Display device, display system, video output device, and control method of display device

• US 9,812,071 B2
• Filed: 05/22/2013
• Issued: 11/07/2017
• Est. Priority Date: 05/22/2013
• Status: Active Grant

• Current Assignee: Sharp NEC Display Solutions, Ltd. (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: NEC Display Solutions, Ltd. (NEC Corporation)
• Inventors: Matsui, Katsuyuki
• Primary Examiner(s): Marinelli, Patrick F
• Application Number:
  US14/889,172
• Publication Number:
  US 20160086551A1
• Time in Patent Office: 1,630 Days
• CPC Class Codes: G09G 2320/0242 Compensation of deficiencies in the appearance of colours
• CPC Class Codes: G09G 2320/045 Compensation of drifts in the characteristics of light emitting or modulating elements
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/0666 for control of colour parameters, e.g. colour temperature
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/145 the light originating from the display screen
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources

Abstract

A display device includes an emission part further including a first light source emitting a first light, a second light source emitting a second light having a longer wavelength than the first light, and a fluorescent substance which is excited by the first light and the second light so as to emit a third light, and a controller configured to generate a drive value of the first light source and a drive value of the second light source based on a luminance of the first light, a luminance of the second light, a luminance of the third light, a first target luminance for the first light source, a second target luminance for the second light source, and a third target luminance for the fluorescent substance, thus controlling two light sources based on the drive values of the first and second light sources.

Claims

1. A display device comprising:

an emission part including a first light source emitting a first light, a second light source emitting a second light having a longer wavelength than the first light, and a fluorescent substance which is excited by the first light and the second light so as to emit a third light; and

a controller configured to generate a drive value of the first light source and a drive value of the second light source based on a luminance of the first light, a luminance of the second light, a luminance of the third light, a first target luminance for the first light source, a second target luminance for the second light source, and a third target luminance for the fluorescent substance, thus controlling two light sources based on the drive values of the first and second light sources,

wherein the controller determines the drive value of the second light source such that the luminance of the second light matches the second target luminance, and

wherein the controller further increases the drive value of the first light source such that the luminance of the first light matches the first target luminance when the luminance of the first light is smaller than the first target luminance at a time at which the controller determines the drive value of the first light source such that the luminance of the third light matches the third target luminance.

2. The display device according to claim 1, wherein the first light source and the second light source are attached to a same substrate.

3. The display device according to claim 1, wherein the controller controls the first light source and the second light source such that a power consumption or a temperature of the emission part falls within a rated value of the emission part.

4. The display device according to claim 1, wherein the first light is a blue light, the second light is a green light, and the third light is a red light.

5. The display device according to claim 1, further comprising:

a storage unit configured to store the first target luminance for the first light, the second target luminance for the second color light, and the third target luminance for the third color light; and

a detector configured to detect the luminance of the first light currently emitted by the first light source, the luminance of the second light currently emitted by the second light source, and the luminance of the third light currently emitted by the fluorescent substance.

6. A display device comprising:

an emission part including a first light source emitting first light, a second light source emitting a second light having a longer wavelength than the first light, a fluorescent substance which is excited by the first light and the second light so as to emit a third light;

a controller configured to generate a drive value of the first light source and a drive value of the second light source based on a luminance of the first light, a luminance of the second light, a luminance of the third light, a first target luminance for the first light source, a second target luminance for the second light source, and a third target luminance for the fluorescent substance, thus controlling two light sources based on the drive values of the first and second light sources;

a video signal adjustment part configured to control a video signal based on a gain of a video signal for each of RGB colors, wherein the controller generates a control signal used to adjust the gain of a video signal for each of RGB colors based on the luminance of the first light to the luminance of the third light and the first target luminance to the third target luminance, thus outputting the control signal to the video signal adjustment part,

wherein the controller determines the drive value of the second light source such that the luminance of the second light match the second target luminance,

wherein the controller generate the control signal to reduce the gain of a video signal corresponding to the luminance of the first light when the luminance of the first light is higher than the first target luminance, and

wherein the controller generates the control signal to reduce the gain of a video signal corresponding to the luminance of the third light when the luminance of the third light is higher than the third target luminance.

7. A display system comprising a display device and a video output device, wherein the display device includes an emission part further including a first light source emitting a first light, a second light source emitting a second light having a longer wavelength than the first light, and a fluorescent substance which is excited by the first light and the second light so as to emit a third light,

wherein the video output device includes a controller configured to generate a drive value of the first light source and a drive value of the second light source based on a luminance of the first light, a luminance of the second light, a luminance of the third light, a first target luminance for the first light source, a second target luminance for the second light source, and a third target luminance for the fluorescent substance, thus controlling two light sources based on the drive values of the first and second light sources,

wherein the controller determines the drive value of the second light source such that the luminance of the second light matches the second target luminance, and

wherein the controller further increases the drive value of the first light source such that the luminance of the first light matches the first target luminance when the luminance of the first light is smaller than the first target luminance at a time at which the controller determines the drive value of the first light source such that the luminance of the third light matches the third target luminance.

8. A video output device comprising a controller configured to generate a drive value of a first light source and a drive value of a second light source based on a luminance of a first light emitted by the first light source, a luminance of a second light, having a longer wavelength than the first light, emitted by the second light source, a luminance of a third light emitted by a fluorescent substance being excited by the first light and the second light, a first target luminance for the first light source, a second target luminance for the second light source, and a third target luminance for the fluorescent substance, thus controlling two light sources based on the drive values of the first and second light sources,

wherein the controller determines the drive value of the second light source such that the luminance of the second light matches the second target luminance, and

wherein the controller further increases the drive value of the first light source such that the luminance of the first light matches the first target luminance when the luminance of the first light is smaller than the first target luminance at a time at which the controller determines the drive value of the first light source such that the luminance of the third light matches the third target luminance.

9. A control method of a display device comprising:

generating a drive value of a first light source and a drive value of a second light source based on a luminance of a first light emitted by the first light source, a luminance of a second light, having a longer wavelength than the first light, emitted by the second light source, a luminance of a third light emitted by a fluorescent substance being excited by the first light and the second light, a first target luminance for the first light source, a second target luminance for the second light source, and a third target luminance for the fluorescent substance; and

controlling two light sources based on the drive values of the first and second light sources;

wherein the drive value of the second light source is determined such that the luminance of the second light matches the second target luminance, and

wherein the drive value of the first light source is increased such that the luminance of the first light matches the first target luminance when the luminance of the first light is smaller than the first target luminance at a time of determining the drive value of the first light source such that the luminance of the third light matches the third target luminance.