TWI322399B - Method and apparatus for controlling a backlight module - Google Patents

Description

1322399

达达编号号: TW2287PA IX. Description of the Invention: [Technical Field] The present invention relates to a control method and device for a backlight module, and more particularly to a control of a backlight module used in a liquid crystal display panel Method and apparatus therefor. [Prior Art] The application of the liquid crystal display panel extends from the personal computer screen to the home flat-panel TV, and the size of the liquid crystal display panel is also increased, so that the liquid crystal display panel has an increased requirement for display brightness, thereby enabling the required backlight mode. The number of lamps is gradually increased from the single lamp in the past to the backlight module design of multiple lamps. Figure 1 is a conventional backlight module and its control device. The first figure includes the control device 10 and the backlight module 20. The backlight module 20 includes a plurality of arrays of cold cathode lamps, and a total of five sets of cold cathode lamps are illustrated by LI, L2, L3 (not shown), L4 and L5. The control device 10 provides an AC drive signal to the backlight module 20 to drive the cold cathode lamps LI, L2, L3 (not shown), L4 and L5. Figure 2 is a timing diagram of a conventional AC drive signal. Fig. 2 is a timing diagram of the AC drive signal of the control device 10 of Fig. 1 for driving the backlight module 20. Figure 2 includes timing diagrams for driving AC drive signals Gl, G2, G3, G4 and G5 and vertical sync signals STV for different lamps. The AC driving signal G1 is used to drive the lighting tube L1, the AC driving signal G2 is used to drive the lighting tube L2, and the AC driving signal G3 is used to drive the lighting tube L3 (not shown), the AC driving signal G4 It is used to drive the lighting tube L4, and the AC driving signal G5 is used to drive the lighting tube L5. Please refer to Figure 2 again, in which the phase between the AC drive signals is not synchronized, and the AC drive signals G1, G2, G3, G4 to G5 are sequentially enabled, in order to follow 5 1322399

• Sanda number: TW2287PA point lamp. This driving method makes it possible to make the eyes feel sharp and sharp and distinguishable when displaying dynamic images. However, if such a driving method is used to display a still-edge screen, the quality of the screen display is degraded. This is because when the static picture is displayed at 60Hz as the update frequency, since the kneading surface has not changed, the lamp is sequentially illuminated, and not all the lamps are lit, so that the human eye feels to the static picture. The phenomenon of flickering causes the eyes to be prone to fatigue and discomfort. The vertical synchronizing signal STV is used to synchronize the AC driving signals gi, G2, G3, G4 and G5, so that the lamp is turned off and the screen is not displayed when the screen data is switched, so as to hide the poor display quality caused by the switching of the face data, People see and feel. Therefore, in order to solve the above problems, the prior art provides different driving signals according to the static picture and the dynamic picture, as shown in FIG. Figure 3 is a timing diagram of another conventional AC drive signal. Figure 3 is an improvement of the driving signal of Figure 2. Figure 3 includes timing diagrams for driving AC drive signals Gl, G2, G3, G4 and G5 and vertical sync signals STV for different lamps. The AC drive signal G1 is used to drive the lighting tube L1, and the G2 is used to drive the lighting lamp f L2' AC driving signal (7) to drive the lighting tube. ^3 (not shown), AC driving signal G4 is used to drive the lighting tube L4, and the AC driving signal G5 is used to drive the lighting tube L5. Please refer to Figure 3 again. Before time T, it is used to display the dynamic picture. After time T, it is used to display the static picture. Therefore, the driving signals (7) to ^ before the time 便 are driven and illuminated by the timing diagrams shown in FIG. 2, respectively, and after the time T, all the high levels are output so that all the lamps The tube is in a lit state. Therefore, the tube is no longer turned on and off in sequence, and the display of the 'static surface is stable without causing a flickering feeling' to the human eye, thereby improving the display quality of the screen. 6 1322399

Sanda number: TW2287PA However, since it is necessary to make all the lamps in the lighting state when the static surface is displayed, if the current of the driving lamp is constant, it is obvious that the power consumption is inevitable for the whole system (and the brightness is also Will be too bright). From another point of view, when the dynamic picture is displayed, in order to make the brightness of the dynamic picture the same as the brightness of the static picture, it is necessary to increase the current of the lamp when the dynamic face display is displayed to compensate the brightness, thus increasing the overall system. Power consumption. With the increase in the size of the liquid crystal display panel, the number of lamps used has gradually increased, and the quality requirements of the screen have also been greatly improved. Therefore, how to maintain the sharpness of the dynamic image in the dynamic image, and the perception of the static surface is not eye-catching. It is an important technical issue to flash to the inside and not to increase the overall power consumption. SUMMARY OF THE INVENTION In view of this, the object of the present invention is to provide a control method and device for a backlight module, which can effectively improve the quality of the face of the liquid crystal display panel. It maintains the sharpness of the screen when displaying the dynamic picture, and solves the problem of the screen flickering when the static picture is displayed, and at the same time achieves the purpose of power saving. According to an object of the present invention, a control method of a backlight module is provided. The backlight φ module includes a plurality of sets of lamps, and the control method includes the following steps. First, a plurality of first driving signals having a first frequency are provided to the backlight module to drive the group of lamps to enable the backlight module to enter a scanning enable mode (Scanning Enable Mode). The number of times of lighting in each cycle corresponds to the first frequency, and the first driving signals are sequentially enabled. Then, a plurality of second driving signals having a second frequency are provided to the backlight module to drive the group of lamps to enable the backlight module to enter a scanning disable mode (Scanning Disable Mode). The number of times of lighting in each cycle corresponds to the second frequency, and the second frequency is greater than the first frequency

Sanda number: TW2287PA According to the purpose of the present invention, a control device for a backlight module is provided. The backlight module includes a plurality of sets of lamps, and the control device includes a scan enabling module, a scanning non-enable module, and a selection circuit. Module. The scan enable module is configured to output a plurality of first motion signals having a _ first frequency. And scanning the non-enable module for outputting and having a plurality of second driving signals of the second frequency, wherein the second frequency is greater than the first frequency. The selection circuit module is connected to the scan enable module and the scan non-enable module for selectively outputting the first drive signals or the second drive signals to the backlight module according to the selection signal, respectively Drive these sets of tubes. According to still another aspect of the present invention, a backlight module system includes a timing controller, a memory, a control device, and a backlight module. The memory system is _ to timing (four). Control the difficult system (4) to the timing controller and memory. The control device includes a scan-enable module, a scan non-enable module, and a selection circuit module. The scan enabling module is configured to output a plurality of first driving signals having a first frequency. The scanning non-enable module is configured to output a plurality of second driving signals having a second frequency, wherein the second frequency system is greater than the first frequency. The selection circuit module is connected to the sweeping (four) m-scan non-four module to the control device, and the backlight module includes multiple sets of lamps. The selection circuit module selects and outputs the first driving signals or the second driving signals to the backlight module according to a selection signal to respectively drive the group of lamps. The above-mentioned objects, features, and advantages of the present invention will become more apparent from the following description of the preferred embodiments of the invention. A timing diagram of an AC drive signal in accordance with a preferred embodiment of the present invention is shown.帛4 diagram includes AC drive signals for driving different lamps f..., (^, with the timing diagram of (7) vertically synchronizing the signal claws to 1322399

Sanda number: TW2287PA and selection signal SCN. The AC drive signal of Fig. 4 is, for example, a circuit suitable for Fig. 1, but is not limited thereto. The AC driving signal G1 is used to drive the lighting tube L1, the AC driving signal G2 is used to drive the lighting tube L2, and the AC driving signal G3 is used to drive the lighting tube L3 (not shown), and the AC driving signal G4 It is used to drive the lighting tube L4, and the AC driving signal G5 is used to drive the lighting tube L5. Among them, the lamps L1 to L5 are, for example, cold cathode lamps. Before the time T, the selection signal SCN is at a high level, and the backlight module is in a scanning enable mode, which is operated when the dynamic surface is displayed. After the time T, the signal SCN is selected to be a low level, and the backlight module is a scanning non-enabling mode, which is operated when the static picture is displayed. Wherein, in the scan enable mode, the phases between the AC drive signals are not synchronized, and the AC drive signals G1, G2, G3, G4 to G5 are sequentially enabled to sequentially illuminate the lamps. The main difference between the AC drive signal of the scan enable mode and the AC drive signal of the scan non-enable mode is the frequency, wherein the frequency of the scan of the non-enable mode AC drive signal is greater than the scan time in each frame time. The frequency of the AC drive signal in the enable mode. Preferably, the frequency of the AC drive signal for scanning the non-enabled mode is not an integer multiple of the frequency of the AC drive signal of the scan enable mode. In addition, the phase system ® of the adjacent two AC drive signals in the non-enabled mode can be 180 degrees out of phase (ie, the phase is opposite), but the phase difference between the two is not limited to 180 degrees. The frequency of the AC drive signal of the scan enable mode is, for example, 60 Hz, and the frequency of the AC drive signal for scanning the non-enable mode is greater than 75 Hz, preferably about 160 Hz to 200 Hz. In other words, the scan enable mode and the scan disable mode are different in the number of times the lamp is lit within one screen time (filed). The main principle is that when the dynamic face is displayed, the human eye is less likely to detect the phenomenon of flashing of the face. However, when the static picture is displayed, if the frequency of the AC drive signal is insufficient, the human eye is very easy. 9 1322399

Sanda number: TW2287PA notices that the screen flickers. In order to avoid this phenomenon, the frequency of the AC drive signal can be increased, and the principle of visual residual of the human eye can be used. Because the human eye is difficult to distinguish the difference between the frequency and the frequency above 75 Hz, That is, when the frequency of the AC drive signal is greater than 75 Hz, the human eye cannot detect the flickering of the screen. Accordingly, in this embodiment, the scan enable mode and the scan non-enable mode are used to drive the backlight module with AC drive signals of different frequencies. The object displayed on the dynamic surface is clear and sharp, and the purpose of avoiding the flashing of the static picture is avoided. In addition, since the scanning non-enable mode drives the lamp with a higher frequency AC drive signal, and not all of the lamps are simultaneously illuminated and maintained at a high level, it is more economical than the conventional technique of '· FIG. Electricity. The reason why the double edge or the triple edge phenomenon can be effectively avoided will be described below for the present embodiment. Figure 5 is a waveform diagram showing an example of an AC drive signal that may produce a two-edge or three-edge phenomenon in the scan non-enabled mode. In Fig. 5, the number of times the AC drive signal G2 is turned into the same is the same in each frame time, that is, the number of times the AC drive signal G2 turns on the L2 is the same. However, when the AC driving signal G2 illuminates the lamp L2 in the A and B time zones, the liquid crystal panel of the liquid crystal panel is still in the transition state, and the brightness of the generated image may be dark. When the AC drive signal G2 illuminates the lamp L2 in the C time zone, the liquid crystal of the liquid crystal panel is in a stable phase, and the brightness of the image produced at this time may be bright. Since the number of times the corresponding AC drive signal G2 is enabled to be the same in each cycle of the vertical sync signal STV is the same, then in each frame time, the A, B and C three time zones are lit. The face of the tube L2 is continuously accumulated by the human eye due to the persistence of the vision, so that the image edge of the picture generated by the two time segments A and B becomes as obvious as the image edge of the picture generated by the C time segment. This is the so-called two-edge or three-edge phenomenon. In order to solve this problem, it is necessary to adjust each face when 1322399

Erda number: TW2287PA, the number of times each AC drive signal is enabled to avoid two edges or three sides. Fig. 6 is a waveform diagram showing an example of an AC drive signal that avoids two-edge or three-edge phenomena in the non-scanning non-enable mode. The main difference between Fig. 6 and Fig. 5 is that the number of times the corresponding AC drive signal G2 is changed to enable in the two adjacent picture times, that is, the number of times the AC drive signal G2 illuminates the lamp L2 is different. Since the number of times of the corresponding AC driving signal G2 is different in the two adjacent picture times, when the AC driving signal G2 illuminates the lamp L2, there is no time zone of A and B as shown in FIG. The face of the face is over a number of face times, causing the eye to accumulate its display effect due to persistence of vision, resulting in two or three sides. Figure 7 is an AC drive signal timing diagram that may be generated when the same drive module is used to drive separately and scan the non-enable mode. The same signals as in Figure 4 are labeled with the same reference numerals. No longer. The main difference between Figure 7 and Figure 4 is that when the backlight module is switched from scan enable mode to scan non-enable mode when the backlight module is at -T, the scan disable mode is enabled. The AC drive signal will be delayed - after a period of time: 'that is, 'the lamp will be lit after a delay. The AC drive signals (1) to (7) of Fig. 7 are all at the same potential (e.g., "potential") during a delay period after time τ, so that the lamps are all turned off during this period. The action of the lamp during this - delay period will temporarily turn the face into a black face, which affects the display quality of the picture, = in order to avoid this phenomenon, the present invention proposes control as shown in Fig. 8. Device to solve this problem. Referring to Figure 8, there is shown a back 62Γ=control device thereof in accordance with the present invention.帛8 diagram includes control device (4) and backlight module VIII, backlight 杈 group 620 includes complex array of cold cathode lamps, here Lu, 11 1322399

Sanda number: TW2287PA L12, L13 (not shown), L14 and L15 a total of 5 sets of cold cathode lamps for instructions. The drive circuit 610 provides an AC drive signal to the backlight module 62A to drive the cold cathode lamps & L11, L12, L13 (not shown), [14 and L15. The control device 61 further includes a scan enable module 612, a scan non-enable module 6丨4, and a selection circuit module 616' for implementing the control method of the f-light module described in FIG. The scan enable module 612 is configured to output an AC drive signal of the scan enable mode, and the scan disable module 614 is configured to output an AC drive signal for scanning the non-enable mode. The selection circuit module 616 is composed of, for example, a multiplexer. The AC drive signal output by the scan enable module 612 or the scan enable module 612 is determined as an output according to the selection signal SCN. ♦ The 'AC drive signal G1 is used to drive the lighting tube u, for example, the AC driving signal G2 is used to drive the lighting tube L2, for example, the AC driving signal G3 is used, for example, the moving point 7C lamp L3 (not drawn) The AC drive signal G4 is used to drive the lighting tube L4, and the AC driving signal G5 is used to drive the lighting tube L5. Since the parent AL drive signal selects the output signal of the scan enable module 612 or the scan disable module 614 through the selection circuit module 616, the desired parent flow drive signal can be quickly switched, that is, the selection signal SCN is high. When switching to the low potential, when the backlight module 620 is switched from the scan enable mode to the scan disable mode, the control device 61G can quickly switch the AC drive signal to be output to the backlight module (4). Alternatively, when the selection signal SCN is switched from the low potential to the high potential backlight module 620 to switch from the scan non-enabling mode to the scan enable mode, the control device _ can quickly switch the AC drive signal to be output to the backlight module 62. At the same time, the delay problem described in Figure 7 is also avoided. Referring to Figure 9, a backlight module system in accordance with a preferred embodiment of the present invention is illustrated. Fig. 9 includes a timing controller 9G2, a memory 9G4, a control device 910, and a temple chess group 92. The memory 9〇4 is coupled to the timing controller 9. The control device 910 is connected to the timing controller 9〇2 and the memory 9〇4, and the control device 12

The three-digit number: TW2287PA is set at 910 and receives, by the timing controller 902, control signals such as a horizontal clock signal Ckh, a vertical clock signal ckv, and a vertical start signal STV. The backlight module 92 〇 (4) is connected to the control device 910' to include a plurality of sets of lamps. The control device 910 includes the scan enable module 612, the scan disable module 614, and the select circuit module 616', as described in FIG. The memory 9〇4 is, for example, an electronic erasable read-only memory (EEPR〇M) for storing, for example, the frequency of the AC drive signal in the scan enable mode or the scan non-enable mode, the scan enable mode or Scanning the duty cycle of the AC drive signal in the non-enabled mode (duty, the number of lamp sets, or a combination of the foregoing information) for use in initializing the entire system to enable the scan enable module 612 and the scan disable module 614 The AC drive signal frequency can be changed by the stylized electronic erasable read-only memory according to different systems to improve the flexibility of the system. The present invention further discloses a liquid crystal display comprising a liquid crystal display panel, a scan driving circuit, - data drive circuit 1 and the above backlight module system. Scan drive circuit to rotate the liquid crystal display panel, the material drive circuit is also used to drive the liquid crystal display panel. The timing controller more carefully controls the scan drive circuit and the data drive circuit. The backlight module is used to provide a line required for the liquid crystal display panel. The control method and device for the backlight module disclosed in the above embodiments of the present invention 'The display object of the dynamic picture © can be kept clear and sharp, and the display of the static picture can be made to make the display of the static picture not be noticeable, and the display quality of the liquid crystal display panel can be effectively improved, and the power consumption of the conventional art can be solved. The problem and the two-edge/three-edge phenomenon. In summary, the present invention has been disclosed in a preferred embodiment as above, but it is not intended to limit the invention to anyone skilled in the art, without departing from the invention 13 1322399

Sanda number: TW2287PA Therefore, within the spirit and scope of the present invention, when various changes and refinements are available, the scope is subject to the definition of the patent application scope.

14 1322399 Sanda Number: TW2287PA [Simple Description of the Drawing] Figure 1 shows the conventional backlight module and its control device. Figure 2 is a timing diagram of a conventional AC drive signal. FIG. 3 is a timing diagram of another conventional AC drive signal. FIG. 4 is a timing diagram of an AC drive signal according to a preferred embodiment of the present invention. FIG. 5 illustrates that in the scan non-enable mode, two edges may be generated. Or a waveform diagram of an example of an AC drive signal with three edge phenomena. Figure 6 is a waveform diagram showing an example of an AC drive signal that avoids two or three edges in the scan non-enabled mode. Figure 7 is a timing diagram of the AC drive signal that may be generated when the same drive module is used to drive the scan enable mode and the scan disable mode, respectively.

8 is a backlight module and a control device thereof according to a preferred embodiment of the present invention. FIG. 9 is a backlight module system according to a preferred embodiment of the present invention. • [Main component symbol description] 10' 610, 910: Control device 20' 620, 920: backlight module 612 · Scanning drive module 614: Pulse driving module 616: multiplexer module 902: Timing controller 904: Memory LI, L2, L4 'L5, L11, L12, L14, L15: Lamp 15 1322399

Sanda number: TW2287PA ckh: horizontal clock signal ckv: vertical clock signal STV: vertical start signal SCN: selection signal

Claims (1)

1322399 Sanda number: TW2287PA X. Patent application scope: 1 A control method for a backlight module, the backlight module comprising a complex array of lamps, the control method comprising the following steps: (a) providing a plurality of first frequencies The first driving signal is sent to the backlight module to drive the group of lamps, so that the backlight module enters a scanning enable mode (Scanning Enable Mode), and the number of times the group of lamps is lit in each cycle corresponds to Up to the first frequency, the first driving signals are sequentially enabled; and (b) providing a plurality of second driving signals having a second frequency to the backlight module to drive the group of lamps, so that The backlight module enters a scanning disable mode (Scanning Disable Mode), and the number of times the group of lamps is lit every time corresponds to the second frequency, and the second frequency is greater than the first frequency. 2. The control method according to claim 1, wherein the step (a) is performed when the dynamic picture is displayed, and the step (b) is operated when the static picture is displayed, and each time is for each picture. Time (frame time). 3. The control method of claim 1, wherein the second | frequency is not an integer multiple of the first frequency. 4. The control method according to claim 1, wherein when the backlight module enters the scanning non-enable mode, the number of times the group of lamps is lit during a first face time is The plurality of sets of lamps are illuminated for different times in a second picture time, and the first picture time is adjacent to the second picture time. 5) The control method of claim 1, wherein the second frequency is greater than 75 Hz. 17 达达编号: TW2287PA 6. The control method as described in the scope of claim 2, wherein the second frequency is between 160 Hz and 200 Hz. 7. The control method of claim 2, wherein the two adjacent second driving signals are opposite in phase with each other. 8. In the control method of claim i, wherein in step (a) and step (b) (iv), at least part of the lamp system remains illuminated at the instant of (10). 9 a control device for a backlight module, the backlight module comprising a plurality of array lamps. The control device comprises: a scan enabling module 1 for outputting a plurality of driving signals having a first frequency; 'for outputting a plurality of first driving signals having a second frequency, wherein the second frequency is greater than the first frequency; and - the selecting circuit module ' _ is connected to the scan enabling module and the sweeping And according to the selection signal, selecting and outputting the first driving signal-μ2 first driving signal to the backlight module to respectively drive the group of lamps. Wherein, the control device of the control device as described in claim 9 is a cold cathode lamp. 18 1322399 Three-face number: TW2287PA U. The control device of claim 9 wherein the second frequency is not an integer multiple of the first frequency. 13. The control device of claim 9, wherein when the second driving signals are used to drive the group of lamps, the number of times the lamps are illuminated in the first written time is Different from the number of times the group of lamps is lit in a second picture time, the first picture time is adjacent to the second picture time. 14. The control device of claim 9, wherein the second Lu frequency is greater than 75 Hz. 15. The control device of claim 9, wherein the second frequency is between 160 Hz and 200 Hz. 16. The control device of claim 9, wherein the two adjacent second drive signals are opposite in phase with each other. The control device of claim 9, wherein the selection circuit module does not cause all of the group of lamps to be turned off or fully illuminated. 18. A backlight module system, comprising: a timing controller; a memory 'coupled to the timing controller; a control device coupled to the timing controller and the memory, comprising: a scan The enabling module is configured to output a plurality of first driving signals having a first frequency; 19 1322399 Sanda number: TW2287PA a scanning non-enabling module for outputting a plurality of second driving having a second frequency a signal, wherein the second frequency is greater than the first frequency; and a selection circuit module coupled to the scan enable module and the scan non-enable module; and a backlight module coupled to the The control device includes a plurality of array lamps, and the selection circuit module selectively outputs the first driving signals or the second driving signals to the backlight module according to a selection signal to respectively drive the group of lamps The backlight module is used to provide light required for the liquid crystal display panel. 22. The liquid crystal display of claim 21, wherein the memory is an electronic erasable read only memory (EEPROM). 23. The liquid crystal display of claim 22, wherein the memory has at least one information selected from the first frequency, the second frequency, and the duty cycle of the first driving signals (duty Cycle), a duty cycle of the second driving signals, a group of the plurality of lamp groups, and a combination thereof. twenty one