Bacground Statement for SEMI Draft Document 4571B New Standard: Measurements For PDP Tone and Color Reproduction Note: This bacground statement is not part of the balloted item. It is provided solely to assist the recipient in reaching an informed decision based on the rationale of the activity that preceded the creation of this document. Note: Recipients of this document are invited to submit, with their comments, notification of any relevant patented technology or copyrighted items of which they are aware and to provide supporting documentation. In this context, patented technology is defined as technology for which a patent has issued or has been applied for. In the latter case, only publicly available information on the contents of the patent application is to be provided. Bacground Different types of flat panel displays (e.g., LCD, PDP, and OLED) have different features and characteristics depending on their nature. For example, the maximum luminance of PDP varies according to the average picture level (APL) by its limitation of power consumption characteristics. The APL characteristics are not always disadvantages but sometimes advantages from a view point of eye fatigue while watching TV. So, PDP module and PDP TV need a reasonable standard for display characteristics. In order to determine a reasonable standard, we can consider a fixed window measurement, for example 1/16 of the display (1/4 of the display both horizontally and vertically) to test gamma. For most scenes the average brightness does not change suddenly, the variation of APL during watching TV has almost no influence on the picture quality. This document is necessary to set an industry standard on PDP tone and color reproduction (gamma and color gamut accuracy) for estimation of basic picture quality for PDPs. This document was initially issued as ballot 4571 in Cycle 4 of 2008 to the FPD Color Filters and Optical Elements Committee, and subsequently failed technical committee review for being out of the scope of the FPD Color Filters and Optical Elements Committee. 4571A in Cycle 7 of 2008 to the FPD Metrology Committee failed technical committee review for language readability problem again, 4571B with English reviewing is being balloted to the FPD Metrology Committee, whose scope is to explore and develop standards that pertain to common criteria, guidelines, and methods for control and comparison of FPD-related metrology. Ballot Voting Information SEMI Standards Regulations requires a 60% return rate from the total number of registered voting members. There are three valid ways to vote on this letter (yellow) ballot: 1 Accept Vote (Including Accept with Comments) If you are in agreement that this document should be approved, vote accept. If you are in agreement that this document should be approved, but have suggestions for editorial clarification or wish to offer related items for future consideration (new business), please vote accept and include your suggestions at the bottom of the voting sheet. 2 Reject Vote If you are not in agreement that this document should be approved, vote reject. A reject vote must be accompanied by a written explanation of your objections to the document. 3 Abstaining Vote If you are not sufficiently familiar with the topic area or have insufficient interest to provide a technical opinion on this document, vote abstain. If you wish to provide editorial clarification on some point or mae a general observation on this document, you may include a comment with an abstention. The results of this ballot will be discussed at the next Korea FPD-Metrology Committee Meeting (June, 2009). Please note that the voting deadline for document #4571B and other Cycle 2 ballots is Monday, March 23, 2009. Therefore, we indly request that you submit your votes in a timely manner for this to move on to the next stage of review.
SEMI Draft Document 4571B NEW STANDARD: MEASUREMENTS FOR PDP TONE AND COLOR REPRODUCTION 1 Purpose 1.1 This measurement standard describes the measurement methods of principal characteristics on PDP (Plasma Display Panel) or PDP-TV, which may be related to TV standard reproduction characteristics of fidelity to original video. This standard can be used to define methodologies used for measurement of PDP s native features based on APL. 2 Scope 2.1 This standard is applicable to standard display quality evaluations of PDP modules or PDP TVs. The standard includes practical methodologies of tone and color reproduction measurements during still image conditions. It does not address optical performance lie contrast or brightness. 2.2 Tone and color of display device are elementary features of a standard display device. For standardization of PDP, high accuracy and fidelity to these standard features are necessary. 2.3 This standard is only for usual PDP and general purpose for methodology. Hence special languages for special features or phenomena are not included. NOTICE: This standard does not support to address safety issues, if any, associated with its use. It is the responsibility of the users of this standard to establish appropriate safety and health practices and determine the applicability of regulatory or other limitations prior to use. 3 Referenced Standards and Documents 3.1 CIE Standards 1 CIE 1931 Color space CIE 1976 Uniform color space 3.2 Other Documents VESA FPDM (Flat Panel Display Measurements) Version 2.0, June 2002 ICDM (International Committee for Display Metrology) Version 3.0, 2009 (Not yet published.) IEC 61988-2-1 Plasma Display Panels: Measuring Method Optical SMPTE 303M-2002 Color Reference Pattern NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions. 4 Terminology 4.1 The definitions of general terms follow the VESA FPDM and ICDM. 4.2 Optical Terminology 4.2.1 tone the gradation of output brightness by a display input variation. This usually means the gradation of gray, but color tone also includes the gradation of color. 4.2.2 color the perceptual concept from hue and saturation of video signals including chrominance components. Generally the term color might be defined to include blac, white and gray colors that have no chrominance component, but here color is defined as output with some chrominance components. 1 CIE International Commission on Illumination, Kegelgasse 27, A-1030 Vienna, Austria Page 1 Doc. 4571B SEMI
4.3 Measurement Terminology 4.3.1 Average picture level (APL) Usually indicates the post-gamma APL because APL is usually used for panel load processing. The post-gamma APL means the average of the total R, G and B data after gamma de-correction, not input signal values (gamma corrected). The unit of APL is usually %. 4.3.1.1 There are two inds of APL, pre-gamma APL (Type 1 APL) for gamma corrected input signal and postgamma APL (Type 2 APL) for gamma de-corrected panel display signal. 4.3.1.2 The average of input signals is different from APL that it is greater than APL because the input signals are gamma corrected. And the gamma de-corrected value of the input signal average is smaller or equal than APL, where the equal case is only when all input data are equal or 0/100 data. 4.3.2 Correlated color temperature (CCT) a term used to describe the color of a light source whose chromaticity lies close to the Plancian (blac body) locus on a CIE 1960 chromaticity chart. Specially, it is the temperature of a blac body radiator which produces the chromaticity most similar to that of the light source evaluated. It is usually expressed in degree Kelvin. CCT is used to adjust white balance. 4.3.3 Gamma the numerical value of the exponent to which a video component R, G, or B is raised, by a power function of the form (V ) γ, to obtain a linear-light (luminance or tri-stimulus) value. Especially, it is called decoding gamma (γ D ), and its reciprocal is called encoding gamma (γ E ). Usually, γ D = 2.2. 4.3.4 Primary Color one of a set of colors that can be combined to produce any desired set of intermediate colors, within a limitation called the gamut. The primary colors for color television are red, green, and blue. The exact red, green, blue colors used are dependent on the television standard. Display devices do not usually use the same primary colors, resulting in minor color changes form ideal. 4.3.5 White Balance adjustment or accuracy of color coordinates at a white input level, usually equal to or greater than 70% APL of full screen. 4.3.6 Gray Balance adjustment or accuracy of color coordinates at all input ranges, usually from 5 to 100 inputs. It can be explained by all range white balance meaning.. 4.3.7 Luminance Uniformity In VESA FPDM, it can be calculated by Minimum luminance divided by Maximum luminance among the defined screen positions and presented by %. For the measurement positions of a screen, refer to VESA FPDM. 5 Tone Measurement 5.1 For tone measurement, all picture quality enhancement functions must be bypassed to preserve the native picture qualities (luminance curve, APL, etc.). Each test pattern in this standard may occupy some percentage of area at over-scan screen mode, but it is not concerned whether it is at just-scan or over-scan mode, but to match the results in PDP module and TV set, the just-scan mode is recommended. The illumination is the condition of a dar room under 1 lux. 5.2 Constant APL Gamma 5.2.1 Gray-bar Window Gamma 5.2.1.1 Since PDP luminance for inputs varies by APL, the gamma can be measured at 10% 90% APL separately with 11 steps gray-bar pattern varying each input data step by 10%. 5.2.1.2 When it is measured on a screen, the bacground level is changed in order according to the APL while maintain gray-bar pattern at the screen center. Page 2 Doc. 4571B SEMI
Outer data Y Inner data array X 0 X 10 (for varying APL) < example of area ratio > Each bar of gray pattern: 0.97 % The whole gray-bar pattern: 10.7%(=0.97x11) Bacground : 89.3% Gray-bar Bacground + = 100% Figure 1 General Pattern of Gray-bar Window Gamma 5.2.1.3 The APL of the pattern in Figure 1 can be calculated by gamma de-correction in 8 bit. In case of conventional 2.2 gamma (shortly 2.2 gamma), APL(%) = 10.7 (0.364) 2.2 + 89.3 (Y/255) 2.2 (1) Here, 36.4% means the APL of 11 step gray-bar data. Outer bacground data Y can be gotten as following equation. Y = 255 (( APL 10.7 (0.364) 2.2 )/89.3 ) 1/2.2 (2) 5.2.1.4 For ITU-R BT. 709 (shortly BT. 709) gamma, the APL and Y value can also be calculated by a similar method. But it is substitute by 2.2 gamma equation because APL is just approximate test case. 5.2.1.5 Figure 2 shows an example of a gamma measurement graph in 9 inds of APL. Luminance (cd/m2) 200 180 160 140 120 100 80 60 40 20 10 APL 20 APL 30 APL 40 APL 50 APL 60 APL 70 APL 80 APL 90 APL Gamma 0 0 10 20 30 40 50 Pattern 60 70 80 90 100 Figure 2 A Sample Result of Gamma Measurement by APLs Page 3 Doc. 4571B SEMI
5.2.2 Single Window Gamma 5.2.2.1 Single window gamma measures white luminance according to APL change of Plasma module in a fixed window. In order to fix the APL, luminance of outer area would be changed down from high to low while a center box is measured from 0 to 100 which means 0 to 255 gray levels. 5.2.2.2 The size of the box is 1/5 horizontal and vertical pixel numbers of source video, using approximately 4% of the total screen area in a display. 1/5H 4% screen area 1/5V Outer data Y (eeping for an APL) Inner data X (Measured) Figure 3 General Pattern of Single Window Gamma 5.2.2.3 The APL of the pattern in Figure 3 can be calculated by gamma de-correction in 8 bit. In case of conventional 2.2 gamma, APL(%) = 4 (X/255) 2.2 + 96 (Y/255) 2.2 (3) Outer bacground data Y can be obtained using the following equation. 5.2.3 RGB Gamma Y = 255 (( APL 4 (X/255 ) 2.2 )/96) 1/2.2 (4) 5.2.3.1 The luminance gamma measurements that are introduced above can be also used for RGB gamma measurement. The explanation is abbreviated because it is a similar method except for APL calculation. The inner window s APL with one color among R, G or B would be one third of Gray pattern. 5.3 Constant-luminance APL Gamma 5.3.1 Generally the APL luminance curve may be approximately characterized by an exponential curve as shown in the following equation and figure. 2 L cd m = b a APL + max [ / ] (5) 1/ Max. Lumi. 1% 4% 100% APL(%) Figure 4 General Luminance Curve of PDP Page 4 Doc. 4571B SEMI
5.3.1.1 Sometimes this approximation may be not suitable at low APL because of the PDP s optical performance limitation lie the lac of the sustain pulse timing. Sometimes, as suggested by the dotted line in the figure, a flat region can be included at low APL for maintaining constant luminance. 5.3.1.2 When a PDP has the APL range with constant luminance up to over 4% APL, it can be measured without varying bacground level to maintain an APL. 5.3.1.3 This measurement is made on the center screen while a box of varying gray level is displayed. The box of a center is fixed up with a box of 0 to 100. 5.3.1.4 The size of the box is 1/5 1/2 horizontal and vertical screen size of the display, using 4% 25% of the total screen area. 5.3.1.5 The larger window means that the display has a constant luminance curve from 0 to the higher APL as large as the window size. 5.3.2 Luminance Gamma 5.3.2.1 Luminance gamma measures the gray scale change in 21 gray patterns on 4% 25% box which changes from white to blac with linear same steps. A level of outer area is fixed up at 0 and its APL is not constant. Usually this measurement is meaning at flat luminance range lie the dotted line of above figure. 5.3.2.2 All gray patterns are presented sequentially from 0 to 100 in steps of 5% 10%. 1/5H 1/2H 1/5V 1/2V 0 1/5H 1/2H 4~25% window 0~100 1/5V 1/2V Figure 5 Window Pattern of Gamma Measurement Luminance Comparison vs. Gray Scale Luminance (cd/m 2 ) 120.00 100.00 80.00 60.00 40.00 20.00 0.00 0 20 40 60 80 100 Figure 6 A sample Result of Gamma Measurement 5.3.3 RGB Gamma 5.3.3.1 RGB gamma measures the luminance scale of the primary colors (R,G,B) using 11 21 color levels at 10% 5% step. As the luminance gamma, 4% 25% area window changes from blac to highest level of the colors, and calculate a gamma value for each color. Page 5 Doc. 4571B SEMI
5.4 Gamma Value Calculation 0 0 4~25% window Red 4~25% Window Green 4~25% window Blue 0 Figure 7 Window Pattern of RGB Gamma Measurement 5.4.1.1 The following table is the data of standard gamma for about 5% step inputs. 5.4.1.2 In ITU-R BT.709, under 8.1% of input data is not used because it is linear slope region. So, gamma calculation for ITU-R BT.709 is done so that the luminance of 8.1% input can be treated as an offset. Table 1 Gamma=2.2 Luminance and Gamma Plot Input Values, I Display Luminance % Full Scale 8 bit Input (0 255 #1, I ) ITU-R BT. 709 % Full Scale (Conventional) 2.2 Gamma % Full Scale 0 0 0.000 0.000 5 13 (no use) 1.133 0.143 10 26 2.292 0.658 15 38 3.659 1.518 20 51 5.543 2.899 25 64 7.864 4.778 30 77 10.639 7.176 35 90 13.881 10.115 40 102 17.298 13.321 45 115 21.473 17.344 50 127 25.770 21.576 55 140 30.917 26.736 60 153 36.584 32.504 65 165 42.283 38.377 Page 6 Doc. 4571B SEMI
% Full Scale Input Values, I 8 bit Input (0 255 #1, I ) ITU-R BT. 709 % Full Scale Display Luminance (Conventional) 2.2 Gamma % Full Scale 70 178 48.973 45.346 75 191 56.208 52.952 80 204 63.994 61.207 85 217 72.339 70.117 90 229 80.544 78.931 95 242 89.983 89.126 100 255 100.000 100.000 #1 Different values when 16 235 range. 5.4.1.3 To calculate the gamma, generally the log 10 vs. log 10 plot from the measured luminance data and the % full scale (x-axis) is constructed. The Y-axis is log 10 (L-L 0 ) where L 0 is the luminance at start point of the exponential gamma curve as 0 in 2.2 gamma and the X-axis is just log 10 of the % full scale applied signal. For example, the logarithmic plot for a gamma curve of Figure 6 is shown in Figure 8. 5.4.1.4 In this figure, 16 slopes of the lines between 0 (or 8.1 for BT.709) and 10 95 are calculated, then the average of the slopes becomes the display gamma. GAMMA Plot 2.50 Log (Net Luminance) 2.00 1.50 1.00 0.50 0.00 1.25 1.45 1.65 1.85 Figure 8 Gamma 2.2 Luminance and Gamma Plot 5.4.1.5 In case of the Constant luminance APL gamma, the gamma is calculated with normalized value by the maximum luminance of the gamma curve. n 1 log Lnorm, γ D = (6) log I n = 1 norm, n : 9 18 (10% 5% input step) from 10 to 95 for 2.2 gamma or ITU-R BT.709 gamma. L norm, : Normalized value of the luminance measured at each level, (L measured L 0 ) / (L max L o ) for 2.2 gamma (L measured L 8.1% ) / (L max L 8.1% ) for BT.709 gamma I norm, : Normalized value of input digital value at each level over 8.1% (21 of 255) I / 255 for 2.2 gamma Page 7 Doc. 4571B SEMI
(I 21) / 234 for BT.709 5.4.1.6 Actually, ITU-R BT. 709 gamma equation has offset 0.099 and scaling factor 1.099, but these are negated by over 8.1% input condition and normalization effect respectively. 5.4.1.7 In case of the Constant APL gamma, the gamma is averaged with normalized graph by max luminance of each gamma curves of 10% 90% APL. m : generally 9 from 10%, 20%,., 90% APL 5.5 Gamma Accuracy γ D γ, + γ +... + γ D 1 D, 2 D, m = (7) m 5.5.1 Although the gamma is calculated near to 2.2, we still don t now the deviation of the gamma values at each level. So, a method to estimate the accuracy of gamma is necessary. Gamma accuracy (%) for Y gamma and RGB gamma is defined as follows. 5.5.2 For the conventional 2.2 gamma and ITU-R BT. 709 gamma, γ S γ S γ D γ accu. = 100 (8) γ S Where: γ S = 2.2 for conventional 2.2 gamma, γ S = 1/0.45 for BT. 709 gamma 6 Color Measurement 6.1 Primary and Secondary Color 6.1.1 This method measures the luminance and chromaticity coordinates of primary Red, Green, Blue of 100 at the center of the full screen or in a window box measuring 4% 25% of the full screen. Additionally, it may be useful to measure the secondary colors (Cyan, Magenta and Yellow) by the same method. 100 Red 100 Green 100 Blue Figure 9 Full Screen Pattern for Primary Color Measurement Page 8 Doc. 4571B SEMI
6.2 Color Gamut 6.2.1 This measures the CIE chromaticity coordinates (x, y) of R, G, B primaries, and computes in CIE 1976 (u' v' ) color area that a display represents. 6.2.2 To do this, firstly, we can display a full screen (or partial screen box, depending on technology) of all the primary and secondary colors (Red, Green, Blue, Cyan, Magenta, and Yellow) and measure the luminance and x, y chromaticity coordinates at the center of the screen. The standard coordinates of these colors are generally available from ITU-R BT.709. Table 2 ITU-R BT. 709 Color Standard Color ITU-R BT. 709 Standard Color Coordinates x Red 0.640 0.330 Green 0.300 0.600 Blue 0.150 0.060 Cyan 0.225 0.329 Magenta 0.321 0.154 Yellow 0.419 0.505 y 6.2.3 To give the CIE 1976 (u', v') coordinates for each for the measured (x, y) values, transform each of the (x, y) pairs using the following equations: u' = 4x/(3 + 12y 2x) (8) v' = 9y/(3 + 12y 2x) (9) Green: BT. 709 gamut Red: Measured gamut Figure 10 General Pattern of Gamut Measurement 6.3 Color Gamut Accuracy 6.3.1 The measured color data are compared to the ITU-R BT. 709 values in order to chec for deviation of Δu v. The color data for R, G, B need to be in compliance with the specification which is ITU-R BT. 709 Standard Color. C, M, Y are for additional references. Page 9 Doc. 4571B SEMI
6.3.2 Using R, G, B primary coordinates on display, the deviation from standard color coordinates lie ITU-R BT.709 can be calculated, and is represented by the Primary Color Accuracy (%). Raccu. = 100 mδu' v' R Gaccu. = 100 mδu' v' G (10) Baccu. = 100 mδu' v' B Raccu. + Gaccu. + Baccu. Pr imary Color Accuracy(%) = 3 where mδ u v : mili-δ u v Δ u v R, Δ u v G, Δ u v B,: 2-dimensional Euclidean distance between the standard primary color coordinate and R, G and B measured data of display. ( u' u' ) 2 + ( v' v' ) 2 Δ u' v' = (11) R R D 6.3.3 For example, red color accuracy 95% means mδ u v R = 5, that is, Δ u v R = 0.005. This is implicitly based on the assumption that Δ u v = 0.1 between two colors means two completely different colors with 0% accuracy. As well as color accuracy for a target color, generally Δ u v can be used to estimate the color similarity between two colors. 6.3.4 Color gamut area is used to evaluate the color range of the display. Generally, it can be calculated with u v coordinate system or xy if necessary. Color gamut related ratio can be defined as follows. R D Display gamut area Color Reproduction Ratio (%) = 100 Standard gamut area (12) Overlap area Standard Reproduction Ratio (%) = 100 Standard gamut area Standard Reproducti on ratio Standard Fidelity (%) = 100 Color Reproducti on ratio (13) (14) 7 White Balance Measurement Overlap area = 100 (15) Display gamut area 7.1 The CCT and Δ uv of PDP vary according to APL and input level as in the following figures. So, the White Balance of PDP needs to be measured for all APL and all input levels. Further, it can be considered as Gray Balance concept rather than White Balance. Page 10 Doc. 4571B SEMI
C C T Δuv 11000 10000 9000 8000 7000 6000 0.02 0.016 0.012 0.008 0.004-0.004-0.008-0.012-0.016-0.02 0 1224 0 3 6 4 86 0 7 2 849 6 108 120 CCT 132144 1 5 61 6 8 180192 204216 228240 252 Input Δuv 0 14 28 42 56 70 84 98 112 126 140 154 168 182 196 210 224 238 252 Input T_4% T_10% T_20% T_30% T_40% T_50% T_60% T_70% T_80% T_90% T_96% duv_4% duv_10% duv_20% duv_30% duv_40% duv_50% duv_60% duv_70% duv_80% duv_90% duv_96% Figure 11 Example of CCT and Δuv according to APL and Input Level (Bare PDP Module) 7.1.1 Δ uv means the perpendicular deviation from Plancian (blac body) locus with plus or minus sign based on a CIE 1960 uv chromaticity space, It is different from Euclidean distance Δ u v for color difference at CIE 1976 u v space. 7.1.2 From the front example, the curves have some fluctuation because they are from bare PDP module before adjusting on TV board. CCT goes up and Δ uv goes down while the level varies high in a APL. But, CCT goes down and Δ uv goes up while the APL varies high in a level. As a result in this module, we can see that at 100% APL and 100 (red circled points), the CCT and Δ uv has approximately middle value of all CCT and Δ uv variation range. So it can be just representatively called the white CCT and white Δ uv of the device. 7.2 Constant APL White Balance Accuracy 7.2.1 White balance is important to display exact colors through all levels because it is the origin of primary colors. So it is effective to describe as concept of accuracy for the standard white points as following table. In the table, B93 means 9300K white point in bloc body locus. Table 3 Standards of White Points White CIE 1976 CIE 1931 Coor- CCT Δ uv dinate u v x y D65 0.1978 0.4683 0.3127 0.3290 6504 0.003 D93 0.1884 0.4463 0.283 0.297 9300 0.003 9300K (B93) 0.1917 0.4435 0.285 0.293 9300 0 Page 11 Doc. 4571B SEMI
7.2.2 For measuring the white balance accuracy, all level input at all APLs are needed, so the Constant APL gamma pattern is used lie Figure 1 or 3. 7.2.3 Besides D65, white accuracy is calculated at any white points according to CCT with following equation. Where: m : 9 (10, 20,.., 90% APL) n : 10 (10, 20,.., 100 ) W accu. m n 1 = 100 mδu' v' j, (16) mn j = 1 = 1 7.3 Constant-luminance APL White Balance Figure 12 Example of CCT According to APL and Input Level (PDP-TV) 7.3.1 For the white balance evaluation of an APL range, Δ u v of chromaticity space and Δ E * based on relatively perceivable lightness viewpoint are measured. Δ u v is convenient for managing the maximum deviation of white point. Δ E * implies the relative luminance deviation added to Δ u v. 7.3.2 These are executed lie the pattern for the Constant-luminance APL gamma which is made on a center screen box with 4% 25% of total screen area while a box of varying gray level is displayed. The input of a center box is varied from 10 to 100. WB _ Where: u, v : the window coordinate from 10 to 100 ( u' u' ) 2 + ( v' v' ) 2 Δ u' v' = (17) W W Δ E * from the VESA FPDM is, Where: * * 2 * 2 * 2 Δ E = ( ΔL ) + ( Δu ) + ( Δv ) (18) Δ L * = L * 1 L * 2, Δ u * = u * 1 u * 2, Δ v * = v * 1 v * 2, u * * ' = 13L ( u W u ' D ) and v * * ' = 13L ( v W v ' D ) 7.3.3 Because we want to now only the white balance deviation not luminance difference, when we assume the maximum luminance up to 4% 25% APL is approximately same (The gamma is constant up to 4% 25% APL), Page 12 Doc. 4571B SEMI
Δ L * = 0. And, we can choose the 100 white of the window as a relative base coordinate, u * 2 = 13L (u W - u W )=0, similarly v * 2 = 0. Then, at the input n of the window, Where: ΔE * WB _ L * = ( u = 13L Y = 116( Y * ref * ) ) 1 3 2 ( u + ( v * ) 2 ' ' 2 W- u ) + ' 16 for Y Y ( v ref ' W -v ' ) 2 0.008856 Here, Y ref can be obtained at 100 of the window and Y means the window luminance from 10 to 100. 7.3.4 The following figure is an example of variable-apl white balance from 10 to 100 by 5% steps (de=δ E * ). 7.3.5 The CCT of the right axis is just for reference to compare with D65 because Δ u v include CCT and Δ uv information together. 7.4 Full-screen CCT and Δ uv 7.4.1 Generally, full-screen CCT and Δ uv have representative values of above all gray points CCT and Δ uv including all APLs and input levels. (19) 10 100% APL Full-screen data Y (for varying APL) Figure 13 Pattern for The Full-screen CCT and Δ uv In above Figure, APL(%) = 100 (Y/255) 2.2 (20) Y = 255 (APL/100 ) 1/2.2 (21) 10 1 CCT = (22) APL CCT j 10 j= 1 Where: j : index for 10, 20,.., 100% APL 10 1 Δuv = Δ (23) APL uv j 10 j = 1 8 Color Reference Pattern 8.1 Geometry and APL of Reference Pattern Page 13 Doc. 4571B SEMI
8.1.1 The next figure is for color reference pattern from SMPTE standard. It is presented that the vertical size is 100%, so the horizontal size is 160% in 16:9 pattern which is symmetrical in up-down and left-right. 27.5% (5% for 4:3) 1 2 3 4. 3% 3% 18% 18% 9.5% Figure 14 Color Reference Pattern Geometry (SMPTE 303M-2002) 8.1.2 The color area of the pattern is 0.7776/1.78 = 43.7%, so the blac bacground is 56.3% without over-scan. 8.1.3 The next table is about the color coordinates and 8bit RGB (0 255) value before gamma correction. 8.1.4 From the color average the APL of the pattern is as following. 24 84.28 + 66.13 + 57.61 APL 16 :9 _ = 43.7 = 11.9% (24) ref 3 255 For 4:3 pattern, it is same as 16:9 color pattern except side blac panel that is 5% instead of 27.5%. The color area is 0.7776/1.33 = 58.5% without over-scan. 8.2 Data of Reference Pattern 84.28 + 66.13 + 57.61 APL 4 :3_ = 58.5 = 15.9% (25) ref 3 255 8.2.1 For getting input data and target color coordinates of the reference pattern, we should now the tri-stimulate value to RGB conversion matrix for the white color temperature. The following table is XYZ RGB Matrix for D65 & 9300K blac body white coordinates based on ITU-R BT.709. About D65, it is referred to SMPTE 303M-2002. Table 4 XYZ RGB Matrices D65 9300K X Y Z X Y Z R 3.24097 1.53738 0.49861 3.6133 1.7140 0.5559 G -0.96924 1.87597 0.04156-0.9760 1.8891 0.0418 B 0.05563-0.20398 1.05697 0.0405-0.1486 0.7701 8.2.2 Following tables are about color coordinates and RGB video data before gamma correction for D65 and 9300K respectively. Page 14 Doc. 4571B SEMI
Table 5 Color Reference Pattern based on D65 and ITU-R BT. 709 primaries Color no.() u v R G B 1 0.2512 0.4999 45 20 13 2 0.2347 0.4930 143 79 57 3 0.1752 0.4213 29 51 86 4 0.1797 0.5195 24 38 13 5 0.1959 0.4160 60 58 113 6 0.1552 0.4770 34 132 103 7 0.2952 0.5342 179 51 6 8 0.1780 0.3510 17 27 96 9 0.3179 0.4832 142 23 31 10 0.2306 0.3897 27 11 37 11 0.1840 0.5445 89 128 12 12 0.2571 0.5404 202 93 7 13 0.1753 0.2920 7 12 79 14 0.1462 0.5349 15 78 15 15 0.3787 0.4993 114 7 11 16 0.2289 0.5481 217 148 3 17 0.2875 0.4237 129 23 76 18 0.1343 0.4148 0 63 98 19 0.1985 0.4720 229 227 215 20 0.1982 0.4699 151 150 147 21 0.1978 0.4695 91 91 89 22 0.1977 0.4691 49 49 49 23 0.1976 0.4691 21 21 21 24 0.1995 0.4679 8 7 8 Ave. 0.2165 0.4666 84.28 66.13 57.61 Table 6 Color Reference Pattern based on 9300K and ITU-R BT. 709 primaries Color no.() u v R G B 1 0.2405 0.4822 45 20 13 2 0.2241 0.4753 142 80 57 3 0.1731 0.3896 29 50 85 4 0.1738 0.5063 23 38 13 5 0.1903 0.3837 60 57 112 6 0.1520 0.4561 28 134 100 Page 15 Doc. 4571B SEMI
7 0.2863 0.5281 183 51 8 8 0.1773 0.3161 18 26 94 9 0.3027 0.4629 144 23 32 10 0.2217 0.3492 28 10 38 11 0.1770 0.5388 86 131 14 12 0.2487 0.5350 205 94 10 13 0.1767 0.2604 8 11 76 14 0.1423 0.5253 12 80 16 15 0.3620 0.4855 114 8 11 16 0.2200 0.5450 217 151 7 17 0.2709 0.3891 131 22 77 18 0.1353 0.3885 0 65 94 19 0.1914 0.4454 225 227 221 20 0.1918 0.4441 149 149 148 21 0.1916 0.4437 91 91 91 22 0.1916 0.4436 52 52 52 23 0.1907 0.4423 23 24 24 24 0.1903 0.4393 8 9 9 Ave. 0.2093 0.4448 84.23 66.71 58.35 8.2.3 The next tables are about the gamma corrected video input value for 8bit R, G and B (0 255). 8.2.4 From this table, the pre-gamma APL is 21.6% for 2.2 gamma and 19.6% for BT. 709 gamma. Mathematically, the average of exponential γ D of positive values is greater than or equal to the exponential γ D of average of the values when γ D > 1. In common video APL with general data distribution, it is roughly 2 times. APL n pre γ APLpost 1 D γ D ( ) = ( pixel / 255) (25) 100 100 n = 1 where APL pre : pre-gamma APL (%) APL post : post-gamma APL (%) the equal : in the case of single data or 0/100 all around full screen n : number of pixel in the screen pixel : 8 bit pixel value γ E = ( original / 255) ) 255 Table 7 Color Reference Pattern Input for D65 and ITU-R BT. 709 Primaries Col. 2.2 Gamma corrected ITU-R BT.709 Gamma corrected no. () R G B R G B 1 116 80 66 103 64 48 2 196 149 129 191 140 117 3 95 122 155 80 110 146 4 87 107 65 72 94 47 Page 16 Doc. 4571B SEMI
5 132 130 176 121 118 169 6 102 189 169 88 183 161 7 217 122 46 214 110 26 8 76 92 164 59 77 155 9 196 86 98 190 70 83 10 93 62 107 78 44 93 11 158 186 64 149 180 46 12 229 161 49 227 153 29 13 49 64 150 30 46 140 14 71 149 71 54 139 54 15 177 51 60 170 31 42 16 237 199 32 236 194 12 17 187 85 147 181 69 137 18 0 136 165 0 125 157 19 243 242 236 242 241 234 20 201 200 198 196 196 193 21 159 159 158 151 151 149 22 121 121 120 108 109 108 23 83 83 82 67 67 66 24 52 51 51 33 32 32 Ave. 136.49 126.10 114.93 126.54 114.20 101.98 Table 8 Color Reference Pattern Input for 9300K and ITU-R BT. 709 Primaries Col. 2.2 Gamma corrected ITU-R BT.709 Gamma corrected no. () R G B R G B 1 116 80 67 104 64 49 2 195 151 129 190 141 117 3 95 122 155 80 109 145 4 86 108 66 70 94 48 5 132 129 175 121 117 168 6 94 190 167 79 185 159 7 219 123 53 216 111 34 8 77 90 162 60 74 153 9 197 86 99 191 70 84 10 94 59 108 79 41 94 11 156 188 69 147 182 51 12 231 162 58 229 153 40 13 52 61 147 33 42 137 14 65 150 73 47 141 56 15 177 52 62 169 33 44 Page 17 Doc. 4571B SEMI
16 237 201 48 235 196 29 17 188 83 148 182 67 138 18 0 137 162 0 126 153 19 241 242 239 240 241 238 20 200 200 199 195 195 194 21 160 160 160 151 151 151 22 123 124 123 111 112 111 23 86 87 87 70 71 71 24 54 55 56 35 36 37 Ave. 136.37 126.57 117.06 126.41 114.71 104.28 Bacground for Maintaining APL Same size to the color square and changing color lie Figure 15 Test Pattern for Bright Mono-Image Retention 8.2.5 For measuring convenience, as long as the screen maintains approximately same APL of the color reference pattern, it can be done using above figure. 8.2.6 For the color reference pattern, the color pattern accuracy can be calculated as following. C = 100 mδu' ' (26) Accu v c 24 1 CRF = (27) Accu C Accu _ 24 = 1 9 Image Retention and Sticing 9.1 Image Retention and Image Sticing from PDP s nature influence clarity of the picture as well as uniformity of the screen. 9.2 Image Retention Image Retention by long time still images causes distinct uniformity changes at the spots for a while. There may be two inds of measurements of recovery performance of image retention and image retention level based on non-uniformity. 9.2.1 Bright Image Retention Recovery 9.2.2 At first, full screen white signal is inputted to the PDP for over 10 minutes as (a) of the following figure. And the test pattern lie (b) is inputted for 60 minutes. 9.2.3 After that, the full screen white signal is inputted again. Page 18 Doc. 4571B SEMI
9.2.4 For estimation of image retention that is also called residual image or latent image, it can be measured the time that all of the relatively negative-retained images shown in (c) of the figure disappear visually. Or if the Luminance uniformity of the normal state without any residual image is ignorable, it can be measured the time that the Luminance Uniformity between normal area and the imaged retained area becomes over 90% by the unit of minute. (a) (b) (c) Figure 16 Test Pattern for Bright Mono-Image Retention 9.2.5 In this case, we call the time White Washing Time and we call the retained image Mono-image Retention or Negative-image Retention. 9.2.6 If we input the full screen blac signal after the test pattern, there is also retained image, but generally we don t measure the disappearing time of the positive retained image. About measurement for this, we treat at the next phrase. 9.2.7 In other case for a color image, the process of Color Image Retention is same as the case of Mono-Image Retention except the test pattern of the following figure. Figure 17 Test Pattern for Bright Color Image Retention 9.2.8 The measuring White Washing Time of Color Image Retention is same as the case of Mono-Image. 9.2.9 White Washing might not be the best method to erase the retained image, so the other washing patterns are available lie scroll bar pattern for the evaluation of image retention recovery level. 9.2.10 Dar Image Retention Estimation 9.2.10.1 Dar image Retention is estimated by the blac level difference instead of the disappearance time of retention image. 9.2.10.2 Firstly, full screen white signal is inputted to the PDP for over 10 minutes as Bright Image Retention. 9.2.10.3 And input full screen blac signal and measure the blac luminance of center and boundary area as the following figure (b). Page 19 Doc. 4571B SEMI
9.2.10.4 After that, input the 4% window signal of the pattern used for single window gamma measurement for 5 minutes as the following figure (c). 9.2.10.5 Finally, input the full screen blac signal again for 30 minutes as figure (d). (a) (c) P a (b) P ai (d) Figure 18 Test Pattern for Dar Image Retention 9.2.10.6 After 30 minutes of the figure (d), we can measure the blac luminance and calculate the image retention level as following. P d P di Dar Image Retention Ratio (%) P = P ai di P a 100 P d (28) This ratio is possible from 0 to over 100%, but the less is the better. 9.3 Image Sticing 9.3.1 Image sticing is permanent retained image disable to recover that is also called Burn-In. 9.3.2 For this, we can estimate the minimum inputted time or period of the Bright Mono-Image Retention signal that mae the visually retained image that is disable to recover permanently by any method. NOTICE: SEMI maes no warranties or representations as to the suitability of the standards set forth herein for any particular application. The determination of the suitability of the standard is solely the responsibility of the user. Users are cautioned to refer to manufacturer's instructions, product labels, product data sheets, and other relevant literature, respecting any materials or equipment mentioned herein. These standards are subject to change without notice. By publication of this standard, SEMI taes no position respecting the validity of any patent rights or copyrights asserted in connection with any items mentioned in this standard. Users of this standard are expressly advised that determination of any such patent rights or copyrights, and the ris of infringement of such rights are entirely their own responsibility. Page 20 Doc. 4571B SEMI