Background Statement for SEMI Draft Document 4759A NEW STANDARD: TEST METHOD OF PERCEPTUAL ANGLE FOR OLED DISPLAYS

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1 Background Statement for SEMI Draft Document 4759A NEW STANDARD: TEST METOD OF PERCEPTUAL ANGLE FOR OLED DISPLAYS Note: This background 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. Background Recent years, the image quality of FPD (Flat Panel Display) is getting important. Therefore more evaluation items and methods for display image quality are required. Quantized by physical measurement, some visual qualities of display devices have been offered to customers. iewing angle, color gamut, motion blur and the number of colors are a few examples. From among these qualities, viewing angle has been measured many different ways. owever, methods considering luminance drop, color shift, and contrast ratio drop, respectively, are not obvious in that human perception is not reflected completely. OLED display technology is rapidly developing, and will soon be applied to notebook PCs, monitors, Ts, etc. Therefore a new standard method which can measure perceptual angle of OLEDs is necessary to help form a new OLED display market. This document issued its first ballot on cycle 7, It was, however, failed committee review on February 4 th, Ballot oting 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 ote (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 ote 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 ote 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 make 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 30, 2010) at SEMI Korea office, Seoul. Please note that the voting deadline for document 4759A and other Cycle 2 ballots are due on Wednesday, March 24, Therefore, we kindly request that you submit your votes in a timely manner for this to move on to the next stage of review.

2 SEMI Draft Document 4759A NEW STADARD: TEST METOD OF PERCEPTUAL ANGLE FOR OLED DISPLAYS 1 Purpose 1.1 This standard describes a method for measuring angle dependent quality for OLED (Organic Light Emitting Diode) displays. 2 Scope 2.1 This standard is applicable to the standard quality evaluation of OLED displays. The standard includes the measuring, analyzing, and calculating methods of perceptual angle. NOTICE: This standard does not purport 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 CIE 15.2:2004, Colorimetry, 3 rd Edition CIE 159: 2004, A Colour Appearance Model For Colour Management Systems:CIECAM IEC Standards IEC :2009, ORGANIC LIGT EMITTING DIODE (OLED) DISPLAYS Part 6-1: Measuring methods of optical and electro-optical parameters IEC :2009, ORGANIC LIGT EMITTING DIODE (OLED) DISPLAYS Part 6-2: Measuring methods of visual quality 3.3 ESA version 2.1 June 1, 2001 NOTICE: Unless otherwise indicated, all documents cited shall be the latest published versions. 4 Terminology 4.1 perceptual angle The angle at which the colour volume drops to specific level comparing to that of on-axis. The colour volume could represent colour quality that human perceives 4.2 colour volume The volume of a colour space in the three-dimensional concept of how much space it occupies correlated with a set of colours. 4.3 colour appearance model A colour appearance model provides perceptual attribute correlates by predicting changes of colour appearance of a visual stimulus under various different viewing conditions. 4.4 primary colour A set of colours that can be combined to produce any desired set of intermediate colours, within a limitation called the gamut The primary colours for colour television are red, green, and blue The exact red, green, blue colours used are dependent on the television standard Display devices do not usually use the same primary colours, resulting in minor colour changes from ideal. 5 Standard Measurement Condition 5.1 Temperature, humidity, and pressure Measurements shall be carried out under the standard environmental conditions (e.g., at a temperature of 25 C ± 3 C, a relative humidity of 25% to 85%, and a pressure of 86 kpa to 106 kpa) When different environmental conditions are used, these shall be noted on the report. 5.2 Measurements shall be not carried out under vibration and windy conditions. 1 International Commission On Illusion, 2 International Electrotechnical Commission, Page 1 Doc. 4759A SEMI

3 5.3 Illuminant Conditions Table 1 Illuminant Conditions Dark room condition Ambient condition Indoor Daylight emispherical Direct emispherical Direct 0.01 cd/m2 T viewing condition: 60lx Office: 300 lx T viewing condition: 40lx Office: 200 lx 15000lx 65000lx Detail conditions follow and of IEC When different conditions are used, these shall be noted on the report In order to measure the correct illuminance of the indoor room with the least amount of light reflection from the display, the display shall be moved from the measurement position or be lined with black solid color The room, including walls, floor, and ceiling, shall be covered in gray or black curtains and rugs. 5.4 Equipment Display power source Display driving equipment and display pattern generator Optical performance measurement device The Measurement device should be calibrated before the measurement is performed Two orthogonal axes of rotation that rotates an object to a particular orientation. 6 Standard measuring method 6.1 Optical performance measurement Patterns types of patterns can be used for measurement Luminance level of DUT (Device under test) may depend on the pattern types due to the loading effect of the OLED display It shall be noted on the report which patterns are used for measurements Full Screen Patterns W255 Figure 1 Black and white full screen patterns Page 2 Doc. 4759A SEMI

4 R255 B255 YELLOW (R255) CYAN (B255) MAGENTA (R255B255) % Window Patterns Figure 2 Full Screen Patterns of Colours W255 Figure 3 Black and White 4% Window Patterns R255 YELLOW (R255) CYAN (B255) MAGENTA (R255B255) Figure 4 4% Window Patterns of Colours Page 3 Doc. 4759A SEMI

5 % Window of Gray Background Patterns R255 YELLOW (R255) W255 Figure 5 Black and White 4% Window of Gray Background Patterns CYAN (B255) MAGENTA (R255B255) Figure 6 4% Window of Gray Background Patterns of Colours Measurement Set up Electrical conditions, warm-up time, standard viewing direction, viewing distance, angular field of view, and adequate integration time follow ICDM (ESA 2.0 version chapter 301-2) methods OLED displays shall be set in the standard illumination conditions The illumination conditions should be noted on the report The center points of each measurement pattern shall be measured from 0 to 90 degrees in left, right, up, and down directions using two rotating axes The maximum degree step shall be 10 degrees The measurement range and step shall be noted on the report. /2 /2 Measurement point /2 /2 Measurement point /2 /2 Measurement point Figure 7 Measurement Point in Each Pattern The measurement device measures the tristimulus values at each angle. These 8 tristimulus values can be defined as a tristimulus values set. 6.2 Analysis method for colour volume of display Colour volume in colour space Tristimulus values set at θ shall be transformed to perceptual attribute correlates to form colour volume on colour space. Page 4 Doc. 4759A SEMI

6 Proper values of LA, Yb, and surround condition in specified viewing condition shall be inputted to get perceptual attribute correlates Usually, the values of LA, Yb and surround condition are set as below. LA0.2 (Luminance of measurement white) Yb20 SurroundAverage or Dim or Dark CIELAB Tristimulus values, X, Y, and Z shall be transformed to a*, b*, and L*. Tristimulus set: [X, Y, Z] θ ColorApper ancemodel _ Transformation [a*, b*, L*] θ (1) Given a set of transformation points, the smallest trigonal pyramid is a set of lines connecting 6 peak points to its natural neighbours with black and white point Calculate the colour volume of trigonal pyramid and add up all volume of trigonal pyramids. Figure 8 The Geometry of Trigonal Pyramid of Connecting Points with an Inside Point 1 ( un vn ) wn 6 θ (2) CIELU Tristimulus values, X, Y, and Z shall be transformed to u*, v*, and L*. Tristimulus set: [X, Y, Z] θ ColorApper ancemodel _ Transformation [u*, v*, L*] θ (3) Calculate the colour volume in the same way the volume of CIELAB is calculated CIECAM Tristimulus values, X, Y, and Z shall be transformed to M: Colourfulness, h: hue, and Q: Brightness. Tristimulus set: [X, Y, Z] θ ColorApper ancemodel _ Transformation [M, h, Q] θ (4) Tristimulus values, X, Y, and Z shall be transformed to C: Chroma, h: hue, and Q: Lightness. Tristimulus set: [X, Y, Z] θ ColorApper ancemodel _ Transformation Calculate the colour volume in the same way the volume of CIELAB is calculated. 6.3 Calculation method of perceptual angle Colour volume ratio to on-axis volume [C, h, J] θ (5) Page 5 Doc. 4759A SEMI

7 The colour volume data of each angle shall be represented as the rate value comparing the colour volume of on-axis. θ Δ θ 100 (6) This equation applies for the colour volume of CIELAB, CIELU, and CIECAM perceptual angle calculation Left-right perceptual angle Left-Right Perceptual Angle defines as angle summation of left side and right side. k ) Left k ) Right Perceptual Angle _ (7) Left Right Top-down perceptual angle Top-Down Perceptual Angle defines as angle summation of top side and down side. k ) Top k ) Down Perceptual Angle Top Down + _ (8) Perceptual Angle is the angle at which the colour volume shrinks to specific level k. k could be 25%, 50%, and 75% to that of on-axis. Table 2 Example of perceptual angle at k 25, 50, 75% k Perceptual Angle [ % ] A B NOTICE: SEMI makes no warranties or representations as to the suitability of the standard(s) set forth herein for any particular application. The determination of the suitability of the standard(s) 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, Semiconductor Equipment and Materials International (SEMI) takes no position respecting the validity of any patent rights or copyrights asserted in connection with any item mentioned in this standard. Users of this standard are expressly advised that determination of any such patent rights or copyrights, and the risk of infringement of such rights are entirely their own responsibility. Page 6 Doc. 4759A SEMI