The present invention relates to an inverter controller, and more particularly, to an inverter controller that includes automatic brightness adjustment circuitry. General utility for the present invention is for LCD panel displays such as may be associated with portable computers and portable electronic devices, and/or stand-alone LCD panel monitors and/or television displays.
Accordingly, in one exemplary embodiment, the present invention provides a brightness controller for an LCD panel display, comprising an optical sensor generating a signal indicative of ambient light around the LCD panel; a look-up table receiving the signal indicative of ambient light around the LCD panel and adapted to generate a selected one of a plurality of target panel brightness level signals based on the signal indicative of ambient light around the LCD panel; and an inverter circuit adapted to receive one of the plurality of target panel brightness level signals to control power delivered to the LCD panel.
The present invention also provides an LCD panel, comprising a plurality of lamps; and a brightness controller controlling the brightness of said lamps, said brightness controller comprising an optical sensor generating a signal indicative of ambient light around said LCD panel; a look-up table receiving said signal indicative of ambient light around said LCD panel and adapted to generate a selected one of a plurality of target panel brightness level signals based on said signal indicative of ambient light around said LCD panel; and an inverter circuit adapted to receive one of said plurality of target panel brightness level signals to control power delivered to said lamps.
The present invention also provides a computer system that includes the LCD panel, lamps and brightness controller.
In another exemplary embodiment, the present invention provides a master/slave brightness controller for an LCD panel display, comprising: an optical sensor generating a signal indicative of ambient light around said LCD panel; a micro controller controlling said optical sensor to generate said signal indicative of ambient light around said LCD panel; a look-up table receiving said signal indicative of ambient light around said LCD panel and adapted to generate a selected one of a plurality of target panel brightness level signals based on said signal indicative of ambient light around said LCD panel; and an inverter circuit adapted to receive one of said plurality of target panel brightness level signals to control power delivered to said LCD panel.
It will be appreciated by those skilled in the art that although the following Detailed Description will proceed with reference being made to preferred embodiments and methods of use, the present invention is not intended to be limited to these preferred embodiments and methods of use. Rather, the present invention is of broad scope and is intended to be limited as only set forth in the accompanying claims.
Other features and advantages of the present invention will become apparent as the following Detailed Description proceeds, and upon reference to the Drawings, wherein like numerals depict like parts, and wherein:
As described above, the optical sensor 12 monitors the ambient light of the operating environment of the LCD panel, and outputs a signal 13 indicative of (or proportional to) the amount of ambient light present. In the exemplary embodiment, an analog to digital converter (A/D) 24 is provided that generates a plurality of binary signals 25 based on the input signal 13. In the drawing, four binary signals are depicted which would generate 16 levels of brightness, but those skilled in the art will recognize that the bit depth of the A/D may be increased or decreased to generate a desired resolution. A look-up table (LUT) 26 receives the binary representation of the ambient light and generates a target or desired brightness for the panel. The formulation of the LUT may include, for example, a plurality of column representing the binary input values and a corresponding column representing the desired or target panel brightness. The value for the target panel brightness may be based on a linear division (i.e., even division given the bit depth of the A/D converter), a weighted division, logarithmic division, etc. The exemplary embodiment depicts the LUT with four digital inputs and one digital output, however, the LUT may be adapted to accommodate any number of inputs and/or outputs depending on the application. Such a construction will be readily understood by those skilled in the art. Of course, the implementation of the LUT may be accomplished in a variety of ways, and the above description represents only one exemplary embodiment.
The output signal from the LUT 26 is a desired or target panel brightness signal. Optionally, a D/A converter 28 can be provided to convert the output of the LUT 26 to an analog signal, although if the inverter topology is adapted to receive digital preset signal the D/A may be omitted. In any event, the target panel brightness signal is used as a control signal for the inverter, such as a threshold value in a closed loop feedback system that regulates power (brightness) to the lamps in the panel. In one exemplary embodiment of
In this example, the target brightness signal is input into the low frequency PWM signal generator 30 that is adapted to generate a burst mode signal for adjusting power to the lamps of the panel. Supplying power to multiple lamps using burst mode techniqaes is disclosed in U.S. Pat. No. 6,501,234 assigned to the same assignee, and hereby incorporated by reference in its entirety. In essence, the target brightness signal sets the pulse width of the burst mode signal generated by the low frequency PWM generator 30. The low frequency PWM generator 30 may also include a user override switch 32 that sets the brightness to a user-defined level regardless of the value of the target brightness signal.
In turn, the burst mode signal generated by the generator 30 is utilized by the inverter topology 34 to generate an AC signal from a DC signal. A transformer 36 steps up the AC signal to a sufficient voltage to both ignite the lamp 38, and operate the lamp 38 in steady state. The inverter topology may include a full bridge (4 switches), half bridge (2 switches), royer, push pull, class D, other type of inverter topology well known in the art.
In the embodiment of
Referring now to
Thus, there has been provided a master mode auto brightness controller for an LCD panel. Those skilled in the art will recognize numerous modifications to the present invention. For example, burst mode dimming techniques described with reference to
These and other modifications will become apparent to those skilled in the art, and all such modifications are deemed within the spirit and scope of the present invention, only as limited by the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
5272327 | Mitchell et al. | Dec 1993 | A |
5487181 | Dailey et al. | Jan 1996 | A |
6114814 | Shannon et al. | Sep 2000 | A |
6316881 | Shannon et al. | Nov 2001 | B1 |
6388388 | Weindorf et al. | May 2002 | B1 |
6396217 | Weindorf | May 2002 | B1 |
6396722 | Lin | May 2002 | B1 |
6501234 | Lin et al. | Dec 2002 | B1 |
6633138 | Shannon et al. | Oct 2003 | B1 |
6703796 | Che-Chen et al. | Mar 2004 | B1 |
6761470 | Sid | Jul 2004 | B1 |
6762741 | Weindorf | Jul 2004 | B1 |
20020101166 | Weindorf et al. | Aug 2002 | A1 |
20030025462 | Weindorf | Feb 2003 | A1 |
20030030386 | Leeb et al. | Feb 2003 | A1 |
20030090913 | Che-Chen et al. | May 2003 | A1 |
20030161164 | Shannon et al. | Aug 2003 | A1 |
20030214655 | Weiss et al. | Nov 2003 | A1 |
20050156536 | Ball | Jul 2005 | A1 |
20050162098 | Ball | Jul 2005 | A1 |
Number | Date | Country |
---|---|---|
419173 | Jan 2001 | TW |
Number | Date | Country | |
---|---|---|---|
20040155853 A1 | Aug 2004 | US |