KR20070092608A - Display method, display device, and electronic apparatus - Google Patents

Abstract

A display method, a display device, and an electronic apparatus are provided to display optimal images by detecting a variation in a panel driving current when temperature variation or brightness deterioration occurs. A display device includes a driving current detection unit(23), a brightness controller(25), a comparing unit(26), and a controller. The driving current detection unit detects a driving current of pixels. The brightness controller generates first and second brightness control signals for illuminating respective illuminating elements with first and second brightness, respectively, so as to display images. The comparing unit compares the detected driving current with a predetermined set value. The controller outputs one of the first and second brightness control signals based on the comparison.

Description

Display method, display device and electronic device {DISPLAY METHOD, DISPLAY DEVICE, AND ELECTRONIC APPARATUS}

1 is a perspective view of an instrument panel of a vehicle on which a display device is mounted.

2 is a schematic diagram showing a display form of an image of a speedometer.

3 illustrates an electrical configuration of a display device according to a first embodiment.

4 illustrates an electrical configuration of a display unit.

5 illustrates an electrical configuration of a pixel.

FIG. 6 is a view showing variation of a drive current due to photoexcitation of an organic electroluminescent device. FIG.

7 is a flowchart for explaining the operation of the display device according to the first embodiment.

8 illustrates an electrical configuration of a display device according to a second embodiment.

9 is a flowchart for explaining the operation of the display device according to the second embodiment.

Explanation of symbols for the main parts of the drawings

G: Image of speedometer as meter image

In: Panel drive current Is: Set current value as set value

LX1 to LXm: Data line LY1 to LYn: Scan line

Qw: Instrument cluster as electronic device Z: Display area

1: display device and vehicle display device 3: control unit

4a: substrate 8: color pixel as pixel

9R, 9G, 9B: Organic Electroluminescent Devices as Light-Emitting Devices

11 data line driving circuit as control means

23: current detection circuit as drive current detection means

25: reference voltage generating circuit as luminance control means

26 panel control circuit as a comparison means

27: image processing circuit as data signal supply means

The present invention relates to a display method, a display device and an electronic device.

Conventionally, the organic electroluminescent display which formed the light emitting element formed in a display area by the organic electroluminescent element (henceforth "organic EL element") (henceforth "organic EL display apparatus") There is. This type of organic EL display device is attracting attention from the viewpoints of light weight, high brightness, high viewing angle, and the like.

However, in the organic EL display device, when strong external light such as sunlight is irradiated to the display area, there is a problem that the contrast of the display is reduced, and as a result, it is difficult to see.

Thus, in order to solve the above problem, an illuminance sensor is provided in the display area, and the illuminance of light (external light) incident on the display area is measured by the sensor. Then, an organic EL display device has been proposed to control light control of an organic EL element with luminance corrected according to the result, that is, bright in a bright place and not dazzling in a dark place (see Patent Document 1, for example). . In the organic EL display device, the illuminance sensor is formed of an organic EL element in the same manner as the organic EL element for displaying an image, and is simultaneously formed when an organic EL element for displaying an image is formed. . As a result, a display device that can perform dimming control without attaching an illuminance sensor externally is realized.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2001-35655

However, in the organic EL display device described in Patent Document 1, it is necessary to provide an illuminance sensor, which causes a problem that the miniaturization and lightening of the display device are disturbed or the layout is restricted. In addition, with respect to a large display area, a deviation may arise in the detection result of the illumination intensity detected by the arrangement position of an illumination intensity sensor, and proper dimming control may not be performed. Moreover, since the element characteristic of the organic electroluminescent element which comprises an illuminance sensor differs from the organic electroluminescent element for image display, appropriate dimming control may not be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a display method and a display device capable of performing appropriate dimming without providing an external sensor.

In the display method of the present invention, each pixel is arranged on a substrate in a display area in which a plurality of pixels including light emitting elements are arranged in a matrix at positions corresponding to intersections of a plurality of scan lines and a plurality of data lines. In a display method of a display device in which a first image is displayed by appropriately driving the display, the driving current of each pixel is detected, the current value of the driving current of each of the pixels is compared with a preset setting value, and Based on this, either the first image or the second image different from the display time of the first image is switched to display on the display area.

According to this, a desired image is displayed suitably according to the change of the drive current which flows through each light emitting element. For example, in the case where the light emitting element is an electroluminescent element, when light having a wavelength corresponding to the energy gap is incident, photoexcitation occurs and electromotive force is generated in each light emitting element. Therefore, if light including light having a wavelength corresponding to the energy gap of each light emitting element is irradiated to the display area while the first image is displayed, the electromotive force generated by the light excitation causes the drive current of each pixel to vary. do. Thus, in the present invention, if the drive current supplied to each pixel is detected and light is irradiated to the display area while displaying the first image, the drive current flowing through the entire display area detected by the above-described light excitation is increased. For example, a second image in which the light emitting element of each pixel is emitted at high luminance is displayed. As a result, even when light is irradiated to the display area, the light emitting element of each pixel emits light with high brightness, so that the contrast can be improved to improve visibility.

In addition, since it is determined whether or not light is irradiated to the display area by using the light emitting element itself to display an image, it is not necessary to install an external illuminance sensor, so that miniaturization and lightening of the display device are disturbed or the layout is restricted. It does not become. Moreover, since the light emitting element itself which displays an image is used, even if it is a large display area, a deviation does not arise in the detection result of the illumination intensity detected by the arrangement position of an illumination intensity sensor. In addition, since the element characteristics of the light emitting element constituting the illuminance sensor are not different from those of the light emitting element for displaying an image, appropriate dimming control can be performed.

In this display method, the first image is a standard luminance image, the second image is a high luminance image in which each of the light emitting elements emits high luminance as compared with the display of the standard luminance image, and external light When the driving current of the pixel by the said standard brightness image becomes more than a predetermined setting value by entering, it may switch from the said standard brightness image to the said high brightness image, and to display it in the said display area.

According to this, when light is irradiated to a display area, since the light emitting element of each pixel emits light with high brightness, contrast can be improved and visibility can be improved.

In this display method, when the driving current consumed in the standard luminance image is equal to or larger than a predetermined setting value, the high luminance image is generated from the standard luminance image by supplying high luminance image data that emits the light emitting element at high luminance as compared with the image data. You may switch to an image and display it in the said display area.

According to this, for example, in the display apparatus provided with the data signal supply means which outputs a data signal to each pixel, the reference voltage with respect to the data signal output from the data signal supply means is compared with the drive current supplied to each pixel. Light control can be performed by controlling accordingly.

In this display method, the image data may be image data for displaying a still image in the display area.

According to this, since the image displayed in a display area is a still image, since the fluctuation | variation of the drive current which arises by one's light emission is small, erroneous light control is not performed. As a result, appropriate light control can be performed.

In this display method, the display device is a vehicle display device, and the image at the standard luminance may be a meter image.

According to this, in a vehicle display apparatus, strong external light often enters the display area, but even in this case, the contrast of the displayed meter image is high, so the visibility of the meter image is improved.

In the display device of the present invention, each pixel is arranged on a substrate in a display area in which a plurality of pixels including light emitting elements are arranged in a matrix at positions corresponding to intersections of a plurality of scan lines and a plurality of data lines. A display apparatus adapted to drive properly to display a first image, comprising: driving current detecting means for detecting a driving current of the pixel, and a means for emitting each of the light emitting elements at a first brightness to display the first image; Brightness control means for generating and outputting a first brightness control signal and a second brightness control signal for causing each of said light emitting elements to emit light at a different brightness than when the first image is displayed; A first luminance based on a comparison means for comparing a set value and a comparison result between the detected driving current and a preset set value; Control signals, or has a control means for outputting either one of the second luminance control signal.

According to this, a desired image is displayed suitably according to the change of the drive current which flows through each light emitting element. For example, when the light emitting element is an electroluminescent element, when light having a wavelength corresponding to the energy gap is incident, photoexcitation occurs and electromotive force is generated in each light emitting element. Therefore, if light including light having a wavelength corresponding to the energy gap of each light emitting element is irradiated to the display area while the first image is displayed, the electromotive force generated by the light excitation causes the drive current of each pixel to vary. do. Therefore, in the present invention, if the drive current supplied to each pixel is detected and light is irradiated to the display area while displaying the first image, the drive current flowing through the entire display area detected by the above-described light excitation is increased. For example, a second image in which the light emitting element of each pixel is emitted at high luminance is displayed. As a result, even when light is irradiated to the display area, the light emitting element of each pixel emits light with high brightness, so that the contrast can be improved, thereby improving visibility.

In addition, since it is determined whether or not light is irradiated to the display area by using the light emitting element itself to display an image, it is not necessary to install an external illuminance sensor, so that miniaturization and lightening of the display device are disturbed or the layout is restricted. It does not become. Moreover, since the light emitting element itself which displays an image is used, even if it is a large display area, a deviation does not arise in the detection result of the illumination intensity detected by the arrangement position of an illumination intensity sensor. In addition, since the element characteristics of the light emitting element constituting the illuminance sensor are not different from those of the light emitting element for displaying an image, appropriate dimming control can be performed.

In this display device, the drive current detecting means may detect the drive current of the pixel caused by the incident of external light into the display area.

According to this, the visibility can be improved by adjusting the contrast of the image by the intensity of light incident on the display area.

In this display device, the brightness control means is data signal supply means for generating and outputting a data signal to be supplied to each pixel based on the image data, and the data signal supply means is a drive consumed in the first image. When the current is equal to or higher than the set value, the second luminance control signal may be output as high luminance image data for causing the light emitting element to emit light at high luminance as compared with the first image.

According to this, dimming control can be performed by controlling the reference voltage with respect to the data signal output from the data signal supply means according to the drive current supplied to each pixel.

In this display device, the display device is a vehicle display device, and the first image may be a meter image.

According to this, in a vehicle display apparatus, strong external light often enters the display area, but even in this case, the contrast of the displayed meter image is high, so the visibility of the meter image is improved.

In this display device, the light emitting element may be an electroluminescent element.

According to this, when an electroluminescent element is irradiated with light, photoexcitation will generate | occur | produce and its drive current will fluctuate, but it becomes possible to perform dimming control based on the fluctuation | variation of the drive current produced by this optical excitation.

In this display device, the electroluminescent element may be an organic electroluminescent element.

According to this, the display apparatus provided with organic electroluminescent element WHEREIN: The display apparatus which can be suitably controlled by dimming without providing an external illuminance sensor is realizable.

The electronic device of this invention is equipped with the display apparatus of the said base material.

According to this, the electronic apparatus provided with the display apparatus which can display the image excellent in visibility which a contrast does not fall even if external light enters into a display area can be provided.

EMBODIMENT OF THE INVENTION Hereinafter, each Example which actualized the display apparatus of this invention to the onboard display apparatus is demonstrated according to drawing.

(First embodiment)

The display device according to the first embodiment will be described with reference to FIGS. 1 to 7.

As shown in FIG. 1, the vehicle display apparatus (it is simply called a "display apparatus") 1 of this embodiment is mounted in the instrument panel Qw as an electronic apparatus of the vehicle C. As shown in FIG. The display apparatus 1 displays the image G of the speedometer as a meter image which shows the vehicle speed of the vehicle C in the display area Z. As shown in FIG.

The image G of the speedometer displayed in this display area Z is compared with the display (standard luminance image) by the standard luminance display mode as a 1st image displayed with the standard luminance as a 1st luminance, and the standard luminance display mode. The display (high brightness image) by the high brightness display mode as a 2nd image displayed as high brightness as a 2nd brightness as a whole is switched and displayed.

2 shows one display form of the image G of the speedometer displayed in each mode. In Fig. 2, the images G of the speedometer are " 0 ", " 20 ", " 40 " , The numerical value Ma representing the vehicle speed of the vehicle C of "160" is displayed at predetermined intervals. In addition, the instruction Mb is displayed at the position surrounded by each numerical value Ma. The instruction | indication Mb is rotated and displayed on the base end Mc in the rotational center according to the vehicle speed of the vehicle C at that time, and it is made to index the vehicle speed at that time.

3 is a diagram for describing an electrical configuration of the display device 1. As shown in FIG. 3, the display device 1 is composed of a display unit 2 and a control unit 3. The display unit 2 is provided with the above-mentioned display area Z which is substantially rectangular in the center on the substrate 4a. On the substrate 4a, a pair of scanning line driver circuits 5 are formed in regions other than the display region Z (hereinafter, referred to as "non-display region"). Moreover, the flexible printed circuit board 4b connected with the same board | substrate 4a and the anisotropic conductive film (ACF) is provided in the lower side of the board | substrate 4a. The data line driving circuit 11 as a control means is mounted on the flexible printed circuit board 4b.

As shown in FIG. 4, the display area Z is extended so as to be orthogonal to the n scanning lines LY1, LY2,..., LYn extending in one direction and to each of the scanning lines LY1 to LYn. m data lines LX1, LX2, ..., LXm-1, LXm are provided. In addition, red, green, and blue pixels 8R, 8G, and 8B are located at positions in the display area Z corresponding to the intersection of the scan lines LY1 to LYn and the data lines LX1 to LXm. Formed.

In the display area Z, m power lines Lo are extended in parallel with the data lines LX1 to LXm. The power supply line Lo extended in parallel to the data lines LX1, LX4, ... is connected to the red pixel 8R and extends in parallel to the data lines LX2, LXm-1. The power supply line Lo is connected to the green pixel 8G, and the power supply line Lo extended in parallel to the data lines LX3, ..., LXm is connected to the blue pixel 8B.

As shown in FIG. 5, the red pixel 8R includes a red organic EL element 9R, a switching element Sw, a sustain capacitor Co, and a driving transistor Qd as light emitting elements. The red organic EL element 9R is an organic electroluminescent element whose light emitting layer (not shown) is composed of an organic material. In this embodiment, the light emitting layer is a polyfluorene-based or polyphenylenevinylene-based organic compound. It is made of a light emitting material.

For example, the switching element Sw is an N-type transistor having a conductivity type, and the gate is connected to the scan lines LY1, LY2,... Which extend in a corresponding position, and the drain has a data line that extends in a corresponding position. It is connected to (LX1, LX4, ...), and the source is connected to one electrode of the sustain capacitor Co. In the sustain capacitor Co, the gate of the driving transistor Qd is connected to one electrode thereof, and the power supply line Lo is connected to the other electrode. As shown in Fig. 5, since the circuit configurations of the green pixel 8G and the blue pixel 8B are the same as those of the red pixel 8R, the green pixel 8G and the blue pixel 8B are applied to the green pixel 8G and the blue pixel 8B. For the same reference numerals, the detailed description thereof is omitted.

As shown in Fig. 4, the red, green, and blue pixels 8R, 8G, and 8B each have a red pixel 8R → green pixel 8G → blue along the scan lines LY1 to LYn. Pixel 8B for red pixel 8R. → The blue pixels 8B are arranged in this order. In addition, the same color is arranged along the data lines LX1 to LXm. And one color pixel 8 is comprised by the red pixel 8R, the green pixel 8G, and the blue pixel 8B which are three pixels arrange | positioned adjacently.

In addition, each of the organic EL elements 9R, 9G, and 9B has a wavelength corresponding to the energy gap of the light emitting layer among the plurality of wavelengths constituting the light because external light (natural light) having a predetermined intensity or more is incident on the display region Z. Light is absorbed, and as a result, electromotive force generated by photoexcitation is generated in the organic EL elements 9R, 9G, and 9B through the same light emitting layer.

For example, in the case where the light emitting layer is made of a known organic light emitting material such as polyfluorene or polyphenylene vinylene, when the external light (natural light) whose intensity is stronger than about 3000 [kW] is irradiated, the wavelength is 400 Light of about nm is absorbed, and electromotive force due to photoexcitation is generated between the anode and the cathode of each of the organic EL elements 9R, 9G, and 9B.

6 is a graph showing the results of experiments on electromotive force due to photoexcitation of each organic EL element 9R, 9G, 9B. As shown in Fig. 6, the electric current (driving current) Id flowing between the anode and cathode layers of each of the organic EL elements 9R, 9G, and 9B is irradiated with external light (natural light) having an intensity of less than about 3000 [kW]. Although it is almost constant, it turns out that when external light (natural light) of about 3000 [kW] or more is irradiated, it increases rapidly.

In addition, as shown in FIG. 3, the scanning line driver circuits 5 are formed on the non-display area in pairs on the left and right side so as to sandwich the display area Z. FIG. Each scan line driver circuit 5 is connected to scan lines LY1 to LYn. As shown in Fig. 4, each scan line driver circuit 5 is a scan signal for selecting a desired group of color pixels 8 from among the n rows of color pixels 8 described above on the scan lines LY1 to LYn. (SC1, SC2, SC3, ... SCn) are output in synchronization. For example, the scanning lines LY1 to LYn are formed from the first scanning line LY1 to the second scanning line LY2 to the third scanning line LY3. ? N scanning line LYn? → scanning line LY1? By outputting the scan signals SC1 to SCn in order, the color pixels 8 in each row are selected in a linear order.

As shown in Fig. 4, the data line driving circuit 11 has m digital-analog conversion circuits D1, D2, D3, ..., Dm-1, Dm corresponding to the respective data lines LX1 to LXm. ). Each digital analog conversion circuit D1 to Dm is a well-known digital analog conversion circuit, and outputs the image data GD for forming the image G of the speedometer for each time output from the control unit 3. The data signal is converted into a data signal having a magnitude corresponding to the reference voltage Vk and output to the corresponding data lines LX1 to LXm.

The reference voltages Vk are two types of reference voltages in the present embodiment: the reference luminance Vkl for standard luminance and the high luminance reference voltage Vkh having a voltage higher than the reference voltage Vkl. Any one of 3) is selected and input. The reference voltage Vkl for standard luminance is a reference voltage for displaying the image G of the speedometer in the standard luminance display mode. The high luminance reference voltage Vkh is a reference voltage for displaying in the high luminance display mode.

When the data line driving circuit 11 generates a data signal output from the input image data GD to the data lines LX1 to LXm, the level of the data signal is the reference luminance Vkl for standard luminance. And high luminance reference voltage Vkh. That is, when the high luminance reference voltage Vkh is input, the level of the data signal for the image data GD becomes higher than the standard luminance reference voltage Vkl. Therefore, even when the image data GD is the same, the light emission luminance of the organic EL elements 9R, 9G, and 9B based on the data signal generated when the high luminance reference voltage Vkh is equal to the standard luminance reference voltage Vkl. It becomes higher than the light emission luminance of the organic EL elements 9R, 9G, 9B based on the generated data signal.

The data signal generated based on the standard luminance reference voltage Vkl (standard luminance display mode) is referred to as image luminance for standard luminance (standard luminance control signal), and the high luminance reference voltage Vkh (high luminance display mode). The data signal generated on the basis of the above is called a high brightness image data signal (high brightness control signal). Therefore, in the high luminance display mode, the image G of the speedometer displayed in the display area Z is displayed at a higher luminance than the standard luminance display mode.

As shown in FIG. 3, the control unit 3 includes a logic power supply circuit 21, a panel power supply circuit 22, a current detection circuit 23 as a drive current detection means, an EEPROM 24, and luminance. The reference voltage generation circuit 25 as a control means, the panel control circuit 26 as a comparison means, and the image processing circuit 27 as a data signal supply means are provided.

The logic system power supply circuit 21 and the panel power supply circuit 22 are each of the driving circuits 5 and 11 provided in the display unit 2 based on a predetermined power supply Eo supplied from an external power supply circuit (not shown) and It is a circuit for generating various power supply voltages for driving the pixels 8R, 8G, and 8B. The logic system power supply circuit 21 generates, for example, a power supply voltage Vs at a level required to drive the scan line driver circuit 5 and the data line driver circuit 11 based on the power source Eo, Output to the scan line driver circuit 5 and the data line driver circuit 11 is performed. The panel power supply circuit 22 generates a power supply voltage Vo based on the power supply Eo, and outputs the power supply voltage Vo to each pixel 8R, 8G, and 8B through each power supply line Lo.

The current detection circuit 23 includes a resistance element 23a and an analog / digital conversion circuit (hereinafter, referred to as an "A / D conversion circuit") 23b and is entirely output from the display unit 2. The panel drive current In, which is the sum total of the drive current Id flowing through the pixels 8 (8R, 8G, 8B), is input. The current detection circuit 23 causes the panel drive current In to flow through the resistance element 23a, and A / D converts the voltage between terminals of the resistance element 23a, thereby driving the panel drive current In. The panel drive current value K is output.

The set current value Is as a set value is stored in advance in the EEPROM 24. The set current value Is of the present embodiment corresponds to the magnitude (panel drive current value K) of the panel drive current In that flows when external light of about 3000 [kW] is incident on the display area Z. Value.

That is, as shown in Fig. 2, the image G of the speedometer is an image in which the numerical value Ma and the proximal end Mc are fixed together, i.e., a still image and only the instruction Mb is rotated and displayed. , A video clip. In addition, since the guide Mb only rotates around the base end Mc, the display area (light emitting area) of the guide Mb does not change even when the guide Mb rotates. Therefore, the sum total of the luminance of all the color pixels 8 of the display area Z when the image G of the speedometer is displayed in the standard luminance display mode is almost constant, and the panel drive current (at this time) In) is the predictable standard value. The standard value for the predicted panel drive current In in the standard luminance display mode is the set current value Is.

The reference voltage generating circuit 25 is provided with two types of reference voltages having different magnitudes (reference voltage Vkl for standard luminance and the same) which are supplied to the digital-to-analog conversion circuits D1 to Dm of the data line driving circuit 11. A high luminance reference voltage Vkh larger than the standard luminance reference voltage Vkl is generated. The reference voltage generator 25 selects one of the standard luminance reference voltage Vkl and the high luminance reference voltage Vkh according to the selection signals SV1 and SVh input from the panel control circuit 26. Output is made to each digital-analog conversion circuit D1-Dm.

The panel control circuit 26 generates timing signals Sa and Sb for performing synchronous control of each scan line driver circuit 5 or data line driver circuit 11 based on a clock signal CLK supplied from the outside. And output to each of the driving circuits 5 and 11.

In addition, the panel control circuit 26 reads the set current value Is from the EEPROM 24. The panel control circuit 26 compares the read set current value Is with the panel drive current value K output from the current detection circuit 23. When the panel control circuit 26 determines that the panel drive current value K is less than the set current value Is, the panel control circuit 26 recognizes that external light having an intensity of less than about 3000 [kW] has entered the display area Z. In this case, the standard luminance display mode is set, and the panel control circuit 26 outputs the selection signal Svl for selecting the standard luminance reference voltage Vkl to the reference voltage generation circuit 25. As a result, the reference voltage generating circuit 25 generates the standard luminance reference voltage Vkl and outputs it to the data line driving circuit 11.

In addition, when the panel control circuit 26 determines that the panel drive current value K is equal to or greater than the set current value Is, the panel control circuit 26 recognizes that external light having an intensity of about 3000 [kW] or more is incident on the display area Z. In this case, the high brightness display mode is set, and the panel control circuit 26 outputs the selection signal Svh for selecting the high brightness reference voltage Vkh to the reference voltage generating circuit 25. As a result, the reference voltage generation circuit 25 generates the high luminance reference voltage Vkh and outputs it to the data line driving circuit 11.

In addition, in this embodiment, when the display device 1 is powered on, the panel control circuit 26 is initially set to the standard luminance display mode, and is set in advance so as to output the selection signal Svl.

The image processing circuit 27 inputs image data GD generated by an external image generating circuit (not shown). In this embodiment, the instruction data Mb constituting the image G of the speedometer is always input in this embodiment, and numerical values Ma and the like which are other fixed images (fixed patterns) are intermittently input at predetermined timings. It is supposed to be.

Next, the operation of the display device 1 configured as described above will be described with reference to FIG. 7.

When the operation key is inserted into the key cylinder in the driver's seat and the engine is started, power is supplied to the display device 1 (step S1-1). At this time, for example, the display unit 2 is initially set to the standard luminance display mode, so that the image G of the speedometer is displayed in the standard luminance mode in the display region Z. FIG.

Subsequently, the panel drive current In is output to the current detection circuit 23 of the control unit 3. Then, the current detection circuit 23 detects the current value K of the panel drive current In and outputs it to the panel control circuit 26 (step S1-2).

Then, the panel control circuit 26 compares the set current value Is stored in the EEPROM 24 with the panel drive current value K from the current detection circuit 23 (step S1-3). When it is determined that the panel drive current value K is less than the set current value Is (that is, when external light of intensity less than about 3000 [kW] enters the display area Z) (at step S1-4) NO and the reference voltage generating circuit 25 supply the standard luminance reference voltage Vkl to the respective digital-analog conversion circuits D1 to Dm of the data line driving circuit 11 (step S1-5).

Therefore, on the display unit 2, the image G of the speedometer is displayed in the standard luminance display mode. As a result, the light emission luminance of the image G of the speedometer is lowered, and the image G is difficult to see because the eyes are broken. In addition, the power consumption can be reduced.

Subsequently, it is checked whether or not the power supply is turned off to the display device 1 (step S1-6), and if it is continuously turned on (NO in step S1-6), the resistance element for current detection of the current detection circuit 23 ( By 23a), panel drive current In is again detected. (Step S1-2) Then, the above-mentioned operation of steps S1-2 to S1-5 is repeated to display the image G of the speedometer as standard luminance. Mode is displayed.

Subsequently, when the external light irradiated to the display area Z becomes strong, the panel driving current In increases and the current value K also increases. Then, when the external light is about 3000 [kV] or more, the panel control circuit 26 determines that the panel drive current value K is equal to or greater than the set current value Is (YES in step S1-4). Then, the panel control circuit 26 supplies the high luminance reference voltage Vkh from the reference voltage generating circuit 25 to each of the digital analog conversion circuits D1 to Dm of the data line driving circuit 11 (step S1). -7).

Then, in the display area Z, the image G of the speedometer is switched from the standard luminance display mode to the high luminance display mode and displayed. Therefore, when the external light irradiated to the display area Z is about 3000 [kV] or more, the light emission luminance of the organic EL elements 9R, 9G, and 9B increases, and the image G of the speedometer displayed in the display area Z is displayed. ) Becomes easy to see.

According to the said Example, the following effect is exhibited.

(1) According to the above embodiment, the panel drive current value K corresponding to the panel drive current In, which is the sum of the drive currents flowing through each of the organic EL elements 9R, 9G, and 9B, is detected, and the panel is driven. The current value K was compared with the preset set current value Is. In the standard luminance display mode, when the panel drive current value K becomes equal to or greater than the set current value Is, it is recognized that strong external light is incident on the display area Z, and the display is switched from the standard luminance display mode to the high luminance display mode. To switch. As a result, the contrast of the image G of the speedometer can be increased. In addition, when the panel drive current value K is compared with the set current value Is, and as a result, the panel drive current value K becomes less than the set current value Is in the high luminance display mode, the display area Z ), It was recognized that no strong external light was incident, and the display was switched from the high luminance display mode to the standard luminance display mode. As a result, the contrast of the image G of the speedometer is lowered.

Therefore, the contrast of the image G of the speedometer can be adjusted without using a special illuminance sensor separately. As a result, it is possible to realize the display device 1 capable of dimming control in which miniaturization and weight reduction are not hindered or layout is restricted.

(2) According to the above embodiment, the standard is based on the panel drive current In by the drive current Id flowing through the organic EL elements 9R, 9G, 9B itself of the color pixel 8 that contributes to the display. Since the brightness display mode and the high brightness display mode are switched, all the color pixels 8 act as illuminance sensors. Therefore, even in a large display device having a large display area Z, since the detection result of the illuminance does not occur depending on the position in the display area Z, appropriate dimming control can be performed.

(3) Moreover, according to the said Example, the display area Z was made to display the image G of the speedometer which shows the vehicle speed of the vehicle C. As shown in FIG. Therefore, even if external light with strong external light enters the display area Z, it is possible to prevent the image G of the speedometer from being difficult to see in advance (second embodiment).

Next, a display device according to the second embodiment will be described with reference to FIGS. 8 and 9.

As shown in Fig. 8, in the display device 1A according to the present embodiment, the reference voltage Vko supplied to the digital-analog conversion circuits D1 to Dm of the data line driving circuit 11 is made constant. That is, the reference voltage Vko of a predetermined level is output from the reference voltage generation circuit 25.

In addition, the panel control circuit 26 of the present embodiment compares the set current value Is read from the EEPROM 24 with the panel drive current value K output from the current detection circuit 23, and compares the result. It outputs to the image processing circuit 27. In addition, in the present embodiment, the external image generating circuit that supplies the image data GD to the image processing circuit 27 prepares the high luminance image data GD1 and the standard luminance image data GD2. The high luminance image data GD1 is image data for an image having a design that is easy to see even when strong light enters the display region Z. The image data GD2 for standard luminance is stored in the display region Z. When strong light enters, it is image data of the image of the design which becomes more difficult to see than the image by the high luminance image data GD1.

When the image processing circuit 27 inputs a result from the panel control circuit 26 that the panel driving current value K is equal to or greater than the set current value Is, the image processing circuit GD1 for high brightness is applied to the external image generating circuit. Outputs a request signal (Sr) requesting. In addition, when the image processing circuit 27 inputs a result from the panel control circuit 26 to the effect that the panel driving current value K is less than the set current value Is, the image for standard brightness with respect to the external image generating circuit is generated. The request signal Sr for requesting the data GD2 is output.

Next, the operation of the display device 1A configured as described above will be described with reference to FIG. 9.

Now, when the operation key is inserted into the key cylinder in the driver's seat and the engine is started, power is supplied to the display device 1A (step S2-1). Thereafter, similarly to the first embodiment, the initial setting is made to the standard luminance display mode, so that the image G of the speedometer is displayed in the standard luminance mode in the display area Z. FIG. Thereafter, the panel drive current In is output to the current detection circuit 23 of the control unit 3. Then, the current detection circuit 23 detects the current value K of the panel drive current In and outputs it to the panel control circuit 26 (step S2-2).

Then, the panel control circuit 26 compares the set current value Is stored in the EEPROM 24 with the panel drive current value K from the current detection circuit 23 (step S2-3). Then, when the panel drive current value K is judged to be less than the set current value Is (that is, when external light of intensity less than about 3000 [kW] enters the display area Z) (at step S2-4) NO) and the effect thereof are output to the image processing circuit 27. The image processing circuit 27 then outputs a request signal Sr for requesting the image data GD2 for standard brightness to the external image generating circuit.

As a result, the external image generating circuit outputs the image data GD2 for standard luminance. The image processing circuit 27 then outputs the standard luminance image data GD2 to the data line driving circuit 11. Therefore, the image for standard brightness is displayed on the display area Z (step S2-5).

Subsequently, it is checked whether or not the power supply is turned off to the display device 1A (step S2-6), and when it is continuously input (NO in step S2-6), the resistance element 23a of the current detection circuit 23 is performed. The panel drive current In is detected again (step S2-2), and then the operations of the above-described steps S2-2 to S2-6 are repeated, whereby the image for standard luminance is continuously displayed.

Subsequently, when the external light irradiated to the display area Z is about 3000 [kV] or more, the panel drive current In increases, and as a result, the panel drive current value (converted by the A / D conversion circuit 23b) K) also increases. Then, when the panel drive current value K is determined to be equal to or higher than the set current value Is (that is, when external light of intensity of about 3000 [kW] or more is incident on the display area Z) (YES in step S1-4) Is output to the image processing circuit 27. The image processing circuit 27 then outputs a request signal Sr for requesting the high luminance image data GD1 to the external image generating circuit.

As a result, the external image generating circuit outputs high luminance image data GD1. The image processing circuit 27 then outputs the high luminance image data GD1 to the data line driving circuit 11. Therefore, the image for high brightness is displayed on the display area Z (step S2-7).

According to the said Example, the following effect is exhibited.

(1) According to the above embodiment, the image processing circuit 27 performs image data GD1 for displaying the design of the image for high luminance and the image for standard luminance that differ in the design of the image displayed in the display area Z. The image data GD2 for display is switched in accordance with the magnitude of the panel driving current In, and outputted to the data line driving circuit 11. Therefore, similarly to the first embodiment, it is possible to realize a display device capable of dimming control without using a special illuminance sensor separately.

In addition, this invention can also be actualized in the following changes.

In each of the above embodiments, the case where the panel drive current In is changed by external light incident on the display area Z has been described, but the present invention is not limited to this. In addition to the external light incident on the display area Z, the panel driving current In is also changed by external temperature or deterioration of luminance of the organic EL elements 9R, 9G, and 9B. Even in the case where the luminance of the elements 9R, 9G, and 9B is deteriorated, an appropriate image may be switched and displayed by detecting a change in the panel driving current In. At this time, the outside air temperature may be detected by a temperature sensor provided around the panel. In addition, detection of the luminance deterioration of the organic EL elements 9R, 9G, and 9B may be estimated by the count value of the cumulative lighting time or the like.

In each of the above embodiments, when the engine is started by inserting the operation key into the key cylinder in the driver's seat and power is supplied to the display device 1, the image G of the speedometer is displayed in the display area Z in the standard luminance mode. I made it appear. When the power is supplied to the display device 1, the panel drive current In is detected at that time, and the panel drive current In at that time is set to the set current value Is, and the luminance is high from the standard luminance mode. The image G of the speedometer in the display mode can also be switched to display. By doing in this way, the light control of the image G of the speedometer immediately after power supply to the display apparatus 1 can be performed suitably.

In each of the above embodiments, the digital-to-analog conversion circuits D1 to Dm are embodied and the reference voltage Vk supplied to the digital-analog conversion circuits D1 to Dm is controlled so that the standard luminance display mode or the high luminance is controlled. The display mode was switched to display the image G of the speedometer. For example, the luminance control means is a panel power supply circuit 22 for supplying a power supply voltage Vo, and the panel power supply circuit 22 supplies the power supply voltage Vo with a standard brightness voltage and its standard voltage. Two kinds of voltages of higher luminance are prepared. The panel control circuit 26 does not control the reference voltage Vk, but controls the panel power supply circuit 22 to switch and supply a standard luminance voltage or a high luminance voltage to each color pixel 8, and thus the speedometer. Image G is displayed. In this manner, the same effects as described above can be obtained.

In each of the above embodiments, the display device 1 displaying the image G and the display method of the speedometer displaying the vehicle speed have been described as an example, but the tachometer indicating the engine speed of the vehicle C other than the speedometer ( It may be embodied as a display device that displays a tachometer, an instrument (an indicator or a warning), or the like.

In each of the above embodiments, the image G of the speedometer displayed in the display area Z only displays the numerical value Ma and the instructions Mb, but in addition to the numerical values Ma and the instructions Mb, The mark of a lamp and various warnings may also be displayed.

In each of the above embodiments, the display device 1 using the organic EL elements 9R, 9G, and 9B is used as the light emitting element, but this is used using a light emitting element other than the other organic EL elements 9R, 9G, and 9cB. Even if it is, this invention is applicable. In short, any light emitting device may be used as long as it absorbs light having a predetermined wavelength and generates electromotive force due to photoexcitation.

In the above embodiment, the instrument panel Qw of the vehicle C has been described as an electronic device, but the present invention is not limited to this and can be widely applied to an instrument display device.

According to the present invention, it is possible to provide a display method and a display device capable of performing appropriate dimming without providing an external sensor.

Claims (12)

On the substrate, the first image is driven by appropriately driving the respective pixels based on image data in a display area in which a plurality of pixels including light emitting elements are arranged in a matrix at positions corresponding to intersections of a plurality of scan lines and a plurality of data lines. In the display method of the display device to display the, The driving current of each pixel is detected, and the current value of the driving current of each pixel is compared with a preset setting value, and based on the result, the display of the first image or the first image A display method characterized by switching to one of the other second images to display in the display area. The method of claim 1, The first image is a standard luminance image, The second image is a high luminance image in which each of the light emitting elements emits high luminance as compared with the display of the standard luminance image, When external light is incident on the display area, when the driving current of the pixel by the standard brightness image is equal to or greater than a predetermined value, the display area is switched to the high brightness image to be displayed on the display area. How to show. The method of claim 2, When the driving current consumed in the standard luminance image is equal to or larger than a predetermined setting value, by supplying high luminance image data which emits the light emitting element at high luminance as compared with the image data, the standard luminance image is converted into the high luminance image and the A display method characterized by displaying on a display area. The method according to any one of claims 1 to 3, And the image data is image data for displaying a still image in the display area. The method of claim 2, The display device is a vehicle display device, and the standard luminance image is a meter image. On the substrate, the first image is driven by appropriately driving the respective pixels based on image data in a display area in which a plurality of pixels including light emitting elements are arranged in a matrix at positions corresponding to intersections of a plurality of scan lines and a plurality of data lines. In the display device to display the, Drive current detection means for detecting a drive current of the pixel; A first luminance control signal for causing each of the light emitting elements to emit light at a first brightness to display the first image, and a second for emitting each of the light emitting elements at a different brightness than when displaying the first image; Luminance control means for generating and outputting a luminance control signal; Comparison means for comparing the detected driving current with a preset setting value; And a control means for outputting either the first brightness control signal or the second brightness control signal based on a result of comparing the detected driving current with a preset setting value. The method of claim 6, And the drive current detecting means detects a drive current of the pixel caused by incident light into the display area. The method of claim 7, wherein The brightness control means is data signal supply means for generating and outputting a data signal supplied to each pixel based on the image data, The data signal supply means outputs the second luminance control signal as high luminance image data for emitting the light emitting element at high luminance compared to the first image when the drive current consumed in the first image is equal to or larger than the set value. Display device characterized in that. The method according to any one of claims 6 to 8, The display device is a vehicle display device, wherein the first image is a meter image. The method of claim 6, And the light emitting element is an electroluminescent element. The method of claim 10, The electroluminescent device is an organic electroluminescent device. An electronic device comprising the display device according to claim 6.

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