JP4422253B2 - Method and apparatus for adjusting flicker balance - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to flicker adjustment in a flat display such as a liquid crystal panel, and more particularly to a flicker balance adjustment method and apparatus that can be used to adjust flicker balance.
[0002]
[Prior art]
Conventionally, the flicker balance of a flat display such as a liquid crystal panel or a plasma display panel (PDP) is usually adjusted visually by a flicker adjusting person. This is because, for example, in a liquid crystal panel, the flicker value is not constant on the panel surface and often has a different flicker value distribution for each liquid crystal panel product. For this reason, for example, it is not sufficient to adjust the flicker of the liquid crystal panel based on the flicker value at one center of the panel, and the degree of flicker received by humans from the entire liquid crystal panel is ultimately important as a product. Adjustment personnel finally determine the amount of flicker adjustment.
[0003]
[Problems to be solved by the invention]
However, flicker adjustment requires skill, and adjustment work is performed over a long period of time based on visual observation of the panel surface. For this reason, the flicker adjustment varies with time. In addition, since it is normal to change the adjustment personnel during manufacturing, there is a variation in the amount of flicker adjustment between different adjustment personnel. As a result, the amount of flicker in the final liquid crystal panel product varies.
[0004]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a flicker balance adjusting method and apparatus that can easily adjust the flicker balance of a flat display.
[0005]
Another object of the present invention is to provide a flicker balance adjustment method and apparatus that can perform flicker balance adjustment based on a more objective standard.
[0006]
Furthermore, another object of the present invention is to provide a flicker balance adjustment method and apparatus which can perform flicker balance adjustment at a higher speed.
Furthermore, another object of the present invention is to provide a flicker adjustment method and apparatus for adjusting the entire flicker of a flat display including the flicker balance adjustment described above.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a flicker balance adjusting method for adjusting the flicker balance of a flat display comprises: a) a mutual arrangement on generally one line passing through a generally central point on the flat display; A flicker value measuring step for measuring flicker values at a first point and a second point separated from each other, wherein the first point and the second point are on opposite sides of the center point; An adjustment step; b) a difference obtaining step for obtaining a difference between the flicker value at the first point and the flicker value at the second point; and c) an adjustment step for adjusting the flicker balance based on the difference. Become.
[0008]
The flicker value measuring step includes a) obtaining a plurality of pairs of flicker values of the first point and the second point when the one line is in a plurality of different directions on the flat display; (B) determining the one line in a direction in which a pair having a maximum difference between the flicker value of the first point and the flicker value of the second point is obtained among the plurality of pairs. it can. Further, the direction of the one line may include at least one of the two diagonal directions and the horizontal direction of the rectangular flat display.
[0009]
The flicker value measuring step includes a) obtaining a distribution of flicker values on the entire surface of the flat display, and b) determining the one line in a direction including the maximum point and the minimum point in the flicker value distribution. And can be included.
[0010]
Further, the adjusting step may include a step of adjusting in a direction in which the difference becomes equal to or less than a first predetermined threshold value.
Further, according to the present invention, a flicker adjustment method for performing flicker adjustment of a flat display includes a step of measuring a flicker value at the center point on the flat display before the flicker balance adjustment method. And b) adjusting the flat display so that a flicker value at the center point is equal to or less than a second predetermined threshold value.
[0011]
According to the present invention, there is also provided a flicker balance adjusting device for adjusting the flicker balance of a flat display. B) First of the flat display separated from each other on a generally one line passing through a generally central point on the flat display. First and second photosensors for detecting first and second luminance signals and generating first and second luminance signals, said first point and said second point being said The first and second photosensors located on opposite sides of the center point, and b) from the first and second luminance signals, the first flicker value of the first point and the second point A flicker balance measuring circuit for obtaining a second flicker value and obtaining a difference between the flicker values.
[0012]
Further, according to the present invention, a flicker adjustment device for performing flicker adjustment of a flat display, in addition to the above flicker balance adjustment device, a) detects the luminance on the center point on the flat display. A third optical sensor that generates a third luminance signal; and b) a flicker value measuring circuit that obtains a third flicker value at the center point from the third luminance signal.
[0013]
The first, second and third sensors may be movably disposed on a linear support member. The support member can be movably disposed on a surface of the flat display.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a basic configuration of a flicker adjusting apparatus according to the present invention. The illustrated flicker adjustment device includes a flicker value measuring unit 12 and a flicker balance measuring unit 14 for adjusting flicker of the flat display 10. The flicker value measuring unit 12 is composed of one optical sensor 120 and a flicker value measuring circuit 122 connected thereto. The flicker balance measuring unit 14 includes two optical sensors 140 and 142, and a flicker balance measuring circuit 144 connected thereto. The flat display 10 is a display such as a liquid crystal panel, a plasma display panel, etc., and usually has a rectangular panel surface 100. As described above, in the flat display 10, the flicker value on the panel surface 100 is not constant but varies over the panel surface. The photosensor 120 is arranged at a position A at the substantially center of the panel surface 100, and the photosensors 140 and 142 are arranged at a position B at the upper right corner and a position C at the lower left corner on the diagonal line 102 rising to the right. ing. These optical sensors detect the luminance at positions A, B, and C on the panel surface of each sensor, and generate luminance signals La, Lb, and Lc representing the luminance.
[0015]
The flicker value measuring circuit 122 that receives the luminance signal La from the optical sensor 120 obtains the flicker value Fa on the position A from the luminance signal. On the other hand, the flicker balance measuring circuit 144 receives the luminance signals Lb and Lc from the optical sensors 140 and 142, obtains the flicker values Fb and Fc at the points B and C from these luminance signals, and further, these flicker values. Difference Fd (= | Fb−Fc |) is obtained. The flicker value Fa and the flicker value difference Fd are instructed by an indicator or the like for manual adjustment by a flicker value adjusting person or output as a signal representing the flicker value for automatic flicker adjustment. be able to. As a method for obtaining the flicker value from the luminance signal, a conventionally known method may be used.
[0016]
Next, with reference to FIG. 2, a flicker adjusting apparatus embodying the present invention will be described. Therefore, the same numbers are given to the same parts as those in the apparatus of FIG. The flicker adjusting apparatus shown in FIG. 2 is roughly divided into a flicker value measuring unit 12A and a flicker balance measuring unit 14A for adjusting the flicker of the liquid crystal panel 10A, as in FIG. The flicker value measuring unit 12A includes one optical sensor 120A and a flicker value measuring circuit 122A connected thereto. The flicker / balance measuring unit 14A includes two optical sensors 140A and 142A, a flicker / balance measuring circuit 144A connected thereto, a difference detecting unit 1444, and a display unit 1446. The liquid crystal panel 10A has a rectangular panel surface 100A. Although not shown in FIG. 2, the photosensor 120A is arranged at a position A (see FIG. 1) approximately at the center of the panel surface 100A, and the photosensors 140A and 142A are arranged on the diagonal line 102 (FIG. 1). (See above), the upper right corner position B and the lower left corner position C are respectively arranged. These optical sensors generate luminance signals La, Lb, and Lc as in FIG.
[0017]
The flicker value measurement circuit 122A that receives the luminance signal La from the optical sensor 120 includes a circuit unit 1220 that obtains the flicker value Fa from the luminance signal La at the position A, and a display unit 1222 that displays the obtained flicker value Fa. . Specifically, the circuit unit 1220 includes an amplifier 12200 that amplifies the luminance signal La, and automatic gain control that normalizes the amplified luminance signal with respect to a reference value Vr provided in the automatic gain control circuit by automatic gain control or scaling ( AGC) circuit 12202, an AC component separation circuit 12204 for extracting an AC component from the output from this circuit by filtering, etc., and a DC representing the peak / peak value of the AC component by detecting the AC component obtained by the separation. And a detection circuit 12206 for outputting a voltage. This DC voltage becomes the flicker value Fa.
[0018]
The flicker value is measured because the panel surface brightness differs depending on the individual difference of LCD panels (backlight brightness variation) and the average brightness of the image pattern used for the inspection. The panel surface luminance component Vdc and the peak / peak value of the AC component (30 Hz) of the luminance signal, that is, the flicker component Vf are read, and the ratio thereof, that is, Vf / Vdc is calculated. By performing normalization by the automatic gain control circuit 12202 and performing gain control so that Vdc coincides with a certain reference value Vr, Vf at that time can be directly set to the flicker value. This normalization is disclosed in Japanese Patent Application No. 11-172837 by the present applicant. In the present invention, this normalization can be omitted.
[0019]
The flicker balance measurement circuit 144A includes circuit units 1440 and 1442 that generate flicker values Fb and Fc from the luminance signals Lb and Lc from the optical sensors 140A and 142A, respectively. These circuit units 1440 and 1442 are: An amplifier 14400 (or 14420) having the same circuit configuration as that of the circuit unit 1220 and amplifying the luminance signal Lb (or Lc) at the position B (or C), and automatic gain control of the amplified luminance signal by automatic gain control or scaling An automatic gain control (AGC) circuit 14402 (or 14422) that normalizes the reference value Vr provided in the circuit, and an AC component separation circuit 14404 (or 14424) that extracts an AC component from the output from this circuit by filtering or the like. And then, the AC component obtained by this separation is detected and A A detection circuit 14406 (or 14426) for outputting a DC voltage representing the peak-to-peak value of the component is made up of. These DC voltages become flicker values Fb and Fc. As described with reference to FIG. 1, the next difference detection unit 1444 that receives both of these flicker values generates a flicker value difference Fd (= | Fb−Fc |) in order to represent the degree of flicker balance. The difference Fd is displayed on the next display unit 1446.
[0020]
FIG. 3 shows luminance signals La, Lb, and B at the panel surface positions A, B, and C when the flicker is maximum (FIG. 3A) and when the flicker is minimum (FIG. 3B). The waveform of Lc is shown. As can be seen, when the flicker is large, the amplitude of each luminance signal is large and the phases are shifted in the order of B, A, and C. It can be seen that when the flicker is minimized by visual flicker adjustment, the amplitude of each luminance signal is small.
[0021]
Next, a method of adjusting the flicker of the liquid crystal panel 10A using the flicker adjusting device of FIG. 2 will be described with reference to the flowchart of FIG. First, in step 200, the counter electrode input voltage for adjusting the flicker of the liquid crystal panel 10 </ b> A is set so that the flicker value Fa at the point A is equal to or less than a predetermined threshold value α while looking at the indication on the display unit 1222. Adjust V _com . Next, at step 202, the flicker difference value Fd between the point B and the point C is opposed so as to become a predetermined threshold value β (for example, 10% or less of the size of Fb or Fc) while viewing the instruction of the display unit 1446. The electrode input voltage V _com is adjusted. Next, at decision step 204, it is checked whether the flicker value Fa at point A at this time is still below the threshold value α. In the case of YES, this liquid crystal panel passes the flicker adjustment. In the case of NO, in the next judgment step 206, it is checked whether or not the number of adjustments is less than n times, and in the case of less than n times and YES, the process returns to step 200 and the above steps are repeated. Note that the value of n may be appropriately selected by the user. If it is determined NO in determination step 206, the liquid crystal panel is rejected and discarded. In the determination step 206, the determination is made based on the number of times, but it can be changed so that the determination is made based on the time required for the adjustment. In the case of manual adjustment by flicker adjustment personnel, this step 206 may be omitted, and a loop to step 200 may be simply performed.
[0022]
Next, the arrangement of the luminance detection positions A, B, and C on the panel surface 100A, that is, the photosensor arrangement will be described with reference to FIG. In the embodiment of FIG. 1 and FIG. 2, the arrangement on the diagonal line 102a that rises to the right in FIG. 5A is selected, but as shown in FIG. 5B and FIG. 5C, it passes through the center of the panel surface. It is also possible to select an arrangement with a diagonal line 102b that is descending to the right or an arrangement with a horizontal line 102c that passes through the center of the panel surface. These different optical sensor arrangements need to be selected in order to properly adjust the flicker balance. This is because it is known that the distribution state of flicker values on the panel surface is different between a liquid crystal panel of one model or model and a liquid crystal panel of another model or model. The selection of the different arrangement rows allows the three optical sensors to be arranged on a linear support member in a movable manner in the longitudinal direction of the support member so that the distance between the sensors can be adjusted, and this support By arranging the entire member so as to be movable in two diagonal directions, a horizontal direction, etc. on the panel surface, selection between arrangement rows can be performed.
[0023]
FIG. 6 shows a two-dimensional flicker value distribution on a rectangular panel surface 100A when a flicker is maximum for a certain liquid crystal panel (hereinafter referred to as panel A), and FIG. 7 shows a three-dimensional flicker value distribution at this time. It is shown in the figure. As clearly shown in FIG. 7, the flicker value increases from the C point toward the B point. In the case of such a flicker value distribution, the arrangement shown in FIG. 5A is the most effective for adjusting the flicker balance rather than the arrangement shown in FIGS. 5B and 5C. .
[0024]
FIG. 8 and FIG. 9 show the flicker value distribution when the flicker is adjusted to the minimum for the panel A by visual adjustment. As can be seen from FIG. 9, the difference in flicker value between points B and C decreases. Note that in FIG. 9, the scale is enlarged as compared to FIG.
[0025]
Next, FIG. 10 and FIG. 11 show the flicker value distribution when the flicker is minimized by visual adjustment for another type of liquid crystal panel (hereinafter referred to as panel B). Even in this panel B, the arrangement of FIG. 5A is effective, but in this case, the horizontal arrangement of FIG. 5B can also be used. Thus, if the model number of the liquid crystal panel is different, it is necessary to reselect the optical sensor arrangement.
[0026]
FIG. 12 shows another optical sensor arrangement example different from FIG. That is, FIG. 12A is a combination of FIGS. 5A and 5B to form a five-point sensor arrangement, and either one of the sensor arrangement row 102a ′ and the sensor arrangement row 102b ′ is replaced. You can select and use. In this arrangement, both arrangement rows 102a ′ and 102b ′ can be used. FIG. 12B shows a seven-point sensor arrangement by combining all of FIGS. 5A, 5B, and 5C. The sensor arrangement row 102a ″, the sensor arrangement row 102b ″, Any one of the sensor arrangement rows 102c ′ can be selected and used. As above, in this arrangement, all of the arrangement rows can be used.
[0027]
FIG. 13 shows a flowchart of a method for selecting one of the arrangement rows in the five-point photosensor arrangement of FIG. As shown, the method first adjusts the counter electrode input voltage V _com of the liquid crystal panel at step 300 so that the flicker value at the center or center point A is minimized. In the next step 302, the flicker balance in each of the diagonally arranged rows 102a ′ and 102b ′ is checked to obtain a flicker value difference Fd. Next, in step 304, an arrangement row having a larger one of these differences, that is, a diagonal line is determined and selected. This is because the diagonal with the larger difference is the most effective for flicker balance adjustment. Accordingly, the flicker balance / center flicker value described with reference to FIG. 4 is adjusted under the selected arrangement row. It should be noted that this optical sensor arrangement row selection can be performed only for the first one liquid crystal panel because it is rare that different models are mixed in a normal mass production line. Furthermore, when the method of FIG. 13 is applied to the seven-point photosensor arrangement of FIG. 12B, the flicker balance may be checked for the horizontal arrangement row 102c ′.
[0028]
In the above embodiment, the manual adjustment by the flicker value adjusting personnel has been particularly described. However, automatic adjustment can be performed without depending on the adjusting personnel.
[0029]
【The invention's effect】
According to the flicker adjustment method and apparatus of the present invention described in detail above, the display gazing time required for flicker adjustment can be shortened, so that the fatigue of the adjustment personnel due to viewing the flickering screen is reduced. Therefore, adjustment can be performed more easily than in the past. In addition, since flicker adjustment is performed by using a certain reference value, variations in adjustment amount among adjustment personnel and variations over time among adjustment personnel can be minimized, thus enabling more objective adjustment. be able to. Furthermore, by using this objective reference value, the adjustment can be performed more quickly than in the past. Furthermore, if the flicker adjustment is automated using the method of the present invention, the adjustment can be completed at a higher speed.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a basic configuration of a flicker adjusting apparatus according to the present invention.
FIG. 2 is a diagram showing an embodiment of a flicker adjustment apparatus that is a more specific version of the apparatus of FIG.
FIGS. 3A and 3B are diagrams showing waveforms of luminance signals La, Lb, and Lc at panel surface positions A, B, and C of a sample liquid crystal panel when the flicker is maximum and (b) when flicker is minimum.
FIG. 4 is a flowchart showing a method for adjusting the flicker of the liquid crystal panel using the flicker adjusting apparatus of FIG. 2;
FIGS. 5A, 5B, and 5C are diagrams showing different photosensor arrangements on the panel surface. FIGS.
FIG. 6 is a diagram showing a two-dimensional flicker value distribution on a rectangular panel surface when the flicker is maximum for the liquid crystal panel A, and the unit of the value in the figure is%.
7 is a diagram showing the flicker value distribution of FIG. 6 in a three-dimensional manner.
FIG. 8 is a diagram showing a two-dimensional distribution of flicker values when flicker is adjusted to the minimum by visual adjustment for panel A.
9 is a diagram three-dimensionally showing the flicker value distribution of FIG. 8. FIG.
FIG. 10 is a diagram showing a two-dimensional flicker value distribution when the flicker is minimized by visual adjustment for a liquid crystal panel B having a different model number from the liquid crystal panel A;
11 is a diagram showing the flicker value distribution of FIG. 10 in a three-dimensional manner.
12 is a diagram showing an example of an optical sensor arrangement different from FIG. 5. FIG.
FIG. 13 is a flowchart showing a photosensor arrangement column selection method for selecting any one arrangement row in the five-point photosensor arrangement of FIG.
[Explanation of symbols]
10, 10A Flat display 12, 12A Flicker value measuring unit 14, 14A Flicker balance measuring unit 100, 100A Panel surface 120, 140, 142 Optical sensor 122, 122A Flicker value measuring circuit 144, 144A Flicker balance measuring circuit La, Lb, Lc Luminance signals Fa, Fb, Fc Flicker value Fd Flicker value difference

Claims (10)

A flicker balance adjustment method for adjusting the flicker balance of a flat display,
B) a flicker value measuring step for measuring flicker values at first and second points that are spaced apart from each other on a generally one line passing through a generally central point on the flat display, The flicker value measuring step, wherein the second point is opposite to the center point;
B) a difference obtaining step for obtaining a difference between the flicker value of the first point and the flicker value of the second point;
C) an adjustment step of adjusting the flicker balance based on the difference;
Flicker balance adjustment method with. The method of claim 1, comprising:
The flicker value measuring step includes
A) obtaining a plurality of flicker value pairs of the first point and the second point when the one line is in a plurality of different directions on the flat display;
(B) determining the one line in a direction in which a pair having a maximum difference between the flicker value of the first point and the flicker value of the second point is obtained among the plurality of pairs;
Including,
Flicker balance adjustment method characterized by The method of claim 2, wherein
The direction of the one line includes at least one of two diagonal directions and a horizontal direction of the rectangular flat display;
Flicker balance adjustment method characterized by The method of claim 1, comprising:
The flicker value measuring step includes
B) obtaining a flicker value distribution over the entire flat display;
B) determining the one line in the direction including the maximum and minimum points in the flicker value distribution;
Including,
Flicker balance adjustment method characterized by The method of claim 1, wherein
The adjustment step includes
Adjusting the difference to be less than or equal to a first predetermined threshold;
Including a flicker balance adjustment method. A flicker adjustment method for performing flicker adjustment of a flat display, wherein the flicker balance adjustment method according to any one of claims 1 to 5,
B) measuring a flicker value at the center point on the flat display;
B) adjusting the flat display so that the flicker value at the center point is less than or equal to a second predetermined threshold;
Flicker adjustment method including A flicker balance adjusting device for adjusting the flicker balance of a flat display,
A) Detecting the respective luminances on the first and second points that are spaced apart from each other on a generally one line passing through a generally central point on the flat display to generate first and second luminance signals First and second photosensors, wherein the first point and the second point are on opposite sides of the central point, and the first and second photosensors,
B) A flicker balance measurement circuit that obtains a first flicker value at the first point and a second flicker value at the second point from the first and second luminance signals and obtains a difference between the flicker values. When,
Flicker balancing device provided with a. A flicker adjustment device for adjusting flicker of a flat display, in addition to the flicker balance adjustment device according to claim 7,
A) a third photosensor for detecting a luminance on the central point on the flat display and generating a third luminance signal;
B) a flicker value measurement circuit for obtaining a third flicker value at the center point from the third luminance signal;
Flicker adjustment device including The apparatus of claim 8.
The first, second and third sensors are movably disposed on a linear support member;
Flicker adjustment device characterized by this. The apparatus of claim 9.
The support member is movably disposed on a surface of the flat display;
Flicker adjustment device characterized by this.

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