JPH0898221A - Characteristic evaluating display pattern for display device and evaluating method using this pattern - Google Patents

Abstract

PURPOSE: To discriminate whether convergence is degraded or not by eliminating influences of picture distortion, etc., which may simultaneously occur. CONSTITUTION: It is discriminated whether the RGB beam which forms a white cross batch pattern element 2 consisting of horizontal lines 2-1 and vertical lines 2-2 on a black background 1 is converged at one point of a fluorescent face or not by pairs of pattern elements 6-1 to 6-4 for focus confirmation, which are arrange symmetrically with respect to the Y axis, to confirm the convergence characteristic. With respect to the focus characteristic, the resolution and the sharpness of the spot shape for light emission of a phosphor are discriminated by elements 6. The spot shape is dependent upon the focus voltage. The background characteristic is evaluated by the change of the black back. Since the picture is reduced in accordance with the rise of the high voltage of the anode and is expanded in accordance with the reduction of this voltage, picture distortion occurs more easily by this influence in a larger picture. However, the center of the picture is not expanded/reduced by the variance. Consequently, changes of convergence, focus, background, etc., are measured and evaluated, and the influence of picture distortion is eliminated from measured results.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cathode ray tube (hereinafter referred to as "C
"RT". The present invention relates to a display pattern for characteristic evaluation suitable for evaluating various characteristics of a display device using (1) and an evaluation method using this display pattern.

[0002]

2. Description of the Related Art In a display device using a CRT, a CR
It is necessary to supply a high voltage (high voltage) (hereinafter referred to as “HV”) to the anode of the CRT in order to make the screen of T emit light. This HV is produced by boosting a pulse voltage (flyback pulse) generated in the blanking period of the horizontal output circuit with a high-voltage generating transformer (flyback transformer; hereinafter referred to as “FBT”) and then rectifying it. The voltage is
For example, it is about 27 [kV].

Further, in the CRT, a voltage relatively lower than the HV (hereinafter referred to as "DV") is also required for the convergence voltage, the focus voltage and the like. For example, the convergence voltage is somewhat lower than HV, and the focus voltage used for the bipotential picture tube is about 7 to 10 [kV].

These DVs are generally supplied by dividing resistors such as IBR (internal dividing resistor for convergence), IFR (internal dividing resistor for focus), focus, and screen voltage pack. Thus, DV is generally the HV generated in the secondary coil of the FBT.
Is less likely to be generated by resistance-dividing, or by further resistance-dividing an intermediate voltage (medium voltage) (hereinafter, referred to as “MV”) obtained by using the intermediate tap of the secondary coil. Absent.

Specifically, the DV is generated as shown in the outline of FIG. 4, for example. Reference numeral 41 in the figure is FBT
The flyback pulse is supplied to the primary coil 42 of this FBT. The voltage generated in the secondary coil 43 is rectified and supplied as the DC HV to the anode electrode 45 of the CRT 44. This HV is a dividing resistor R
The voltage is divided by h1 and Rh2, and the division point voltage DV1 is obtained at the division point 46.

To obtain a lower voltage DV, FB
The voltage MV generated in the intermediate tap 47 of the secondary coil 43 of T41, for example, a voltage of 10 to 13 [kV] is rectified into a DC voltage, which is divided by the dividing resistors Rm1 and Rm2 and divided into division points 48. The point voltage DV2 is obtained.

These division point voltages DV1 and DV2 are H
Regardless of fluctuations in V and MV, the dividing resistors Rh1 and Rh2,
Alternatively, they are supplied at a division ratio defined by Rm1 and Rm2. That is, as shown in FIG. 5, the voltage at the dividing points of the dividing resistors R1 and R2 is as follows.

DV = HV · R2 / (R1 + R2) ... (1)

When the intermediate pressure MV is divided, the equation (1) is used.
HV becomes MV, and DV = MV.R2 / (R1 + R2
). With respect to the following description, the configuration, action, and effect are the same when the HV is resistance-divided and when the MV is resistance-divided. Therefore, the HV will be described below.

However, this DV is not simply determined by the resistance value of the dividing resistor, but the dividing resistor itself R1,
Due to the stray capacitance of R2, it has a constant time constant, and DV cannot transiently follow the fluctuation of HV (or MV) due to the time constant, and has a phase difference of a lead phase or a lag phase. In some cases, the performance of the display device may be significantly deteriorated due to this phase difference. As shown in FIG. 6, when the stray capacitances C1 and C2 are taken into consideration with respect to the dividing resistors R1 and R2, respectively, the transient voltage DV at the dividing point when HV is resistance-divided is as follows.

DV = HV · R2 / (R1 + R2) + HV · [(R1 · C1−R2 · C2) / {(R1 + R2) (C1 + C2)}] ・ ek ... (3) where k = (R1 + R2) .t / {R1.R2. (C
1 + C2)}

HV (or MV) applied to the dividing resistor
Often occurs mainly due to fluctuations in the anode current. When the bright pattern is displayed, the HV voltage value slightly decreases in response to the increase in the anode current, and when the bright pattern is stopped, the anode current decreases. Correspondingly HV
Voltage tends to rise slightly. This phenomenon is often found in consumer television receivers and low-cost computer display devices that do not use a stabilizing circuit in the HV generation circuit.

The transient follow-up of the division point voltage DV with respect to the fluctuation of HV (or MV) is advanced or delayed from HV or MV depending on whether the coefficient of e in the equation (3) is positive or negative.
Here, the sign of the coefficient of e is (R1 * C1−R2 * C2)
Is determined by the value of.

That is, referring to FIG. 7, (1) In the case of R1C1 = R2C2, the division point voltage DV is DV = HVR2 / (R1 + R2)
Therefore, as shown in FIG. 7A, the HV changes in the same phase as the HV changes.

(2) In the case of R1 · C1> R2 · C2 The dividing point voltage DV is DV = HV · R2 / (R1 + R2)
+ A · e−k (however, A> 0), and as shown in FIG. 7B, the HV fluctuations follow the fluctuations in a phase advance.

(3) When R1 · C1 <R2 · C2 The dividing point voltage DV is DV = HV · R2 / (R1 + R2)
It is −A · e−k, and as shown in FIG. 7 (c), the HV fluctuations follow the fluctuations in a slow phase.

When the DV always follows the variation of HV at the same phase and the same variation rate, as in the case of DV corresponding to R1C1 = R2C2, the convergence, focus and background characteristics are apparent. It does not show up as a big change.

However, when the DV transiently follows the lead phase or the lag phase, the convergence, focus and background characteristics deteriorate and appear as follows.

[0019] In the case of the change evaluation item raising and lowering convergence phase advance of the HV / MV over under late phase 〃 under over-focus the fast 〃 over under late phase 〃 under over background the fast 〃 blackout back float late phase 〃 back float black Collapse Note) Convergence over: Focus in front of fluorescent screen, 〃 Under: Focus before, Focus over: Spot with halo, 〃 Under: Spot with flat spread.

Therefore, in manufacturing and inspecting a CRT, it is necessary to accurately measure and evaluate the deterioration of the convergence, focus and background characteristics.

FIG. 8 shows a display pattern for measuring and evaluating the deterioration of the convergence, focus and background characteristics which are caused by the fluctuations of the HV and MV which have been conventionally used.

In the drawings of the display pattern in this specification and the drawings, for convenience of illustration, white and black are reversed from the actual image. That is, the portion shown in black in the drawing is displayed in white in the actual image of the display device, while the portion shown in white (ground color in the drawing) is displayed in black in the actual image. However, unless otherwise specified, the description of the patterns in the specification shows white and white in the actual image.
Based on the black display.

The conventional display pattern shown in FIG. 8 is formed by superposing the following pattern elements. (1) Reference numeral 82 indicates a white line crosshatch pattern element on a black background (black background) 81, and (2) reference numeral 83
Shows white window pattern elements arranged in the center of the screen.

The role of each pattern element is as follows. In the CRT, the white window pattern element 83 is arranged because the anode current increases in order to display a bright pattern. The influence of HV (or MV) fluctuations (generally, these voltage drops) on the convergence and the focus induced by the increase of the anode current is shown by a circle mark in the figure located outside the white window pattern 83. It was measured at different locations. Similarly, the influence on the background was measured by the change of the black background 81.

That is, when the current increases due to the bright white window 83 and the voltage value of HV slightly decreases, the screen tends to widen. Therefore, the influence of the variation of HV (or MV) on the convergence and the focus is superimposed on the crosshatch pattern element 82 and the white window pattern 83
The RGB beams forming the cross-hatch pattern element 82 at the place surrounded by a circle in the drawing with and without the are concentrated at one point of the fluorescent screen and are in a state of just convergence, or in front of the fluorescent screen. It was evaluated whether it was over-convergence that concentrates in or the misconvergence state of under-convergence that concentrates in the future.

[0026]

However, in most cases, the change that occurs in the crosshatch pattern element 82 in the area surrounded by a circle in the figure is the same as the change caused by the deterioration of the convergence or the like of the evaluation target. The change caused by the distortion is also generated. The change caused by this image distortion is
Since it gets larger from the center of the screen toward the periphery,
In the current measurement method that measures the change in the area surrounded by the circle in the figure which is the peripheral part of the screen, the change due to deterioration of convergence etc. and the change due to the distortion of the screen itself occur at the same time, There is a problem that the measurement result may lack accuracy.

As the image distortion, for example, as shown in FIG.
At the portion (upper part of the screen) 94 where the black background (background) 91 becomes a white window 93 (the upper part of the screen), the anode current increases and HV drops at the moment when the window becomes a window, and the screen tends to become large. The line (vertical line) is moving in a direction that bends and spreads (outward of the screen).
Next, from the white window 93 to the black background (background) 91.
At the point (the lower part of the screen) 95, where the black background 91 is reached, the anode current decreases and the HV rises, and the screen tends to become smaller. Therefore, the straight line (vertical line) originally bends. Moving in the direction of contraction (inward on the screen).

Therefore, convergence, focus,
When trying to judge changes in characteristics such as the background at the circles on the screen, changes in the image distortion due to changes in the HV also occur at these circles, so whether the convergence has deteriorated. It was difficult to judge exactly.

It is an object of the present invention to provide an evaluation pattern which can be accurately measured by removing the influence of image distortion and the like which may occur at the same time when the characteristics such as convergence, focus and background are deteriorated.

[0030]

A characteristic evaluation display pattern for evaluating the characteristics of a display device having voltage dependence in a display device using a cathode ray tube according to the present invention specifies a positional relationship between pattern elements. For this reason, assuming an XY coordinate system in which the center of the screen of the display device is the coordinate axis origin, the horizontal axis passing through the origin is the X axis, and the vertical axis passing through the origin is the Y axis, on the black background 1, X Multiple horizontal lines parallel to the axis 2-1
And a cross hatch pattern element 2 of a white line composed of a plurality of vertical lines 2-2 parallel to the Y-axis, and the voltage of the voltages arranged on the left and right of the screen in axial symmetry with respect to the Y-axis. White window pattern elements 3-1 and 3 that induce fluctuations
-2, 3-3, 3-4, and a pair of focus confirmation pattern elements 6-1, 6-2, 6-arranged in the vicinity of the Y axis in axial symmetry with respect to the Y axis
3 and 6-4.

Further, according to the present invention, the characteristic evaluation display pattern for evaluating the characteristic of the display device having the voltage dependence in the display device using the cathode ray tube has, in addition to the above-mentioned configuration, the brightness setting / position located at the origin. It has a white window pattern element 7 for confirmation.

Further, according to the present invention, a method for evaluating the characteristics of a display device having a voltage dependency in a display device using a cathode ray tube is to display the above-mentioned characteristic evaluation display pattern on a screen and perform the characteristic evaluation. White window pattern elements 3-1 and 3-for inducing voltage fluctuations from the display pattern
2, 3-3, 3-4 are removed, and the step of evaluating the amount of change in display device characteristics in the presence or absence of white window pattern elements 3-1, 3-2, 3-3, 3-4.

[0033]

As described above, the characteristic evaluation display pattern according to the present invention has a plurality of horizontal lines 2-1 parallel to the X axis and a plurality of vertical lines 2-2 parallel to the Y axis on the black background 1. And a cross-hatched pattern element 2 of a white line consisting of and a white window pattern element 3 arranged on the left and right in axial symmetry with respect to the Y axis and arranged at the upper and lower parts of the screen to induce fluctuations in voltage.
-1,3-2,3-3,3-4 and a pair of focus confirmation pattern elements 6-1 and 6-arranged in the vicinity of the Y axis in axial symmetry with the Y axis
2, 6-3, 6-4.

Convergence characteristics are evaluated using the characteristic evaluation display pattern, as shown in FIG. 3, with white window pattern elements 33-1 and 33-3 that induce voltage fluctuations.
-2, 33-3, 33-4 almost start point 34, 36, and immediately after the end point 35, 37, and misconvergence at 4 points surrounded by ellipses ◯ arranged on the Y axis in the screen. Measure and evaluate whether or not it has occurred. The focus characteristics are evaluated by the focus confirmation pattern elements 36-1, 36-2, 36-3, 36-4 arranged in the vicinity of the Y-axis in the screen, and the grid shape and spot shape ( Figure 2) is evaluated. The background characteristic is evaluated by determining whether or not the black background or the background floating occurs in the black background 1 arranged in the screen.

Convergence and focus characteristics are evaluated at a portion where the movement of the pattern does not occur without being affected by the image distortion even if the image distortion occurs on the screen, that is, the central portion of the screen (the portion along the Y axis). To be done. Therefore, even if the HV fluctuates and the voltage increases and the screen shrinks, or conversely decreases and the screen expands, the center of the screen in the evaluation of these characteristics is expanded or contracted on or near the Y axis. Hardly affected by.

Therefore, if changes in convergence, focus, background, etc. are measured and evaluated at the center of the screen, the effect of image distortion can be removed from the measurement results.

[0037]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a characteristic evaluation display pattern of a display device using a cathode ray tube according to the present invention will be described below with reference to the drawings. FIG. 1 shows a display pattern for characteristic evaluation of a display device using a cathode ray tube according to this example.

The characteristic evaluation display pattern of FIG. 1 is formed by superposing the following pattern elements. Here, in order to specify the positional relationship of each pattern element, an XY coordinate system in which the center of the screen of the display device is the coordinate axis origin, the horizontal axis passing through the origin is the X axis, and the vertical axis passing through the origin is the Y axis is defined. Suppose. (1) Reference numeral 2 is a white cross hatch consisting of a plurality of horizontal lines 2-1 parallel to the X-axis and a plurality of vertical lines 2-2 parallel to the Y-axis on a black background (black background) 1. The pattern elements (2), reference numerals 3-1, 3-2, 3-3, 3-4 are arranged on the left and right symmetrically with respect to the Y-axis, and are arranged on the upper and lower parts of the screen (or MV). ) Shows the white window pattern element for inducing the fluctuation of (3), and the reference numerals 6-1, 6-2, 6-3,
Reference numeral 6-4 denotes a pair of two focus confirmation pattern elements which are arranged symmetrically with respect to the Y-axis in the vicinity of the Y-axis, and (4)
Reference numeral 7 indicates a white window pattern element for brightness setting / confirmation located at the origin.

The display pattern for characteristic evaluation according to this example is
In particular, it is suitable for targeting convergence, focus, and background as evaluation items. This is because there is an anode voltage dependency that changes according to the change in the anode voltage.

The DV used for these convergence, focus and background is always HV.
If the fluctuations follow (or in the same phase) proportionally (in the same phase) with respect to the fluctuation of (or MV) including the time, it does not appear as a large change in appearance.

However, as described above, due to the stray capacitance component and the like of the dividing resistor, the DV that has been resistance-divided from the HV (or MV) can properly follow the fluctuation of the HV (or MV). In the case of advancing or delaying, the DV is used as a convergence voltage or a focus voltage, so that it appears as a movement of convergence, a change of focus or a background on the image.

Convergence characteristics are ascertained whether or not the three RGB beams forming the white cross hatch pattern element 2 are concentrated at one point on the phosphor screen at four locations surrounded by ellipses ◯ on the screen. To do.

With respect to the focus characteristic, the electron beam hits the phosphor screen to cause the phosphor to emit light, and the spot shape of the dot pattern at that time is evaluated. Therefore, the focus confirmation pattern element 6 is arranged to determine the resolution and sharpness of the spot shape. In particular, the spot shape depends on the focus voltage.

The background characteristics are evaluated by the change in black background.

The basis of the display pattern for characteristic evaluation according to the present example is that even if image distortion occurs on the screen, it is not affected by the image distortion and the pattern does not move, that is, the central portion of the screen (Y-axis). Along the line). When the HV fluctuates and the voltage rises, the screen tends to shrink, and conversely, when the voltage drops, the screen tends to widen. Therefore, the deflection around the screen is large and the wider the screen is, the larger the influence of the HV fluctuation and the image distortion occurs. easy. However, since the center of the screen does not move even if the HV changes, the expansion / contraction of the center of the screen is hardly affected.

Therefore, if changes in convergence, focus, background, etc. are measured and evaluated at the center of the screen, the effect of image distortion can be removed from the measurement results.

The role of the white window pattern element 3 is:
It is as follows. This is because it is necessary to create a bright pattern in which a large amount of anode current flows, and the voltage value of HV (or MV) tends to decrease slightly as the current increases due to the bright white window. Therefore, the white window pattern element 3 is arranged to consciously promote the variation of the HV (or MV). That is, the white window pattern element 3 is the white window pattern element 83 arranged in the center of the screen of the conventional evaluation pattern (FIG. 4).
It plays the same role as (Fig. 8). Although the area is relatively smaller than that of the conventional white window pattern element 83, this white pattern element 3 is sufficient to promote the voltage fluctuation of the HV due to the increase in current.

The role of the focus confirmation pattern element 6 is as follows. The focus confirmation pattern element 6 is arranged in the vicinity of the Y axis in axial symmetry with respect to the Y axis. In this embodiment, due to the symmetric relationship with the Y axis in the vicinity of the Y axis, a total of 4 to 6-1, 6-2, 6-3, almost immediately after the start position and the end position of the white pattern element 3 that promotes high-voltage fluctuations, is obtained. 6-4 are arranged. White pattern elements 3-1, 3-2, 3-3, 3
This is because the focus characteristics when the HV is falling can be confirmed at the start position of -4, and the focus characteristics when the HV is rising at the end position.

FIG. 2 shows the details of an example of each focus confirmation pattern element, and this pattern is the same as that generally used in the past. The focus characteristics are evaluated by evaluating the grid shape and the spot shape of each micro-grating shown in FIG.

The role of the white window pattern element 7 for brightness setting / confirmation is that the brightness setting / confirmation is generally performed in the center of the screen in the CRT. It is arranged.

Each of the white window pattern element 3, the focus confirmation pattern element 6 and the brightness setting / confirmation white window pattern element 7 is exemplified in FIG. 1 as long as it fulfills the above-mentioned respective roles. It is not limited to the shape, position, number, etc. of each pattern element.

FIG. 3 shows the effect of image distortion due to HV (or MV) fluctuations in the characteristic evaluation pattern according to this example. At the point 34 where the white window patterns 3-1 and 3-2 are started, a voltage drop of HV (or MV) is induced, the screen tends to spread, the vertical line moves outward, and the white window patterns 3-1 and 3-2. H at point 35 where 3-2 ends
The screen tends to shrink due to the increase in V (or MV) voltage, and the vertical line moves inward. This situation is the same in the places 38 and 39 affected by the white window patterns 3-3 and 3-4. However, the effect of image distortion decreases as it approaches the central part of the screen, and does not occur in the central part marked with an ellipse.

Points 34 and 3 susceptible to these voltage fluctuations
RBG inside the ellipse ◯ arranged at 5, 36, 37
The change in convergence characteristics is evaluated depending on the concentration state of the beam, and the pair of focus confirmation pattern elements 6-1 and 6 are used.
The change of the focus characteristic is evaluated by the grid shape and the spot shape of -2, 6-3, 6-4, and the change of the background characteristic is evaluated by whether or not the black background 31 is crushed or lifted. The brightness setting / confirmation is performed by the white window pattern element 37.

Next, a method for evaluating the characteristics of a display device using a CRT using this characteristic evaluation display pattern is as follows.
It is as follows. First, when the white window pattern element 3 is arranged, the HV (or MV) tends to fall, and conversely, when the white window pattern element 3 is eliminated, the HV (or MV) tends to rise,
Convergence with / without window pattern element 3
Determine changes in focus and background. For example, when the window pattern element 3 is not arranged, each element 2, 6, 7 and the black background 1 are used as a reference, and when the window pattern element 3 is arranged, changes in each element and black background when the HV rises and falls. To judge.

Although the characteristic evaluation pattern has been mainly described above, the device required for generating this display pattern can be a signal generator which is commonly used for pattern generation of CRTs at present.

According to the characteristic evaluation display pattern thus constructed, the characteristic of the display device is evaluated in the central portion of the screen which is not affected by the image distortion, so that the accurate evaluation can be performed without being affected by the image distortion. Can be done.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0058]

According to the characteristic evaluation display pattern of the present invention, it is possible to accurately measure changes in convergence and focus characteristics due to changes in HV and MV without being affected by image distortion due to changes in HV. There is.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a display pattern for characteristic evaluation of a display device according to the present invention.

FIG. 2 is a diagram showing an example of focus confirmation pattern elements forming the characteristic evaluation display pattern shown in FIG. 1;

FIG. 3 is a diagram for explaining how the characteristic evaluation display pattern changes when a voltage fluctuation occurs in the characteristic evaluation display pattern according to the present invention shown in FIG. 1;

FIG. 4 is a diagram illustrating a manner in which a relatively lower voltage than an anode voltage HV or an intermediate voltage MV of an intermediate tap is created by resistance division in a display device using a CRT.

FIG. 5 is a diagram illustrating a dividing point voltage by a dividing resistor.

FIG. 6 is a diagram for explaining a division point voltage due to resistance division in consideration of the stray capacitance of the division resistor in comparison with FIG.

FIG. 7 is a diagram showing how the division point voltage changes when the anode voltage HV changes.

FIG. 8 is a diagram showing an example of a display pattern for characteristic evaluation of a display device that has been conventionally used.

FIG. 9 is a diagram for explaining how the characteristic evaluation display pattern changes when a voltage variation occurs in the characteristic evaluation display pattern of a display device that has been conventionally used.

[Explanation of symbols]

1,31,81 Black background 2,32,82 White line crosshatch pattern element 3,33,83 White window pattern element 34,38,94 Start position of white window pattern element 35,39,95 White window pattern element End position 6,36 Focus confirmation pattern element 37 White window pattern element for brightness setting / confirmation 41 Flyback transformer (FBT) 44 Anode electrode 45 Cathode ray tube (CRT) 46,48 Dividing point

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[Procedure amendment]

[Submission date] October 31, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0034

[Correction method] Change

[Correction content]

Convergence characteristics are evaluated using the characteristic evaluation display pattern, as shown in FIG. 3, with white window pattern elements 33-1 and 33-3 that induce voltage fluctuations.
Substantially starting point 34,3 8, and almost ends point after 35, 3 9 a A by mistake at four points inside the ellipse .smallcircle disposed on the Y axis in the screen of -2,33-3,33-4 Measure and evaluate whether or not convergence has occurred. The focus characteristics are evaluated by the focus confirmation pattern elements 36-1, 36-2, 36-3, 36-4 arranged in the vicinity of the Y-axis in the screen, and the grid shape and spot shape ( Figure 2) is evaluated. The background characteristic is evaluated by determining whether or not the black background or the background floating occurs in the black background 1 arranged in the screen.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0053

[Correction method] Change

[Correction content]

Points 34 and 3 susceptible to these voltage fluctuations
5,3 8, 3 in the ellipse 〇 disposed 9, RBG
The change in convergence characteristics is evaluated depending on the concentration state of the beam, and the pair of focus confirmation pattern elements 6-1 and 6 are used.
The change of the focus characteristic is evaluated by the grid shape and the spot shape of -2, 6-3, 6-4, and the change of the background characteristic is evaluated by whether or not the black background 31 is crushed or lifted. The brightness setting / confirmation is performed by the white window pattern element 37.

Claims (3)

[Claims] 1. A characteristic evaluation display pattern for evaluating characteristics of a display device having voltage dependence in a display device using a cathode ray tube, wherein the characteristic evaluation display pattern specifies a positional relationship between respective pattern elements. Assuming an XY coordinate system in which the center of the screen of the display device is the origin of the coordinate axes, the horizontal axis passing through the origin is the X axis, and the vertical axis passing through the origin is the Y axis, the X axis is on the black background. A white cross hatch pattern element consisting of a plurality of parallel horizontal lines and a plurality of vertical lines parallel to the Y-axis, and arranged symmetrically with respect to the Y-axis on the left and right, and at the top and bottom of the screen. A display pattern for characteristic evaluation, comprising: a white window pattern element that induces a voltage change; and a focus confirmation pattern element that is arranged axially symmetrically with respect to the Y axis and near the Y axis. 2. The display pattern for characteristic evaluation according to claim 1, further comprising a white window pattern element for brightness setting / confirmation located at the origin. 3. The display pattern for characteristic evaluation according to claim 1 or 2 is displayed on a screen, and a white window pattern element for inducing a voltage variation is removed from the display pattern for characteristic evaluation, A method for evaluating the characteristics of a display device, comprising the step of evaluating the amount of change in the characteristics of the display device depending on the presence or absence of a window pattern element.