel 14 emits light.

  Further, when the R5 row shown in FIG. 17C is selected, the driver IC 12 selects the GND by the data selection switch 36 and causes the data selection switch 37 to emit the “O” and “Δ” organic EL pixels 14. 38, constant current sources 40, 41 are selected. Thus, as shown in FIG. 16, when the R5 row is selected, the signal on the data side (column) is a signal in which the drive current does not flow in the C0 column and the C1 column but the drive current flows in the C2 column. . That is, “◯” and “Δ” organic EL pixels 14 emit light.

  In this way, the organic EL pixel 14 of “◯” can be controlled to light twice in total during the scanning period of the R3 to R5 rows assigned to the dot display unit 7.

  The organic EL pixels 14 related to “◯” may be lit continuously in the R4 row and the R5 row without being lit in the R3 row.

(Third embodiment)
In the present embodiment, parts different from the first and second embodiments will be described. In each of the above embodiments, the lighting time is controlled so that the product of the pixel area of each organic EL pixel 13, 14 and the current density is constant. In this embodiment, the light emission of each organic EL pixel 13, 14 is controlled. The lighting time is controlled according to the efficiency characteristics.

  FIG. 18 is a diagram showing the relationship between the current density and the instantaneous luminance of the elements A and B having different light emission efficiency characteristics. The element A corresponds to the organic EL pixel 13 of the dot display unit 7, and the element B corresponds to the organic EL pixel 14 of the segment display unit 8.

  As for the relative luminous efficiency characteristics of the element A and the element B, the luminous efficiency of the element B is 0.33 while the luminous efficiency of the element A is 1. Such a difference in luminous efficiency characteristics is, for example, a difference in emission color. Therefore, as shown in FIG. 18, the display luminance (instantaneous luminance) of each of the elements A and B is proportional to the current density (= drive current / pixel area), but the inclination of the element A having relatively high light emission efficiency. The instantaneous brightness is high even at the same current density.

  For example, if the drive current applied to one pixel from the data electrode is 0.6 mA, the elements A and B are classified as shown in FIG. In the present embodiment, the shapes of the organic EL pixels 13 and 14 are both dots (□), and the pixel areas of the organic EL pixels 13 and 14 are the same.

  As shown in FIG. 19, when the area of the dot (□) which is the element A (the organic EL pixel 13 of the dot display unit 7) is 0.001 cm 2, the current density is 600 mA / cm 2. Thus, the instantaneous luminance is 27000 cd / m 2 from FIG. On the other hand, the area of the element B (the organic EL pixel 14 of the segment display unit 8) is also 0.001 cm 2 and the current density is 600 mA / cm 2. However, since the light emission efficiency of the element B is relatively low with respect to the element A, the instantaneous luminance is 9000 cd / m 2.

  Therefore, in order to make the instantaneous luminances of the elements A and B (organic EL pixels 13 and 14) shown in FIG. 19 the same, the lighting time of the element B may be set to three times the lighting time of the element A. In this way, the light emission efficiency characteristics of the organic EL pixels 13 and 14 are different, and the magnitudes of the drive currents applied to the organic EL pixels 13 and 14 are the same. If the lighting time is controlled in order to display the image, the display luminance of the pixels having different light emission efficiency characteristics can be made the same.

  For this reason, in this embodiment, the driver IC 12 determines the relative luminous efficiency ratio of the organic EL pixels 13 and 14 and the lighting time of the organic EL pixels 13 and 14 according to the luminous efficiency characteristics of the organic EL pixels 13 and 14. The lighting time is controlled so that the product of becomes constant.

  Specifically, the driver IC 12 controls the lighting time as follows. First, FIG. 20A is a diagram showing an example of displaying an image on the organic EL panel 2 in the present embodiment. The (0,0), (0,1), (1,2), (2,0) organic EL pixels 13 in the matrix of the dot display unit 7 are caused to emit light, and the rightmost side of the segment display unit 8, that is, ( Assume that the organic EL pixel 14 of 3 and 2) emits light. As shown in FIG. 20B, display data is stored in the RAM 17 so that the organic EL pixels 13 and 14 emit light as shown in FIG.

  FIG. 21 is a diagram illustrating a driving waveform of the driver IC 12. FIG. 22 is a circuit diagram showing a circuit operation in accordance with the second selection period 46 in the drive waveforms shown in FIG. The circuit operation of the R0 to R2 rows on the scanning side (row) and the C0 to C2 columns on the data side (column), that is, the circuit operation in the first selection period 45 is the same as in the first embodiment.

  When the R3 to R5 rows shown in FIGS. 22A to 22C are selected, the driver IC 12 uses the data selection switches 36 and 37 to cause one of the three organic EL pixels 14 to emit light. The GND is selected, and the constant current source 41 is selected by the data selection switch 38. Further, the driver IC 12 selects the voltage VddR (dot) by the scan electrode selection switches 42 to 44, and selects the GND by the segment COM signal generation circuit 5 by outputting a synchronization signal.

  As a result, as shown in FIG. 21, when the R3 to R4 rows are selected, the signal on the data side (column) does not flow in the C0 and C1 columns but flows in the C2 column. It becomes. That is, the hatched portion of the organic EL pixel 14 shown in FIG. 20A emits light.

  As described above, since the light emission efficiency of the organic EL pixel 13 of the dot display unit 7 is three times the light emission efficiency of the organic EL pixel 14 of the segment display unit 8, the lighting time of the organic EL pixel 14 of the segment display unit 8. Is three times the lighting time of the organic EL pixel 13 of the dot display section 7. Thus, since the lighting time is controlled so that the product of the relative luminous efficiency ratio of the organic EL pixels 13 and 14 and the lighting time of the organic EL pixels 13 and 14 is constant, the relative light emission is performed. The display brightness of the organic EL pixels 13 and 14 having different efficiency ratios can be made uniform. Therefore, a display with no luminance unevenness can be obtained by the dot display unit 7 and the segment display unit 8.

(Fourth embodiment)
In the present embodiment, parts different from the first to third embodiments will be described. The present embodiment is characterized in that the lighting time is controlled in accordance with the pixel area and the light emission efficiency characteristics of each of the organic EL pixels 13 and 14.

  FIG. 23 is a diagram showing the relationship between the current density and the instantaneous luminance of the elements A and C having different pixel areas and light emission efficiency characteristics. The element A corresponds to the organic EL pixel 13 of the dot display unit 7, and the element C corresponds to the organic EL pixel 14 of the segment display unit 8.

  The element A and the element C have different pixel areas, and the light emission efficiency of the element A is 1 while the light emission efficiency of the element A is 1 in terms of the relative light emission efficiency characteristics of the element A and the element C. The efficiency is 1.5. Therefore, as shown in FIG. 23, the display luminance (instantaneous luminance) of each of the elements A and C is proportional to the current density (= driving current / pixel area), but the inclination of the element C having relatively high light emission efficiency. The instantaneous brightness is high even at the same current density.

  For example, if the drive current applied to one pixel from the data electrode is 0.6 mA, the elements A and C are classified as shown in FIG. That is, when the area of the dot (□) that is the organic EL pixel 13 of the dot display unit 7 is 0.001 cm 2, the current density is 600 mA / cm 2 and the instantaneous luminance is 27000 cd / m 2.

  On the other hand, as shown in FIG. 24, the organic EL pixel 14 of the segment display unit 8 has a current density of 400 mA / cm 2 and an instantaneous luminance of 27000 cd / m 2 when the area of the segment A (Ａ) is 0.0015 cm 2. . Further, when the areas of both the seg B (Δ) are 0.003 cm 2, the current density is 200 mA / cm 2 and the instantaneous luminance is 13500 cd / m 2. When the area of the segment C (グ) is 0.0045 cm 2, the current density is 133.3 mA / cm 2 and the instantaneous luminance is 9000 cd / m 2.

  Therefore, in order to make the instantaneous luminances of the organic EL pixels 13 and 14 shown in FIG. 24 the same, the lighting time of the element C (seg A; ▽) is set to be one time that of the element A (dot), and the element C ( The lighting time of the segment B (Δ) may be twice that of the element A (dot), and the lighting time of the element C (seg C;）) may be three times that of the element A (dot). As described above, the pixel areas and the light emission efficiency characteristics of the organic EL pixels 13 and 14 are different, and the magnitudes of the drive currents applied to the organic EL pixels 13 and 14 are the same. Therefore, the pixel areas and the light emission efficiency characteristics are different. In order to display each pixel with the same display luminance, if the lighting time is controlled, the display luminance of the pixels having different pixel areas and light emission efficiency characteristics can be made the same.

  For this reason, the driver IC 12 determines the current density (= drive current / pixel area) flowing through the organic EL pixels 13 and 14 and the organic EL pixels 13 and 14 in accordance with the pixel areas and the light emission efficiency characteristics of the organic EL pixels 13 and 14. The lighting time is controlled so that the product of the relative light emission efficiency ratio and the lighting time of the organic EL pixels 13 and 14 becomes constant.

  FIG. 25A is a diagram showing an example of displaying an image on the organic EL panel 2. The organic EL pixels 13 of (0,0), (0,1), (1,2), (2,0) in the matrix of the dot display unit 7 are caused to emit light, and “ Assume that all the organic EL pixels 14 of “Δ” and “◇” emit light.

  When the area of the organic EL pixel 13 of the dot display unit 7 is S, the area of the organic EL pixel 14 of “▽” of the segment display unit 8 is 1.5S, and the area of the organic EL pixel 14 of “Δ” is 3S. , The area of the organic EL pixel 14 of “４．５” is 4.5S. As described above, in order to make the product of the current density, the relative luminous efficiency ratio, and the lighting time constant, the lighting time of the organic EL pixel 14 of “▽” is set to the value of the organic EL pixel 13. The lighting time of the organic EL pixel 14 of “Δ” is set to twice the lighting time of the organic EL pixel 13, and the lighting time of the organic EL pixel 14 of “◇” is the lighting time of the organic EL pixel 13. 3 times as much.

  Therefore, as shown in FIG. 25B, display data is stored in the RAM 17 so that the organic EL pixels 13 and 14 emit light as shown in FIG. That is, in the R3 to R5 rows related to the segment display unit 8, display data is stored so as to light up once in the C0 column, twice in the C1 column, and three times in the C2 column.

  FIG. 26 is a diagram illustrating a driving waveform of the driver IC 12. FIG. 27 is a circuit diagram showing a circuit operation in accordance with the second selection period 46 in the drive waveforms shown in FIG. The circuit operations of the R0 to R2 rows on the scanning side (row) and the C0 to C2 columns on the data side (column) are the same as those in the first embodiment.

  First, when the R3 to R5 rows are selected (second selection period 46), the driver IC 12 selects the voltage VddR (dot) by the scan electrode selection switches 42 to 44 and outputs a synchronization signal, thereby generating a segment COM signal generation circuit. 5 selects GND. Thereby, the organic EL pixel 14 selected by the data selection switches 36 to 38 emits light.

  Specifically, when the R3 row shown in FIG. 27A is selected, the driver IC 12 causes the data selection switches 36 to 36 to emit all the organic EL pixels 14 of “▽”, “Δ”, and “◇”. 38 selects constant current sources 39-41. Accordingly, as shown in FIG. 26, when the R3 to R5 rows are selected, the data side (column) signal is a signal in which the drive current flows in the C0 to C2 columns. That is, all the organic EL pixels 14 of “▽”, “Δ”, and “◇” emit light.

  Subsequently, when the R4 row shown in FIG. 27B is selected, the driver IC 12 selects GND by the data selection switch 36 so that the organic EL pixels 14 of “Δ” and “◇” are emitted, and the data selection switch The constant current sources 40 and 41 are selected by 37 and 38, respectively. Thus, as shown in FIG. 26, when the R4 row is selected, the signal on the data side (column) is a signal in which the drive current does not flow in the C0 column and the drive current flows in the C2 and C3 columns. That is, the organic EL pixels 14 of “Δ” and “◇” emit light.

  Thereafter, when the R5 row shown in FIG. 27C is selected, the driver IC 12 selects GND by the data selection switches 36 and 37 and causes the data selection switch 38 to emit light to the organic EL pixel 14 of “◇”. The constant current source 41 is selected. Thus, as shown in FIG. 26, when the R5 row is selected, the signal on the data side (column) is a signal in which the drive current does not flow in the C0 and C1 columns but the drive current flows in the C2 column. . That is, only the organic EL pixel 14 of “◇” emits light.

  Thereby, in the second selection period 46, among the organic EL pixels 14 of the segment display unit 8, “部” emits once, “Δ” emits twice, and “◇” emits three times. That is, the lighting time is controlled by the number of times of light emission. When the organic EL pixel 14 of “Δ” is caused to emit light, the light may be emitted at the timing of the R3 row and the R5 row as in the second embodiment.

  As described above, in the present embodiment, when the organic EL pixels 13 and 14 having different pixel areas and light emission efficiency characteristics are caused to emit light in the dot display unit 7 and the segment display unit 8, the current density flowing through the organic EL pixels 13 and 14 is increased. The lighting time is controlled so that the product of the relative luminous efficiency ratio and lighting time is constant. Thereby, the display luminance of the organic EL pixel 13 of the dot display unit 7 and the display luminance of the organic EL pixel 14 of the segment display unit 8 can be made uniform. Therefore, a display with no luminance unevenness can be obtained in the dot display section 7 and the segment display section 8.

(Fifth embodiment)
In the present embodiment, parts different from the first to fourth embodiments will be described. In the present embodiment, the dot display unit in the dimming period according to the first selection period 45 for displaying an image on the dot display unit 7 and the second selection period 46 for displaying an image on the segment display unit 8. 7, the reverse bias voltage applied to the organic EL pixel 13 is changed.

  FIG. 28 is a diagram illustrating a driving waveform of the driver IC 12. As shown in this figure, in the present embodiment, the reverse bias voltage (voltage VddR (dot)) applied to the dot row wiring 10 corresponding to the R0 to R2 rows during the second selection period 46 is reduced. .

  Changing the reverse bias voltage, that is, reducing the reverse bias voltage will be described with reference to FIGS. In the present embodiment, the same image display (see FIG. 11) as in the first embodiment is performed. Further, it is assumed that voltage VddR (dot) = voltage VddR (seg).

  First, in the reset period before the n-row selection shown in FIG. 29A, the driver IC 12 selects GND by the data selection switches 36 to 38, selects GND by the scan electrode selection switches 42 to 44, and performs segment use. The COM signal generation circuit 5 selects GND. Thereby, as shown in FIG. 29B, for example, the organic EL pixel 13 of the circuit constituted by (0, 2), (1, 2), (2, 2), (3, 2), The electric charge accumulated in 14 is discharged to GND. Further, the electric charges accumulated in the organic EL pixels 13 and 14 of the circuit constituted by (0, 2), (1, 2), (2, 2), (3, 2) are discharged to GND.

  Thereafter, when the R1 row shown in FIG. 30A is selected, the driver IC 12 selects the data from the state of the switch shown in FIG. 29A in order to cause the organic EL pixels 13 of (1, 2) to emit light. A constant current source 41 is selected by the switch 38. In addition, the driver IC 12 selects the voltage VddR (dot) by the scan electrode selection switches 42 and 44. In addition, the driver IC 12 outputs a synchronization signal and the segment COM signal generation circuit 5 selects the voltage VddR (seg).

  Thus, when each switch is switched by the driver IC 12, as shown in FIG. 30 (b), at the start of the selection of the (1, 2) organic EL pixel 13, the (1, 2) The voltage applied to the organic EL pixel 13 instantaneously increases to the voltage VddR (seg) = voltage VddR (dot). Such an effect similarly occurs in the R0 and R2 rows.

  Subsequently, when the R4 row shown in FIG. 31A is selected, the driver IC 12 switches the switches shown in FIG. 29A so that the organic EL pixels 14 of (3, 1) and (3, 2) emit light. In this state, the constant current sources 40 and 41 are selected by the data selection switches 37 and 38. In addition, the driver IC 12 selects the voltage VddR (dot) by the scan electrode selection switches 42 to 44.

  By such switching of the switches, as shown in FIG. 31B, when the selection of the organic EL pixel 14 of (3, 1) is started, it is applied to the organic EL pixel 14 of (3, 1) via the parasitic capacitance. The applied voltage instantaneously tries to rise to the voltage VddR (seg). The same applies to the (3, 2) organic EL pixel 14. Such an effect similarly occurs in the R3 and R5 rows.

  As described above, the reset driving has an effect of instantaneously raising the potential of the selection line (dot row wiring 10) by wraparound from the parasitic capacitance of each organic EL pixel 13 and 14 at the time of reset release.

  That is, when the organic EL pixels 13 and 14 having different areas are caused to emit light with the same driving current as shown in FIG. 32, the forward voltage applied to the organic EL pixels 13 and 14 decreases as the pixel area increases. . When the entire data electrode selection period is sufficiently wide (for example, 200 μs) with respect to the rising period (10 μs) of the data electrode (column side), instantaneous light emission (about 5 μs) due to the wraparound of the reverse bias voltage can be ignored. When dimming is performed by PWM control and the pulse width of the data electrode selection period is narrow (for example, 12 μs), there is a problem that instantaneous light emission (about 5 μs) due to wraparound of the reverse bias voltage cannot be ignored. The same applies to the case where the organic EL pixels 13 and 14 have different luminous efficiencies.

  Accordingly, the voltage VddR (seg) and the voltage VddR (dot) are set to be the same in the first selection period 45 for driving the dot display unit 7, and the voltage VddR (dot) is set in the second selection period 46 for driving the segment display unit 8. By reducing the above, it is possible to eliminate the influence of overshoot due to the reverse bias voltage wraparound at the time of reset release.

  FIG. 33 shows a rising period after a reset period in a dot pixel (organic EL pixel 13 of the dot display unit 7; 0.09 m 2) and a segment pixel (organic EL pixel 14 of the segment display unit 8; 4 mm 2) having different pixel areas. It is the figure which showed the column waveform and optical waveform in. The column waveform is a voltage waveform of the column wiring 9, and the optical waveform is a waveform indicating light emission.

  As shown in FIG. 33, when the reverse bias voltage is 13 V, the optical waveform in the rising period of the segment pixel has a sharp rise, and the influence of the overshoot due to the reverse bias voltage sneaking out. When the dimming ratio is 100%, the data electrode selection period is sufficiently wide as 200 μs with respect to the rising period (10 μs) of the data electrode (column side), but when the dimming ratio is 5%, the data electrode selection period is 12 μs. Therefore, the influence of overshoot cannot be ignored for the rising period. When comparing the area ratio of the optical waveforms of the dot pixels and the segment pixels, that is, the luminance unevenness, the luminance unevenness when the light reduction ratio is 100% is about 95%, but the luminance unevenness when the light attenuation ratio is 5% is 80%. It gets worse to the extent.

  However, if the reverse bias voltage applied to the organic EL pixel 13 of the dot display unit 7 is lowered from 13 V to 11 V in the second selection period 46 for driving the segment display unit 8, the optical waveform in the rising period becomes gentle in the segment pixel. This eliminates the influence of overshoot caused by the reverse bias voltage. For this reason, the rising waveform of the optical waveform related to the dot pixel and the optical waveform related to the segment pixel becomes uniform. When comparing the area ratio of the optical waveforms of the dot pixels and the segment pixels, that is, the luminance unevenness, the luminance unevenness when the dimming ratio was 5% was improved to about 95%.

  As described above, the sneak charges from the parasitic capacitance due to the reset drive can be reduced, so that the rising waveform after the reset drive can be made uniform regardless of the pixel area, and a good display with less luminance unevenness can be achieved. It becomes possible to obtain.

  As described above, in Patent Documents 3 and 4, the reverse bias is generally reduced during dimming. However, when applied to the present embodiment in which the organic EL pixels 13 and 14 having different areas are driven, FIG. As in the case of the reverse bias voltage of 11 V, the area ratio of the optical waveforms of the dot pixels and the segment pixels, that is, the luminance unevenness is about 70% when the dimming ratio is 5%, and the luminance unevenness was not improved.

(Sixth embodiment)
In the present embodiment, parts different from the first to fifth embodiments will be described. The present embodiment is characterized in that the reset driving is stopped at the dot display unit 7 in the second selection period 46 during the dimming period.

  FIG. 34 is a diagram showing a drive waveform of the driver IC 12. As shown in this figure, when driving the dot display unit 7, the driver IC 12 performs reset driving in the first selection period 45, but does not perform reset driving in the second selection period 46. As described above, when reset driving is performed, the potential of the dot row wiring 10 instantaneously rises from the parasitic capacitance of each of the organic EL pixels 13 and 14 when the reset is released. The drive itself is not performed. In FIG. 34, the drive waveforms for performing the same image display (see FIG. 11) as in the first embodiment are shown.

  FIG. 35 is a diagram showing optical waveforms of segment pixels when reset driving is stopped. As shown in this figure, when reset driving is stopped when the reverse bias voltage is 12 V, no overshoot occurs during the rising period of the optical waveform of the segment pixel, and the reverse bias voltage of 12 V, dot pixel of FIG. The same rising waveform as the optical waveform shown in FIG. Comparing the area ratio of the optical waveforms of the dot pixels and the segment pixels, that is, the luminance unevenness, in the case of reset driving, the luminance unevenness with the dimming ratio of 5% is about 80%, but the second selection period 46 for driving the segment display unit 8 When the reset driving was stopped, the luminance unevenness with the dimming ratio of 5% was improved to about 95%.

  As described above, when driving the dot display unit 7, the dot display unit 7 stops reset driving in the second selection period 46, thereby eliminating the influence of overshoot due to the reverse bias voltage wraparound in the segment display unit 8. be able to.

(Seventh embodiment)
In the present embodiment, parts different from the first to sixth embodiments will be described. Also in the present embodiment, the same image display (see FIG. 11) as in the first embodiment is performed.

  FIG. 36 is a diagram showing display data of the RAM 17 according to the present embodiment. FIG. 37 shows the drive waveform of the driver IC 12. 36 to 38, as an example, the output of the driver IC 12 is shown as three on the column (data) side and eight on the row (scanning) side.

  As shown in FIG. 36, R3 and R7 rows where display data is not provided are provided between R0 to R2 rows corresponding to the dot display portion 7 and R4 to R6 rows corresponding to the segment display portion 8. ing. In these R3 row and R7 row, as shown in FIG. 37, a voltage change period 47 (1 Vsync) in which no signal is input to the data side (column) is set. As described above, the driver IC 12 includes the voltage change period 47 for changing the reverse bias voltage before and after the period for driving the organic EL pixels 14 of the segment display unit 8 in the second selection period 46.

  Specifically, the switch is switched as shown in FIG. The circuit operation for the R0 to R2 rows is the same as that in the first embodiment.

  First, after selecting the R2 row, when selecting the R3 row shown in FIG. 38 (a), the data selection switches 36 to 38 are used to switch the reverse bias voltage applied to the organic EL pixel 13 of the dot display section 7 with certainty. Select GND. In addition, the driver IC 12 selects the voltage VddR (dot) by the scan electrode selection switches 42 to 44, outputs a synchronization signal, and selects the GND by the segment COM signal generation circuit 5. This selection of the R3 row corresponds to the voltage change period 47.

  Next, when the R4 and R5 rows shown in FIG. 38B are selected, the driver IC 12 selects GND by the data selection switch 36 so that the “O” and “Δ” organic EL pixels 14 emit light. The constant current sources 40 and 41 are selected by the selection switches 37 and 38.

  Thereafter, when the R6 row shown in FIG. 38C is selected, the driver IC 12 selects GND by the data selection switches 36 and 37 and causes the data selection switch 38 to emit light so that the “Δ” organic EL pixel 14 emits light. The constant current source 41 is selected.

  As described above, after the organic EL pixel 14 is caused to emit light, in the R7 row selection, that is, the voltage change period 47 shown in FIG. Then, the voltage VddR (dot) is selected by the scan electrode selection switches 42 to 44, the synchronization signal is output, and the segment COM signal generation circuit 5 selects GND.

  As described above, in the second selection period 46, the voltage change period 47 for applying the reverse bias voltage to the organic EL pixel 13 of the dot display unit 7 at the switching timing between the first selection period 45 and the second selection period 46 is provided. Therefore, it is possible to avoid switching the selection period when the reverse bias voltage is in a transitional transition state, and the reverse bias voltage can be switched reliably in the voltage change period 47.

(Eighth embodiment)
In the present embodiment, parts different from the first to seventh embodiments will be described. The present embodiment is characterized in that the display brightness of the dot display unit 7 and the segment display unit 8 is made uniform by using gradation.

  In the first embodiment, as described with reference to FIG. 8, the current density (= drive current / pixel area) and the instantaneous luminance are in a proportional relationship. For example, assuming that the drive current applied to one pixel is 0.6 mA, each pixel is classified as shown in FIG.

  As shown in FIG. 39, when the area of the dot (organic EL pixel 13 of the dot display unit 7) is 0.001 cm 2, the current density is 600 mA / cm 2 and the instantaneous luminance is 27000 cd / m 2. On the other hand, for the seg D to F (the organic EL pixel 14 of the segment display unit 8), the shape of the seg D is “←”, the area is 0.00133 cm 2, the current density is 450 mA / cm 2, and the instantaneous luminance Is 20300 cd / cm 2. The shape of the segment E is “↑”, the area is 0.002 cm 2, the current density is 300 mA / cm 2, and the instantaneous luminance is 13500 cd / cm 2. The shape of the segment F is “→”, the area is 0.00267 cm 2, the current density is 225 mA / cm 2, and the instantaneous luminance is 10100 cd / cm 2.

  In order to make the instantaneous luminance of each pixel the same, the lighting time of the segment D may be 1.33 times the lighting time of the dots. Similarly, the lighting time of Seg E may be set to twice the lighting time of dots, and the lighting time of Seg F may be set to 2.67 times the lighting time of dots. Therefore, in the present embodiment, the number of scanning lines of the driver IC 12 is M, the number of scanning lines of the dot display unit 7 (number of row wirings 10 for dots) is m, and the number of gradations that can be controlled by the driver IC 12 is n. Then, the driver IC 12 controls the lighting time in the (M−m) × (n−1) stage.

  FIG. 40 is a diagram showing a column pulse width applied to the column wiring 9. As shown in this figure, in one scanning period, the pulse width is T1 for the 1/3 gradation, the pulse width is T2 twice the T1 for the 1/3 gradation, and is T1 for the 3/3 gradation. It is 3 times T3. By using the gray scale in this way, it is possible to control the pulse width of the drive current applied to the column wiring 9, that is, the lighting time.

  FIG. 41A is a diagram showing an example of displaying an image on the organic EL panel 2. The organic EL pixels 13 (0, 0), (0, 1), (1, 2), (2, 0) in the matrix of the dot display unit 7 are caused to emit light, and “←” in the segment display unit 8 Assume that the organic EL pixels 14 of “↑” and “→” emit light. The organic EL pixels 13 and 14 that emit light are hatched.

  When the dot area of the organic EL pixel 13 of the dot display unit 7 is S, the area of the organic EL pixel 14 of “←” in the segment display unit 8 is (4/3) S, and the organic EL pixel 14 of “↑”. Is (6/3) S, and the area of the organic EL pixel 14 of “→” is (8/3) S.

  FIG. 41B is a diagram showing the contents (display data) of the RAM 17 when the organic EL pixels 13 and 14 emit light as shown in FIG. In the present embodiment, for example, since an image is displayed with 4 gradations, each area is classified into “11”, “10”, “01”, and “00” according to each gradation. For example, “00” means that the pulse width is 0, that is, no light emission, “01” is a predetermined pulse width, “10” is twice the pulse width of “01”, and “11” is “01”. This means a triple pulse width.

  FIG. 42 is a diagram showing a drive waveform of the driver IC 12. As shown in this figure, each signal on the data side (column) has a pulse width according to the gradation stored in the RAM 17. For this reason, the light emission time of each organic EL pixel 13 and 14 which light-emits in the dot display part 7 and the segment display part 8 is each adjusted.

  As described above, since the fine pixel area can be corrected by using the gradation, the fine lighting time can be controlled. Therefore, a display with no luminance unevenness can be obtained by the dot display unit 7 and the segment display unit 8.

(Ninth embodiment)
In the present embodiment, parts different from the first to eighth embodiments will be described. As described in the second embodiment, it has been described that the lighting time may be continuous or divided if the total lighting time corresponds to the desired lighting time. This can also be applied to the case shown in the eighth embodiment.

  That is, as shown in FIG. 43A, display data in the RAM 17 may be set. For example, in the eighth embodiment, the organic EL pixels 14 of “←” and “↑” are not made to emit light when the R5 row is selected, but in this embodiment, as shown in FIG. The light is emitted. In this manner, by using the gradation and adjusting the pulse width on the data side (column), it is possible to freely set the timing and time of light emission.

(10th Embodiment)
In the present embodiment, parts different from the first to ninth embodiments will be described. In each of the above embodiments, the pixel area of the organic EL pixel 14 of the segment display unit 8 is not extremely large compared to the pixel area of the organic EL pixel 13 of the dot display unit 7. However, when the pixel area of the organic EL pixel 14 of the segment display unit 8 is larger than the pixel area of the organic EL pixel 13 of the dot display unit 7, the organic EL pixel 14 of the segment display unit 8 is divided into a plurality of parts. Just drive each one.

  In this case, assuming that the area of the dot display section 7 is S, the area of the segment display section 8 is Sx, the number of scanning lines of the driver IC 12 is M, and the number of scanning lines of the dot display section 7 is m, the segment display section The organic EL pixel 14 is divided so that the area Sx of 8 satisfies the relationship of Sx ≦ (M−m) × S. For example, as shown in the eighth embodiment, the lighting time is corrected in the (M−m) × (n−1) stage.

  Specifically, the gradation n of the driver IC 12 is n = 4 gradations, M = 32 (the number of scanning lines possessed by the driver IC 12), m = 29 (the number of scanning lines of the dot display unit 7, that is, the dot row wiring 10). Number).

  FIG. 44 is a schematic diagram in which the organic EL pixel 14 of the segment display unit 8 is divided. As shown in this figure, for example, each organic EL pixel 14 constituting the number “8” is divided into two or three. In this case, as shown in FIG. 45A, the area ratio of each column wiring 9 (corresponding column), the segment number, and the pixel area of the organic EL pixel 13 of the dot display unit 7 is set. Further, display data is set in the RAM 17 as shown in FIG.

  For example, as shown in FIG. 44, when S1 and S2 constituting the same segment are driven by one column wiring 9, the area becomes six times the pixel area of the organic EL pixel 13 of the dot display section 7, so that the current density Becomes 1/6. In order for the product of the current density and the lighting time to be constant, the lighting time six times that of the dot display unit 7 is required. However, since (M−m) = 3, the lighting time is actually three times as long. Therefore, the brightness is lowered and brightness unevenness occurs. Therefore, by dividing the same segment so that it cannot be seen by human eyes, the pixel area of S1 and S2 becomes three times that of the organic EL pixel 13 of the dot display unit 7, and 3 of the organic EL pixel 13 of the dot display unit 7 is obtained. By adding twice the lighting time, a display with no luminance unevenness can be obtained.

  In the case of the organic EL panel 2 used in the meter 16 or the like of the vehicle 15, since the viewer (passenger etc.) and the organic EL panel 2 are separated by about 500 to 800 mm, the same segment is actually divided by about 100 μm. However, it is possible to obtain a good display that the viewer does not care. In addition, when the same segment is divided, by equalizing each area, the same rise time and lighting time can be obtained, so that it is possible to obtain a display with no luminance unevenness in the same segment. Furthermore, if the driver IC 12 has a gradation function based on the pulse width as described above, it becomes possible to correct the lighting time more finely according to each area.

(Other embodiments)
In each of the above-described embodiments, the organic EL display device 1 has been described as being mounted on the vehicle 15. However, this is an example of the use of the organic EL display device 1 and is not limited to the vehicle 15 and is used for displaying an image. be able to. Moreover, the light emission color of the organic EL pixel 13 of the dot display unit 7 and the light emission color of the organic EL pixel 14 of the segment display unit 8 may be different regardless of the difference in the light emission efficiency characteristics.

  In each of the above embodiments, the segment COM signal generation circuit 5 is provided outside the driver IC 12, but may be built in the driver IC 12. In this case, the driver IC 12 corresponds to the “driver” in the claims.

  When the area of the segment display unit 8 is large, that is, the area of the dot display unit 7 is S, the area of the segment display unit 8 is Sx, the number of scanning lines of the driver IC 12 is M, and the dot display unit 7 is scanned. When the number of lines is m, when the dot display unit 7 and the segment display unit 8 satisfy the relationship of Sx> (M−m) × S, the segment display unit 8 satisfies Sx ′ ≦ (M−m) × S. The organic EL pixel 14 of the segment display unit 8 may be divided.

  Further, the reverse bias voltage applied to the organic EL pixel 13 of the dot display unit 7 is Vr1 (voltage VddR (dot)), and the reverse bias voltage applied to the organic EL pixel 14 of the segment display unit 8 is Vr2 (voltage VddR (seg). )), The driver IC 12 and the voltage generators 24, 25, and 26 may change the reverse bias voltage so as to satisfy the relationship of Vr1 ≦ Vr2.

  Further, when driving more segment pixels, the second selection period 46 may be driven in a time-sharing manner by providing a plurality of segment COM signal generation circuits 5.

5 segment COM signal generation circuit 7 dot display section 8 segment display section 9 column wiring 10 dot row wiring 11 segment COM wiring 12 driver IC
13 Organic EL pixel in dot display section 14 Organic EL pixel in segment display section 17 RAM
45 First selection period 46 Second selection period 47 Voltage change period

Claims (13)

A first pixel group (7) having a plurality of organic EL pixels (13) having a uniform pixel area with respect to one scanning line (10);
A second pixel group (8) having one or more organic EL pixels (14) having a pixel area different from that of the organic EL pixels (13) of the first pixel group (7) for one scanning line (11);
Drivers (5, 12) for driving the first pixel group (7) and the second pixel group (8), respectively.
The driver (5, 12) causes the current density flowing in the organic EL pixel (13, 14) and the lighting of the organic EL pixel (13, 14) according to the pixel area of the organic EL pixel (13, 14). An organic EL display device that controls the lighting time so that the product with time is constant,
The organic EL pixel (13, 14) is dimmed by PWM control,
In the first selection period (45) in which the driver (5, 12) displays an image on the first pixel group (7) during the dimming, a scan period and a next scan period are displayed. In the meantime, during the scanning period, reset driving is performed to discharge the charges charged in the parasitic capacitance formed in the organic EL pixel (13, 14), and a second image is displayed in the second pixel group (8). The organic EL display device is characterized in that the reset driving is stopped in the selection period (46). A first pixel group (7) having an organic EL pixel (13) having a plurality of uniform pixel areas and luminous efficiency characteristics with respect to one scanning line (10);
A second pixel group (1) having one or more organic EL pixels (14) having different pixel areas and light emission efficiency characteristics from the organic EL pixels (13) of the first pixel group (7) for one scanning line (11). 8) and
Drivers (5, 12) for driving the first pixel group (7) and the second pixel group (8), respectively.
The driver (5, 12) causes the current density flowing through the organic EL pixel (13, 14) and the organic EL pixel (13, 14) according to the pixel area and the luminous efficiency characteristics of the organic EL pixel (13, 14). 14) an organic EL display device that controls the lighting time so that the product of the relative luminous efficiency ratio of 14) and the lighting time of the organic EL pixels (13, 14) is constant;
The organic EL pixel (13, 14) is dimmed by PWM control,
In the first selection period (45) in which the driver (5, 12) displays an image on the first pixel group (7) during the dimming, a scan period and a next scan period are displayed. In the meantime, during the scanning period, reset driving is performed to discharge the charges charged in the parasitic capacitance formed in the organic EL pixel (13, 14), and a second image is displayed in the second pixel group (8). The organic EL display device is characterized in that the reset driving is stopped in the selection period (46). The area of the first pixel group (7) is S, the area of a pixel in the second pixel group (8) is Sx, the number of scanning lines of the driver (5, 12) is M, and the first If the number of scanning lines of the pixel group (7) is m,
3. The organic EL display device according to claim 1, wherein a pixel in the second pixel group (8) satisfies a relationship of Sx ≦ (M−m) × S. The area of the first pixel group (7) is S, the area of a pixel in the second pixel group (8) is Sx, the number of scanning lines of the driver (5, 12) is M, and the first If the number of scanning lines of the pixel group (7) is m,
When a pixel in the second pixel group (8) satisfies a relationship of Sx> (M−m) × S, a pixel in the second pixel group (8) satisfies Sx ′ ≦ (M−m) × S. The organic EL display device according to any one of claims 1 to 3, wherein the organic EL pixels (14) of the second pixel group (8) are divided so as to satisfy.   The organic EL display device according to claim 4, wherein the organic EL pixels (14) of the second pixel group (8) are divided into a plurality of areas so as to have the same area. A first pixel group (7) having a plurality of organic EL pixels (13) having a uniform luminous efficiency characteristic for one scanning line (10);
A second pixel group (8) having one or more organic EL pixels (14) having different emission efficiency characteristics from the organic EL pixels (13) of the first pixel group (7) for one scanning line (11); ,
Drivers (5, 12) for driving the first pixel group (7) and the second pixel group (8), respectively.
According to the light emission efficiency characteristic of the organic EL pixel (13, 14) by the driver (5, 12), the relative light emission efficiency ratio of the organic EL pixel (13, 14) and the organic EL pixel (13, 14) 14) an organic EL display device for controlling the lighting time so that the product of the lighting time with 14) is constant;
The organic EL pixel (13, 14) is dimmed by PWM control,
In the first selection period (45) in which the driver (5, 12) displays an image on the first pixel group (7) during the dimming, a scan period and a next scan period are displayed. In the meantime, during the scanning period, reset driving is performed to discharge the charges charged in the parasitic capacitance formed in the organic EL pixel (13, 14), and a second image is displayed in the second pixel group (8). The organic EL display device is characterized in that the reset driving is stopped in the selection period (46).   The organic EL according to any one of claims 1 to 6, wherein the first pixel group (7) is a dot matrix display portion, and the second pixel group (8) is a segment display portion. Display device.   The emission color of the organic EL pixel (13) of the first pixel group (7) is different from the emission color of the organic EL pixel (14) of the second pixel group (8). The organic EL display device according to any one of the above. A first pixel group (7) having a plurality of organic EL pixels (13) having a uniform pixel area with respect to one scanning line (10);
A second pixel group (8) having one or more organic EL pixels (14) having a pixel area different from that of the organic EL pixels (13) of the first pixel group (7) for one scanning line (11);
Drivers (5, 12) for driving the first pixel group (7) and the second pixel group (8), respectively.
The driver (5, 12) causes the current density flowing in the organic EL pixel (13, 14) and the lighting of the organic EL pixel (13, 14) according to the pixel area of the organic EL pixel (13, 14). A driving method of an organic EL display device for controlling the lighting time so that the product with time is constant,
In the first selection period (45) in which an image is displayed on the first pixel group (7) by the driver (5, 12), the organic layer is scanned during the scanning period between the scanning period and the next scanning period. Reset driving is performed to discharge charges charged in the parasitic capacitance formed in the EL pixel (13, 14), and the reset driving is performed in the second selection period (46) in which an image is displayed on the second pixel group (8). The organic EL display device driving method is characterized by stopping the operation. A first pixel group (7) having a plurality of organic EL pixels (13) having a uniform luminous efficiency characteristic for one scanning line (10);
A second pixel group (8) having one or more organic EL pixels (14) having different emission efficiency characteristics from the organic EL pixels (13) of the first pixel group (7) for one scanning line (11); ,
Drivers (5, 12) for driving the first pixel group (7) and the second pixel group (8), respectively.
According to the light emission efficiency characteristic of the organic EL pixel (13, 14) by the driver (5, 12), the relative light emission efficiency ratio of the organic EL pixel (13, 14) and the organic EL pixel (13, 14) 14) A driving method of an organic EL display device for controlling the lighting time so that the product of the lighting time with 14) is constant.
In the first selection period (45) in which an image is displayed on the first pixel group (7) by the driver (5, 12), the organic layer is scanned during the scanning period between the scanning period and the next scanning period. Reset driving is performed to discharge charges charged in the parasitic capacitance formed in the EL pixel (13, 14), and the reset driving is performed in the second selection period (46) in which an image is displayed on the second pixel group (8). The organic EL display device driving method is characterized by stopping the operation. A first pixel group (7) having an organic EL pixel (13) having a plurality of uniform pixel areas and luminous efficiency characteristics with respect to one scanning line (10);
A second pixel group (1) having one or more organic EL pixels (14) having different pixel areas and light emission efficiency characteristics from the organic EL pixels (13) of the first pixel group (7) for one scanning line (11). 8) and
Drivers (5, 12) for driving the first pixel group (7) and the second pixel group (8), respectively.
The driver (5, 12) causes the current density flowing through the organic EL pixel (13, 14) and the organic EL pixel (13, 14) according to the pixel area and the luminous efficiency characteristics of the organic EL pixel (13, 14). 14) a driving method of an organic EL display device for controlling the lighting time so that the product of the relative luminous efficiency ratio of 14) and the lighting time of the organic EL pixel (13, 14) is constant;
In the first selection period (45) in which an image is displayed on the first pixel group (7) by the driver (5, 12), the organic layer is scanned during the scanning period between the scanning period and the next scanning period. Reset driving is performed to discharge charges charged in the parasitic capacitance formed in the EL pixel (13, 14), and the reset driving is performed in the second selection period (46) in which an image is displayed on the second pixel group (8). The organic EL display device driving method is characterized by stopping the operation. When the number of scanning lines of the driver (5, 12) is M, the number of scanning lines of the first pixel group (7) is m, and the number of gradations that can be controlled by the driver (5, 12) is n. ,
The organic EL display device according to claim 9, wherein the lighting time is controlled by the driver (5, 12) in (M−m) × (n−1) stages. Driving method.   The driver (5, 12) drives the one used for the vehicle display as the first pixel group (7) and the second pixel group (8). A method for driving the organic EL display device according to claim 1.

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