KR100548229B1 - Projection ?? capable of compensating convergence error, and method of the same - Google Patents

Abstract

Disclosed are a projection TV having a convergence compensation function and a compensation method thereof. A projection TV for compensating convergence distortion between electron beams, comprising: a mode selector for applying a convergence compensation mode selection signal, a light detector provided in the display unit and detecting a luminance change of an electron beam moving on a screen, and convergence distortion is generated; If the storage unit and the mode selection unit in which the reference position at which the maximum luminance is detected is stored among the electron beam luminances detected by the photodetector are selected before and the maximum luminance is not detected from the luminance change with respect to the electron beam output from the photodetector, the predetermined electron beam And a convergence processing unit configured to upwardly adjust the luminance level of the predetermined unit and control the cathode ray tube to emit the predetermined electron beam at the adjusted luminance.

Convergence, compensation, luminance level, current

Description

Projection TV capable of compensating convergence error, and method of the same

1 is a diagram illustrating a predetermined reference pattern for convergence compensation in a general projection TV;

2 is a block diagram schematically showing a projection TV having a convergence compensation function according to a preferred embodiment of the present invention;

3A and 3B are views for explaining a reference position at which the maximum luminance of the G electron beam is detected after the reference pattern is set in the production step of FIG. 2;

4A and 4B are diagrams for explaining a current position at which the maximum luminance of the G electron beam is detected after convergence distortion occurs in a home where FIG. 2 is installed;

5 is a graph for explaining a case where the luminance of the G electron beam is not detected by ambient light, and

FIG. 6 is a flowchart for schematically describing a convergence compensation method of the projection TV illustrated in FIG. 2.

Explanation of symbols on the main parts of the drawings

200: projection TV 205: CRT unit

210: display unit 215a: mode selection unit;

220: light detector 230: ADC

240: convergence processing unit 265: control unit

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection TV having a convergence compensation function and a compensation method thereof, and more particularly, even when ambient light such as sunlight is incident on a screen, the distortion of convergence can be compensated without malfunction. The present invention relates to a projection TV having a convergence compensation function and a compensation method thereof.

Projection TVs each equipped with R, G, and B CRTs (Cathode Ray Tubes) realize color images by scanning electron beams corresponding to R, G, and B colors on a screen.

In the production line of the projection TV, the convergence is adjusted by applying a geomagnetic field so that the cathode rays of the R, G, and B electron beams exactly match the desired positions on the screen, and the pattern in which the convergence is adjusted is called a reference pattern. That is, the reference pattern is a pattern in which each of the R, G, and B electron beams is scanned in a lattice pattern on the screen as shown in FIG. 1, and the R, G, and B electron beams are matched with each other. The luminance of the R, G and B patterns corresponding to the intersections is stored as initial values in the production stage of the projection TV.

However, a certain geomagnetic deviation occurs between the magnitude of the geomagnetic field at the location where the production line is provided and the magnitude of the geomagnetic field applied to the home where the projection TV is installed. As a result, in the projection TV installed in the user's home, convergence distortion occurs in which the cathode rays of the respective R, G, and B electron beams are inconsistent on the screen.

Accordingly, the projection TV compensates for the convergence distortion caused by the geomagnetic field variation by using the luminance of the previously stored reference pattern. That is, the projection TV detects the luminance of the current convergence pattern with respect to the screen on which the convergence distortion occurs, and then calculates a deviation between the luminance of the detected current convergence pattern and the luminance of the pre-stored convergence reference pattern to perform convergence compensation.

However, the conventional projection TV detects the luminance of the current convergence pattern and performs convergence compensation. In this case, a malfunction occurs due to the influence of ambient light such as home lighting and sunlight. That is, if the luminance of the ambient light incident on the screen is higher than the luminance of the current convergence pattern, the luminance of the current convergence pattern is not detected and the convergence compensation mode is terminated.

Accordingly, the image is implemented on the screen without the convergence distortion being compensated for, thereby providing a visually disturbing image. In addition, in the same ambient light condition described above, the same result occurs even if the convergence compensation is retried, so that the viewer may misjudge the failure of the projection TV.

SUMMARY OF THE INVENTION The technical problem to be solved by the present invention is to compensate for convergence distortion caused by a geomagnetic field, whereby distortion of convergence can be compensated without malfunctioning by ambient light such as sunlight incident on a screen. The present invention provides a projection TV having a convergence compensation function and a compensation method thereof.

The projection TV for compensating for the distortion distortion of the plurality of electron beams emitted from the at least one cathode ray tube according to the present invention for solving the above technical problem, the mode selection unit for applying a mode selection signal for the convergence distortion compensation And a light detector configured to detect a change in luminance of each of the electron beams moving on the screen of the display unit in a predetermined order, at a predetermined position of the display unit, and detected by the light detector before the convergence distortion occurs. A storage unit storing a reference position at which the maximum luminance is detected among the luminance of each of the electron beams, and when the luminance of the ambient light input to the display unit is higher than the maximum luminance of the predetermined electron beam, the maximum luminance of the predetermined electron beam is undetected, and the predetermined electron beam Adjust the luminance level of the predetermined unit up to a predetermined unit, and And a control unit for controlling the cathode ray tube to emit a predetermined electron beam, and a control unit for controlling the convergence processing unit to upwardly adjust the brightness level of the predetermined electron beam.

In more detail, the convergence processor detects the maximum brightness among the brightness changes of the predetermined electron beam to determine a current position where the maximum brightness is detected, and outputs an error signal to the controller when the maximum brightness is not detected. And a level adjusting unit for adjusting the luminance level of the predetermined electron beam upward by a predetermined unit under the control of the controller, wherein the cathode ray tube is configured to display the predetermined electron beam having the luminance adjusted upward by the level adjusting unit. To emit.

In addition, the convergence processing unit compares the level of the adjusted brightness with a predetermined threshold luminance level, and sets the adjusted brightness to the cathode ray tube only when the level of the adjusted brightness is equal to or less than the threshold luminance level. It further comprises a level comparison unit to provide.

In addition, when the level of the upwardly adjusted luminance exceeds the threshold luminance level, the controller processes an error message indicating that the convergence compensation has failed to be displayed on the display unit.

In addition, if it is determined that the maximum luminance of the predetermined electron beam is detected from the convergence processor after the mode selection unit is selected, the convergence processing unit may detect the current position and the convergence distortion of each of the plurality of electron beams. Convergence compensation data is calculated based on the deviation between the respective reference positions previously stored before generation, and the deflection is adjusted by the calculated compensation data.

On the other hand, the compensation method of the projection TV to compensate for the convergence distortion between the plurality of electron beams emitted from the at least one cathode ray tube according to the present invention for solving the above technical problem, the mode selection signal for the convergence distortion compensation Outputting, after the mode selection signal is output, detecting a luminance change of a predetermined electron beam among the plurality of electron beams, and detecting the maximum luminance among the detected luminance changes to detect the maximum luminance. Determining a current position; if the luminance of the ambient light is higher than the maximum luminance of the predetermined electron beam, detecting the maximum luminance of the predetermined electron beam; and if the maximum luminance is not detected, outputting an error signal; and outputting the error signal. And adjusting the brightness level of the predetermined electron beam by a predetermined unit, and adjusting the brightness level by the adjusted brightness. And emitting a predetermined electron beam, and compensating for the convergence distortion when the maximum luminance is detected in the determining step.

More specifically, after the upward adjustment step, further comprising the step of comparing the level of the adjusted brightness and the predetermined threshold luminance level, wherein the level of the adjusted brightness is less than the threshold luminance level in the comparison step. Only when the cathode ray tube emits the predetermined electron beam at the adjusted brightness.

The method may further include displaying a guide message indicating that the convergence compensation has failed when the level of the upwardly adjusted luminance exceeds the threshold luminance level.

Preferably, when the current position at which the maximum luminance of the predetermined electron beam is detected is determined, calculating convergence compensation data based on a deviation between the detected current position and a previously stored reference position before the convergence distortion occurs. And compensating for the convergence distortion by adjusting the deflection based on the calculated compensation data, wherein the reference position is detected by detecting the maximum luminance among the luminances of the electron beams detected before the convergence distortion occurs. Location.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

2 is a block diagram schematically illustrating a projection TV having a convergence compensation function according to a preferred embodiment of the present invention.

Referring to FIG. 2, the projection TV 200 includes a CRT unit 205, a display unit 210, a key operation unit 215, a light detector 220, a switching unit 225, and an analog / digital converter. Converter, hereinafter referred to as " ADC " 230, the convergence processor 240, the first storage unit 245, the amplifier 250, the deflection control unit 255, the second storage unit 260 and the control unit 265. It includes. 2 shows only the blocks related to the convergence correction of the projection TV 200, and the illustration of the other blocks is omitted for convenience of description.

The CRT unit 205 converts an image signal into an electron beam and emits it to a fluorescent surface (not shown) to form an image. Three CRTs (not shown) are provided to emit R, G, and B electron beams, respectively. That is, the projection TV 200 to which the present invention is applied is a three-panel projection TV, and three CRTs (not shown) form images independently for R, G, and B colors, respectively.

The display unit 210 displays an image formed by the CRT unit 205.

The key operation unit 215 includes a plurality of operation keys (not shown) for outputting a signal for selecting or setting a function supported by the projection TV 200 to the control unit 265. In the present invention, the key operation unit 215 is provided with a mode selection unit 215a capable of selecting the convergence automatic compensation mode. Convergence auto-compensation is a function of automatically compensating for convergence distortion caused by geomagnetic field deviation while watching an image through the projection TV 200 so that the R, G, and B electron beams match at a predetermined position. Hereinafter, the convergence auto compensation function is called an automatic color matching function.

The photodetector 220 includes first to fourth optical sensors S1, S2, S3, and S4 that detect luminance in a predetermined order for each of the R, G, and B electron beams. As illustrated in FIG. 3, the first to fourth optical sensors S1 to S4 are installed on the top, bottom, left, and right sides of the display unit 210.

First, in the production line of the projection TV 200, the reference pattern is set as shown in Fig. 1, the coordinate value of each intersection is stored in the first storage unit 245, and then the mode selection unit 215a is selected, the display unit A convergence compensation screen as shown in FIG. 3A is displayed at 210. Then, a G electron beam (shown by a thick solid line) is emitted from the CRT unit 205, and the emitted G electron beam flows between predetermined intervals d with respect to the first optical sensor S1. At this time, the first optical sensor S1 detects the luminance of the flowing G electron beam, converts the detected luminance into a current value, and outputs it.

FIG. 3B is a graph showing current values for luminance of the G electron beam detected by the first optical sensor S1 in the production step of FIG. 2.

Referring to FIG. 3B, in a state in which a reference pattern is set by reflecting the magnitude of the geomagnetic field in the production stage, that is, in the state of convergence control, the output current of the first optical sensor S1 that is the luminance detection result of the G electron beam It has the maximum current value A at the x1 position.

When the luminance of the G electron beam is detected by the first optical sensor S1, the second to fourth optical sensors S1 to S4 sequentially detect the luminance of the G electron beam and convert the output into a current value in a similar manner to that described above. do. When the luminance detection for the G electron beam is completed, the luminance of the R and B electron beams is also sequentially detected by the first to fourth light sensors S1 to S4. The reference position at which the maximum current value is detected among the current values for the luminance of the R, G, and B electron beams detected by the first to fourth optical sensors S1 to S4 is stored in the first storage unit 245 to be described later. .

In addition, when the projection TV 200 is installed in a place other than a production line such as a home, and a convergence error occurs, when the mode selection unit 215a is selected, the display unit 210 displays the convergence compensation screen as shown in FIG. 4A. do. Then, the G electron beam is emitted from the CRT unit 205, and the emitted G electron beam flows between the predetermined intervals d as shown in FIG. 4A around the first optical sensor S1. At this time, the start position of the predetermined interval d through which the G electron beam flows is (a + Δx), which is a position distorted by Δx at a distance shown in FIG. 3A. This means that convergence distortion has occurred by Δx.

Therefore, the current value for the luminance of the G electron beam detected by the first optical sensor S1 has a result as shown in FIG. 4B. Referring to FIG. 4B, when the projection TV 200 is placed at a different position from the production line, since the degree of influence of the geomagnetic field is different, the luminance of the G electron beam is deviated by Δx from x1, that is, the maximum current value at the current position. It has B, and at x1 it has a current value C.

The switching unit 225 selectively switches the first to fourth optical sensors S1 to S4 to provide current values for the R, G, and B electron beams to the ADC 230.

The ADC 230 converts current values for each of the R, G, and B electron beams selectively provided from the switching unit 225 into digital data.

The convergence processor 240 includes a determiner 242, a level adjuster 244, a level comparator 246, and a calculator 248. The convergence processing unit 240 is a position where each of the first to fourth optical sensors S1 to S4 outputs a maximum current value based on the data of the ADC 230, that is, each of the first to fourth optical sensors ( S1 to S4 determine the detected position that the luminance of each of the R, G, and B electron beams is the maximum, and compare the position of the determined maximum luminance with the position stored in the first storage unit 245 to obtain data to compensate. Calculate.

In particular, the convergence processor 240 performs convergence compensation by adjusting the luminance level of the electron beam emitted from the CRT unit 105 when the maximum luminance is not detected by ambient light such as sunlight or indoor lighting.

Hereinafter, when convergence distortion occurs in the projection TV 200 installed in the home and enters the automatic color matching mode, a description will be given of detecting and compensating for the luminance of the G electron beam among the R, G, and B electron beams. The description for is similar to that for the G electron beam and thus will be omitted.

In detail, the determination unit 242 determines the maximum current value among the current values for the luminance of the G electron beam converted from the ADC 230 and provides the calculation unit 248 with the position where the maximum current value is detected. However, there is a case where the maximum current value for the G electron beam cannot be detected depending on the position where the projection TV 200 is installed.

For example, when ambient light such as sunlight or fluorescent light is brighter than the brightness of the G electron beam, the first light sensor S1 does not detect the brightness of the G electron beam but detects the brightness of the ambient light. Accordingly, the current value provided to the determination unit 242 has a current value D having almost no change as shown in FIG. 5, and the determination unit 242 detects the detection error signal by not detecting the maximum current value. Will output

In response to the response signal from the controller 265, the level adjuster 244 adjusts the luminance level of the G electron beam upward. In other words, the level adjusting unit 244 adjusts the current value upward by a predetermined unit to upwardly adjust the luminance level of the G electron beam.

The level comparison unit 246 compares the upwardly adjusted current value with a predetermined threshold current value and determines whether to apply the upwardly adjusted current value. In detail, the level comparator 246 provides the up-regulated current value to the amplifier 250 only when the up-regulated current value is less than or equal to a predetermined threshold current value. This is because the maximum luminance may not be detected even if the operation of adjusting upward until the maximum luminance is detected may be inefficient.

The amplifier 250 amplifies the upwardly adjusted current value and provides it to the CRT unit 205.

Accordingly, the CRT unit 205 emits a G electron beam having a luminance corresponding to the upwardly adjusted current value. Then, the compensation screen as shown in FIG. 4A is displayed on the display unit 210, and the light detector 220, the switching unit 225, the ADC 230, and the convergence processor 240 perform the above-described operations. Therefore, detailed descriptions of the light detector, the switching unit 225, the ADC 230, and the convergence processor 240 will be omitted, but only the convergence processor 240 will be briefly described.

That is, the determination unit 242 does not detect the maximum current value when the current value for the G electron beam having the adjusted brightness level output from the ADC 230 is displayed as a result as shown in FIG. Is output to the control unit 265.

In response to the response signal from the controller 265, the level adjuster 244 readjusts the luminance level of the G electron beam again.

The level comparator 246 compares the re-adjusted current value with the preset threshold current value and repeats the above-described operation if the re-adjusted current value is less than the preset threshold current value. On the other hand, it is recognized that the convergence distortion cannot be compensated if the re-adjusted current value exceeds the preset threshold current value. In addition, the display unit 210 displays an error message (not shown) indicating that convergence compensation has failed under the control of the controller 265. At this time, an error message (not shown) displayed on the display unit 210 is processed as an OSD.

On the other hand, if the current value for the brightness of the G electron beam output from the ADC 230 is varied for each position on the x-axis as shown in Figure 4b, the determination unit 242 determines the maximum current value of the current value for the G electron beam to the maximum The current position at which the current value is determined is provided to the calculator 248. The current position at which the maximum current value is detected is the position where the luminance of the G electron beam is detected to be the maximum, and in the case of FIG.

The calculation unit 248 is configured to determine the current position (x1 + Δx1, y1) of the maximum current value B with respect to the luminance of the G electron beam provided from the determination unit 242 and the maximum of the luminance of the G electron beam stored in the first storage unit 245. Comparing the reference position (x1, y1) of the current value A to calculate the data to be compensated. That is, the calculator 248 calculates data for compensating for the convergence distortion biased by Δ × 1 due to the geomagnetic field deviation.

As shown in FIGS. 3A and 3B, the first storage unit 245 stores coordinate values in which the maximum current value of each of the R, G, and B electron beams detected in the production stage is detected. For example, the first storage unit 245 stores a reference position at which the maximum current value determined by the determination unit 242 is detected among the current values for the G electron beams detected in the production stage, which are R and B electron beams. The same applies to. Preferably, the reference position of the maximum current value stored in the production stage is a position of the first to fourth light sensors S1 to S4, that is, (x1, y1), (x2, y2), (x3, y3), has (x4, y4)

The deflection adjustment unit 255 compensates for the influence of the geomagnetic field applied to the CRT unit 205 by using the compensation data output from the calculation unit 248. For example, the deflection adjustment unit 255 adjusts the G scan line deflection degree of the CRT unit 205 under the control of the convergence processing unit 240.

Data output from the deflection adjuster 255 is amplified by the amplifier 250 and provided to the CRT unit 205. Accordingly, the compensation of the convergence distortion by the geomagnetic field is completed, and a display message (not shown) indicating that the convergence compensation has been successfully performed by the control of the controller 265 is displayed on the display unit 210 of the projection TV 200. When the guide message (not shown) is displayed for a predetermined time, the display unit 210 is restored to the screen before entering the automatic color matching mode under the control of the controller 265.

The second storage unit 260 stores a control program for driving the overall operation of the projection TV 200.

The controller 265 controls the overall operation of the projection TV 200 according to various control programs stored in the second storage unit 260 and key operation signals corresponding to the key operation unit 215.

In particular, when the mode selection unit 215a is selected and a switch signal to the automatic color matching mode is received, the control unit 265 enters the automatic color matching mode and controls the convergence processing unit 240 to perform convergence compensation. In addition, the controller 265 adjusts the current value of the G electron beam upward by a predetermined unit when the signal determined to have not detected the maximum luminance of the G electron beam is received from the convergence processor 240. On the other hand, if it is determined that the maximum luminance of the G electron beam is detected, the controller 265 controls the convergence processor 240 to compensate for the convergence distortion.

In addition, the controller 265 controls the display unit 210 to display an error message indicating that convergence compensation has failed when the current of the upstreamed G electron beam exceeds a preset threshold current value.

FIG. 6 is a flowchart for schematically describing a convergence compensation method of the projection TV illustrated in FIG. 2.

2 to 6, first, when the power is supplied to the projection TV 200, the convergence compensation method is automatically performed before outputting the tuned broadcast signal on the CRT 125, or in the present invention. Likewise, when an automatic color matching command is input by the user. In addition, the present invention describes a method for compensating convergence distortion on the assumption that convergence distortion has occurred.

When the automatic color matching command selection signal is output through the mode selection unit 215a, the CRT unit 205 emits the G electron beam (shown in bold solid line) to the display unit 210 under the control of the convergence processing unit 240. (S605). In this case, the G electron beam is displayed on the display unit 210 in the form as shown in FIG. 4A and reciprocates between the predetermined distances d.

The first optical sensor S1 detects the luminance of the G electron beam reciprocating between the predetermined distances d, and converts it into a current (S610).

The current for the converted G electron beam is converted into digital data by the ADC 230, and the determination unit 242 detects the maximum current among the converted currents (S615). The maximum current detected in step S615 means that the maximum luminance is detected.

When the maximum current of the G electron beam is not detected in step S615, the level adjusting unit 244 adjusts the luminance level of the G electron beam upward by a predetermined unit under the control of the control unit 265 (S620). That is, the level adjusting unit 244 adjusts the amount of current supplied to the CRT unit 205 upward by a predetermined unit so that the luminance of the G electron beam is adjusted upward.

When the step S620 is performed, the level comparison unit 246 compares the current of the up-regulated G electron beam with a predetermined threshold current value (S625). If the current increased in step S625 exceeds the threshold current value, the controller 265 controls the display unit 210 to display an error message indicating that convergence compensation has failed (S630).

On the other hand, if the current adjusted in step S625 is less than the threshold current value, the CRT unit 205 is controlled to emit a G electron beam having the adjusted current (S635).

On the other hand, if the maximum current is detected in step S615, the determination unit 242 determines the current position where the maximum current is located (S640). In operation S645, the calculator 248 calculates compensation data based on a deviation between the current position determined in operation S640 and the reference position previously stored in the first storage unit 245.

The deflection control unit 255 adjusts the deflection by using the compensation data calculated in step S645, and the CRT 205 emits an electron beam by the adjusted deflection data (S650). As a result, convergence compensation is performed, and the controller 265 controls the display unit 210 to display a guide message indicating that the convergence compensation is successful (S655).

After the guide message is displayed for a predetermined time, the projector TV 200 returns to the mode before the mode selector 215a is selected.

In the above-described projection TV 200 having a convergence compensation function and a compensation method thereof, in the present invention, when the maximum luminance is not detected, the current amount (ie, the luminance level) of the electron beam emitted from the CRT unit 105 is predetermined. After the unit was adjusted upward, the threshold current value was compared, but this order is not limited to the present description. That is, after comparing the current of the electron beam emitted from the CRT unit 105 and the threshold current value, it is also possible to adjust the amount of current upward by a predetermined unit if the threshold current value is less than.

Although the present invention has been described in detail through the representative embodiments, those skilled in the art to which the present invention pertains can make various modifications without departing from the scope of the present invention with respect to the embodiments described above. Will understand. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the claims below and equivalents thereof.

As described above, according to the projection TV having the convergence compensation function and the compensation method thereof according to the present invention, even when ambient light having a predetermined luminance is incident on the screen when the convergence distortion caused by the geomagnetic field variation is compensated, Convergence compensation can be performed. That is, in order to prevent convergence compensation error caused when the luminance of the incident ambient light is higher than the luminance of the electron beam emitted from the CRT, it is possible to more accurately perform the convergence compensation by automatically adjusting the luminance of the electron beam.

Claims (10)

A projection TV that compensates for convergence distortion between a plurality of electron beams emitted from at least one cathode ray tube, A mode selection unit for applying a mode selection signal for the convergence distortion compensation; A light detecting unit provided at a predetermined position of the display unit and detecting a change in luminance of each of the electron beams moving on the screen of the display unit in a predetermined order; A storage unit for storing a reference position at which the maximum luminance among the luminance of each of the electron beams detected by the photodetector is detected before the convergence distortion occurs; When the luminance of the ambient light input to the display unit is higher than the maximum luminance of the predetermined electron beam, the maximum luminance of the predetermined electron beam is not detected, the luminance level of the predetermined electron beam is adjusted upward by a predetermined unit, and the predetermined electron beam is adjusted by the upwardly adjusted luminance. A convergence processor configured to control the cathode ray tube to emit light; And And a control unit which controls the convergence processing unit to upwardly adjust the luminance level of the predetermined electron beam. The method of claim 1, The convergence processing unit, A determination unit which detects the maximum luminance among the luminance changes of the predetermined electron beam to determine a current position where the maximum luminance is detected, and outputs an error signal to the controller when the maximum luminance is not detected; And And a level adjusting unit configured to adjust the luminance level of the predetermined electron beam upward by a predetermined unit under the control of the controller. And the cathode ray tube emits the predetermined electron beam having the brightness adjusted up by the level adjusting section to the display section. The method of claim 2, The convergence processing unit, A level comparison unit comparing the level of the adjusted brightness with a preset threshold brightness level to provide the adjusted brightness to the cathode ray tube only when the level of the adjusted brightness is equal to or less than the threshold brightness level; And a projection TV having a convergence compensation function. The method of claim 3, wherein And if the level of the adjusted luminance exceeds the threshold luminance level, the controller processes an error message indicating that the convergence compensation has failed to be displayed on the display unit. delete The method of claim 1, After the mode selection unit is selected, if it is determined that the maximum luminance for the predetermined electron beam is detected from the convergence processing unit, the convergence processing unit may generate the current position and the convergence distortion of which the maximum luminance is detected for each of the plurality of electron beams. And calculating convergence compensation data based on the deviation between the previously stored reference positions, and adjusting the deflection according to the calculated compensation data. A compensation method of a projection TV that compensates for convergence distortion between a plurality of electron beams emitted from at least one cathode ray tube, Outputting a mode selection signal for the convergence distortion compensation; Detecting a change in luminance of a predetermined electron beam among the plurality of electron beams after the mode selection signal is output; Determining a current position at which the maximum luminance is detected by detecting the maximum luminance among the detected luminance changes; Detecting the maximum luminance of the predetermined electron beam when the luminance of the input ambient light is higher than the maximum luminance of the predetermined electron beam, and outputting an error signal when the maximum luminance is not detected; Adjusting the luminance level of the predetermined electron beam by a predetermined unit when the error signal is output; And Emitting the predetermined electron beam at the adjusted brightness; The convergence compensation method of the projection TV, characterized in that to compensate for the convergence distortion when the maximum luminance is detected in the determining step. The method of claim 7, wherein After the upward adjustment step, And comparing the level of the adjusted brightness with a predetermined threshold brightness level. And the cathode ray tube emits the predetermined electron beam at the adjusted luminance only when the level of the adjusted luminance is equal to or less than the threshold luminance level in the comparing step. The method of claim 8, And displaying a guide message informing that the convergence compensation has failed, if the level of the adjusted brightness exceeds the threshold luminance level in the comparing step. The method of claim 8, Calculating convergence compensation data based on a deviation between the detected current position and a reference position previously stored before the convergence distortion occurs when the current position at which the maximum luminance of the predetermined electron beam is detected is determined; And Compensating for the convergence distortion by adjusting the deflection based on the calculated compensation data; And the reference position is a position where the maximum luminance among the luminance of each of the electron beams detected before the convergence distortion occurs is detected.

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