CN1567032A - Display panel leakage current or charge balancing device - Google Patents

Abstract

A display panel leakage current or charge balancing device can effectively neutralize the leakage current and leakage charge generated by parasitic capacitance between the display and the backlight module (large or small movable billboards or advertising light boxes with only backlight modules), so that the current flowing through each group of lamps can be eliminated due to the imbalance of leakage current, thereby maintaining a consistent lamp light source and achieving a wide range of average brightness of the panel.

Description

Display panel leakage current or charge balancing device

technical field

The invention relates to a display panel leakage current or charge balance device, in particular to a device capable of eliminating, neutralizing or balancing the charge remaining between the lamp tube and the external metal cover structure of the display panel module.

Background technique

On a general display device, taking a liquid crystal display as an example, there is usually a backlight projection light source, and it is composed of multiple sets of lamp tubes, (refer to Figure 1) where R _S1 /R _S2 are line resistances (not necessarily equivalent), and C ₁ , C ₂ is the main equivalent stray capacitance of the lamp tube, and it is not necessarily equivalent, and due to manufacturing factors, or due to the location of the mechanism, or due to the configuration of the wires, in most cases, C ₁ and C ₂ are unbalanced. Among them, R _X1 and R _X2 are the series resistance of the stray equivalent capacitance, because the backlight tube usually uses a high-frequency and high-voltage power supply inverter, so the equivalent circuit of the stray parasitic effect becomes complicated and difficult Distribute evenly and maintain balance. As a result, the tube currents flowing through L ₁ and L ₂ are different or uneven due to the unbalanced parasitic components, which makes the overall brightness and grayscale performance of the panel The unbalanced or uneven phenomenon not only affects the image quality performance of the display, but also affects the visual health of the human body to a certain extent.

Because for a long time, there is no method that can effectively solve this problem. After many years of hard work and thinking in the related work, the present invention finally uses a signal synthesized by multiple harmonics, which is verified by experiments and finally solves the problem that has been troubled for many years.

Contents of the invention

The main purpose of the present invention is to solve the above-mentioned traditional defects. In order to avoid the existence of the defects, the present invention relates to a waveform signal generating device, which can eliminate, neutralize or balance the residual leakage current and leakage charge of the display panel.

In order to achieve the above-mentioned purpose, the device used in the present invention is directly connected or connected to the outer metal cover structure of the display panel module, or the plastic material of the middle layer through cross-connection, and can directly inject a signal into the middle layer of the outer metal cover structure. On the plastic material, the remaining charge on the display panel can be excluded or neutralized or balanced.

Description of drawings

FIG. 1 is a schematic diagram of an equivalent connection between a display and a backlight module of the present invention.

Fig. 2-1 is a schematic diagram of a passive embodiment of the present invention.

Fig. 2-2 is a schematic diagram of another passive embodiment of Fig. 2-1.

Fig. 3 is a schematic diagram of the first active embodiment of the present invention.

FIG. 4 is a schematic diagram of the actual circuit in FIG. 3 .

Fig. 5 is a schematic diagram of the second active embodiment of the present invention.

Figure 6-1 is a schematic block diagram of the actual circuit in Figure 5 .

Figure 6-2 is a schematic diagram of the internal circuit of the waveform synthesis module and waveform analysis module IC of Figure 6-1.

Fig. 6-3 is a schematic diagram of the filter circuit in Fig. 6-1.

FIG. 7 is a schematic diagram of the operation flow of FIG. 5 .

Fig. 8 is a schematic diagram of a front-end injection embodiment of the present invention.

Detailed ways

Relevant detailed content and technical specification of the present invention, now cooperate accompanying drawing to illustrate as follows:

Please refer to FIG. 1 , which is a schematic diagram of the equivalent connection between the display and the backlight module of the present invention. As shown in the figure: the leakage current or charge balance device of the display panel can effectively neutralize the leakage current and leakage charge generated by the parasitic capacitance between the display and the backlight module, so that the current flowing through each group of lamp tubes, due to the leakage current The unbalanced phenomenon is eliminated, and then the consistent lamp light source is maintained, so that the panel can obtain a wide range of brightness average.

In order to achieve the above object, the present invention connects a waveform signal generating device 2 on the outer metal cover structure 1 of the display panel 20 or the plastic material 40 of the middle layer. This device 2 can be used as a leakage current and leakage charge balance generator, including: A signal calculation function loop 21, an equivalent (rms root mean square) frequency 22 of a waveform generation loop, an output impedance 23 of a signal generation loop, and a balanced signal injection coupling component 24 (capacitor, transformer, battery or direct injection).

First, the unbalanced leakage current of i _c1 +i _c2 +i _c ...... before the unbalance is obtained from S _i , because the output of the drive inverter (transformer) 30 for lighting is high frequency 10K _HZ high voltage (hundreds of volts), so an unbalanced voltage will be obtained on RFC or on the equivalent output impedance (R _o ) 23 of the output of the present invention, and this voltage will have different phases between the currents of i _c1 and i _c2 difference and signal difference, so the signal after the waveform synthesis will be different from the signal added to the lamp tubes 3 and 4, and there may even be an amplitude error in the amplitude, and theoretically the sum (difference) between the phase shift difference and the original signal A low-frequency spurious or leakage signal value will be generated.

The signal obtained by S _i is then input to the signal calculation function loop 21. This circuit is a controlled voltage generator with an initial potential of 0V. At this time, S _i has an unbalanced signal input, which makes the circuit continuously increase the voltage. The controlled voltage is added to the waveform signal generating device 2, which is a voltage-controlled variable frequency generator. When 0V is input, it is an extremely low-frequency signal input. When the input control voltage continues to increase, the waveform signal generating device 2 The output frequency will also gradually increase until the signal frequency is consistent with the low-frequency value of the front phase shift difference and the input lighting frequency difference, and the S _i signal will be injected into the coupling component 24 to the outside due to V _AC through the output impedance 23 and a balanced signal. The leakage current of the metal cover structure 1 is neutralized by the leakage charge, so that the signal of _Si gradually approaches zero (or minimum).

Because the sum of the split-phase quantities of the balance signal injected by S _BAL into the external metal cover structure 1 will be decomposed into the split-phase quantities of i _c1 and i _c2 , because the leakage current and leakage charge of i _c1 and i _c2 are neutralized or removed respectively , so that the signal of S _i will reach the lowest value when it reaches a certain frequency to output a balanced signal, then the signal calculation function loop 21 will be at the lowest value of S _i , and the output control voltage will be fixed, so that the V _AC signal will be generated The output of device 2 always tracks a certain reference frequency to maintain _Si as the lowest point, that is, to maintain the entire capacitance C ₁ +C ₂ +C... The parasitic stray components are canceled or balanced status.

Since the leakage current and leakage charge flowing through parasitic stray components such as capacitors C ₁ and C ₂ are offset by this device, it will not interfere with the current flowing through the main lamp tubes 3 and 4, so that the current of the lamp tubes 3 and 4 is thus Maintaining an average and stable state, thereby enabling the entire surface of the display device to obtain uniform brightness and grayscale results, greatly improving the years of troubles and major quality defects of this type of display device.

Please refer to Figs. 2-1 and 2-2, which are schematic diagrams of a passive embodiment of the present invention and another passive embodiment in Fig. 2-1. As shown in the figure: this embodiment is roughly the same as above, the difference is that the outer metal cover structure 1 or the middle layer plastic material 40 is connected with a cross-connection component 5, and this cross-connection component 5 can be composed of capacitors, inductors, and transformers , if it is connected with a capacitor, it will be affected by the capacitance value of the capacitor and the positive and negative terminals, and LOW ESR (equivalent series resistance) is the best.

Please refer to Figs. 3 and 4, which are the first active embodiment of the present invention and the actual circuit schematic diagram. As shown in the figure: this embodiment is roughly the same as the above, the only difference is that the cross-connection component 5 is connected with a neutralization signal waveform generator 6, which can provide gain and relatively large current, and inject a waveform signal with a fixed pattern (The waveform signal can be injected into the outer metal cover structure 1 or the plastic material 40 of the middle layer), although this signal is a fixed frequency and amplitude, it can be a more complex composite function waveform of multi-phase, multi-frequency, and multi-amplitude, which can be offset Leakage current and leakage charge flowing through parasitic stray components such as capacitors C ₁ and C ₂ .

Please refer to Figures 5, 6-1, 6-2, 6-3, and 7, as shown in the figure: this embodiment is roughly the same as the above, the only difference is that the connection component 5 and the outer cover metal structure 1 A waveform synthesis module 7 and a waveform analysis module 8 are connected.

When the above two modules are activated, a scanning frequency (generated by DAC) 9 is sent out, and the signal value is read back by the ADC at 10, and then judgment is made to find the lowest point of the read back value at 11, if it is not the lowest point, return to step 9 Among them, if it is the lowest point, then maintain the signal waveform 12, then send the waveform data to the DAC13, and then send the signal waveform 14; or judge whether the readback value drifts 15, if not, then return to maintain the signal waveform 12; if so, then After the output signal waveform 16 is corrected, it returns to the maintaining signal waveform 12 .

Please refer to FIG. 8 , which is a schematic diagram of a front-end injection embodiment of the present invention. As shown in the figure: in this embodiment, a first switch 17 and a second switch 18 can be directly connected between the front end of the display panel 20 and the inverter 30, and the second switch 18 is sequentially connected to the above-mentioned cross-connection assembly 5 and In the neutralization signal waveform generating device 6, the aforementioned first and second switches 17, 18 can be formed by the MOS of the high-voltage switching component or any other active and passive components. The remaining charges on the display panel 20 are eliminated or neutralized or balanced.

Although the present invention has been described with reference to the accompanying drawings and preferred embodiments, the above embodiments are only illustrative, and various modifications and changes may be made to the present invention by those skilled in the art. Various modifications, changes and equivalents of the present invention are covered by the content of the appended claims.

Claims (10)

1. display pannel leakage current or charge balance device, comprise: an inverter (30) and a display panel module (20), remain in the fluorescent tube (3,4) of described display panel module (20) and the electric charge between external metallization cover structure (1) in order to elimination or neutralization or balance, it is characterized in that: described device (2) is directly connected on the external metallization cover structure (1) of described display panel module (20), can directly inject a waveform signal on described external metallization cover structure (1), can be got rid of or neutralize or balance being positioned at the remaining electric charge of display panel.

2. display pannel leakage current according to claim 1 or charge balance device, it is characterized in that described device (2) can be a waveform signal generation device, the equivalent frequency (22), a waveform signal that described waveform signal generation device comprises a calculated signals function loop (21), a waveform generation loop produces the output impedance (23) and a balanced signal in loop and injects passive component (24), described passive component can be electric capacity, inductance, transformer, battery any constitute.

3. display pannel leakage current according to claim 1 or charge balance device, it is characterized in that, it is one active that described device (2) can be, waveform signal with fixed pattern injects, though be a fixed frequency, wave amplitude, can be the more complicated composite function waveform of leggy, multi-frequency, many wave amplitudes.

4. display pannel leakage current according to claim 3 or charge balance device is characterized in that, described active be to connect a neutralisation signals Waveform generating apparatus (6) by a commissure assembly (5) to be constituted.

5. display pannel leakage current according to claim 3 or charge balance device is characterized in that, a described active commissure assembly (5), the synthetic module (7) of a waveform and the wave form analysis module (8) of can be again constitutes.

6. display pannel leakage current according to claim 1 or charge balance device is characterized in that, described device (2) is directly connected on the middle layer plastic material (40) of described display panel module (20).

7. display pannel leakage current according to claim 1 or charge balance device, it is characterized in that, described device (2) is directly connected between described display panel module (20) and described inverter (30), utilize time division type or split-phase type, will be positioned at the remaining electric charge of display panel to give eliminating or neutralization or to balance.

8. display pannel leakage current according to claim 7 or charge balance device, it is characterized in that, described device (2) is by one first switch (17) and second switch (18), and the described commissure assembly (5) that is connected with described second switch (18) constitutes with described neutralisation signals Waveform generating apparatus (6).

9. display pannel leakage current according to claim 8 or charge balance device is characterized in that, described first and second switch (17,18) can be the MOS of high pressure changeover module or other main passive component any constitute.

10. display pannel leakage current according to claim 1 or charge balance device is characterized in that, described inverter (30) also can be transformer.

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