Display device and display panel device

1. A display device, comprising:

a plasma display panel having a screen including a plurality of cells;

a functional sheet having at least an optical filter function to light emitted from the screen, being brought into intimate contact with a front surface of the plasma display panel and having a structure in which heat diffusion is superior to heat insulation between the plasma display panel and outside air;

a drive voltage output circuit for giving the screen a drive voltage pulse train that generates display discharge plural times corresponding to a gradation; and

a controller for controlling the drive voltage pulse train so that power consumption in a unit area in a light emission region within the screen is limited under a set value when one image is displayed.

2. The display device according to claim 1 , wherein the controller includes means for detecting a display ratio that is a ratio of the number of cells to be energized to a total number of cells in accordance with display data, and the controller changes a frequency of the drive voltage pulse train in accordance with the detected display ratio.

3. The display device according to claim 1 , wherein in an operation under an environment less than or equal to 40° C., a temperature on a front surface of the functional sheet is kept lower than or equal to 70° C., and a temperature on the front surface of the plasma display panel is kept lower than or equal to 80° C.

4. The display device according to claim 1 , wherein a weight per square meter of the functional sheet is a value within the range of 0.2–3.0 kilograms.

5. The display device according to claim 1 , wherein a thermal conductivity ratio of a material constituting a surface of the functional sheet contacting the plasma display panel is a value within the range of 0.1 W·m −1 ·K −1 to 0.4 W·m −1 ·K −1 .

6. The display device according to claim 1 , wherein the set value is 2500 watts per square meter.

7. The display device according to claim 6 , wherein the controller converges power consumption in the unit area to 1500 watts per square meter in 30 minutes when power consumption per unit area exceeds 1500 watts per square meter.

8. The display device according to claim 1 , wherein an instantaneous peak luminance of light emission of the screen on a front surface of the functional sheet is more than or equal to 200 candela per square meter, and a stationary peak luminance of light emission of the screen on the front surface of the functional sheet is more than or equal to 100 candela per square meter.

9. The display device according to claim 1 , wherein the functional sheet is a layered film including a front portion containing a coloring matter that absorbs light in a specific wavelength range and a rear portion that does not contain the coloring matter, and a thickness of the rear portion is more than or equal to 0.1 mm.

10. The display device according to claim 9 , wherein the rear portion is thicker than the front portion.

11. The display device according to claim 9 , wherein the rear portion is a resin layer having a visible light transmittance more than or equal to 80%, which is made of a resin having a variation in the transmittance that is less than 5% over the entire visible light wavelength range after being exposed to an environment at 80° C. for 500 hours.

12. The display device according to claim 9 , wherein the rear portion is a resin layer having a visible light transmittance more than or equal to 80%, which is made of a resin having a variation in the transmittance that is less than 5% over the entire visible light wavelength range after being exposed to an environment at 60° C. and of humidity 90% for 500 hours.

13. A display panel device, comprising:

a plasma display panel having a screen including a plurality of cells;

a functional sheet having at least an optical filter function to light emitted from the screen, and being brought into intimate contact with a front surface of the plasma display panel; and

a driving circuit board arranged at the rear side of the plasma display panel, wherein

the driving circuit board includes a drive voltage output circuit for giving the screen a drive voltage pulse train that generates display discharge plural times corresponding to a gradation, and a controller for controlling the drive voltage pulse train so that power consumption in a unit area in a light emission region within the screen is limited under a set value when one image is displayed.