Display driver and electronic equipment

• US 20080284712A1
• Filed: 08/03/2007
• Published: 11/20/2008
• Est. Priority Date: 08/04/2006
• Status: Abandoned Application

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Muto, Kota, Sawada, Munenori
• Application Number:
  US11/890,198
• Publication Number:
  US 20080284712A1
• Time in Patent Office: Days
• US Class Current: 345/101
• CPC Class Codes: G09G 2310/06 Details of flat display driving waveforms
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 3/3651 using multistable liquid crystals, e.g. ferroelectric liquid crystals

Abstract

A display driver for driving a display element includes an electro-optical layer to which a drive voltage is applied, the drive voltage being a voltage corresponding to a scanning voltage and a data voltage, the scanning voltage being a voltage applied to a scanning electrode, the data voltage being a voltage applied to a data electrode. The display driver includes: a display driver circuit configured to apply the drive voltage to the electro-optical layer, the drive voltage corresponding to one of at least two operation modes including a first drive mode and a second drive mode, the first drive mode having a first temperature range for representing two tones, the second drive mode having a second temperature range for representing two tones, the first temperature range and the second temperature range being different from each other; an input interface configured to input temperature information, the temperature information being information relating to temperature of the display element; and an operation mode determining unit configured to determine operation mode of the display driver circuit on the basis of the temperature information.

Claims

1. A display driver for driving a display element including an electro-optical layer to which a drive voltage is applied, the drive voltage being a voltage corresponding to a scanning voltage and a data voltage, the scanning voltage being a voltage applied to a scanning electrode, the data voltage being a voltage applied to a data electrode, the display driver comprising:

a display driver circuit configured to apply the drive voltage to the electro-optical layer, the drive voltage corresponding to one of at least two operation modes including a first drive mode and a second drive mode, the first drive mode having a first temperature range for representing two tones, the second drive mode having a second temperature range for representing two tones, the first temperature range and the second temperature range being different from each other;

an input interface configured to input temperature information, the temperature information being information relating to temperature of the display element; and

an operation mode determining unit configured to determine operation mode of the display driver circuit on the basis of the temperature information.

2. The display driver according to claim 1,

wherein the temperature information includes temperature dispersion showing a dispersion of temperature within a predetermined area of the display element.

3. The display driver according to claim 2,

wherein the second temperature range is wider than the first temperature range;

the display driver further includes a condition determining unit configured to determine whether the temperature dispersion included in the temperature information is greater than a threshold; and

the operation mode determining unit is configured to determine that the operation mode of the display driver circuit is the second drive mode in a case that the condition determining unit determines that the temperature dispersion is greater than the threshold.

4. The display driver according to claim 2,

wherein the maximum temperature in the second temperature range is greater than that in the first temperature range;

the display driver further includes a condition determining unit configured to determine whether the temperature dispersion included in the temperature information satisfies a condition, the condition showing the temperature dispersion is higher than a threshold and temperature of a region where the temperature dispersion is higher than the threshold is higher than the temperature of the periphery of the region; and

the operation mode determining unit is configured to determine that the operation mode of the display driver circuit is the second drive mode in a case that the condition determining unit determines that the temperature dispersion satisfies the condition.

5. The display driver according to claim 2,

wherein the minimum temperature in the second temperature range is less than that in the first temperature range;

the display driver further includes a condition determining unit configured to determine whether the temperature dispersion included in the temperature information satisfies a condition, the condition showing the temperature dispersion is higher than a threshold and temperature of a region where the temperature dispersion is higher than the threshold is lower than the temperature of the periphery of the region; and

the operation mode determining unit is configured to determine that the operation mode of the display driver circuit is the second drive mode in a case that the condition determining unit determines that the temperature dispersion satisfies the condition.

6. The display driver according to claim 2, further comprising:

an IR information input interface configured to input IR information showing an intensity of infrared rays irradiated onto the display element; and

a condition determining unit configured to determine whether the IR intensity included in the IR information satisfies a condition, the condition showing that the IR intensity is higher than a predetermined threshold,

wherein the maximum temperature of the second temperature range is higher than that in the first temperature range; and

the operation mode determining unit is configured to determine that the operation mode of the display driver circuit is the second drive mode in a case that the condition determining unit determines that the IR intensity satisfies the condition.

7. The display driver according to claim 2, further comprising:

a standard temperature determining unit configured to determine a standard temperature, the standard temperature being standard on the basis of which the drive voltage is determined; and

a parameter memory configured to store a plurality of parameter sets, each of the plurality of parameter set defining the drive voltage at a certain temperature in an operation mode,

wherein the display driver circuit is configured to apply the drive voltage in accordance with one of the plurality of parameter sets, the one parameter set being determined on the basis of the standard temperature and the operation mode determined by the operation mode determining unit.

8. The display driver according to claim 1,

wherein the electro-optical layer includes image-retaining liquid crystal molecules that represent a tone in response to orientation state of the image-retaining liquid crystal molecules;

the display driver circuit is configured to apply the drive voltage by dividing the drive voltage into a plurality of stages including a selection phase during which a selection voltage that determines the orientation state of the image-retaining liquid crystal molecules is applied,

the range of the selection voltage in the first drive mode and in the second drive mode is different from each other.

9. The display driver according to claim 1,

wherein the temperature information includes temperature variation showing time dependency of the temperature of the display element.

10. The display driver according to claim 9,

wherein the maximum temperature in the second temperature range is higher than that in the first temperature range;

the display driver further includes a condition determining unit configured to determine whether the temperature variation included in the temperature information satisfies a condition, the condition showing that the temperature of the display element decreases; and

the operation mode determining unit is configured to determine that the operation mode of the display driver circuit is the second drive mode in a case that the condition determining unit determines that the temperature variation satisfies the condition.

11. The display driver according to claim 9,

wherein the minimum temperature in the second temperature range is lower than that in the first temperature range;

the display driver further includes a condition determining unit configured to determine whether the temperature variation included in the temperature information satisfies a condition, the condition showing that the temperature of the display element increases; and

the operation mode determining unit is configured to determine that the operation mode of the display driver circuit is the second drive mode in a case that the condition determining unit determines that the temperature variation satisfies the condition.

12. The display driver according to claim 1,

wherein the temperature information includes the temperature of the display element;

the display driver further includes a threshold memory configured to store a threshold showing the temperature at which the operation mode is switched;

the operation mode determining unit is configured to determine that the operation mode of the display driver circuit is the second drive mode in a case that the temperature shown by the temperature information is lower than the threshold.

13. An electronic device, comprising:

a display element including an electro-optical layer to which a drive voltage is applied, the drive voltage being a voltage corresponding to a scanning voltage and a data voltage, the scanning voltage being a voltage applied to a scanning electrode, the data voltage being a voltage applied to a data electrode, the display driver comprising;

a display driver circuit configured to apply the drive voltage to the electro-optical layer, the drive voltage corresponding to one of at least two operation modes including a first drive mode and a second drive mode, the first drive mode having a first temperature range for representing two tones, the second drive mode having a second temperature range for representing two tones, the first temperature range and the second temperature range being different from each other;

an input interface configured to input temperature information, the temperature information being information relating to temperature of the display element; and

an operation mode determining unit configured to determine an operation mode of the display driver circuit on the basis of the temperature information.

14. The electronic device according to claim 13, further comprising:

two glass substrates configured to sandwich the electro-optical layer;

a plurality of temperature sensors mounted on a plane of at least one of the two glass substrates;

at least one radiation sheet pasted on the same plane as the temperature sensors.

15. The electronic device according to claim 14,

wherein the plurality of temperature sensors are laid out at intervals;

the electronic device includes a plurality of radiation sheets, each of which covers at least one of the temperature sensors, and is arranged so as not to overlap each other.

16. The electronic device according to claim 14,

wherein the radiation sheet includes a graphite sheet.

17. The electronic device according to claim 14,

wherein at least one of the temperature sensors is arranged at a position whose distance from the edge of the plane is greater than a threshold;

some of the temperature sensors other than the at least one of the temperature sensors is arranged at a position whose distance from the edge of the plane is less than a threshold; and

the temperature information shows temperature difference between the at least one of the temperature sensors and some of the temperature sensors.