Image projection apparatus for adjusting white balance in consideration of temperature of LED and method thereof

• US 20060203204A1
• Filed: 02/07/2006
• Published: 09/14/2006
• Est. Priority Date: 03/09/2005
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Yu, Byung-cheol
• Application Number:
  US11/348,338
• Publication Number:
  US 20060203204A1
• Time in Patent Office: Days
• US Class Current: 353/52
• CPC Class Codes: G03B 27/72 Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus
• CPC Class Codes: G09G 2310/0235 Field-sequential colour display
• CPC Class Codes: G09G 2320/041 Temperature compensation
• CPC Class Codes: G09G 2320/0633 by amplitude modulation of the brightness of the illumination source
• CPC Class Codes: G09G 2320/064 by time 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 3/3413 Details of control of colour illumination sources
• 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

Abstract

An image projection apparatus for adjusting a white balance in consideration of a temperature of an LED and a method thereof. The image projection apparatus includes a light source unit to sequentially emit lights generated by a red (R)-light emitting element, a green (G)-light emitting element, and a blue (B)-light emitting element. Light levels of the R-light emitting element, the G-light emitting element and the B-light emitting element change depending on changes in temperature. An image generation unit generates an image using the lights sequentially emitted from the light source unit and projects the image. A driving unit drives the light source unit and the image generation unit. A temperature sensor measures a temperature of the light source unit, and a controller controls a driving operation of the driving unit based on the temperature of the light source unit measured by the temperature sensor to adjust a white balance of the image projected from the image generation unit.

Claims

1. An image projection apparatus comprising:

a light source unit to sequentially emit lights generated by a red (R)-light emitting element, a green (G)-light emitting element, and a blue (B)-light emitting element, wherein light levels of the R-light emitting element, the G-light emitting element and the B-light emitting element change depending on changes in temperature;

an image generation unit to generate an image using the lights sequentially emitted from the light source unit and project the image;

a driving unit to drive the light source unit and the image generation unit;

a temperature sensor to measure a temperature of the light source unit; and

a controller to control a driving operation of the driving unit based on the temperature of the light source unit measured by the temperature sensor to adjust a white balance of the image projected from the image generation unit.

2. The image projection apparatus as claimed in claim 1, wherein the temperature sensor is provided near at least one of the R-light emitting element, the G-light emitting element, and the B-light emitting element to measure a temperature of the at least one light emitting element.

3. The image projection apparatus as claimed in claim 2, wherein the temperature sensor is provided on a panel to which at least one of the R-light emitting element, the G-light emitting element, and the B-light emitting element is attached.

4. The image projection apparatus as claimed in claim 1, further comprising a heat discharging unit to discharge heat generated from at least one of the R-light emitting element, the G-light emitting element and the B-light emitting element, wherein the temperature sensor is provided on at least one of the heat discharging unit and a location near the heat discharging unit to measure the temperature of the light source unit.

5. The image projection apparatus as claimed in claim 1, wherein the driving unit comprises a light source driving unit to generate and supply driving pulses for the respective R-light emitting element, G-light emitting element, and B-light emitting element of the light source unit, thereby driving the light source unit, and

wherein the controller determines levels of the driving pulses for the respective R-light emitting element, G-light emitting element, and B-light emitting element based on the temperature of the light source unit measured by the temperature sensor, and controls the light source driving unit to generate the driving pulses according to the determined pulse levels.

6. The image projection apparatus as claimed in claim 1, wherein the driving unit comprises a light source driving unit to generate and supply driving pulses for the respective R-light emitting element, G-light emitting elements, and B-light emitting element, thereby driving the light source unit, and

wherein the controller determines pulse-widths and starting times of driving pulses for the respective R-light emitting element, G-light emitting element and B-light emitting element based on the temperature of the light source unit measured by the temperature sensor, and controls the light source driving unit to generate the driving pulses according to the determined pulse-widths and starting times.

7. The image projection apparatus as claimed in claim 1, wherein the driving unit comprises an image generation driving unit to generate reflection angle adjustment signals to adjust reflection angles for the lights sequentially entering the image generation unit from the light source unit, and to supply the reflection angle adjustment signals to the image generation unit such that the image generation unit generates and projects the image;

and

wherein the controller determines levels of the reflection angle adjustment signals based on the temperature of the light source unit measured by the temperature sensor, and controls the image generation driving unit to generate reflection angle adjustment signals according to the determined levels of reflection angle adjustment signals.

8. A method of adjusting a white balance of an image projection apparatus comprising a light source unit to sequentially emit lights generated by a plurality of light emitting elements, wherein light levels of the plurality of light emitting elements changes depending on changes in temperature, and an image generation unit to generate an image using the lights sequentially emitted from the light source unit and project the image, the method comprising:

a) measuring a temperature of the light source unit; and

b) controlling a driving operation of one of the light source unit and the image generation unit based on the measured temperature of the light source unit and thereby adjusting a white balance of the image projected from the image generation unit.

9. The method as claimed in claim 8, wherein step a) comprises using a temperature sensor provided near at least one of the plurality of light emitting elements to measure a temperature of the light emitting element.

10. The method as claimed in claim 9, wherein step a) comprises using a temperature sensor provided on a panel to which at least one of the plurality of light emitting elements is attached and measures a temperature of the light emitting element.

11. The method as claimed in claim 8, wherein step a) comprises using a temperature sensor provided on one of a heat discharging unit and a location near the heat discharging unit to measure a temperature of the light source unit, wherein the heat discharging unit discharges heat generated from at least one of the plurality of light emitting elements.

12. The method as claimed in claim 8, wherein step b) comprises:

determining levels of driving pulses for the respective plurality of light emitting elements based on the measured temperature of the light source unit; and

supplying the driving pulses according to the determined pulse levels to the light source unit and driving the light source unit such that a white balance of the image projected from the image generation unit is adjusted.

13. The method as claimed in claim 8, wherein step b) comprises:

determining pulse-widths and starting times of driving pulses for the respective plurality of light emitting elements based on the measured temperature of the light source unit; and

supplying the driving pulses according to the determined pulse-widths and starting times to the light source unit and driving the light source unit such that a white balance of the image projected from the image generation unit is adjusted.

14. The method as claimed in claim 8, wherein step c) comprises:

determining levels of reflection angle adjustment signals based on the measured temperature of the light source unit, wherein the reflection angle adjustment signals adjust reflection angles for the lights sequentially emitted from the light source unit to the image generation unit; and

supplying the reflection angle adjustment signals according to the determined signal levels to the image generation unit in order for the image generation unit to generate and project the image, such that a white balance of the image projected from the image generation unit is adjusted.