CN1845650B - Display lamp tube frequency control system and method thereof - Google Patents

Abstract

The invention relates to a display lamp tube frequency control system, which comprises: a drive control device and a lamp frequency control device. The driving control device is provided with a driving mode selector which is used for selecting one of at least two driving modes and outputting at least one corresponding frequency control signal according to the selected driving mode. The lamp tube frequency control device obtains at least one corresponding lamp tube frequency according to the frequency control signal. The lamp frequency control system of the display device obtains the corresponding lamp frequency according to different driving modes, and the lamp frequency can be correspondingly adjusted to match with different driving modes. Therefore, the frequency of the lamp tube can be adjusted in the frequency section without water ripple interference, so that the display lamp tube frequency control system can solve the water ripple interference phenomenon.

Description

Display lamp tube frequency control system and method

technical field

The present invention relates to a frequency control system and method, in particular to a display lamp tube frequency control system and method.

Background technique

As shown in FIG. 1 , a current lamp 11 of a display (for example, a liquid crystal display) is converted from DC to AC by a converter 12 to supply the power required by the lamp. And, the display panel 15 of the display is driven by a driving device 16 to display, and the driving mode of the driving device 16 currently has multiple driving modes such as dot inversion mode (dot inversion) and column inversion mode (column inversion). Each driving mode has a different driving method and scanning frequency.

It is currently known that water flow noise occurs under the interaction between the working frequency of the converter and the scanning frequency. There are three conventional solutions to improve the water ripple phenomenon. The first method is to shield EMI with indium tin oxide (ITO). The second method is to use a converter operating frequency that is synchronized with the horizontal scanning frequency. The third method is that the polarities of two adjacent lamp tubes are opposite, so as to offset the electric field interference intensity and reduce the water ripple interference phenomenon.

However, the cost of the first method is relatively high, and the ITO layer will be yellowed due to quality problems and use for a long time, resulting in the problem of color deviation. The second method must accurately lock the horizontal scanning frequency, if there is a slight deviation, water ripple interference will appear immediately. The third method can only reduce the phenomenon of water ripple interference, but cannot completely solve the phenomenon of water ripple interference.

In addition, the current driving device 16 has at least two driving modes that can be switched and controlled (for example: dot inversion mode and column inversion mode). converter operating frequency. Therefore, on a display with a driving device having at least two driving modes, the water moiré phenomenon cannot be solved by the second method.

Therefore, it is necessary to provide an innovative and progressive display lamp frequency control system and method to solve the above problems.

Contents of the invention

The object of the present invention is to provide a display lamp tube frequency control system, which includes: a drive control device and a lamp tube frequency control device. The drive control device has a drive mode selector for selecting one of at least two drive modes, and outputs at least one corresponding frequency control signal according to the selected drive mode. The lamp frequency control device obtains at least one corresponding lamp frequency according to the frequency control signal.

The display lamp frequency control system of the present invention obtains the corresponding lamp frequency according to different driving modes, because the lamp frequency can be correspondingly adjusted to match different driving modes. Therefore, the frequency of the lamp tube can be adjusted in the frequency range without water ripple interference, so the phenomenon of water ripple interference can be solved by using the display lamp tube frequency control system of the present invention.

Description of drawings

Fig. 1 is a schematic diagram of a commonly used display lamp tube frequency control and drive control display panel;

Fig. 2A is the water ripple interference spectrum analysis figure in point inversion mode;

Figure 2B is a water ripple interference spectrum analysis diagram in point inversion mode; and

FIG. 3 is a schematic diagram of the display lamp frequency control system of the present invention.

Detailed ways

Referring to Figures 2A and 2B, a spectral analysis of water ripple interference is shown. 2A is the frequency spectrum analysis of the water ripple interference in the dot inversion mode, which shows that there is no water ripple interference phenomenon between the frequencies of 41K to 48.5KHz. Also refer to FIG. 2B . FIG. 2B is a frequency spectrum analysis of the water-ripple interference in the column inversion mode, which shows that there is no water-ripple interference phenomenon between 29.5K and 36.5KHz.

Referring to FIG. 3 , the display lamp frequency control system 30 of the present invention includes: a drive control device 31 and a lamp frequency control device 32 . The driving control device 31 has a driving mode selector 311 for selecting one of at least two driving modes, and outputs at least one corresponding frequency control signal 312 according to the selected driving mode.

The driving modes of the driving control device 31 can be dot inversion mode, column inversion mode or other driving modes. In this embodiment, the dot inversion mode and column inversion mode are taken as examples for illustration. The driving mode selector 311 selects the dot inversion mode or the column inversion mode. When the drive mode selector 311 selects the point inversion mode as the drive mode, the frequency control signal 312 is set to a high potential (H); when the drive mode selector 311 selects the column inversion mode as the drive mode, the frequency The control signal 312 is set to a low potential (L).

And, when the drive mode selector 311 selects the dot inversion mode as the drive mode, the display panel 33 of the display is driven by the dot inversion mode driver 313 of the drive control device 31 to display; when the drive mode selector 311 After the column inversion mode is selected as the driving mode, the display panel 33 of the display is driven by the column inversion mode driver 314 of the driving control device 31 to display.

The lamp frequency control device 32 receives the frequency control signal 312 and obtains at least one corresponding lamp frequency according to the frequency control signal 312 . In this embodiment, the lamp frequency control device 32 utilizes a corresponding table 321 in order to obtain the corresponding lamp frequency. Therefore, when the corresponding table 321 receives the high-potential frequency control signal 312, it means that the drive mode selector 311 selects the point inversion mode as the drive mode, and sets the lamp tube frequency to 44±3KHz (according to FIG. 2A , There is no water ripple interference in this frequency range) between one of the frequencies. When the corresponding table 321 receives the frequency control signal 312 of low potential, it means that the drive mode selector 311 selects the column inversion mode as the drive mode, and sets the lamp tube frequency as 33±3KHz (according to FIG. 2B, the One of the frequencies between the frequency range without water ripple interference).

The lamp frequency obtained from the corresponding table 321 is output to a converter 322 of the lamp frequency control device 32 . The converter 322 converts DC to AC according to the operating frequency of the lamp tube, so as to provide the power required by the lamp tube 34 .

Since the working frequency of the converter 322 can be correspondingly adjusted to match different driving modes. Therefore, regardless of whether the drive control device 31 selects the dot inversion mode or the column inversion mode, the operating frequency of the converter 322 can be switched to a frequency that does not generate water ripple interference. Under the operation of the operating frequency, the The display will not produce water ripple interference.

In order to stabilize the current of the lamp tube 34, the display lamp tube frequency control system 30 of the present invention also includes a feedback circuit 35, which is used to feed back and compensate the lamp tube current, so that the lamp tube 34 can still switch between different operating frequencies. The current of the lamp tube 34 is stabilized.

The above-mentioned embodiments are only used to illustrate the principles and effects of the present invention, but not to limit the present invention. Therefore, those skilled in the art can make modifications and changes to the above-mentioned embodiments without departing from the spirit of the present invention. The scope of rights of the present invention should be listed in the scope of the preceding claims.

Claims (8)

1. A display lamp tube frequency control system, comprising: A driving control device having a driving mode selector for selecting one of at least two driving modes, and outputting at least one corresponding frequency control signal according to the selected driving mode; A lamp frequency control device for driving a lamp, which obtains at least one corresponding lamp frequency according to the frequency control signal, wherein the lamp frequency is provided to the lamp to control the lamp Tube; Wherein the two driving modes are dot inversion mode and column inversion mode, the corresponding lamp frequency of the dot inversion mode is 44±3KHz; the corresponding lamp frequency of the column inversion mode is 33±3KHz 3KHz. 2. The display lamp tube frequency control system according to claim 1, further comprising a converter for performing DC to AC conversion according to the lamp tube frequency as the working frequency. 3. The display lamp frequency control system according to claim 1, wherein the lamp frequency control device has a corresponding table, and obtains at least one corresponding lamp frequency according to the frequency control signal. 4. The display lamp frequency control system according to claim 1, wherein the corresponding frequency control signal of the dot inversion mode is a high potential; the corresponding frequency control signal of the column inversion mode is a low potential. 5. The display lamp tube frequency control system according to claim 1, wherein the lamp tube frequency control device further comprises a feedback circuit for feeding back and compensating the lamp tube current to stabilize the lamp tube current. 6. A method for controlling the frequency of a display lamp tube, comprising the following steps: (a) select one of at least two driving modes; (b) outputting at least one corresponding frequency control signal according to the selected driving mode; (c) obtaining at least one corresponding lamp frequency according to the frequency control signal, and providing the lamp frequency to a lamp to control the lamp; Wherein the two driving modes are dot inversion mode and column inversion mode, the corresponding lamp frequency of the dot inversion mode is 44±3KHz; the corresponding lamp frequency of the column inversion mode is 33±3KHz 3KHz. 7. The method for controlling the frequency of the lamp tube of a display according to claim 6, further comprising a converting step of converting DC to AC according to the frequency of the lamp tube. 8. The method for controlling the frequency of the lamp tube of a display according to claim 6, further comprising a feedback step for feeding back and compensating the lamp current to stabilize the lamp current.

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