Image display apparatus and display correction method

Patent metadata

Field	Value
Publication number	US-10397444-B2
Application number	US-201615540745-A
Country	US
Kind code	B2
Filing date	Jan 7, 2016
Priority date	Jan 19, 2015
Publication date	Aug 27, 2019
Grant date	Aug 27, 2019

Abstract

An image display apparatus includes: a light source unit including three or more light sources, combining lights from the light sources and emitting the combined light; a wavelength detector that detects, for each light source, wavelength information indicating the wavelength of light from the light source; a color value determiner that determines, for each light source, from the wavelength information, a color value indicating a color of light from the light source in a predetermined color space; a correction value determiner that determines, based on the color values, a correction value for correcting a ratio between the intensities of lights from the light sources so that the color of the combined light is a color to be displayed; and a driver that drives the light sources so that the ratio between the intensities of lights from the light sources is a ratio corrected based on the correction value.

First claim

The invention claimed is:

1. An image display apparatus comprising:
a light source unit including three or more light sources that emit lights of different wavelengths, the light source unit combining the lights emitted from the three or more light sources and emitting the combined light;
a wavelength detector that detects, for each of the light sources, wavelength information indicating the wavelength of the light emitted from the light source;
a color value determiner that determines, for each of the light sources, from the wavelength information of the light source detected by the wavelength detector, a color value indicating a color of the light from the light source in a predetermined color space;
a correction value determiner that determines, based on the color values of the lights from the respective light sources determined by the color value determiner, a correction value for correcting a ratio between the intensities of the lights from the respective light sources so that the color of the light obtained by combining the lights from the respective light sources is a color to be displayed; and
a driver that drives the light sources so that the ratio between the intensities of the lights from the respective light sources is a ratio corrected based on the correction value determined by the correction value determiner,
wherein the correction value determiner:
determines a ratio between the intensities of the lights from the respective light sources when the color values of the lights from the respective light sources are the color values determined by the color value determiner and the color of the light obtained by combining the lights from the respective light sources is a reference white; and
determines the correction value from the determined ratio between the intensities of the lights and a ratio between the intensities of the lights from the respective light sources when the wavelengths of the lights from the respective light sources are reference wavelengths of the respective light sources and the color of the light obtained by combining the lights emitted from the respective light sources is the reference white.

2. The image display apparatus of claim 1 , further comprising a correction necessity determiner that determines whether the correction is required,
wherein when the correction necessity determiner determines that the correction is required, the color value determiner determines the color values.

3. The image display apparatus of claim 2 , wherein the correction necessity determiner determines whether the correction is required, based on the wavelength information detected by the wavelength detector.

4. The image display apparatus of claim 1 , wherein the color value determiner determines tristimulus values in an XYZ color system as the color values.

5. The image display apparatus of claim 1 , wherein:
the driver supplies each of the light sources with a drive signal indicating an output intensity that is an intensity of light to be emitted by the light source;
each of the light sources emits light having an intensity corresponding to the drive signal supplied from the driver;
the three or more light sources are first, second, . . . , Nth (N is an integer of 3 or more) light sources;
the image display apparatus further comprises a memory that stores a ratio Kc 1 :Kc 2 : . . . :KcN between the output intensities indicated by the drive signals supplied to the first, second, . . . , Nth light sources when the wavelengths of the lights from the respective light sources are reference wavelengths and the color of the light emitted from the light source unit is a reference white;
the correction value determiner determines, based on the color values of the lights from the respective light sources determined by the color value determiner, as the correction value, correction coefficients α 1 , α 2 , . . . , αN for correcting the ratio Kc 1 :Kc 2 : . . . :KcN; and
the driver corrects, based on the correction coefficients α 1 , α 2 , . . . , αN determined by the correction value determiner, the ratio Kc 1 :Kc 2 : . . . :KcN stored in the memory to a ratio α 1 ·Kc 1 :α 2 ·Kc 2 : . . . :αN·KcN, determines a ratio between the output intensities of the respective light sources using the corrected ratio, and supplies the light sources with the drive signals according to the ratio between the output intensities.

6. The image display apparatus of claim 5 , wherein the correction value determiner:
calculates a ratio Ka 1 :Ka 2 : . . . :KaN between the intensities of the lights from the first, second, . . . , Nth light sources when the color values of the lights from the respective light sources are the color values determined by the color value determiner and the color value of the light obtained by combining the lights from the respective light sources is a color value of a reference white in the color space;
calculates a ratio Kr 1 :Kr 2 : . . . :KrN between the intensities of the lights from the first, second, . . . , Nth light sources when the color values of the lights from the respective light sources are color values corresponding to the reference wavelengths in the color space and the color value of the light obtained by combining the lights from the respective light sources is the color value of the reference white in the color space; and
determines, from the ratio Ka 1 :Ka 2 : . . . :KaN and the ratio Kr 1 :Kr 2 : . . . :KrN, Ka 1 /Kr 1 , Ka 2 /Kr 2 , KaN/KrN as the correction coefficients α 1 , α 2 , . . . , αN.

7. The image display apparatus of claim 5 , wherein for each of pixels constituting an image to be displayed, the driver receives grayscale values I 1 , I 2 , . . . , IN respectively corresponding to the first, second, . . . , Nth light sources, and determines α 1 ·Kc 1 ·I 1 :α 2 ·Kc 2 ·I 2 : . . . :αN·KcN·IN as the ratio between the output intensities of the first, second, . . . , Nth light sources.

8. The image display apparatus of claim 7 , wherein the driver:
determines, based on a maximum value Imax of the grayscale values I 1 , I 2 , . . . , IN, and predetermined upper limits Pu 1 , Pu 2 , . . . , PuN of the output intensities of the first, second, . . . , Nth light sources, a coefficient β that satisfies β·α 1 ·Kc 1 ·Imax≤Pu 1 , β·α 2 ·Kc 2 ·Imax≤Pu 2 , . . . , β·αN·KcN·Imax≤PuN; and
determines, for each of the pixels, β·α 1 ·Kc 1 ·I 1 , β·α 2 ·Kc 2 ·I 2 , . . . , β·αN·KcN·IN as the output intensities of the first, second, . . . , Nth light sources.

9. The image display apparatus of claim 1 , wherein the driver receives image data representing an image to be displayed, corrects a ratio between the intensities of the lights from the respective light sources indicated by the image data based on the correction value determined by the correction value determiner, and drives the light sources to emit light at the corrected ratio between the intensities.

10. The image display apparatus of claim 1 , wherein:
the wavelength detector detects wavelength information for a subset of the three or more light sources, instead of detecting the wavelength information for each of the light sources;
the color value determiner determines a color value of light from each of the subset of the light sources, instead of determining the color value of light from each of the light sources; and
the correction value determiner uses, for each of the subset of the light sources, the color value determined by the color value determiner, and uses, for each of the three or more light sources other than the subset, a predetermined color value.

11. The image display apparatus of claim 1 , wherein each of the light sources is a laser light source.

12. A display corre

Assignees

• Mitsubishi Electric Corp

Inventors

• Kishigami Tomo
• Takeshita Nobuo

Classifications

• G09G3/20

  for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix {no fixed position being assigned to or needed to be assigned to the individual characters or partial characters} · CPC title

• H04N9/31

  Projection devices for colour picture display {, e.g. using electronic spatial light modulators [ESLM]} · CPC title

• H04N1/6077

  Colour balance, e.g. colour cast correction · CPC title

• H04N1/6008 Primary

  with primary colour signals, e.g. RGB or CMY(K) · CPC title

• H04N9/3194

  including sensor feedback · CPC title