JP2004021057A - Luminance compensation method and system for cathode-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily determine a luminance modulation curve for uniformizing luminance in an overlap area of a screen in a multiple electron gun cathode-ray tube. <P>SOLUTION: Luminance is measured in a plurality of positions of an area including an overlap area OL. An arithmetic part 55 obtains a luminance distribution of the overlap area OL in accordance with a result of luminance measurement with respect to each divided screen and obtains the luminance modulation curve for to be utilized to obtain a signal modulation curve, on the basis of the luminance distribution. At least two measurement positions are set in each divided picture. Measurement positions in each divided screen are so set that one measurement position may include an area in the vicinity of a boundary (in the vicinity of a joint) on the side of this divided screen of the overlap area OL. <P>COPYRIGHT: (C)2004,JPO

Description

【００４８】
ここで、Ｙｍａｘは信号レベルが最大の時の輝度、Ｗはオーバ・ラップ領域ＯＬの幅、ｘはオーバ・ラップ領域ＯＬでの位置（左端、ｘ＝０）を示している。
【００４９】
輝度分布を考慮する場合には、式（１）におけるＹｍａｘは通常、オーバ・ラップ領域ＯＬにおける自画面側の境界付近の領域９１Ｌ（図９（Ａ））の位置（ｘ＝０）での輝度Ｙ（０）ｍａｘが用いられる。すなわち、輝度分布を考慮した左側の分割画面６Ｌについてのオーバ・ラップ領域ＯＬの輝度変調曲線は、以下の式（２）のようになる。右側の分割画面６Ｒについての輝度変調曲線を求める場合にも同様の考え方で、Ｙｍａｘは通常、位置ｘ＝Ｗ（右端）における輝度Ｙ（Ｗ）ｍａｘを用いる。左側の分割画面６Ｌについての輝度変調曲線の一例を、図７において符号６２を付して示す。
【００５０】
【数２】

【００５１】
このように、各分割画面６Ｌ，６Ｒの輝度の測定箇所に、少なくとも、オーバ・ラップ領域ＯＬにおける自画面側の境界付近の領域、すなわち、オーバ・ラップ領域ＯＬとその測定対象となる分割画面側の他の領域との境界部分の領域９１Ｌ，９１Ｒを含めるようにして、輝度変調曲線を求めるようにしたのは、以下の理由による。オーバ・ラップ領域ＯＬの視認性は、オーバ・ラップ領域ＯＬのみでなく、その隣り合う自画面側の輝度・色度によって大きく影響する。このため、オーバ・ラップ領域ＯＬの輝度の適正化を図るに当たっては、オーバ・ラップＯＬ領域における自画面側の境界付近の領域の輝度が重要となってくる。この視認性に影響を及ぼす部分を測定箇所に含め、その測定結果に基づいて輝度変調曲線を求めることで、視認性に最も影響を及ぼす部分の輝度の変調精度を高めることができる。これにより、少ない測定箇所であっても、適正な輝度変調曲線を決定することができる。
【００５２】
次に、信号レベルＳ（ｘ）および輝度Ｙ（ｘ）の関係（図４）と、輝度変調曲線とを比較し、各位置ｘごとに輝度Ｙ（ｘ）を出力する信号レベルＳ（ｘ）を求める。これをオーバ・ラップ領域ＯＬすべてにおいて行い、左側の分割画面６Ｌのオーバ・ラップ領域ＯＬについての信号変調曲線を導出する（ステップＳ１３）。右側の分割画面６Ｒについても、同様の処理を行い、信号変調曲線を求める。
【００５３】
なお、輝度の分布はオーバ・ラップ領域ＯＬの上下（縦）方向にもある。従って、上下方向において複数箇所の輝度の測定を行い、上下方向についての輝度分布を求めて、信号変調曲線を導出するようにしても良い。これにより、横方向のみならず上下方向についても考慮した、より良質な繋ぎ目処理を施すことが可能となる。
【００５４】
以上説明したように、本実施の形態によれば、輝度の測定箇所に、オーバ・ラップ領域ＯＬにおける自画面側の境界付近の領域９１Ｌ，９１Ｒ（図９（Ａ），（Ｂ））を含めるようにしたので、視認性に最も影響を及ぼす部分の輝度の変調精度を高めることができる。これにより、少ない測定箇所で、適正な輝度変調曲線を決定することができ、輝度変調曲線を容易に決定することができる。
【００５５】
また、本実施の形態によれば、実際の陰極線管における輝度の不均一性を考慮した輝度補正システムを用いることで、ばらつきに対する許容性を高めることができる。また、輝度測定を行って輝度変調曲線を求めることで、実際に商品化した場合における陰極線管の輝度の自動調整の基本にすることができる。また、横方向の輝度分布のみならず、上下方向にも応用することで、さらに良好に輝度補正を行うことができる。カラー陰極線管の場合には、各色について、それぞれ輝度変調曲線を求めることで、輝度だけでなく色度も調整することができる。
【００５６】
なお、本発明は、上記実施の形態に限定されず種々の変形実施が可能である。例えば、上記実施の形態では、入力信号と輝度との関係を測定し、入力信号を変調する場合について説明したが、入力信号のかわりに電子銃を駆動する電圧と輝度との関係を測定し、電子銃に印加する電圧を変調することによっても、オーバ・ラップ領域ＯＬにおける輝度の均一化を図ることができる。この場合、輝度変調曲線は、電子銃の駆動電圧を変調するための電圧変調曲線の算出に用いられる。
【００５７】
また例えば、本発明は、３つ以上の電子銃を備え、１つの画面を３つ以上の走査画面を合成して形成するようにしたものにも適用することが可能である。
【００５８】
【発明の効果】
以上説明したように、請求項１ないし４のいずれか１項に記載の陰極線管の輝度補正システムまたは請求項５記載の陰極線管の輝度補正方法によれば、各分割画面の測定箇所に、少なくとも、重複領域とその測定対象となる分割画面側の他の領域との境界部分を含めるようにしたので、視認性に最も影響を及ぼす部分の輝度の変調精度を高めることができる。これにより、少ない測定箇所で、適正な輝度変調曲線を決定することができ、複電子銃陰極線管において、画面の重複領域における輝度を均一化するための輝度変調曲線を容易に決定することができる。
【図面の簡単な説明】
【図１】本発明の一実施の形態に係る輝度補正システムが適用される陰極線管の概略を示す図であり、（Ｂ）は、陰極線管の画面構成を示す正面図、（Ａ）は、（Ｂ）におけるＩＡ−ＩＡ線断面図である。
【図２】図１に示した陰極線管における電子ビームの走査方式および画面構成の例を示す説明図である。
【図３】本発明の一実施の形態に係る陰極線管の輝度補正システムの概略を示すシステム構成図である。
【図４】信号レベルと輝度との関係を示す図である。
【図５】輝度変調曲線を示す図である。
【図６】信号変調曲線を示す図である。
【図７】輝度変調曲線の算出方法についての説明図である。
【図８】輝度変調曲線の合成についての説明図である。
【図９】輝度の測定点の説明図である。
【図１０】変調信号の算出方法を説明するための流れ図である。
【符号の説明】
ＯＬ…重複（オーバ・ラップ）領域、ＯＳ…過走査（オーバ・スキャン）領域、５Ｌ，５Ｒ…電子ビーム、６Ｌ，６Ｒ…分割画面、１０…パネル部、１１Ａ…蛍光面、１１Ｂ…管面、２０…ファンネル部、２１Ｌ，２１Ｒ…偏向ヨーク、２２…内部導電膜、２３…外部導電膜、２７…ビームシールド、３０Ｌ，３０Ｒ…ネック部、３１Ｌ，３１Ｒ…電子銃、５１…駆動部、５２…信号発生部、５３…輝度検出部、５４…制御部、５５…演算部、５６…検出器。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a brightness correction system and method for a cathode ray tube used in a television receiver, various monitor devices, and the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a cathode ray tube (CRT; Cathode Ray Tube) has been widely used in television receivers and various monitor devices. The cathode ray tube has an electron gun, and an electron beam is emitted from the electron gun in response to an input signal. A screen is formed by irradiating the electron beam on a phosphor screen formed on the panel side and scanning the screen.
[0003]
A cathode ray tube generally has a configuration provided with a single electron gun, but in recent years, a configuration provided with a plurality of electron guns has been developed. A method using a plurality of electron guns in a cathode ray tube is called a "double electron gun method" or the like. In a double electron gun type cathode ray tube (double electron gun cathode ray tube), since the screen is composed of a plurality of electron guns, higher brightness (improvement of electron beam current density) is achieved as compared with the case where only one electron gun is used. ), The overall depth can be shortened, and the spot characteristics of the electron beam can be improved.
[0004]
In the double electron gun cathode ray tube, a screen area is divided into a plurality of screen areas, and the divided screen areas (hereinafter, also referred to as “split screens”) are connected to each other to form one screen as a whole. . The electron guns are usually provided in a number corresponding to the number of screen divisions. Each of the divided screens is scanned by an electron beam emitted from a corresponding electron gun.
[0005]
[Problems to be solved by the invention]
As a method of composing a screen in a double electron gun cathode ray tube, there are a method in which adjacent divided screens partially overlap (overlap), and a method in which each divided screen is simply overlapped without overlapping each other. Some parts are connected linearly. In the non-overlapping method, it is necessary to form the screens so that the edges of the screens are not visible at the joints and that there is no space between adjacent screens. Therefore, it is necessary to control the trajectory of the electron beam and to perform precise adjustment.
[0006]
On the other hand, in the overlapping method, since the overlapping area of the screen is overlapped and scanned by a plurality of electron beams, the brightness of that area becomes higher than that of other screen areas as it is. For this reason, it is necessary to control the luminance of the overlap area and perform processing so that the luminance becomes uniform.
[0007]
The technique relating to the luminance control in the overlap region is disclosed in, for example, a paper "Philips Digest p351-354 23.4:" The Camel CRT "" by Philips in 1998. In this paper, a method of cosine-varying the beam current by each electron gun is proposed. In addition, the applicant of the present application has proposed an invention in Japanese Patent Application Laid-Open No. 2001-56658 for preventing a luminance difference and luminance unevenness from occurring in an overlap region. The present invention is a system in which correction data for performing luminance modulation is held in advance, thereby enabling luminance control for all input signals and gradations. However, the means for deriving the correction data for performing the luminance modulation is not described in detail.
[0008]
By the way, in a cathode ray tube, generally, carbon is used for a phosphor screen to improve contrast characteristics. For example, there is one in which carbon is formed in a stripe shape, and a phosphor is formed therebetween. Depending on the ratio of carbon contained in the phosphor screen, the amount of light reaching the outside through the glass from the phosphor screen changes. However, this proportion is not necessarily uniform over the entire surface, and the cathode ray tube is manufactured. Variations also occur due to changes in conditions and the like.
[0009]
In addition, the cathode ray tube has "landing deviation" caused by various factors such as variations in manufacturing and adjustment, in addition to the environment in which it is used. In a color cathode ray tube, for example, it is necessary that the center of an electron beam for emitting green light is applied to a center position of a predetermined green phosphor on a phosphor screen. Landing shift refers to a state in which the center of the electron beam shifts without being applied to the center position of a predetermined phosphor. When the landing deviation becomes large, the light emission luminance is reduced, so that the light emission luminance varies. In a color cathode ray tube, the emission of phosphors of different colors is affected depending on the amount of the landing deviation. For this reason, the landing deviation also affects the chromaticity.
[0010]
Further, the cross-sectional shape of the electron beam emitted from the electron gun differs depending on the position on the screen. This is due to various factors such as a geometric change caused by the distance or angle between the radiating electron gun and the screen position, and a distortion caused by the deflection yoke.
[0011]
In an actual cathode ray tube, a plurality of factors described above are intricately entangled, and the luminance is generally not uniform in an image area but has a distribution. On the other hand, in a double electron gun cathode ray tube having an overlap region, it is indispensable to perform luminance modulation in the overlap region in order to obtain a uniform and high-quality image. When performing this luminance modulation, it is necessary to take into account the characteristics of the luminance distribution on the phosphor screen for each cathode ray tube.
[0012]
The present invention has been made in view of such a problem, and an object of the present invention is to make it possible to easily determine a luminance modulation curve for equalizing luminance in an overlapping region of a screen in a double electron gun cathode ray tube. To provide a cathode ray tube brightness correction system and method.
[0013]
[Means for Solving the Problems]
A brightness correction system and method for a cathode ray tube according to the present invention forms a single screen as a whole by partially overlapping a plurality of divided screens and joining them together, and performs brightness modulation on the overlapping area to perform screen modulation. The present invention is applied to a cathode ray tube adapted to optimize the brightness of the image.
[0014]
A luminance correction system for a cathode ray tube according to the present invention includes a measuring unit that measures the luminance of a plurality of points on a screen at least in an overlapping area for each divided screen, and a measuring unit for measuring the luminance on a screen in the overlapping area based on the measurement result. First calculating means for obtaining a luminance distribution for each divided screen; and, when the divided screens are joined based on the obtained luminance distribution for each divided screen, the luminance is calculated for the overlapping area and the other area. And a second calculating means for obtaining a luminance modulation curve for making the luminance uniform in each divided screen. The measurement location of each split screen includes at least a boundary portion between the overlapping area and another area on the split screen side to be measured.
[0015]
The luminance correction method for a cathode ray tube according to the present invention includes the steps of measuring the luminance of at least a plurality of locations on the screen in the overlapping area for each divided screen, and based on the measurement result, the luminance on the screen in the overlapping area. A step of obtaining a distribution for each divided screen; and, based on the obtained luminance distribution of each divided screen, when the divided screens are joined, the luminance is made uniform in the overlap region and other regions. Obtaining such a luminance modulation curve for each divided screen. The measurement location of each split screen includes at least a boundary portion between the overlapping area and another area on the split screen side to be measured.
[0016]
In the brightness correction system and method for a cathode ray tube according to the present invention, the brightness of at least a plurality of locations on the screen in the overlapping area is measured for each divided screen, and based on the measurement result, the brightness on the screen in the overlapping area is determined. A distribution is determined for each split screen. A luminance modulation curve is obtained for each divided screen based on the obtained luminance distribution for each divided screen.
[0017]
In optimizing the luminance of the overlapping area, the luminance at the boundary of the overlapping area on the own screen side has the greatest influence on visibility. Therefore, by including at least the boundary portion between the overlapping region and the other region on the divided screen side to be measured in the measurement location of each divided screen, the luminance modulation accuracy of the portion that most affects visibility is improved. Can be increased. Thus, an appropriate luminance modulation curve can be determined even in a small number of measurement locations.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0019]
First, the configuration of a cathode ray tube to which the brightness correction system and method according to the present embodiment is applied will be described. As shown in FIGS. 1A and 1B, a cathode ray tube according to the present embodiment includes a panel section 10 having a fluorescent screen 11A formed inside, and a funnel section integrated with the panel section 10. 20. Two neck portions 30L, 30R each containing a built-in electron gun 31L, 31R are formed on the left and right of the rear end portion of the funnel portion 20, respectively. The entire shape portion including the panel portion 10, the funnel portion 20, and the neck portions 30L and 30R is also called an "envelope". The surface of the panel section 10 is an image display surface (tube surface) 11B on which an image is displayed by emission of the fluorescent screen 11A.
[0020]
Inside the cathode ray tube, a color selection mechanism (color selection mechanism) 12 made of a thin metal plate is disposed so as to face the phosphor screen 11A. The outer periphery of the color selection mechanism 12 is supported by a frame 13.
[0021]
The funnel unit 20 is provided with an anode terminal (anode button) (not shown) for supplying an anode voltage HV. Deflection yokes 21L, 21R and convergence yokes 32L, 32R are attached to the outer peripheral portion from the funnel portion 20 to each of the neck portions 30L, 30R. The deflection yokes 21L and 21R deflect the electron beams 5L and 5R emitted from the electron guns 31L and 31R. The convergence yokes 32L, 32R are for performing convergence (concentration) of the electron beams for each color emitted from each of the electron guns 31L, 31R.
[0022]
The inner peripheral surface from the neck parts 30L, 30R to the fluorescent screen 11A of the panel part 10 is covered with a conductive internal conductive film 22. The internal conductive film 22 is electrically connected to the anode terminal and is kept at the anode voltage (high voltage) HV. The outer peripheral surface of the funnel portion 20 is covered with a conductive external conductive film 23.
[0023]
Although not shown, the electron guns 31L and 31R each have a cathode (hot cathode). In the case of a color cathode ray tube, each has three cathodes corresponding to each of R, G, and B colors. The electron beams 5L and 5R emitted from the electron guns 31L and 31R pass through the color selection mechanism 12 and the like and irradiate the phosphor of the corresponding color on the phosphor screen 11A.
[0024]
Here, with reference to FIG. 1B and FIG. 2, a specific example of the screen configuration of the cathode ray tube and the scanning method of the electron beam will be described. In this cathode ray tube, about the left half of the screen is drawn by the electron beam 5L from the electron gun 31L arranged on the left side, and about the right half of the screen is drawn by the electron beam 5R from the electron gun 31R arranged on the right side. Half is drawn. Then, the end portions of the divided screens 6L and 6R formed by the left and right electron beams 5L and 5R are partially overlapped and joined to form a single screen SA as a whole and image display is performed. . The central portion of the screen SA is an area OL where the left and right divided screens 6L and 6R overlap (overlap). The fluorescent screen 11A in the overlap area OL is shared (scanned in common) by the electron beams 5L and 5R.
[0025]
In the present embodiment, the overscanning area refers to an area outside each scanning area of the electron beams 5L and 5R forming an effective screen in each scanning area of the electron beams 5L and 5R. In FIG. 1, the area SW1 is a horizontal effective screen area for the electron beam 5R, and the area SW2 is a horizontal effective screen area for the electron beam 5L.
[0026]
In the scanning method shown in FIGS. 2A and 2B, so-called line scanning (main scanning) is performed in the vertical direction (vertical direction) on the screen, and so-called field (or frame) scanning is performed in the horizontal direction (horizontal direction). It is intended to be performed. In this scanning method, the line scanning is performed in the vertical direction, and is hereinafter referred to as “vertical scanning method”. In the scanning examples shown in FIGS. 2A and 2B, line scanning can be performed from the bottom of the screen to the top (−Y direction).
[0027]
In the scanning method shown in FIG. 2C, line scanning is performed in the horizontal direction, and field (or frame) scanning is performed in the vertical direction, similarly to a general cathode ray tube. In this example, the line scanning and the field scanning by the electron beams 5L and 5R are exactly reversed with respect to the scanning method shown in FIG. 2B.
[0028]
As described above, in this cathode ray tube, since the image of the overlap area OL is created by the electron beams 5L and 5R from the two electron guns 31L and 31R, the brightness becomes higher than other areas as it is. Would. For this reason, it is necessary to modulate the luminance of the overlap region OL so that the luminance of the overlap region OL coincides with that of another region. In general, since the luminance is proportional to the electron beam current, by controlling the electron beam current, it is possible to make the luminance coincide between the overlap region OL and other regions.
[0029]
The brightness correction system according to the present embodiment derives a modulation waveform for matching the brightness (electron beam), and measures the input signal level (or the drive voltage applied to the electron guns 31L and 31R) and the brightness. The modulation waveform is derived from the result so that the luminance of each screen region matches.
[0030]
FIG. 3 shows a system configuration for calculating a signal modulation waveform in consideration of luminance non-uniformity. This system comprises a driving unit 51 for driving a cathode ray tube, a signal generating unit 52 capable of generating an input signal S1 of any gradation (signal level) for the driving unit 51, and a luminance for measuring the luminance of the cathode ray tube. And a detection unit 53.
[0031]
This system also includes a control unit 54 that controls the signal generation unit 52 and the luminance detection unit 53, and a calculation unit 55 that derives a signal modulation curve from the relationship between the input signal level and the luminance. A detector 56 having a light receiving element is connected to the luminance detecting section 53. As will be described later, the detector 56 is arranged corresponding to a predetermined position of the overlap area OL whose luminance is to be detected. The luminance measurement data D1 by the luminance detection unit 53 is output to the control unit 54.
[0032]
A method of optimizing the luminance of the overlap region OL based on the signal modulation curve is specifically described in, for example, Japanese Patent Application Laid-Open No. 2001-56658 by the present applicant, and thus description thereof is omitted here. I do.
[0033]
Note that, in the present embodiment, the luminance detecting section 53 mainly corresponds to a specific example of “measuring means” in the present invention, and the calculating section 55 includes “first calculating means” and “first calculating means” in the present invention. Calculation means ”.
[0034]
Next, the operation of the brightness correction system and the brightness correction method will be described.
[0035]
The controller 54 controls the signal generator 52 to control the level of a signal input to the driver 51. The control unit 54 also controls the luminance detection unit 53 to detect the luminance for the input signal level while synchronizing with the control of the input signal level for the signal generation unit 52.
[0036]
The measurement of the luminance in the overlap area OL is individually performed on each of the divided screens 6L and 6R. That is, the measurement is performed both when the overlap region OL emits light only by the electron beam 5L from the electron gun 31L and when it emits light only by the electron beam 5R from the electron gun 31R. Further, in the color cathode ray tube, the luminance is measured individually for three colors of red, blue and green.
[0037]
For example, in the case of 8-bit signal decomposition (256 gradations), the luminance measurement for the input signal is not necessarily performed for all gradations, and is performed at appropriate steps for simplification of processing. Data may be supplemented by interpolation. The step may be a gradation that is constant in the entire region or a gradation that is changed.
[0038]
Generally, in a cathode ray tube, the relationship between the signal level S (x) and the luminance Y (x) at an arbitrary position x is as shown in FIG. In a cathode ray tube, an electron beam starts to be output from a certain signal level Sk, and the signal level Sk at this time is generally called a cutoff level.
[0039]
The calculation unit 55 determines a signal modulation curve as shown in FIG. 6 based on the measured relationship between the input signal level and the luminance. The waveform of the signal modulation curve to be determined naturally depends on the circuit system that actually operates the cathode ray tube. However, here, as an example, some of the waveforms described in JP-A-2001-56658 are described in advance. A description will be given of a case where the data of the signal modulation curve at the determined gradation is held as a table and the luminance modulation of all gradations is performed to derive the signal modulation waveform at the one gradation.
[0040]
When deriving a signal modulation waveform in the arithmetic unit 55, it is necessary to first determine a luminance modulation curve required for uniform luminance. In general, the luminance is additive. The luminance modulation curve for each of the divided screens 6L and 6R may be any waveform as long as the sum of the luminance of each of the divided screens 6L and 6R is a waveform that achieves the target luminance. Here, as an example, as shown in FIG. 5, a curve based on a cosine function is used as a luminance modulation curve.
[0041]
FIG. 8 shows an example in which the luminance is made constant in the left and right divided screens 6L and 6R using the luminance modulation curve. In FIG. 8, a curve 71L is a luminance modulation curve for the left divided screen 6L, and a curve 71R is a luminance modulation curve for the right divided screen 6R. A straight line 72 indicates a result obtained by adding the luminance modulation curves 71L and 71R. As shown in the figure, by adding the luminance modulation curves 71L and 71R on the left and right divided screens 6L and 6R, the luminance of the overlap area OL and other areas can be made constant.
[0042]
Hereinafter, the process of deriving the signal modulation curve by the arithmetic unit 55 will be described more specifically with reference to the flowchart of FIG. Here, as an example, a case where a signal modulation waveform at the time of the maximum gradation is derived will be considered. When calculating the luminance modulation curve, the luminance is measured at a plurality of locations in the area including the overlap area OL for each of the divided screens 6L and 6R (each of the electron beams 5L and 5R) in order to consider the non-uniformity of the luminance. I do. The arithmetic unit 55 acquires the measurement data D2 related to the luminance and the signal level via the control unit 54 (Step 10).
[0043]
At least two measurement locations are set for each of the divided screens 6L and 6R. One of these is, as shown in FIGS. 9A and 9B, for each of the divided screens 6L and 6R, an area 91L near the boundary on the own screen side in the overlap area OL (near a joint). , 91R. The other portion may be arbitrarily set, but is preferably set, for example, in an area 92 near the center of the overlap area OL.
[0044]
From the result of the luminance measurement, the luminance distribution at each position of the overlap area OL, that is, the relationship between the luminance Y (x) and the position (x) at the measured signal level is obtained for each of the divided screens 6L and 6R. It is determined (step S11). An example of this luminance distribution is shown with reference numeral 61 in FIG. In this example, the luminance distribution is non-uniform, such that the luminous efficiency decreases as approaching the periphery of the divided screen 6L. That is, when driven at the same signal level, the distribution is such that the luminance decreases as going to the peripheral portion.
[0045]
Note that the luminance distribution of all areas cannot be directly obtained by measuring only two points, but in this case, the areas other than the measured points can be estimated and calculated by simple linear interpolation or the like. Conceivable. It is needless to say that it is more accurate to actually measure the luminance plane distribution of the entire overlap region OL using a camera or the like instead of estimating the entire luminance distribution by measuring a plurality of locations. .
[0046]
Next, based on this luminance distribution, a luminance modulation curve used when obtaining a signal modulation curve is obtained (step S12). For example, when a cosine function is used, a luminance modulation curve of the overlap area OL for the left divided screen 6L is basically represented by the following equation (1).
[0047]
(Equation 1)

[0048]
Here, Ymax is the luminance when the signal level is the maximum, W is the width of the overlap area OL, and x is the position (left end, x = 0) in the overlap area OL.
[0049]
When considering the luminance distribution, Ymax in the equation (1) is usually the luminance at the position (x = 0) of the area 91L (FIG. 9A) near the boundary on the self screen side in the overlap area OL. Y (0) max is used. That is, the luminance modulation curve of the overlap area OL for the left divided screen 6L in consideration of the luminance distribution is represented by the following equation (2). In the same way, when calculating the luminance modulation curve for the right divided screen 6R, Ymax normally uses the luminance Y (W) max at the position x = W (right end). An example of the luminance modulation curve for the left divided screen 6L is indicated by reference numeral 62 in FIG.
[0050]
(Equation 2)

[0051]
As described above, at least the area near the boundary of the overlapped area OL on the own screen side, that is, the overlapped area OL and the split screen side to be measured are located at the measurement positions of the luminance of each of the divided screens 6L and 6R. The luminance modulation curve is obtained by including the regions 91L and 91R at the boundary with other regions for the following reason. The visibility of the overlap area OL is greatly affected not only by the overlap area OL but also by the luminance and chromaticity of the adjacent self screen. Therefore, in optimizing the luminance of the overlap area OL, the luminance of the area near the boundary on the own screen side in the overlap OL area becomes important. By including the portion that affects the visibility in the measurement location and calculating the brightness modulation curve based on the measurement result, the modulation accuracy of the brightness of the portion that most affects the visibility can be increased. Thus, an appropriate luminance modulation curve can be determined even in a small number of measurement locations.
[0052]
Next, the relationship between the signal level S (x) and the luminance Y (x) (FIG. 4) is compared with a luminance modulation curve, and the signal level S (x) for outputting the luminance Y (x) for each position x. Ask for. This is performed for all the overlap areas OL, and a signal modulation curve for the overlap area OL of the left divided screen 6L is derived (step S13). The same processing is performed on the right divided screen 6R to obtain a signal modulation curve.
[0053]
Note that the luminance distribution also exists in the vertical direction (vertical direction) of the overlap area OL. Therefore, it is also possible to measure the luminance at a plurality of positions in the vertical direction, obtain the luminance distribution in the vertical direction, and derive the signal modulation curve. As a result, it is possible to perform higher quality joint processing in consideration of not only the horizontal direction but also the vertical direction.
[0054]
As described above, according to the present embodiment, the areas 91L and 91R (FIGS. 9A and 9B) near the boundary on the self-screen side in the overlap area OL are included in the luminance measurement location. With this configuration, it is possible to improve the modulation accuracy of the luminance of the portion that most affects visibility. Thus, an appropriate luminance modulation curve can be determined at a small number of measurement points, and the luminance modulation curve can be easily determined.
[0055]
Further, according to the present embodiment, by using a luminance correction system that takes into account the non-uniformity of luminance in an actual cathode ray tube, tolerance for variations can be increased. Further, by obtaining a luminance modulation curve by performing luminance measurement, the luminance modulation curve can be used as a basis for automatic adjustment of the luminance of a cathode ray tube when the product is actually commercialized. Further, by applying the present invention not only to the luminance distribution in the horizontal direction but also to the vertical direction, the luminance can be corrected more favorably. In the case of a color cathode ray tube, not only luminance but also chromaticity can be adjusted by obtaining a luminance modulation curve for each color.
[0056]
Note that the present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the case where the relationship between the input signal and the luminance is measured and the input signal is modulated has been described, but the relationship between the voltage for driving the electron gun and the luminance instead of the input signal is measured, By modulating the voltage applied to the electron gun, it is possible to make the luminance uniform in the overlap region OL. In this case, the luminance modulation curve is used for calculating a voltage modulation curve for modulating the driving voltage of the electron gun.
[0057]
Further, for example, the present invention can be applied to an apparatus having three or more electron guns and forming one screen by combining three or more scanning screens.
[0058]
【The invention's effect】
As described above, according to the brightness correction system for a cathode ray tube according to any one of claims 1 to 4 or the brightness correction method for a cathode ray tube according to claim 5, at least a measurement location on each divided screen is provided. Since the boundary between the overlapping area and another area on the divided screen side to be measured is included, the luminance modulation accuracy of the part that most affects visibility can be improved. As a result, an appropriate luminance modulation curve can be determined in a small number of measurement points, and a luminance modulation curve for equalizing luminance in an overlapping region of a screen can be easily determined in a double electron gun cathode ray tube. .
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a cathode ray tube to which a luminance correction system according to an embodiment of the present invention is applied, (B) is a front view showing a screen configuration of the cathode ray tube, and (A) is It is the IA-IA sectional view taken on the line (B).
FIG. 2 is an explanatory diagram showing an example of an electron beam scanning method and a screen configuration in the cathode ray tube shown in FIG.
FIG. 3 is a system configuration diagram schematically showing a luminance correction system for a cathode ray tube according to an embodiment of the present invention.
FIG. 4 is a diagram illustrating a relationship between a signal level and luminance.
FIG. 5 is a diagram showing a luminance modulation curve.
FIG. 6 is a diagram showing a signal modulation curve.
FIG. 7 is a diagram illustrating a method of calculating a luminance modulation curve.
FIG. 8 is a diagram illustrating the synthesis of a luminance modulation curve.
FIG. 9 is an explanatory diagram of luminance measurement points.
FIG. 10 is a flowchart for explaining a method of calculating a modulation signal.
[Explanation of symbols]
OL: overlap (overlap) area, OS: overscan (overscan) area, 5L, 5R: electron beam, 6L, 6R: split screen, 10: panel unit, 11A: fluorescent screen, 11B: tube face, Reference Signs List 20: funnel portion, 21L, 21R: deflection yoke, 22: internal conductive film, 23: external conductive film, 27: beam shield, 30L, 30R: neck portion, 31L, 31R: electron gun, 51: drive portion, 52 ... Signal generation unit, 53: luminance detection unit, 54: control unit, 55: calculation unit, 56: detector.

Claims (5)

A plurality of divided screens are partially overlapped and connected to each other to form a single screen as a whole, and the overlap area is subjected to luminance modulation to optimize the screen luminance. An applied brightness correction system,
Measuring means for measuring the luminance of at least a plurality of locations on the screen in the overlapping area for each divided screen,
First calculating means for obtaining a luminance distribution on a screen in the overlapping area for each of the divided screens based on the measurement result;
Based on the obtained luminance distribution for each of the divided screens, when the divided screens are joined, a luminance modulation curve such that luminance is uniformed in the overlapping area and other areas, Second calculation means for each divided screen,
A brightness correction system for a cathode ray tube, wherein at least a measurement portion of each of the divided screens includes a boundary portion between the overlapping region and another region on the divided screen side to be measured. 2. The brightness correction system for a cathode ray tube according to claim 1, wherein the measurement location of each of the divided screens further includes at least a central portion of the overlapping area. Applied to a cathode ray tube that optimizes luminance by modulating the signal level of the video signal,
The brightness correction system according to claim 1, wherein the brightness modulation curve is used for calculating a signal modulation curve for modulating a signal level of the video signal. The invention is applied to a cathode ray tube having a plurality of electron guns for emitting electron beams forming the plurality of divided screens, and modulating a driving voltage of the electron guns to optimize luminance.
The brightness correction system according to claim 1, wherein the brightness modulation curve is used for calculating a voltage modulation curve for modulating a driving voltage of the electron gun. A plurality of divided screens are partially overlapped and connected to each other to form a single screen as a whole, and the overlap area is subjected to luminance modulation to optimize the screen luminance. A brightness correction method to be applied,
Measuring the luminance of at least a plurality of locations on the screen in the overlapping area for each divided screen,
Obtaining a luminance distribution on a screen in the overlapping area for each of the divided screens based on the measurement result;
Based on the obtained luminance distribution for each of the divided screens, when the divided screens are joined, a luminance modulation curve such that luminance is uniformed in the overlapping area and other areas, Determining for each split screen,
A brightness correction method for a cathode ray tube, wherein at least a boundary between the overlapping area and another area on the divided screen side to be measured is included in a measurement location of each of the divided screens.

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