PROJECTION DISPLAY APPARATUS

• US 20080246927A1
• Filed: 04/08/2008
• Published: 10/09/2008
• Est. Priority Date: 04/09/2007
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Tanase, Susumu, Haraguchi, Masahiro, Hiranuma, Yoshinao, Abe, Takaaki, INOUE, Masutaka, Tsuchiya, Seiji
• Granted Patent: US 8,598,503 B2
• Time in Patent Office: Days
• US Class Current: 353/85
• CPC Class Codes: G03B 21/2053 Intensity control of illuminating light controlled by video signal processing H04N5/74 or H04N9/31
• CPC Class Codes: G09G 2320/0233 Improving the luminance or brightness uniformity across the screen
• CPC Class Codes: G09G 2320/043 Preventing or counteracting the effects of ageing
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• 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 3/002 to project the image of a two-dimensional display, such as an array of light emitting or modulating elements or a CRT
• CPC Class Codes: H04N 9/3155 for controlling the light source light source control per se H05B35/00 – H05B47/00; control of an illumination source for displays in general G09G3/3406
• CPC Class Codes: H04N 9/3194 including sensor feedback
• CPC Class Codes: H05B 41/38 Controlling the intensity of light

Abstract

A projection display apparatus includes: a light amount sensor which detects an amount of light emitted from an array light source; a deterioration rate calculator which acquires an amount of light of a measurement target light source from the amount of light detected by the light amount sensor; a reference light amount storage which stores a reference amount of light of an amount of light emitted from plurality of solid state light sources, for each of the solid state light sources; and a light source controller which controls the amount of light emitted from the plurality of solid state light sources for each of the solid state light sources, and the deterioration rate calculator determines whether the measurement target light source has deteriorated, in accordance with a result of a comparison between the amount of light detected by the light amount sensor, and the reference amount of light.

Claims

1. A projection display apparatus provided with an array light source in which a plurality of solid state light sources are disposed in an array, comprising:

a sensor provided on a light path of light emitted from the array light source, and configured to detect an amount of light omitted from the array light source;

an acquisition unit configured to acquire an amount of light of a measurement target light source which is any one of the plurality of solid state light sources, from an amount of light detected by the sensor;

a reference light amount storage configured to store a reference amount of light of an amount of light emitted from each of the plurality of solid state light sources;

a light source controller configured to control the amount of light emitted from each of the plurality of solid state light sources, so that the acquisition unit acquires the amount of light of the measurement target light source; and

a determination unit configured to determine whether or not the measurement target light source has deteriorated, in accordance with a result of a comparison between the amount of light of the measurement target light source acquired by the acquisition unit, and the reference amount of light.

2. The projection display apparatus according to claim 1, further comprising:

a contribution degree storage configured to store a contribution degree which is a degree of light reaching the sensor, emitted from each of the plurality of solid state light sources; and

a correction unit configured to correct the amount of light of the measurement target light source acquired by the acquisition unit, or the reference amount of light, based on the contribution degree corresponding to the measurement target light source,

wherein the determination unit determines whether or not the measurement target light source has deteriorated, using a result of correction made by the correction unit.

3. The projection display apparatus according to claim 1, wherein

the light source controller sequentially controls the amounts of light of the respective solid state light sources one by one, in a turn-on phase turning on the array light source, and

the acquisition unit acquires the amount of light of the measurement target light source, in accordance with the amount of light detected by the sensor in the turn-on phase.

4. The projection display apparatus according to claim 1, wherein

the light source controller sequentially controls the amounts of light of the respective solid state light sources one by one, in a turn-off phase turning off the array light source, and

the acquisition unit acquires the amount of light of the measurement target light source, in accordance with the amount of light detected by the sensor in the turn-off phase.

5. The projection display apparatus according to claim 1, wherein

the light source controller sequentially controls the amounts of light of the respective solid state light sources one by one, in a back light control switching the amount of light of the array light source in accordance with an image signal, and

the acquisition unit acquires the amount of light of the measurement target light source in accordance with the amount of light detected by the sensor in the back light control.

7. The projection display apparatus according to claim 5, further comprising

a calculation unit configured to calculate a deterioration rate of the measurement target light source in accordance with the result of the comparison between the amount of light of the measurement target light source acquired by the acquisition unit, and the reference amount of light, wherein

the light source controller controls the amount of light of the solid state light source having a large deterioration rate, prior to the solid state light source having a small deterioration rate, in the back light control reducing the amount of light of the array light source.

8. The projection display apparatus according to claim 7, wherein

the light source controller controls the amount of light of the solid state light source having a small deterioration rate, prior to the solid state light source having a large deterioration rate, in the back light control increasing the amount of light of the array light source is increased.

6. The projection display apparatus according to claim 6, further comprising:

a start position storage configured to store a start position which is a position of the solid state light source of which an amount of light is controlled at a time of starting the back light control; and

a start position updating unit configured to update the start position, in accordance with a terminate position which is the position of the solid state light source of which an amount of light is controlled at a time of terminating the back light control.