EP2220640B1 - Method for diagnosing an electronic display device - Google Patents

Description

The invention relates to a method for diagnosing an electronic display device with a screen and a graphics memory in which image data of an image displayed or displayed by your screen are stored or changed, wherein a value characterizing the current consumption or the change of the power consumption of the screen or the display device and, based on the image data or the change of the image data, a reference value characterizing the current consumption or the change in the current consumption of the screen or the display device is determined and compared with the measured value. Furthermore, the invention relates to a device for carrying out the method.

Such a method is known from US 6 147 617 A known.

In currently available on the market display devices with organic light emitting diodes (OLED), a diagnosis of the displayed image via a readout of the graphics memory is possible. This means that it can be recognized as an error if the image data of an image sent to the display device via a data line were not stored properly in the memory. By comparing the transmitted image content and the image content read errors can be diagnosed and appropriate action can be taken. However, this would not be detected if the nil display caused by the design of the OLED driver in the area between the graphics memory and the OLED screen.

The invention has for its object to provide a way to diagnose an electronic display device, so that a faulty Screen display of stored in the graphics memory image data can be detected, which can be distinguished between different, displayable from the screen characters that would lead to an equal power consumption.

This object is achieved by a method according to claim 1. Preferred developments are given in the dependent claims.

In the method according to the invention for diagnosing an electronic display device with a screen and a graphic memory in which image data of an image displayed or to be displayed by the display device are stored and / or changed, a value characterizing the current consumption or the change of the current consumption of the screen or the display device becomes measuring, based on the image data or the change of the image data, a reference value characterizing the current consumption or the change of the current consumption of the screen or the display device and compared with the measured value (measured value), and wherein a character to be displayed by the screen has at least two partial images of which a first forms the image whose image data are stored in the graphics memory, the sub-images are selected so that their power consumption of a respectively previously displayed (and to be overwritten) Distinguish image.

Each pixel has, depending on its mode of operation, a certain current consumption, which is determined, for example, by its color and / or brightness. If it is a monochromatic display device (eg in black and white), then the current consumption of each pixel depends only on its set brightness and / or whether it is switched on or off. Because the image data includes information about which pixel is to be activated, the image data can also be used to determine which pixel is causing or causing which current consumption. Thus, by summing up the power consumption determined for each pixel, the total current consumption of all pixels for an image can be determined. Is also the additional power consumption of other electronic components of Display device and / or the screen known, this additional power consumption can be considered as an offset and added to the total power consumption of all pixels. Thus, for the screen and / or the display device, the current consumption that occurs or should occur when displaying a specific image can be determined. If the determined current consumption does not match the measured current consumption within specified tolerances, then there is an error in the display. Preferably, a status signal is generated as a function of the comparison, which contains, for example, information about whether there is an error in the display.

To distinguish between different characters, which lead to an equal current consumption, one of the characters is decomposed into at least two fields. Thus, it is possible to check a partial image, after which the remaining image data for the character is loaded into the graphics memory to fully display it. This gradual loading or reloading of the image data takes place in particular so fast that it is not visible to the eye of a viewer. For this it seems rather as if all pixels are displayed simultaneously. Furthermore, a displayed image may be deleted before loading a new image, e.g. to monitor the decreasing power consumption.

The screen comprises, in particular, a plurality of electrical lighting means, wherein each pixel is assigned at least one electrical lighting means and / or each pixel is formed by at least one electric lighting means. However, it is also possible for each pixel to have several, e.g. three, electrical lighting means, which in particular radiate or can emit light of different colors. The electrical lamps are preferably light emitting diodes. In particular, the or at least a part of the electrical lighting means are designed as organic light-emitting diodes (OLED).

The graphics memory is preferably a memory that is writable and / or readable, in particular, the graphics memory is a random access memory (RAM).

The measurement of the current consumption or the change of the current consumption preferably takes place via a measuring resistor. Alternatively, the measurement of the current consumption or of the change in the current consumption can take place by means of an inductance whose current consumption proportional magnetic field is detected by a magnetic field-sensitive sensor.

The screen and / or the display device is preferably connected between a ground line and a supply line, via which the screen and / or the display device is supplied with power. In this case, the measurement of the current consumption or the change of the current consumption takes place e.g. in the supply line or in the ground line.

Preferably, the display device is used to display characters, so that it can be checked by means of the method according to the invention whether the character to be displayed is actually displayed. If different characters can be displayed and checked, they must lead to different power consumption, if the result should be unique. In the event that several characters would result in an equal current consumption, e.g. in one of the characters, a certain number of pixels of a hidden screen area are switched on (i.e., a non-visible additional pattern is switched on). Thus, it is possible to distinguish these characters by their different power consumption, although their visible areas would cause or cause an identical current consumption. Since the added number of pixels is not visible to a user because of the hidden screen area, the visual impression of the affected character does not change.

The number of pixels of the additional pattern is in particular equal to a value rounded up to a whole number of a quotient whose divident corresponds to the number of pixels of the screen, the divisor of the quotient being equal to a power whose base is the number two, the exponent of the quotient Potency of the resolution of the measuring system, in particular in bits, corresponds.

If a character is loaded in the graphics memory in several stages, also a current difference can be determined, which occurs when changing from one stage to a subsequent stage. If the display device is operating correctly, the measured current difference corresponds to a calculated current difference, which is determined on the basis of the image data, which are different for the two stages.

The invention further relates to a device having an electronic display device with a screen and a graphics memory in which image data of an image displayed or to be displayed by the display device are stored or changed, a current measuring device, by means of which the current consumption or the change of the power consumption of Screen or the display device characterizing value (measured value) is or can be measured, and an evaluation, by means of which on the basis of the image data or the change of the image data, a current consumption or the change of the current consumption of the screen or the display device characterizing reference value and determines the measured value is compared to a to be displayed on the screen characters at least two fields are assigned, of which a first forms the image whose image data are stored in the graphics memory, the Tei be selected so that their current recordings differ from a previously displayed image. This device is used in particular for carrying out the method according to the invention and can be developed according to all the configurations mentioned in this connection.

The method according to the invention and / or the device according to the invention are preferably used for the diagnosis or for checking the display device of a selector lever device of a motor vehicle. From such a display device, e.g. the currently engaged gear of a transmission of the vehicle is shown.

By measuring the current consumption characteristic of each displayed image or changing the current consumption caused by a change in image data can be diagnosed a correct reproduction. The current measurement can be carried out via a measuring resistor (shunt) or by means of an inductance whose current proportional to the magnetic field via a magnetic field-sensitive element, such as a Hall element, is detected. Depending on the application, the current measurement can be carried out in the supply line or in the ground line.

With (random) equality of the number of pixels, a specific number of pixels can be used as a diagnosis cluster by a hidden area of the screen. In particular, these pixels can be switched on and / or switched off to identify the image for additional current consumption. The size of the cluster in

Pixel (s) is preferably dependent on the size of the screen in pixels (p) and the resolution of the measuring system in bit (b): n = p / 2 ^ b (n is the rounded integer value).

An advantage of the invention is the extended error diagnostic capability of such display devices with regard to the possibility of error in the driver IC of an OLED display device between the graphics memory and the OLED screen. In this case, the diagnosis of the display device via the current measurement.

Fig. 1

ein schematisches Blockschaltbild einer Anzeigevorrichtung mit einer Diagnoseschaltung gemäß einer ersten Ausführungsform der Erfindung,

Fig. 2

ein schematisches Schaltbild einer Anzeigevorrichtung mit einer Diagnoseschaltung gemäß einer zweiten Ausführungsform der Erfindung,

Fig. 3

schematische Darstellungen vom Inhalt des Grafikspeichers und von der Anzeige des Bildschirms der Anzeigevorrichtung und

Fig. 4

ein schematisches Schaltbild einer Anzeigevorrichtung mit einer Diagnoseschaltung gemäß einer dritten Ausführungsform der Erfindung.

The invention will be described below with reference to preferred embodiments with reference to the drawing. In the drawing show:

Fig. 1

1 is a schematic block diagram of a display device with a diagnostic circuit according to a first embodiment of the invention,

Fig. 2

1 is a schematic circuit diagram of a display device with a diagnostic circuit according to a second embodiment of the invention,

Fig. 3

schematic representations of the contents of the graphics memory and the display of the screen of the display device and

Fig. 4

a schematic diagram of a display device with a diagnostic circuit according to a third embodiment of the invention.

Out Fig. 1 is a display device 1 with a graphics memory 2 and a display or screen 3 can be seen, which is supplied via a supply line 4 with electric current I. Furthermore, the display device 1 is connected to a ground line 5, via which the electric current I is dissipated. The screen 3 has a plurality of LEDs 18, of which pixels of the screen 3 are formed. In a monochromatic screen corresponds to each pixel, for example, a light emitting diode 18. Bei a color screen, each pixel may have a plurality, in particular three light-emitting diodes 18, which preferably emit light of different wavelengths.

In the supply line 4, a measuring resistor 6 is connected, at which a voltage U drops, which is measured by means of a measuring device 7. Since the voltage U dropping across the measuring resistor 6 is proportional to the flowing current I, the measuring resistor 6 and the measuring device 7 together form a current measuring device which outputs a measured value 15 characterizing the flowing current I to an evaluating device 8 which is electrically connected to the measuring device 7 is. The evaluation device 8 compares the measured value 15 with a reference value 16, which is determined on the basis of image data 14 stored in the graphics memory 2, which are supplied to the evaluation device 8. If the measured value 15 and the reference value 16 agree within predetermined tolerances, then the display device 1 operates properly. The current measuring device and the evaluation device 8 thus together form a diagnostic circuit for the display device 1, wherein information about the state of the display device 1, e.g. is output as a state signal 17.

Out Fig. 2 a display device 1 with a diagnostic circuit according to a second embodiment of the invention can be seen, wherein identical or similar features to the first embodiment are denoted by the same reference numerals as in the first embodiment. The second embodiment differs only in that the measuring resistor 6 is connected in the ground line 5. For the further description of the second embodiment, reference is made to the description of the first embodiment.

Out Fig. 4 a display device 1 with a diagnostic circuit according to a third embodiment of the invention can be seen, wherein the previous embodiments similar or identical features with the same reference numerals as in the previous embodiments are designated. The third embodiment differs from the second embodiment in particular in that, instead of the measuring resistor, an inductance 9 (for example an electrical coil) in the ground line 5 is switched. Alternatively, the inductance 9 could be connected in the supply line 4. The current-carrying inductance 9 generates a magnetic field, which is detected by a Hall element 10, which outputs a voltage U to the measuring device 7 as a function of the magnetic field, which forms a current measuring device together with the Hall element 10 and the inductance 9. For further description of the third embodiment, reference is made to the description of the preceding embodiments.

Out Fig. 3 an illustration of the diagnosis can be seen, wherein in the first column, the content of the graphics memory 2, in the second column, the display of the screen 3 and in the third column, a judgment is given whether a display error has occurred or not.

According to "Image 1", image data for the digit "1" is stored in the graphics memory 2. This image data lead arithmetically to a characteristic current consumption of the display device of 2.51 mA. The measured current consumption is also 2.51 mA, so that from the screen 3, the content of the graphics memory is displayed correctly. An error does not exist. In this case, the two current consumption values match. In practice, however, the measured value may also deviate from the calculated value. In spite of such a deviation, there is preferably no error if this lies within certain tolerances.

According to "Image 2", image data of the numeral "2" is stored in the graphics memory 2. These image data lead arithmetically to a characteristic current consumption of 2.85 mA. However, the measured current consumption is only 2.51 mA, so there is a faulty representation. How out Fig. 3 can be seen, from the screen, the figure "1" according to "Figure 1" shown.

LIST OF REFERENCE NUMBERS

1

display device

2

graphics memory

3

screen

4

supply line

5

ground line

6

measuring resistor

7

measuring device

8th

evaluation

9

inductance

10

Hall element

11

hidden area of the screen

12

additional pattern

13

Memory area of the graphics memory

14

image data

15

reading

16

reference value

17

state signal

18

led

Claims (6)

1. Method for diagnosing an electronic display device (1) having a screen (3) and a graphics memory (2) in which image data (14) relating to an image displayed by the screen (3) are stored or changed,
   wherein, for the displayed image, a check is carried out in which a value (15) characterizing the power consumption or the change in the power consumption of the screen (3) or of the display device (1) is measured,
   and, on the basis of the image data (14) or the change in the image data (14), a reference value (16) characterizing the power consumption or the change in the power consumption of the screen (3) or of the display device (1) is determined and is compared with the measured value (15), characterized in that at least two partial images are assigned to a character to be displayed by the screen (3), a first partial image of which forms the image whose image data are stored in the graphics memory,
   in that the partial images are selected in such a manner that their power consumptions differ from a respective previously displayed image,
   and in that, after the check of the first partial image, the remaining image data for the character are loaded into the graphics memory in order to fully display the character.
2. Method according to Claim 1, characterized in that the power consumption or the change in the power consumption is measured using a measuring resistor (6) or an inductance (9), the magnetic field of which that is proportional to the power consumption is recorded using a sensor (10) sensitive to magnetic fields.
3. Method according to Claim 1 or 2, characterized in that the display device (1) is connected between an earth line (5) and a supply line (4) which is used to supply the display device (1) with power, wherein the power consumption or the change in the power consumption is measured in the supply line (4) or in the earth line (5).
4. Method according to one of the preceding claims, characterized in that the electronic display device (1) has light-emitting diodes (18).
5. Method according to one of the preceding claims, characterized in that a state signal (17) is generated on the basis of the comparison of the reference value (16) with the measured value (15).
6. Device for carrying out the method according to one of the preceding claims, characterized by an electronic display device (1) having a screen (3) and a graphics memory (2) in which image data (14) relating to an image displayed by the display device (1) are or can be stored or changed,
   a power measuring device (6, 7) which is or can be used to measure a value (15) characterizing the power consumption or the change in the power consumption of the screen (3) or of the display device (1), and
   an evaluation device (8) which is or can be used, on the basis of the image data (14) or the change in the image data (14), to determine a reference value (16) characterizing the power consumption or the change in the power consumption of the screen (3) or of the display device (1) and to compare it with the measured value (15),
   wherein the device is designed to assign at least two partial images to a character to be displayed by the screen (3), a first of which partial images forms the image whose image data are stored in the graphics memory,
   wherein the device is designed to select the partial images in such a manner that their power consumptions differ from a respective previously displayed image, and wherein, after the check of the first partial image, the remaining image data for the character are loaded into the graphics memory in order to fully display the character.

Images