Light emitting device and method of controlling the same

• US 20070279371A1
• Filed: 12/07/2006
• Published: 12/06/2007
• Est. Priority Date: 06/02/2006
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kang, Jeong-il, Lee, Sang-Hoon
• Granted Patent: US 8,605,068 B2
• Time in Patent Office: Days
• US Class Current: 345/102
• CPC Class Codes: H05B 45/10 Controlling the intensity of the light
• CPC Class Codes: H05B 45/325 Pulse-width modulation [PWM]
• CPC Class Codes: H05B 47/165 following a pre-assigned programmed sequence; Logic control [LC]

Abstract

Provided is a light emitting device and a method of controlling the same are disclosed. The light emitting unit includes a power supply unit for supplying a drive voltage to the light emitting unit, and a control unit for comparing a first current level previously applied to the light emitting unit with a second current level to be applied to the light emitting unit in accordance with image information to be displayed using the light emitting unit, and controlling a voltage level applied to the light emitting unit based on a result of comparison.

Claims

1. A light emitting device including a light emitting unit for emitting light, comprising:

a power supply unit for supplying a drive voltage to the light emitting unit; and

a control unit for comparing a first current level previously applied to the light emitting unit with a second current level to be applied to the light emitting unit in accordance with image information to be displayed using the light emitting unit, and controlling a voltage level applied to the light emitting unit based on a result of comparison.

2. The light emitting device of claim 1, wherein the control unit controls the power supply unit such that if the second current level is higher than the first current level and a difference between the first current level and the second current level is higher than a threshold current value, the control unit applies the drive voltage to the light emitting unit by increasing the voltage level corresponding to the first current level by a specified offset voltage, while if the second current level is lower than the first current level and the difference between the first current level and the second current level is higher than the threshold current value, the control unit applies the drive voltage to the light emitting unit by reducing the voltage level corresponding to the first current level by a specified offset voltage.

3. The light emitting device of claim 2, wherein the control unit controls the power supply unit such that if a difference between the first current level and the second current level is less than the threshold current value and the drive voltage is greater than a threshold voltage level, the control unit applies the drive voltage to the light emitting unit by decreasing the voltage level by a corrected value, wherein if a difference between the first current level and the second current level is less than the threshold current value and the drive voltage is less than a threshold voltage level, the control unit applies the drive voltage to the light emitting unit by increasing the voltage level by a corrected value.

4. The light emitting device of claim 1, further comprising a memory comprising a lookup table for storing corrected values for the voltage level to be applied to the light emitting unit corresponding to the result of comparing the first and second current levels;

wherein the control unit adjusts the voltage level of the drive voltage to be output from the power supply unit with reference to the lookup table.

5. The light emitting device of claim 1, wherein the control unit controls the power supply unit such that if the second current level is higher than the first current level, the control unit applies the drive voltage to the light emitting unit by increasing the voltage level corresponding to the first current level by a specified level, while if the second current level is lower than the first current level, the control unit applies the drive voltage to the light emitting unit by reducing the voltage level corresponding to the first current level by a specified level.

6. The light emitting device of claim 1, wherein the control unit controls the power supply unit such that if the second current level is higher than a minimum current level the control unit compares the first current level with the second current level, while if the second current level is lower than the minimum current level the control unit applies the drive voltage to the light emitting unit corresponding to the first current level.

7. A method of controlling a light emitting device including a light emitting unit for emitting light, comprising:

supplying a drive voltage to the light emitting unit; and

comparing a first current level previously applied to the light emitting unit with a second current level to be applied to the light emitting unit in accordance with image information to be displayed using the light emitting unit, and controlling a voltage level applied to the light emitting unit based on a result of comparison.

8. The method of claim 7, wherein the second current level is higher than the first current level and a difference between the first current level and the second current level is higher than a threshold current value, the drive voltage is applied to the light emitting unit by increasing the voltage level corresponding to the first current level by a specified offset voltage, while if the second current level is lower than the first current level and the difference between the first current level and the second current level is higher than the threshold current value, the drive voltage is applied to the light emitting unit by reducing the voltage level corresponding to the first current level by a specified offset voltage.

9. The method of claim 8, wherein if a difference between the first current level and the second current level is less than the threshold current value and the drive voltage is greater than a threshold voltage level, the drive voltage is applied to the light emitting unit by decreasing the voltage level by a corrected value, wherein if a difference between the first current level and the second current level is less than the threshold current value and the drive voltage is less than a threshold voltage level, the drive voltage is applied to the light emitting unit by increasing the voltage level by a corrected value.

10. The method of claim 7, wherein the drive voltage level to be applied to the light emitting unit is adjusted with reference to a lookup table, wherein the lookup table stores corrected values for the drive voltage level to be applied to the light emitting unit corresponding to the result of comparing the first and second current levels.

11. The method of claim 7, wherein if the second current level is higher than the first current level, the drive voltage applied to the light emitting unit by increasing the voltage level corresponding to the first current level by a specified level, while if the second current level is lower than the first current level, the drive voltage is applied to the light emitting unit by reducing the voltage level corresponding to the first current level by a specified level.

12. The light emitting device of claim 7, wherein if the second current level is higher than a minimum current level the first current level and the second current level are compared, while if the second current level is lower than the minimum current level the drive voltage is applied to the light emitting unit corresponding to the first current level.