Patent Application
20090040172
This application claims priority to Taiwan Patent Application Serial Number 96128901, filed Aug. 06, 2007, which is herein incorporated by reference.
1. Field of Invention
The invention relates to a liquid crystal display and, in particular, to a liquid crystal display with an indicating apparatus for automatically indicating the state of its backlight module.
2. Related Art
Liquid crystal displays (LCDs) have the advantages of good image quality, small volume, lightness, low driving voltage, low power consumption, and wide applications. Therefore, they are largely used in middle- to small-size portable televisions (TVs), mobile phones, video cameras, notebook computers, desktop displays, projection TVs, as well as other computer-related products. The display quality of the LCD, such as the natural colors, high color saturation, high brightness, and high contrast, has become an important feature demanded by users.
Current techniques utilize the gamma correction, color temperature control, or color images to adjust the colors in images. However, these color adjusting methods have to be performed under stable backlight conditions. If the backlight state is not stable enough, the color adjusting methods become impractical and meaningless. Nevertheless, currently there is no LCD that can,self-check its backlight condition and report to its user.
An objective of the invention is to provide an LCD that contains a backlight module and an indicating apparatus. The indicating apparatus detects the light brightness of the backlight module and issues a warning when the light brightness is lower than a predetermined value.
Another objective of the invention is to provide an indicating apparatus for the LCD. The disclosed indicating apparatus includes at least one color light detection unit that includes a detector, an analog-to-digital converter (ADC), a controller, and a warning display. The detector detects the brightness of a color light of the backlight module, and generates a light brightness voltage. The ADC converts the light brightness voltage into a digital signal. The controller determines whether the light brightness of the color light is lower than a predetermined value. If the color light brightness is below the predetermined value, the control sends out a warning via the warning display.
A further objective of the invention is to provide a light brightness indicating method for the LCD. The method includes the steps of: detecting the light brightness of a color of a backlight module to generate a light brightness voltage; converting the light brightness voltage into a digital signal; determining whether the light brightness of the color light is below a predetermined value according to the digital signal; and sending out a warning when the color light brightness is below the predetermined value.
These and other features, aspects and advantages of the invention will become apparent by reference to the following description and accompanying drawings which are given by way of illustration only, and thus are not limitative of the invention, and wherein:
The present invention will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.
The indicating apparatus 120 includes at least one light detection unit, such as a red light detection unit 130a, a green light detection unit 130b and a blue light detection unit 130c. Each light detection unit 130a (or 130b, 130c) includes a detector 132a (or 132b, 132c), an ADC 134a (or 134b, 134c), a controller 136a (or 136b, 136c), and a warning display 138. It should be mentioned that the shared warning display 138 in this embodiment is drawn outside the frame of the three color light detection units 130a, 130b, 130c to simplify the drawing.
In the following, the red light detection unit 130a is used to explain its operating process. The detector 132a detects the red light emitted by the backlight module 110 and generates a red light brightness voltage accordingly. The ADC 134a converts the red light brightness voltage into a digital signal. Afterwards, the controller 136a determines whether the red light brightness of the backlight module 110 is lower than a predetermined value. When the red light brightness is lower than the predetermined value, the controller 136a sends out a warning via the warning display 138.
Moreover, this embodiment also provides a light brightness indicating method for the LCD.
In this embodiment, the ADC 134a (or 134b, 134c) coverts the light brightness voltage into a digital signal according to the reference voltage of the corresponding color (i.e., the red, green, or blue light reference voltage). The light brightness voltage of each color can first be processed by a program amplifier 133a (or 133b, 133c) before it is sent to the ADC 134a (or 134b, 134c) for a comparison with the above-mentioned reference voltage. The controller 136a (or 136b, 136c) used in this embodiment is also equipped with a function to adjust the color light brightness of the backlight module 100 according to the digital signal. More explicitly, the original backlight module controlling circuit can be modified to implement the color light brightness adjusting function. In this case, when the variation in the color light brightness of the backlight module 100 is small, the controller 136a (or 136b, 136c) can adjust the color light brightness by changing the pulse width modulation (PWM) signal or increase the signal voltage. When the variation in the color light brightness of the backlight module 100 becomes too large, the controller 136a (or 136b, 136c) makes the warning display 138 send out a warning message.
The warning display 138 can be a light-emitting diode (LED), an on-screen-display (OSD) image generator, a warning program, or some other hardware or software warning display device. For example, the LED can be directly disposed on the case of the LED to send warnings by emitting a light or a flashing signal. The OSD image generator can be integrated in the LCD to send out warnings on its screen. Alternatively, a warning program can be installed in the computer host or some other electronic device connected with the LCD. When the computer host or electronic device is in use, a warning is displayed or recorded in a record file. Moreover, the warning can be sent via a network to a remote end.
In the prefer embodiment, the backlight module 110 can be a cold cathode fluorescent lamp (CCFL) or an LED backlight module. Moreover, the backlight module 110 can be a monochromic or multi-color backlight module.
The detector 432 detects the white light emitted by the backlight module 410 and generates a white light brightness voltage according to the brightness of the white light. Afterwards, the ADC 434 converts the white light brightness voltage into a digital signal. In particular, a programmed amplifier 433 can initially process the white light brightness before the white light brightness is sent to the ADC 434 to be compared with the white light reference voltage. The controller 436 then determines whether the white light brightness is below a predetermined value according to the digital signal. When the white light brightness is below the predetermined value, the controller 436 sends the warning display 438 a signal and a warning is issued.
The indicating apparatus 120 in
In other words, the devices included in different color light detection units can be shared or devoted. They can be implemented by software or hardware. Thus, the invention is not restricted by the embodiments mentioned herein.
While the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 96128901 | Aug 2007 | TW | national |
