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EP-3948836-B1 - OPERATION OF A DEVICE COMPRISING A LIGHT EMITTING DIODE

EP3948836B1EP 3948836 B1EP3948836 B1EP 3948836B1EP-3948836-B1

Inventors

  • HUNT, ALEXANDER

Dates

Publication Date
20260506
Application Date
20190328

Claims (15)

  1. A method (100) for operating a device comprising a Light Emitting Diode, LED, display, the method, performed in the device, comprising: obtaining (110) a representation of temperatures to which different areas of the display are subjected; generating (120) a display heat map from the obtained representation; and managing (130) a luminance of the different areas of the display on the basis of the display heat map; the method being characterized in that managing (130) the luminance of the different areas of the display on the basis of the display heat map comprises: obtaining (232) a representation of an image to be shown on the display, wherein obtaining a representation of an image to be shown on the display comprises obtaining a representation of required luminance of different pixels of the display to show the image; combining (234) the obtained representation of the image with the generated display heat map, wherein combining (234) the obtained representation of the image with the generated display heat map comprises: mapping (234a) the required luminance of different pixels of the display to show the image to a required current to be passed through the pixels of the display to generate the required luminance; wherein combining the obtained representation of an image with the generated display heat map comprises performing an image blending operation; and generating (234b) a combined representation of temperature and required pixel current in the different areas of the display; comparing (236) the combined representation of an image and display heat map to an operational specification for pixels of the display, wherein comparing (236) the combined representation of an image and display heat map to an operational specification for pixels of the display comprises: comparing (236a) the temperature and required pixel current combination for pixels in the combined representation with a maximum temperature and current combination in the operational specification for the pixels; and adjusting (238) the luminance of the pixels of the display as a function of a result of the comparison, wherein adjusting (238) the luminance of the pixels of the display as a function of a result of the comparison comprises: for pixels for which the temperature and required pixel current combination in the combined representation exceed the maximum temperature and current combination in the operational specification, reducing (238a) the current to be passed through the pixels such that the maximum temperature and current combination in the operational specification is respected.
  2. A method as claimed in claim 1, wherein obtaining (110) a representation of temperatures to which different areas of the display are subjected comprises obtaining (210) temperature readings from one or more temperature sensors positioned relative to the different areas of the display.
  3. A method as claimed in claim 1 or 2, wherein obtaining (110) a representation of temperatures to which different areas of the display are subjected comprises obtaining (212) temperature readings from one or more temperature sensors positioned on at least one component of the display.
  4. A method as claimed in claim 1 or 2, wherein obtaining (110) a representation of temperatures to which different areas of the display are subjected comprises obtaining (214) temperature readings from one or more temperature sensors positioned on components adjacent the display.
  5. A method as claimed in claim 4, wherein the device comprises a Printed Circuit Board, PCB, and wherein obtaining a representation of temperatures to which different areas of the display are subjected comprises obtaining (214) temperature readings from one or more temperature sensors positioned on components of the printed circuit board.
  6. A method as claimed in claim 5, wherein the PCB comprises one or more shield cans arranged to at least partially protect components within the shield can from electro-magnetic and radio frequency interference, and wherein obtaining (110) a representation of temperatures to which different areas of the display are subjected comprises obtaining (214) temperature readings from one or more temperature sensors positioned relative to one or more shield cans.
  7. A method as claimed in any one of the preceding claims, wherein generating (120) a display heat map from the obtained representation of temperatures comprises combining (220) the obtained representation of temperatures with a representation of the physical arrangement of the different areas of the display.
  8. A method as claimed in claim 7 when dependent upon claim 5 or claim 6 wherein the PCB comprises one or more shield cans arranged to at least partially protect components within the shield can from electro-magnetic and radio frequency interference, and wherein the different areas of the display correspond to areas occupied by different shield cans (222).
  9. A method as claimed in claims 1-8, wherein reducing the current to be passed through the pixels such that the maximum temperature and current combination in the operational specification is respected comprises reducing (238a) the current by a value that is less than or equal to a maximum reduction value, wherein the maximum reduction value corresponds to a reduction in luminance of the pixels of 30% compared to the required luminance to show the image.
  10. A method as claimed in any one of claims 1-9, wherein adjusting the luminance of the pixels of the display as a function of a result of the comparison comprises respecting (238) a maximum rate of change of luminance per pixel row of the display.
  11. A method as claimed in any one of the preceding claims, further comprising performing the steps of: obtaining (110) a representation of temperatures to which different areas of the display are subjected; and generating (120) a display heat map from the obtained representation; in a first processing unit, and performing the step of: managing (130) the luminance of the different areas of the display on the basis of the display heat map; in a second processing unit.
  12. A method as claimed in any one of claims 1 to 10, further comprising performing the steps of: obtaining (110) a representation of temperatures to which different areas of the display are subjected; generating (120) a display heat map from the obtained representation; and managing (130) the luminance of the different areas of the display on the basis of the display heat map; in a first processing unit.
  13. A device (900) comprising a Light Emitting Diode, LED, display, the device comprising a processor (902) and a memory (904), the memory (904) containing instructions which when executed by the processor carry out a method as claimed in any one of claims 1 to 12.
  14. A computer program comprising instructions which, when executed on at least one processor, cause the at least one processor to carry out a method according to any one of claims 1-12.
  15. A computer program product comprising non transitory computer readable media having stored thereon a computer program as claimed in claim 14.

Description

Technical Field The present disclosure relates to a method for operating a device comprising a Light Emitting Diode (LED) display, which may be an Organic LED (OLED) display. The present disclosure also relates to a device comprising a LED display and to a computer program product configured to carry out a method for operating a device comprising a LED display. Background Light Emitting Diodes (LEDs) are used in displays for a wide variety of electronic devices. Liquid Cristal Displays (LCDs), which are widely used in televisions as well as smaller electronic devices, typically use LEDs to provide the necessary backlight. Such displays are particularly popular in electronic devices that are subject to functional restrictions in volume. Examples of such devices include wireless devices such as mobile phones or smartphones, headphones, watches, smart bands, Helmet Mounted Displays (HMDs), Heads-Up Displays (HUDs) etc. Organic LED (OLED) displays are increasingly being adopted in larger and smaller electronic devices, and offer certain advantages over conventional LCD displays with a LED backlight, including improved contrast and viewing angles. In contrast to conventional LCD displays, which use a LED backlight to illuminate pixels, each OLED pixel produces its own light, with an OLED display being formed from an array of individual red, blue and green OLEDs. The light of an OLED display can therefore be controlled on a pixel-by-pixel basis. Micro-LED based displays are also in development, and operate on a similar principle to OLED displays, with individual micro-LED pixels producing their own light, and display formed form an array of red, blue and green micro-LEDs. All types of LED display are sensitive to temperature, and age faster in high temperatures. OLED displays are particularly affected by heat-related aging, and in addition, OLEDs of different colour age differently. This differential ageing of OLEDs of different colours can cause the white point of the display to shift over time. Considerable efforts have been made to control the ageing of OLED displays through active management of temperature, current, and luminance, but heat related ageing remains an issue for all LED displays, and particularly for OLED displays. Document US 2013/321361 A1 (LYNCH STEPHEN BRIAN [US] ET AL) discloses a heat map and a method of boosting currents of pixels to compensate for the heat effect. It solves the problem of maintaining the brightness despite an increase in temperature. Document US 2016/293102 A1 (CHAJI GHOLAMREZA [CA]) solves the problem of heat in a display device: if the temperature rises in an area, the luminance of high brightness pixels is decreased. Summary It is an aim of the present disclosure to provide a method, device and computer readable medium which at least partially address one or more of the challenges discussed above.The invention is defined by the appended claims. According to a first aspect of the present disclosure, there is provided a method for operating a device comprising a LED display, such as an OLED display or a micro-LED display. The method, performed in the device, comprises obtaining a representation of temperatures to which different areas of the display are subjected, generating a display heat map from the obtained representation, and managing the luminance of the different areas of the display on the basis of the display heat map. According to examples of the present disclosure, the different areas of the display may comprise two or more areas into which the display may be divided. According to examples of the present disclosure, the device may comprise a Wireless Device such as a UE, headphones, watches, smart bands, heads-up or helmet mounted displays etc. According to examples of the present disclosure, obtaining a representation of temperatures to which different areas of the display are subjected may comprise obtaining temperature readings from one or more temperature sensors positioned relative to the different areas of the display. According to examples of the present disclosure, obtaining a representation of temperatures to which different areas of the display are subjected may comprise obtaining temperature readings from one or more temperature sensors positioned on at least one component of the display. According to examples of the present disclosure, the sensors may for example be positioned on a metal coating on a LED panel forming the display, such as the reflecting cathode or anode on the back of an OLED display panel, or in another example on individual pixels of the display. According to examples of the present disclosure, obtaining a representation of temperatures to which different areas of the display are subjected may comprise obtaining temperature readings from one or more temperature sensors positioned on components adjacent the display. According to examples of the present disclosure, the device may comprise a Printed Circuit Board, PCB, and obtaining