Display apparatus and method for controlling display apparatus

Patent metadata

Field	Value
Publication number	US-9542911-B2
Application number	US-201313969646-A
Country	US
Kind code	B2
Filing date	Aug 19, 2013
Priority date	Sep 24, 2012
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

A display apparatus includes: a display unit including a modulator that modulates a plurality of color light fluxes and a light source section that includes a plurality of light sources corresponding to at least any of the color light fluxes; a light source driver that supplies the light sources with pulse currents; and a controller that sets the cycle of each of the pulse currents and an ON-period of the pulses in the pulse current in accordance with the luminance of the light source, wherein when the luminance of any of the light sources is so set that the ON-period of the pulse current is shorter than a preset lower limit, the controller sets the length of the ON period of the pulse current to be equal to the lower limit or at a value longer than the lower limit and reduces the current value of the pulse current.

First claim

What is claimed is:

1. A display apparatus comprising:
a display unit including a modulator that modulates a plurality of color light fluxes and a light source section that includes a plurality of light sources each corresponding to at least one of the color light fluxes;
a light source driver that supplies the light sources with pulse currents to cause the light sources to emit light fluxes; and
a controller that sets the cycle of the pulse current supplied to each of the light sources by the light source driver and an ON-period of the pulses in the pulse current in accordance with a luminance of the light source,
wherein
when the luminance of any of the light sources is so set that the ON-period of the pulse current flowing through the light source is shorter than a preset lower limit, the controller sets a length of the ON-period of the pulse current flowing through the light source to be equal to the lower limit or at a value longer than the lower limit and reduces the current value of the pulse current flowing through the light source,
when the luminance of a first light source of the plurality of light sources is adjusted and the luminance of a second light source of the plurality of light sources is not adjusted:
the controller sets the length of the ON-period of the pulse current flowing through the first light source to be equal to the lower limit or at a value longer than the lower limit and reduces the current value of the pulse current flowing through the first light source from a first current value to a second current value, and
the controller sets the current value of the pulse current value flowing through the second light source to match the second current value of the first light source and sets the length of the ON-period of the pulse current flowing through the second light source to be a value that, when combined with the second current value of the first light source, maintains the luminance of the second light source at a same level as before the pulse current value of the second light source is changed to the second current value of the first light source, and

the controller switches the first current value of the pulse current flowing through each of the light sources to the second current value in a stepwise manner such that at least one intermediate current value having a value between the first current value and the second current value is supplied after the first current value and before the second current value.

2. The display apparatus according to claim 1 ,
wherein an ON-period ratio among the pulse currents flowing through the light sources or a luminance ratio among the light sources is set to achieve a preset ratio among the amounts of the plurality of color light fluxes.

3. The display apparatus according to claim 1 ,
wherein when the current value of the pulse current flowing through one of the light sources is reduced, the controller sets a longer ON-period of the pulse current flowing through the light source than the ON-period in a case where the current value is not reduced.

4. The display apparatus according to claim 1 ,
further comprising a current setting unit that sets a current value common to the plurality of light sources,
wherein when the current setting unit changes the current value of the currents supplied to the light sources to a lower value, the controller changes the ON-period of the pulse current flowing through any of the light sources in such a way that a decrease in the luminance thereof due to the decrease in the current value is compensated.

5. A method for controlling a display apparatus that modulates a plurality of color light fluxes to display an image, the method comprising:
supplying a plurality of light sources with pulse currents to cause the light sources to emit light fluxes;
setting a cycle of the pulse current supplied to each of the light sources and an ON-period of the pulses in the pulse current in accordance with the luminance of the light source;
when the luminance of any of the light sources is so set that the ON-period of the pulse current flowing through the light source is shorter than a preset lower limit, setting the length of the ON-period of the pulse current flowing through the light source to be equal to the lower limit or at a value longer than the lower limit and reducing the current value of the pulse current flowing through the light source, and
when the luminance of a first light source of the plurality of light sources is adjusted and the luminance of a second light source of the plurality of light sources is not adjusted:
setting the length of the ON-period of the pulse current flowing through the first light source to be equal to the lower limit or at a value longer than the lower limit and reduces the current value of the pulse current flowing through the first light source from a first current value to a second current value, and
setting the current value of the pulse current value flowing through the second light source to match the second current value of the first light source and sets the length of the ON-period of the pulse current flowing through the second light source to be a value that, when combined with the second current value of the first light source, maintains the luminance of the second light source at a same level as before the pulse current value of the second light source is changed to the second current value of the first light source,

wherein the first current value of the pulse current flowing through each of the light sources switches to the second current value in a stepwise manner such that at least one intermediate current value having a value between the first current value and the second current value is supplied after the first current value and before the second current value.

6. The method according to claim 5 , further comprising
setting an ON-period ratio among the pulse currents flowing through the light sources or a luminance ratio among the light sources to achieve a preset ratio among the amounts of the plurality of color light fluxes.

7. The method according to claim 5 , further comprising
when the current value of the pulse current flowing through one of the light sources is reduced, setting a longer ON-period of the pulse current flowing through the light source than the ON-period in a case where the current value is not reduced.

8. The method according to claim 5 , further comprising
setting a current value common to the plurality of light sources, and
when the current value of the currents supplied to the light sources is changed to a lower value, changing the ON-period of the pulse current flowing through any of the light sources in such a way that a decrease in the luminance thereof due to the decrease in the current value is compensated.

Assignees

• Seiko Epson Corp

Inventors

• Tsukagoshi Shinichi

Classifications

• H04N9/3161

  using laser light sources (using laser beams scanning the display screen H04N9/3129) · CPC title

• H04N9/3158

  for controlling the spectrum · CPC title

• G09G3/2037 Primary

  with specific control of sub-frames corresponding to the least significant bits · CPC title

• G09G3/2077

  by a combination of two or more gradation control methods · CPC title

• G09G3/3413

  Details of control of colour illumination sources · CPC title