Display apparatus and luminance control method

• US 8,587,567 B2
• Filed: 11/05/2007
• Issued: 11/19/2013
• Est. Priority Date: 11/07/2006
• Status: Active Grant

• Current Assignee: Sharp NEC Display Solutions, Ltd.
• Original Assignee: NEC Display Solutions, Ltd. (NEC Corporation)
• Inventors: Mori, Kengo
• Primary Examiner(s): A, Minh D
• Application Number:
  US12/312,184
• Publication Number:
  US 20100090939A1
• Time in Patent Office: 2,206 Days
• Field of Search: 315/291, 315/307, 315/310, 315/312, 315/112, 315/117, 345/204, 345/207, 345/691, 345/84, 345/87
• US Class Current: 345/204
• CPC Class Codes: G02F 1/133604 with lamps
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G02F 2203/60 Temperature independent
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H05B 41/2858 for protecting the lamp against abnormal operating conditions
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A display apparatus according to the present invention using a cold cathode fluorescent lamp as a light source includes: a gradient detector which detects a condition in which one end of the cold cathode fluorescent lamp is disposed higher than an other end thereof; and a controller which conducts control so that emitted luminance of the cold cathode fluorescent lamp is inhibited when the condition in which the one end of the cold cathode fluorescent lamp is disposed higher than the other end thereof is detected by the gradient detector.

Claims

1. A display apparatus, comprising:

a cold cathode fluorescent lamp as a light source;

a screen comprising a long side coinciding with an axial direction of the cold cathode fluorescent lamp;

a gradient detector which comprises a sensor detecting a degree of an inclination of the cold cathode fluorescent lamp, wherein the gradient sensor detects a condition in which one end of the cold cathode fluorescent lamp is disposed higher than an other end thereof; and

a controller which conducts a control so that emitted luminance of the cold cathode fluorescent lamp is inhibited when the condition in which the one end of the cold cathode fluorescent lamp is disposed higher than the other end thereof is detected by the gradient detector.

2. The display apparatus according to claim 1, further comprising an image display unit which displays a message,

wherein the controller causes the image display unit to display a message indicating that control of emitted luminance is performed when control of emitted luminance of the cold cathode fluorescent lamp is conducted.

3. The display apparatus according to claim 1, wherein the screen switches between a horizontally long screen configuration in which the long side is arranged horizontally and a vertically long screen configuration in which the long side is arranged vertically,

wherein the gradient detector detects whether the screen is in the horizontally long screen configuration or in the vertically long screen configuration, and

wherein the controller conducts a control such that the emitted luminance of the cold cathode fluorescent lamp is inhibited when a condition in which the screen is in the vertically long screen configuration is detected by the gradient detector.

4. The display apparatus according to claim 1, wherein the controller conducts a control such that the emitted luminance of the cold cathode fluorescent lamp is inhibited when a condition, in which the long side is arranged vertically, is detected by the gradient detector.

5. A display apparatus, comprising:

a cold cathode fluorescent lamp as a light source;

a screen comprising a long side coinciding with an axial direction of the cold cathode fluorescent lamp;

a temperature detector which detects an internal temperature of a housing of the display apparatus;

a time measurement unit which measures an elapsed time from initiation of lighting of the cold cathode fluorescent lamp;

a gradient detector which comprises a sensor detecting a degree of an inclination of the cold cathode fluorescent lamp, wherein the gradient sensor detects a condition in which one end of the cold cathode fluorescent lamp is disposed higher than an other end thereof; and

a controller which projects a saturation temperature of the cold cathode fluorescent lamp based on the elapsed time and an internal temperature difference of the housing between a time of the initiation of lighting of the cold cathode fluorescent lamp and a present time, and which conducts a control so that emitted luminance of the cold cathode fluorescent lamp is inhibited in accordance with the saturation temperature, when the condition in which the one end of the cold cathode fluorescent lamp is disposed higher than the other end thereof is detected by the gradient detector.

6. The display apparatus according to claim 5, further comprising an external temperature detector which detects an external temperature of the housing,

wherein the controller conducts correction of the projected saturation temperature according to a temperature difference between an external temperature of the housing and an internal temperature of the housing at a present time.

7. The display apparatus according to claim 6, further comprising an image display unit which displays a message,

wherein the controller causes the image display unit to display a message indicating that control of emitted luminance is performed when control of emitted luminance of the cold cathode fluorescent lamp is conducted.

8. The display apparatus according to claim 6, wherein the screen switches between a horizontally long screen configuration in which the long side is arranged horizontally and a vertically long screen configuration in which the long side is arranged vertically,

wherein the gradient detector detects whether the screen is in the horizontally long screen configuration or in the vertically long screen configuration, and

wherein the controller conducts a control such that the emitted luminance of the cold cathode fluorescent lamp is inhibited when a condition in which the screen is in the vertically long screen configuration is detected by the gradient detector.

9. The display apparatus according to claim 5, further comprising an image display unit which displays a message,

wherein the controller causes the image display unit to display a message indicating that control of emitted luminance is performed when control of emitted luminance of the cold cathode fluorescent lamp is conducted.

10. A display apparatus, comprising:

a cold cathode fluorescent lamp as a light source;

a screen comprising a long side coinciding with an axial direction of the cold cathode fluorescent lamp;

a gradient detector which comprises a sensor detecting a degree of an inclination of the cold cathode fluorescent lamp, wherein the gradient sensor detects conditions in which one end of the cold cathode fluorescent lamp is disposed higher than an other end thereof;

a temperature detector which detects a temperature of the cold cathode fluorescent lamp; and

a controller which conducts a control so that emitted luminance of the cold cathode fluorescent lamp is inhibited according to the temperature detected by the temperature detector, when the condition in which the one end of the cold cathode fluorescent lamp is disposed higher than the other end thereof is detected by the gradient detector.

11. The display apparatus according to claim 10, further comprising an image display unit which displays a message,

wherein the controller causes the image display unit to display a message indicating that control of emitted luminance is performed when control of emitted luminance of the cold cathode fluorescent lamp is conducted.

12. The display apparatus according to claim 10, wherein the screen switches between a horizontally long screen configuration in which the long side is arranged horizontally and a vertically long screen configuration in which the long side is arranged vertically,

wherein the gradient detector detects whether the screen is in the horizontally long screen configuration or in the vertically long screen configuration, and

wherein the controller conducts a control such that the emitted luminance of the cold cathode fluorescent lamp is inhibited when a condition in which the screen is in the vertically long screen configuration is detected by the gradient detector.

13. A luminance control method for a display apparatus comprising a cold cathode fluorescent lamp as a light source and a screen comprising a long side coinciding with an axial direction of the cold cathode fluorescent lamp, the method comprising:

a gradient detection of detecting a degree of an inclination of the cold cathode fluorescent lamp, wherein the gradient detection comprises detecting a condition in which one end of the cold cathode fluorescent lamp is disposed higher than an other end thereof; and

conducting a control so that emitted luminance of the cold cathode fluorescent lamp is inhibited when the condition in which one end of the cold cathode fluorescent lamp is disposed higher than the other end thereof is detected by the gradient detection.

14. A luminance control method for a display apparatus comprising a cold cathode fluorescent lamp as a light source and a screen comprising a long side coinciding with an axial direction of the cold cathode fluorescent lamp, the method comprising:

a temperature detection of detecting an internal temperature of a housing of the display apparatus;

a time measurement of measuring an elapsed time from initiation of lighting of the cold cathode fluorescent lamp;

a gradient detection of detecting a degree of an inclination of the cold cathode fluorescent lamp, wherein the gradient detection comprises detecting a condition in which one end of the cold cathode fluorescent lamp is disposed higher than an other end thereof; and

projecting a saturation temperature of the cold cathode fluorescent lamp based on the elapsed time and an internal temperature difference of the housing between a time of the initiation of lightning of the cold cathode fluorescent lamp and a present time, and conducting a control so that emitted luminance of the cold cathode fluorescent lamp is inhibited in accordance with the saturation temperature, when the condition in which the one end of the cold cathode fluorescent lamp is disposed higher than the other end thereof is detected by the gradient detection.

15. A luminance control method for a display apparatus comprising a cold cathode fluorescent lamp as a light source and a screen comprising a long side coinciding with an axial direction of the cold cathode fluorescent lamp, the method comprising:

a gradient detection of detecting a degree of an inclination of the cold cathode fluorescent lamp, wherein the gradient detection comprises detecting a condition in which one end of the cold cathode fluorescent lamp is disposed higher than an other end thereof;

a temperature detection of detecting a temperature of the cold cathode fluorescent lamp; and

conducting a control so that emitted luminance of the cold cathode fluorescent lamp is inhibited according to the temperature detected by the temperature detection when the condition in which the one end of the cold cathode fluorescent lamp is disposed higher than the other end thereof is detected by the gradient detection.

16. A display apparatus, comprising:

a light source;

a screen which comprises a long side, and switches between a horizontally long screen configuration in which the long side is arranged horizontally and a vertically long screen configuration in which the long side is arranged vertically;

a gradient detector which comprises a sensor detecting whether the screen is in the horizontally long screen configuration or in the vertically long screen configuration; and

a controller which conducts a control such that emitted luminance of the light source is inhibited when a condition in which the screen is in the vertically long screen configuration is detected by the gradient detector.