JP4843156B2 - Display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a display device and a display control method. In particular, the present invention relates to a display device and a display control method for controlling the luminance of a display unit.
[0002]
[Prior art]
In recent years, thin display devices have been generally used. As an example of a thin display device, there is an organic EL display device using an organic EL element (organic electroluminescence element).
[0003]
[Problems to be solved by the invention]
However, the organic EL element is a self-luminous element and has a short optical life. Accordingly, it is known that the luminance decreases as the driving time increases.
[0004]
Accordingly, an object of the present invention is to provide a display device and a display control method that can solve the above-described problems. This object is achieved by a combination of features described in the independent claims. The dependent claims define further advantageous specific examples of the present invention.
[0005]
[Means for Solving the Problems]
That is, according to the first aspect of the present invention, the display device controls the luminance displayed by the display unit based on the display unit for displaying information, the accumulated operation time of the display unit, and the temperature of the display unit. A control unit.
[0006]
The system further includes a cumulative operating time storage unit that stores the cumulative operating time in which the display unit is operated in association with the temperature at which the display unit is operated, and the control unit displays the cumulative operating time stored in the cumulative operating time storage unit, and a display The luminance may be controlled based on the temperature of the part.
[0007]
A temperature detection unit that is provided near the display unit and detects a use environment temperature of the display unit may be further provided, and the control unit may use the temperature detected by the temperature detection unit as the temperature of the display unit.
[0008]
According to a second aspect of the present invention, there is provided a display control method for controlling the brightness of a display device, wherein the cumulative operation time for displaying information and the temperature of the display device are managed, the cumulative operation time, and the display device The brightness is controlled based on the temperature.
[0009]
The above summary of the invention does not enumerate all the necessary features of the present invention, and sub-combinations of these feature groups can also be the invention.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described through embodiments of the invention. However, the following embodiments do not limit the claimed invention, and all combinations of features described in the embodiments are the solution of the invention. It is not always essential to the means.
[0011]
FIG. 1 is a block diagram showing a functional configuration of an organic EL display device 10 as an example of a display device according to the present embodiment. The organic EL display device 10 includes a control unit 20, a display unit 30, a power supply unit 40, and a cumulative operation time storage unit 50. The display unit 30 includes a temperature detection unit 60 such as a temperature sensor. The temperature detection unit 60 detects the environmental temperature of the display unit 30. The organic EL display device 10 controls the operating power of the display unit 30 based on the accumulated operation time. The accumulated operation time storage unit 50 stores the accumulated operation time during which the display unit 30 has been operated for each range of the detected value of the environmental temperature of the display unit 30 at the time of operation. The control power storage unit 70 stores information indicating the power that the power supply unit 40 should supply to the display unit 30 when it is determined that the luminance of the display unit 30 has decreased.
[0012]
The control unit 20 sends information indicating the power to be supplied to the display unit 30 to the power supply unit 40. The power supply unit 40 supplies power to the display unit 30 based on the information received from the control unit 20. Next, the control unit 20 acquires the environmental temperature of the display unit 30 from the temperature detection unit 60 when it is determined that a predetermined time has elapsed since the power supply unit 40 began to supply power to the display unit 30. When the control unit 20 receives the environmental temperature of the display unit 30, the control unit 20 adds a predetermined time to the cumulative operation time stored in the cumulative operation time storage unit 50 in association with the temperature range including the received environmental temperature. The accumulated operation time storage unit 50 is updated.
[0013]
Next, the control unit 20 calculates, for each temperature range stored in the cumulative operation time storage unit 50, a result for each temperature obtained by multiplying the cumulative operation time by a weighting coefficient. Furthermore, the control unit 20 calculates the total of the calculated results for each temperature, and controls the power consumption of the power supply unit 40 based on the control power storage unit 70 when the calculated total value is a certain value or more.
[0014]
When the control unit 20 controls the power consumption of the power supply unit 40, the power value stored in the control power storage unit 70 in association with the calculated total value becomes the power supplied to the display unit 30. The power supply unit 40 is controlled.
[0015]
FIG. 2 shows an example of the data format of the cumulative operation time storage unit 50. The accumulated operation time storage unit 50 includes an element temperature field, an accumulated time field, a coefficient field, and a temperature-specific result field. The element temperature field stores the environmental temperature range of the organic EL element. The accumulated time field stores the accumulated operating time during which the display unit 30 is operated in each environmental temperature range. The coefficient field stores a weighting coefficient at the environmental temperature used by the control unit 20. The temperature-specific result field stores a temperature-specific result, which is a value obtained by multiplying the cumulative operation time by the weighting coefficient calculated by the control unit 20.
[0016]
FIG. 3 shows an example of the data format of the control power storage unit 70. The control power storage unit 70 has a total value range field and a power control field. The total value range field stores information indicating the range of the total value calculated by the control unit 20. The power control field stores information indicating the power that the power supply unit 40 should supply to the display unit 30 when the total value calculated by the control unit 20 is included in the total value range.
[0017]
FIG. 4 shows an outline of the relationship between power consumption and luminance of a display device using a normal organic EL element. The horizontal axis indicates the power consumption supplied to the organic EL element. The vertical axis represents the luminance of the organic EL element. The power consumption and the luminance are in a substantially proportional relationship as shown by the straight line B in FIG. The greater the power consumption, the higher the luminance of the organic EL element. The inclination of the straight line B varies depending on the size of the panel of the display unit 30, the display color, and the like. Based on the slope of the straight line B, an initial value of power consumption is set. The initial setting value of the luminance corresponding to the power consumption set here is A, and the power value that the power supply unit 40 supplies to the display unit 30 when the display unit 30 starts operating.
[0018]
According to FIG. 4, the organic EL display device 10, which is a display device using organic EL elements, increases the luminance of the display unit 30 when the amount of power supplied to the display unit 30 is increased. Moreover, in the organic EL display device 10 which is a display device using an organic EL element, the luminance decreases as the operating time of the display unit 30 increases. Therefore, when the operating time increases and the luminance of the display unit 30 decreases, the organic EL display device 10 can increase the power supplied to the display unit 30 and keep the luminance of the display unit 30 at a certain value or more. .
[0019]
FIG. 5 shows an example of the relationship between the set luminance and the half life of the organic EL element. Furthermore, the curve C shows an example of the relationship between the set luminance and the half-life when the environmental temperature is −20 ° C. Curve D shows an example of the relationship between the set brightness and the half-life when the environmental temperature is + 20 ° C. Curve E shows an example of the relationship between the set brightness and the half-life when the environmental temperature is + 60 ° C.
[0020]
As shown in the example of FIG. 5, the half-life is shorter as the environmental temperature is higher and the initially set luminance is higher. Therefore, when the environmental temperature of the display unit 30 is high, the luminance of the display unit 30 decreases faster than when the environmental temperature of the display unit 30 is low.
[0021]
FIG. 6 shows an example of the relationship between the weighting coefficient stored in the accumulated operating time storage unit 50 and the environmental temperature. In this embodiment, when the weighting coefficient for the set temperature + 20 ° C. is ± 0, the weighting coefficient at a low temperature is set to a negative value compared to + 20 ° C., and the temperature is high compared to + 20 ° C. Is set to a positive value. That is, according to FIG. 3, the higher the environmental temperature, the shorter the half-life, so the weighting coefficient is set higher.
[0022]
As shown in the examples of FIGS. 4 and 5, in order to keep the luminance of the display unit 30 at a certain value or higher, the organic EL display device 10 has a higher cumulative operating time as the environmental temperature of the display unit 30 is higher. The power supplied to the display unit 30 needs to be increased. Accordingly, the organic EL display device 10 calculates a value obtained by multiplying the cumulative operating time of the display unit 30 by the weighting coefficient set based on the environmental temperature, and controls the power supply unit 40 based on the calculated value, thereby displaying the display unit. The luminance of the display unit 30 can be maintained at a constant value for a longer period after the operation of 30 starts.
[0023]
FIG. 7 is a flowchart showing the operation of the organic EL display device 10. The power supply unit 40 applies power to the display unit 30 to start operation of the display unit 30 (S100). Next, the control unit 20 determines whether or not a predetermined time has elapsed since the power source unit 40 began to apply power to the display unit 30 (S102). When the control unit 20 determines that the predetermined time has elapsed, the temperature detection unit 60 detects the environmental temperature of the display unit 30. In addition, the control unit 20 adds a predetermined time to the accumulated operation time stored in the accumulated operation time storage unit 50 (S104). Next, the control unit 20 stores the added accumulated operation time in the accumulated operation time storage unit 50 in association with the environmental temperature of the display unit 30 detected by the temperature detection unit 60 (S106).
[0024]
Next, the control unit 20 calculates a result for each temperature by applying the weighting coefficient stored in association with the accumulated operation time stored in the accumulated operation time storage unit 50 to the accumulated operation time (S108). Next, the control unit 20 extracts the calculated temperature-specific results for each environmental temperature range, and calculates the sum total (S110). Next, the control part 20 controls the power supply part 40 based on the electric power value stored in the control electric power storage part 70, when the calculated total value is more than a fixed value (S112). The organic EL display device 10 repeats the operations from S104 to S112 every predetermined time. In this embodiment, the organic EL display device, which is a display device using an organic EL element, is described. However, the display device may be one using another arbitrary element such as a liquid crystal.
[0025]
As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.
[0026]
【The invention's effect】
As is apparent from the above description, the brightness of the display unit can be controlled according to the present invention.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a functional configuration of an organic EL display device 10 according to the present embodiment.
FIG. 2 is a diagram illustrating an example of a data format of an accumulated operation time storage unit 50.
3 is a diagram illustrating an example of a data format of a control power storage unit 70. FIG.
FIG. 4 is a diagram showing an outline of the relationship between power consumption and luminance of a display device using a normal organic EL element.
FIG. 5 is a diagram showing an outline of the relationship between set luminance and half-life of an organic EL element.
FIG. 6 is a diagram showing an outline of a relationship between a weighting coefficient and an environmental temperature.
7 is a flowchart showing an operation of the organic EL display device 10. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Organic EL display apparatus 20 Control part 30 Display part 40 Power supply part 50 Cumulative operation time storage part 60 Temperature detection part 70 Control electric power storage part

Claims (1)

A display device,
A display for displaying information;
A control unit that controls the luminance displayed by the display unit based on the cumulative operating time of the display unit and the use environment temperature of the display unit ;
An accumulated operating time storage unit that stores the accumulated operating time in which the display unit has been operated in association with an operating environment temperature at the time of operation;
With
The control unit controls the luminance based on the accumulated operation time stored in the accumulated operation time storage unit and a use environment temperature of the display unit.

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