radiation testing of oled microdisplays technology for an

Ref. LS_HMD_RTR Date 14 August 2006 Issue A

Radiation Testing of OLED microdisplays technology for an Astronaut DVDT

Study of Auxiliary Direct Visualization of Information Tools for Space Application of 57

© LusoSpace, Ltd. The copyright of this document is property of LusoSpace, Ltd. This document and its content cannot be reproduced or revealed in any form without the consent of LusoSpace.

Study of Auxiliary Direct Visualization of Information Tools for Space Application

(DVDT)

Radiation Testing of OLED microdisplays technology for an

Astronaut DVDT

Reference: LS_HMD_RTR

Test Report: 001

Issue: A

Date: 14 August 2006




© LusoSpace, Ltd. The copyright of this document is property of LusoSpace, Ltd. This document and its content cannot be reproduced or

Contribution Log Prepared by Organization Signature Date Issue Paulo Gordo LusoSpace 04 August 2006 A Pedro Teodoro LusoSpace 11 August 2006 A Checked by Organization Signature Date Issue Paulo Gordo LusoSpace 04 August 2006 A Ivo Vieira LusoSpace 11 August 2006 A Approved by Organization Signature Date Issue Ivo Vieira LusoSpace 14 August 2006 A Document History Log Issue Date Description of changes A 14 August 2006 First Issue

revealed in any form without the consent of LusoSpace.





Table of Contents 1. REFERENCE DOCUMENTS........................................................................................... 4 2. ACRONYMS AND ABBREVIATIONS............................................................................. 4 3. SCOPE ............................................................................................................................ 5 4. TEST OBJECTS.............................................................................................................. 5

4.1 eMagin SVGA+ OLED ..................................................................................................5 4.2 OSRAM Pictiva OLED..................................................................................................7

5. TEST EQUIPMENT.......................................................................................................... 9 5.1 Electrical characterization ............................................................................................9

5.1.1 eMagin SVGA+ OLED........................................................................................9 5.1.1.1 PCB Measure Board ...................................................................................9

5.1.2 OSRAM Pictiva OLED ......................................................................................11 5.1.2.1 PCB Measure Board .................................................................................11

5.2 Optical characterization ..............................................................................................12 5.2.1 eMagin SVGA+ OLED......................................................................................12

5.2.1.1 Overall light emission analysis .................................................................14 5.2.1.2 Functional defect analysis.........................................................................15

5.2.2 OSRAM Pictiva OLED ......................................................................................17 5.2.2.1 Overall light emission analysis .................................................................17 5.2.2.2 Functional defect analysis.........................................................................18

5.2.3 Image Processing Software ................................................................................18 5.3 Radiation boards ..........................................................................................................23

6. COBALT-60 IRRADIATION........................................................................................... 29 7. RESULTS OF THE EMAGIN OLED TESTING.............................................................. 31

7.1 Luminous intensity analysis results ............................................................................31 7.1.1 Overall light emission analysis...........................................................................31 7.1.2 Pixel-level luminous intensity statistics .............................................................34

7.2 Functional defects analysis results..............................................................................37 7.3 Electrical analysis results.............................................................................................38

8. RESULTS OF THE PICTIVA OLED TESTING.............................................................. 42 8.1 Luminous intensity analysis results ............................................................................42

8.1.1 Overall light emission analysis...........................................................................42 8.1.2 Pixel-level luminous intensity statistics .............................................................43

8.2 Functional defects analysis results..............................................................................45 8.3 Electrical analysis results.............................................................................................46

9. CONCLUSIONS............................................................................................................. 47 10. ANNEX I - TECHNICAL SPECIFICATIONS OF TEST OBJECTS................................ 48

10.1 eMagin SVGA+ OLED ................................................................................................48 10.2 OSRAM Pictiva OLED................................................................................................52






1. Reference Documents [AD1] - Christopher S. Allen, Rebeka Burnett, John Charles, Frank Cucinotta, Richard Fullerton, Jerry

R. Goodman, Anthony D. Griffith, Sr., Joseph J. Kosmo, Michele Perchonok, Jan Railsback, Sudhakar Rajulu, Don Stilwell, Gretchen Thomas, and Terry Tri “Guidelines and Capabilities for Designing Human Missions” reference - NASA/TM–2003–210785; NASA/Johnson Space Center

[AD2] - ESA-ESCC Basic Specification No. 22900 "Total dose steady-state radiation test method" [AD3] - Lusospace report "Consolidated list of requirements for DVDT for Space Applications" WP210

output. From the LusoSpace/ESA project - Direct Visualization Display Tool (DVDT). [AD4] - Gary B. Levy, Patrick Farrell, David Wheeler, "An 852 600 Pixel OLED-on-Silicon Color

Microdisplay Using CMOS Subthreshold-Voltage-Scaling Current Drivers" IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 37, NO. 12, DECEMBER 2002

[AD5] - "Radiation Design Handbook" ESA PSS-01-609

2. Acronyms and Abbreviations CCD - Charge Coupled Device CMOS - Complementary Metal-Oxide-Semiconductor COF - Chip-On-Flex DC - Direct Current DVDT - Direct Visualization Display Tools EVA - Extra-Vehicular Activity FPDM - Flat-Panel Display Measurement HMD - Head Mounted Display HUD - Head-Up Display I2C - Inter-Integrated Circuit LCD - Liquid-Crystal Display NTSC - National Television System(s) Committee OLED - Organic LED PC - Personal Computer PCB - Printed-Circuit Board PLL - Phase-Locked Loop RGB - Red, Green and Blue VESA - Video Electronics Standards Association VSIS - Very Small Information Systems SVGA - Super Video Graphics Array ZIF - Zero insertion force






3. Scope The work described in this report is concerned with the radiation testing of two OLED display devices. The two OLEDs devices were exposed to Gamma radiation. This study is the final deliverable for CCN No: 1 of the “Fast Track: Study of Auxiliary Direct Visualization of Information Tools for Space Application (DVDT)” project (C18652). The main contract involves the study and design of a Direct Visualization of Information Tools (DVDT) for astronaut use. The OLED devices are a critical component of the DVDT. The DVDT is a device to be used on EVA missions or other astronaut missions (like mars exploration). Therefore, total dose levels used to expose the device to Cobalt-60 irradiation, were planned considering the radiation levels that the astronaut will be exposed during space missions [AD3]. In Section 4 the main characteristics of the two test objects, OSRAM Pictiva and eMagin SVGA+ OLEDs displays, are presented. In section 5 the test equipment (characterization hardware/software) test procedure and the radiation boards, are presented. In Section 6, the Co60 irradiation conditions are reported. In ANNEX I, the complete specifications of the test objects are presented.

4. Test objects The two test objects were:

Microdisplay Technology Origin OSRAM Pictiva 128x64 (Passive Matrix OLED) Germany eMagin SVGA+ OLED (Active Matrix OLED) U.S.A.

The objects tested are composed by OLED material, CMOS technology and electronic discrete components. The two objects to be tested do not have manufacturer irradiation test specifications.

4.1 eMagin SVGA+ OLED The eMagin microdisplay that was evaluated is the SVGA+ Color, manufacturer reference EMA -100080. The eMagin SVGA+ Color is an active matrix OLED-on-silicon microdisplay; it has a resolution of 852 x 3 x 600 pixels. The microdisplay design permits users to run either standard SVGA 800 x 600 or 852 x 480 pixels. The integrated circuit accepts DC-coupled R, G, B inputs with separate external vertical and horizontal synchronization inputs, in accordance with the VESA VSIS standard. Selection between the video modes is done through a register set accessible via the on-chip serial interface protocol (I2C). The serial interface also provides user adjustments such as contrast, brightness, PLL parameters, and display orientation. The power-up default video mode is 852x600 pixels at 60Hz, so to provide a VGA (800x600) image to the microdisplay it is necessary to change microdisplay video mode using an I2C command. SVGA+ Series OLEDs also have an internal NTSC monochrome video decoder for low power night vision systems.





© LusoSpace, Ltd. The copyright of this

In the photography bellow, the eMagin OLED CMOS circuit (where the RGB video signal processing is performed) and several discrete components are pinpointed. Discrete components

S

Discrete co

Figure 1- Pictures of the eM

The microdisplay’s main char

Table 1

revealed in any form without the conse

CMO

document is property of LusoSpace, Ltd. This document and its content cannot be reproduced or

mponents

(a) (b)

agin OLED microdisplay. (a) Top of the OLED. (b) Back of the OLED.

acteristics are listed in the following table.

- General characteristics of eMagin SVGA+ OLED microdisplay.

nt of LusoSpace.





More detailed technical characteristics and specifications are presented in ANNEX I. The OLEDs references and allocations during the Cobalt-60 tests were as follows:

OLED reference

OLED state during the radiation test

Date of irradiation

CBMJR Biased1 09-May-2006 CBML6 Biased 09-May-2006 CBMKX Biased 09-May-2006 CBMK8 Biased 09-May-2006 CBMLA Biased 09-May-2006 CBMJW Unbiased 10-May-2006 CBMKS Unbiased 10-May-2006 CBML4 Unbiased 10-May-2006 CBMKP Unbiased 10-May-2006 CBMJX Unbiased 10-May-2006

Table 2 - eMagin allocation table.

The CBMKA OLED was put apart and used as reference

4.2 OSRAM Pictiva OLED The Pictiva OLED is a passive matrix polymer OLED display module, which is shown in Figure 2. The Pictiva OLED has 126 x 64 pixels resolution, a gray scale of 4 bit and is controlled by parallel protocol.

Figure 2 – Pictiva OLED microdisplay mounted on the developer kit.

The general specifications of the Pictiva OLED are presented in Table 3.

1 During the radiation test the Biased's eMagin OLEDs were turned on. Also a white image was loaded on the OLED.






Table 3 - Technical specifications of the “OSRAM Pictiva” OLED display.

More detailed technical characteristics and specifications are presented in ANNEX I. The OLEDs references and allocations during the Cobalt-60 tests were as follows:

OLED LusoSpace reference

OLED state during the radiation test

Date of irradiation

A02 Unbiased 09-May-2006 A03 Unbiased 09-May-2006 A04 Unbiased 09-May-2006 A05 Unbiased 09-May-2006 A06 Unbiased 09-May-2006 A07 Biased2 10-May-2006 A08 Biased 10-May-2006 A09 Biased 10-May-2006 A010 Biased 10-May-2006 A011 Biased 10-May-2006

Table 4 - Pictiva allocation table.

The A01 OLED was put apart and used as reference

2 During the radiation test the Biased's Pictiva OLEDs were turned on. All pixels of the OLEDs were turned on.






5. Test equipment In this section the test setup (OLED test setup) used to characterise the eMagin and Pictiva microdisplays is described. Also the test radiation boards and the test procedures are described. The main objective of this test setup is to record all the relevant information of the OLEDs during the radiation campaign. The OLEDs were characterized optically and electrically:

Optically o Overall light emission analysis - Display level inspection: light uniformity; relative

energy emission; chromatic relative energy emission. o Functional defect analysis - pixel level inspection: pixel defects; cluster defects

Electrically o The power supply currents were probed, during the radiation test.

5.1 Electrical characterization

5.1.1 eMagin SVGA+ OLED The eMagin microdisplay has the following power interface signals:

Logic/Analog Supply 3.3V DC @ 50mA maximum Van 4.0V DC @ 50mA maximum Vcommon -3.0V DC @ 50mA maximum

Table 5 - eMagin SVGA+ OLED power interface signals. Three reference voltage levels are used in the pixel driver circuit: Vblack, Vbh and Vbl. The Vbl voltage is the reference level used during the programming phase of the pixel driver operation. Vbh is the reference level used during the light emission phase of the pixel driver operation which lasts most of the video frame. Vbh operates typically at 200mV above Vbl. Varying Vbh causes the current through the OLED to change and thus the luminance to change. These levels can be generated internally or provided externally. For application that require a luminance level adjustment over a large range, or for applications that use more than one display and need their luminance levels closely matched, the use of external references for Vbl and Vbh is recommended. Considering the reasons just explained external references for the Vblack, Vbh and Vbl voltages were used. To apply this voltages a laboratory power supply (with the values present in Table 6), was used.

Vblack 3.6V DC Vbh 2.2V DC Vbl 2.0V DC

Table 6 - eMagin SVGA+ OLED pixel driver signals.

5.1.1.1 PCB Measure Board

To study the eMagin OLED behaviour with radiation exposure the current of the signals present in Table 5 and Table 6 were measured, between radiation steps.






rTo accomplish this, a PCB named “eMagin_MeasureBoard” was developed (Figure 3). This board allows the measurement of the currents during the Optical Characterization Procedu e.

Figure 3 – Photo of the eMagin_MeasureBoard PCB. The block diagram of the Electrical Characterization Procedure is shown in Figure 4.

Figure 4 – eMagin OLED electrical characterization block diagram. The electrical signals measured during the radiation test are presented in the table bellow.

Parameters to be measured

Min Typical Max

IDD N/A 42 mA 100 mA Icommon N/A 17 mA 100 mA Ian N/A 15 mA 100 mA Ibl N/A 0.18 mA 50 mA Ibh N/A 0.17 mA 50 mA

Table 7 - Electrical parameters measured between the radiation steps.






The following laboratory equipment was used: - 1 power supply capable to supply 2.0V, 2.2V and 3.6V signals simultaneously - 5 amp-meters

5.1.2 OSRAM Pictiva OLED This OLED has the following power interface signals:

Logic Supply 2.4-3.5V DC OLED Supply 12.0-13.0V DC

Table 8 - Pictiva OLED power interface signals.

The currents that address these voltages were probed between the radiation steps. These power interface signals were supplied by the Pictiva Evaluation Kit.

5.1.2.1 PCB Measure Board

To study the Pictiva OLED behaviour with radiation exposure the current of the signals present in Table 8 were measured, between radiation steps. To accomplish this, a PCB named “Pictiva_MeasureBoard”, was developed (Figure 5). This board allows the measurement of the currents during the Optical Characterization Procedu e. r

Figure 5 – Photo of the Pictiva_MeasureBoard PCB. The block diagram of the Electrical Characterization Procedure is shown in Figure 6.






Figure 6 - Pictiva OLED electrical characterization block diagram. The measured currents typical and maximum values are presented in the following table.

Parameters to be measured

Min Typical Max

IDD N/A N/A 1.3 mA ICC N/A 22 mA 48 mA

Figure 7 - currents measured between the radiation steps.

To measure these currents two amp-meters were used.

5.2 Optical characterization It was performed two distinct optical characterizations:

Overall light emission analysis. This analysis consisted in the photography of all area of the OLEDs with all pixels on, and image processing of the photos. The image processing of these photos allows to measure (relative measurements) and study of the: light uniformity; relative energy emission; chromatic relative energy emission.

Functional defect analysis. This analysis consisted in the loading of patterns into the OLEDs, followed by a sequence of photography of the active area of the OLEDs and image processing of the photos. The photos taken have pixel resolution. Note that the eMagin OLED has an pixel pitch of 15 µm. This analysis allows the inspection of the pixels of the OLEDs; pixel defects can be studied.

5.2.1 eMagin SVGA+ OLED The optical characterization of the eMagin OLEDs was performed using an image acquisition system composed by both hardware and software elements. This system is present in Figure 8.






Figure 8 - Layout of the optical characterization system. The acquisition system is composed by:

- 1 megapixel-resolution camera - 1 microscope - 1 support structure for the OLED, with 2 degree of freedom (x-y plane) - 1 laptop running LusoSpace’s software - 1 OLED microdisplay PC interface kit - 1 laboratory power supply (Note that the OLED microdisplay is enveloped by a black box, which reduce stray light)

In Figure 9 one can see a zoomed view of the support structure for the OLED (this is the structure that is enveloped by the black box). This support structure is composed by two parts: - 1 PCB that is connected to the OLED microdisplay PC interface kit - 1 X-Y (two-axis), manual, linear positioner






Figure 9 - OLED support structure. 5.2.1.1 Overall light emission analysis To perform this analysis the images presented in Figure 10 (a) to (e) were loaded into the OLEDs and photographed (Figure 10 (f) to (j)). Note that the images loaded into the OLEDs had a resolution of 800x600, which corresponds to the OLED resolution. The photographs taken, used different exposure times for the different images loaded (colours).

(a) (b) (c) (d) (e)

(f) (g) (h) (i) (j)

Figure 10 - Images loaded into the OLEDs from (a) to (e), and correspondent taken photos from (i) to (j). The R, G, B and white patters allow the comparison between the light intensity of the three colors. The White pattern allows also the OLED's light intensity measurement. This will function like an imaging photometer. Note that these measurements are relative, since the optical setup is not calibrated with respect to light measurement intensity.






To analyse these photographs, dedicated image processing software was developed in-house (see section 0). This software allows the measurement of the relative intensity (from 1 to 256 the CCD has 8 bytes) of the photographs (emitted by the OLED), the calculation of the light uniformity and the study of OLED functional defects (pixels defects). Also the software corrects the vignetting of the optical system. 5.2.1.2 Functional defect analysis To inspect the eMagin OLED functional defects (pixels, clusters, lines and columns) and also the luminosity uniformity, it is necessary to take pictures of the OLED and view the OLED's individual pixels. In order to do so, the use of high magnifications is required, since the OLED's pixels pith is 15µm. Therefore, one has to divide the OLED area in 16 different fractions, as presented in the figure bellow. Each area must be studied separately.

Figure 11 - eMagin display area, 800x600 pixels, dived in 16 smaller areas. To fully characterize one OLED it is necessary to load two different checkerboards (Figure 12) into each area and photograph them (Figure 13). To fully characterize the OLEDs, 32 photographs are required. The process of analyzing the full area of one OLED is time consuming and is not compatible with the available time between radiation exposure steps. Therefore during the radiation test only area 6, 7, 10 and 11 (see Figure 11) were photographed. Note that each one of these “sub-areas” of the OLED includes 30 000 pixels and thus, four areas of the OLED have 120 000 pixels. Therefore, four of these areas are fully representative of the OLED. To inspect each OLED sub-area, the two checkerboard patterns (see Figure 12) will be loaded sequentially and photographed (see Figure 13). Note that each white point on the pattern will address only one pixel of the OLED. Also, the white/black areas of the two checkerboard patterns are the reverse of each other.

a) b)

Figure 12 - eMagin OLED pattern images.






The figure bellow shows the photographs of 1/16 area of the OLED, with the two different checkerboard patterns loaded. Note that the individual pixels of the OLEDs are observed.

Figure 13 - Photos of the chequerboard patterns.

The procedure for the functional defect analysis, to photograph the four parts of the eMagin OLED is the following one:

1. Verify that the laboratory power supply outputs and the OLED Microdisplay PC Interface Kit are turned-off.

2. Put the eMagin OLED in the “eMagin_MeasureBoard”. 3. Turn-on the outputs of the laboratory power supply. 4. Turn-on the OLED Microdisplay PC Interface Kit. 5. Load the correspondent alignment image into the OLED. 6. Align the OLED with the x-y two-axis movement. 7. Load the pattern image into the OLED. 8. Acquire image of the OLED. 9. Repeat step 7 and 8 10. Repeat steps 5 to 9 for all four sub-areas. 11. Turn-off the OLED Microdisplay PC Interface Kit. 12. Turn-off the outputs of the laboratory power supply.






5.2.2 OSRAM Pictiva OLED The optical characterization of the Pictiva OLEDs was performed using, an image acquisition system, composed by both hardware and software elements, like the one present in Figure 14.

Figure 14 - Optical characterization system layout for the Pictiva OLED. The acquisition system is composed by:

- 1 megapixel-resolution camera. - 1 support structure for the OLED. - 1 laptop running LusoSpace’s and OLED Graphical User Interface software. - 1 Pictiva Evaluation Kit.

5.2.2.1 Overall light emission analysis In order to study the energy emission of the OLED, the display area with all pixels tuned on, was photographed. The Photographic Camera CCD was used, as an imaging photometer; note that these measurements are relative measurements. A typical photography of the OLEDs in this situation is presented in Figure 15. All Pictiva OLEDs were photographed in the same conditions (Photographic camera parameters) before, during and after the radiation test.






Figure 15 - Photography of the Pictiva OLED.

5.2.2.2 Functional defect analysis For the Pictiva's OLEDs, the procedure of this analysis was similar to the one of the eMagin's OLEDs (section 5.2.1.2). Two checkerboards were loaded in the OLEDs and photographed; results of these photographs are presented bellow.

(a) (b)

Figure 16 - Photos of the chequerboard patterns. (a) and (b) white/black are the reverse of each other.

5.2.3 Image Processing Software The images acquired using the described hardware setup were processed and analysed using a software tool which was developed in-house, specifically for this purpose. This tool was developed with “National Instruments LabVIEW” and “National Instruments Vision Development Module” platforms, and is able to handle the high-resolution images resultant from the OLED optical inspection process. This image processing software was used, in LusoSpace’s premises, during the “Evaluation of Samples” (CCN1-WP300) and the “Test Analysis” (CCN1–WP600) phases of the “OLED Evaluation Programme”. The relationship between the image acquisition and processing phases is shown in Figure 17.






Figure 17 – Integration between the image acquisition and image analysis phases. The image processing and analysis software tool is able to perform the following tasks:

- Load an image file (from hard disk) and perform the necessary adjustments in order to make it suitable to be analysed (namely, extraction of the region of interest; tilt adjustment; and correction of lens distortion, using spatial calibration);

- Process the image in order to identify and measure the OLED pixels, regarding both geometric and luminosity aspects;

- Analyse the obtained data and characterize the OLED. The output from the analysis can be divided in two main categories:

o OLED luminosity statistics. The approach used describes the luminance spread using an overall non-uniformity metric, which includes many types of defects related with luminance degradation (including localized regions of luminance variations - “cosmetic” defects”);

o Detection, classification and summing up of functional defects, namely: failure of isolated pixels and 2-D pixel clusters.

- Store the resulting data to disk, to constitute a measurement database that can be further analysed.






In Figure 18, the front-panel of the image analysis tool is shown, where the areas related with the main features are indicated.

Display where the original image (that will be

processed) is shown

Interface used to perform the initial image adjustments (extraction of region of interest and

spatial corrections)

Display showing the results of the image

processing steps

Interface for the control of the image processing and

analysis steps, as well as the type of results that will be

stored to disk

Results from the OLED pixel analysis: age geometric characteristics; statistianalysis of the luminance; and map

owing the luminosity distribution over theOLED surface

aver cal

sh

analysi ristics Results from the functional defect

s: geometric characteof the defects and classification into several distinct categories

Figure 18 – Features of the image processing and data analysis software tool.

In Figure 19, Figure 20 and Figure 21, several snapshots of the image analysis software are shown, where the later was being used to analyse photos of actual OLED samples acquired using previously described hardware setup.






Pixel detection and defect superimposed to the original image. Zoomed original imageOriginal image

Figure 19 – Analysis of a fraction of an OLED MicroDisplay area, which has no functional or “cosmetic” defects

(photo of an actual eMagin OLED MicroDisplay displaying a test pattern image).






Figure 20 – Analysis results of an OLED MicroDisplay. In this analysis was detected a pixel defect.






Figure 21 – Results from the analysis of an “OSRAM Pictiva” OLED (the relatively large luminance spread is due

to the fact that the OLED’s plastic protector cover has not yet been removed).

5.3 Radiation boards The OLEDs going into radiation were mounted in a mechanical mounting supplied by LusoSpace. According with ESA/SCC 22900 standard the ESA standards 10 test objects of each type (Pictiva and SVGA+) will be exposed to radiation, 5 will be biased and the other 5 will not. To base the OLED material of the displays, it's necessary to turn on the displays and to load an image on it.

• SVGA + eMagin OLEDs For the Biased OLEDs the bias voltages can be obtained directly from a laboratory power supply. The SVGA+ OLEDs were biased at 3.3V (VDD), 4 V (VAN) and -3V (VCOMMON), these three different voltages address to logic supply and OLED supply. The following power on sequence that must be used:

1. Turn on VCC3, 2. Turn on VAN. The VAN voltage should be set to 0 V and increased slowly to 3.3V (10 to 50

ms ramp is a good starting-point for implementation into a circuit design), 3. Turn on VCOMMON

All useful pixels of the OLED should be turned on, so an white image was be loaded into the OLED. The video signal received by the OLEDs was a RGB signal with horizontal and vertical synchronism. This signal can be supplied by a computer, through the analog video output connector (15-pin D-sub connector), but during the OLED start-up an I2C command that change the OLED video mode to SVGA, must be sent. Note that the computer screen refresh rate parameter should be set to 60Hz. 3 VCC, VAN and VCOMMON voltages are document on ANNEX I, Table 13






The eMagin SVGA+ has 28 I/O pins, the minimum connections required for RGB input, taking into account external voltage reference for the pixel driver operations, are listed in the table bellow:

Pin Notes

Pin 1 VDD (3.3V)

Pin 2 Reset should be pulled high through an RC network to VDD to ensure that reset stays on low for 100 µsecs after all other lines have stabilized.

Pin 3 SCL (2.2kΩ pull-up to VDD)

Pin 4 SDA (Note: there is a 2.2kΩ pull-up resistor on the display board)

Pin 6 Should be grounded for normal operation



Pin 9 VAN (4.0V)

Pin 10 COMMON (-3.0V)

Pin 11 Ground

Pin 12 VBLACK

Pin 13 VBH

Pin 14 VBL

Pin 17 Ground

Pin 18 RED (analog video signal input)

Pin 19 Ground

Pin 20 GREEN (analog video signal input)

Pin 21 Ground

Pin 22 BLUE (analog video signal input)

Pin 23 Ground

Pin 25 Vertical Sync logic input

Pin 26 Horizontal Sync logic output

Table 9 - Minimum connections required for RGB input.

To power-on and initialize five SVGA+ OLEDs a PC, a laboratory power supply and an interface kit connected to a Power\Control board was used. The block diagram for connecting ten OLEDs is schemed in the Figure 2. For closely matched luminance levels in all five OLEDs, an external voltage references for Vbl, Vbh and Vblack, was used. These references are the ones used in the pixel driver operations and will be generated in the Power\Control board.






Figure 2 - Irradiation mounting scheme, for the eMagin OLEDs.

A photo of the irradiation apparatus parts is presented bellow.

Figure 22 - Irradiation apparatus parts.






A photo of the irradiation board with the biased OLEDs is presented bellow.

Figure 23 - photo of the eMagin OLEDs mounted on the radiation board and biased. Note that during the radiation test it was loaded on the OLEDs a white image.

• Pictiva OLED

The Pictiva OLED was biased at 2.4-3.5V (Logic) and 12-13V (OLED supply). To initialize the Pictiva display it is necessary to send several commands to the microdisplay microprocessor (SD0323 driver), so the radiation board has available all the necessary connection for communication. The OLED pin-out is shown in the table bellow. Note that the microdisplay driver I/O connections are active low.






Table 10 - Pictiva pin-out

Communication with the OLED is done by parallel protocol (through PIN7 to PIN14). To manage the parallel communication was necessary to control the input ports correspondent to PIN1 to PIN6. It is important to point out that CS# (PIN1) input enable and disable the OLED communications (0 = enabled, 1 = communications disabled). One microprocessor (in our case we used the developer kit) can control several Pictiva OLEDs simultaneously, providing that CS#=0 to only one OLED at a time. To power-on and initialize five Pictiva OLED, the developer kit and a laboratory power supply were used. The block diagram for connecting five OLEDs is schemed in the figure bellow:






Figure 2 - Irradiation mounting scheme, for the Pictiva OLEDs.

A photo of the irradiation apparatus parts is presented bellow.

Figure 24 - Irradiation apparatus parts.






A photo of the irradiation board with the biased OLEDs is presented bellow.

Figure 25 - Photo of the Pictiva OLEDs mounted on the radiation board and biased.

6. Cobalt-60 Irradiation Devices were irradiated with Cobalt-60 gamma rays at the facility at ESA ESTEC during the 10 May 2006 and 10 May 2006. The dose rate was approximately 330 rad/hr and the devices were kept at ambient room temperature. The irradiation procedure is compliant with the ESA-SCC Standards, particularly, the requirements given by ESA/SCC 22900 – “Total dose steady-state irradiation test method” [AD2]. Due to the high inspection time (between radiation steps) of the OLEDs it was necessary to separate the tests period in two days (9 May 2006 and 10 May 2006). In each day half of the OLEDs samples were irradiated and inspected, the irradiation steps and the OLEDs allocations is presented in the following tables.






rad rate [rad/min]= 5,5 rad rate [rad/min]= 5,5Rad rate [rad/hr]= 330 Rad rate [rad/hr]= 330

Total dose [rad] Absorbed dose [rad] Duration time [min]

Total dose [rad] Absorbed dose [rad] Duration time [min]

Rad step 1 100 100,200 18,2 Rad step 1 100 100,030 18,2Inspection 50,0 Inspection 50,0






Total 8:01 Total 8:01

5 eMagin OLEDs turned on5 Pictiva OLEDs off

5 - > eMagin OLEDs off5 - > Pictiva OLEDs turned on

Radiation Group A09 May 2006 10 May 2006

Radiation Group B

Table 11 - Radiation doses tables

After the irradiations the devices were taken back to LusoSpace, where further post-irradiation measurements, annealing measurements and accelerated aging were made. The Annealing took place for 168 hrs at room temperature and the accelerated aging took further 168 hrs at 60 °C, with bias supplied (as during irradiation). Note that the Annealing and the accelerated aging were performed in part of the irradiated samples. The annealing and accelerated aging tables are presented bellow. During annealing and accelerated aging the OLEDs were inspected after the first 24h (of each process) and at the end of each process.

Allocation of the OLEDs for the annealing and accelerated aging

OLED ref OLED type CBMJW eMagin OLED CBMKS eMagin OLED CBMJR eMagin OLED CBML6 eMagin OLED A02 Pictiva OLED A03 Pictiva OLED A07 Pictiva OLED A08 Pictiva OLED

Table 12 - OLED Allocation for the annealing and accelerated aging






7. Results of the eMagin OLED testing In this section, the results of the eMagin OLEDs are reported.

7.1 Luminous intensity analysis results The luminous intensity of the eMagin OLED devices was analysed, using the results from both display-level and pixel-level optical inspections. Using display-level results, the overall luminosity of each OLED sample was characterized for the different loaded image conditions, namely Black, Red, Blue, Green and White full image patterns. From the pixel-level optical inspection, the resultant pixel’s luminosity statistics were used to characterize the OLED’s average luminous intensity and its non-uniformity along the OLED surface.

7.1.1 Overall light emission analysis The variation of overall luminous intensity, with respect to radiation exposure dose and to thermal processing time (annealing and accelerated aging phases), for each image colour in the 5 eMagin OLED samples which were biased during the radiation exposure process (devices CBMJR, CBML6, CBMKX, CBMK8 and CBMLA, referred here as 01-JR, 02-L6, 03-KX, 04-K8 and 05-LA, respectively), is shown in Figure 26 to Figure 29. As previously mentioned, only the 01-JR and 02 L6 OLEDs were subjected to the annealing and accelerated aging phases.

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Figure 26 – Variation of overall luminous intensity of WHITE, in eMagin biased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






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Figure 27 – Variation of overall luminous intensity of RED, in eMagin biased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 28 - Variation of overall luminous intensity of GREEN, in eMagin biased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 29 - Variation of overall luminous intensity of BLUE, in eMagin biased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

What concerns the 5 eMagin OLED samples which were not biased during the radiation exposure process (devices CBMJW, CBMKS, CBML4, CBMKP and CBMJX, referred here as 06 JW, 07-KS, 08-L4, 09-KP and 10-JX, respectively), the variation of the overall luminous intensity is shown in Figure 30

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to Figure 33. Also, only 06-JW and 07-KS OLEDs were subjected to the annealing and accelerated aging phases.

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Figure 30 – Variation of overall luminous intensity of WHITE, in eMagin unbiased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 31 – Variation of overall luminous intensity of RED, in eMagin unbiased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 32 - Variation of overall luminous intensity of GREEN, in eMagin unbiased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






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Figure 33 - Variation of overall luminous intensity of BLUE, in eMagin unbiased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

On the charts concerning the luminosity vs. radiation dose, the first points (optical inspection at LusoSpace premises, before the radiation exposure campaign) show slightly higher levels, because the OLED biasing conditions were different. The biasing conditions were changed for the radiation campaign (as well as for the annealing and accelerated aging phases), in order to avoid possible saturation of the camera’s CCD sensor. Namely, the Vbh voltage, used to control the luminance level of the OLED was changed from Vbh = 2.22 V (before the radiation phase) to Vbh = 2.25 V (during radiation and after). As shown in the presented charts, there was not a significant change in the luminous intensity level as a result of the increase in the radiation exposure dose. On the other hand, both the annealing and the accelerated aging phases cause an important decrease in the luminosity of the OLEDs, which decreases to levels that are roughly 2 - 4 times lower than the values before these “thermal processing” phases. Also, it cannot be noticed any considerable difference between the behaviour of different OLED pixel colors and therefore, the luminosity degradation (namely due to aging effects) appears to be even for all these colors. It should be noted that the photos, which concern Red and Blue images loaded onto the OLEDs, were acquired using different conditions than those of the Green and White. Namely, in the photos of Red and Blue an exposure time of 1 second was used, which is four times larger than the one used for the photos of Green and White (1/4 s). With respect to the results from the conditions were an all-black image was loaded onto the eMagin OLEDs, a residual brightness, with arbitrary and very low levels was detected on some devices. Moreover, although the detected levels appeared to lack measurement reliability, it was not noticed any correlation between the results and the different study phases. Specifically, it was not observed any significant variation/ degradation with respect to the increase of the radiation absorbed dose.

7.1.2 Pixel-level luminous intensity statistics The average pixel luminous intensity in each eMagin OLED and its non-uniformity along the respective emitting surface, as a function of radiation dose and thermal processing time (annealing and accelerated aging phases), are shown in Figure 34 and Figure 35 for the 5 biased devices (CBMJR, CBML6, CBMKX, CBMK8 and CBMLA, referred here as 01-JR, 02-L6, 03-KX, 04-K8 and 05-LA, respectively). Figure 36 and Figure 37 show the results for the 5 OLEDs which were not biased during the radiation exposure process (CBMJW, CBMKS, CBML4, CBMKP and CBMJX, referred here as 06-JW, 07-KS, 08-L4, 09-KP and 10-JX, respectively).






-As previously mentioned, only the 01-JR/ 02-L6 biased and the 06-JW/ 07 KS unbiased OLEDs were subjected to the annealing and accelerated aging phases. It should also be noted that, in the image processing/ analysis software, the intensity of each OLED pixel was calculated by multiplying its area (in CCD pixel units) by its mean grey-level value (which can vary from 0 to 255). The notation of A.U. (arbitrary units) was used in the charts as the units for the average pixel luminous intensity. The dispersion, or non-uniformity, was calculated from the coefficient of variation (i.e. the standard deviation divided by the mean) for the luminous intensity values of all the pixels in each OLED.

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Figure 34 - Average pixel intensity in eMagin biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 35 - Pixel luminosity non-uniformity in eMagin biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






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Figure 36 - Average pixel intensity in eMagin unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 37 - Pixel luminosity non-uniformity in eMagin unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

As in the case of the results for overall luminous intensity (obtained from the display-level optical inspection), the luminosity vs. radiation dose charts reveal slightly higher levels for the first points, which concern the optical inspection before the radiation exposure campaign. As previously mentioned, this was due to the use of different OLED biasing conditions during this first phase. As shown in the pixel luminosity charts, there is a significant difference between the behaviour of biased and unbiased OLEDs. Given that, apart from the opposite biasing conditions all other aspects of the experiment (namely the setup and used procedures) were identical for the two data sets, the different behaviour can be attributed to different radiation absorption/ effects for the biased and non-biased conditions. Moreover, although different devices exhibit distinct behaviours, it can be noticed a general tendency to lower and more varying luminosity levels in the eMagin OLED devices which were biased during the radiation exposure phases. Additionally, and in agreement with what was observed in the display-level overall luminosity analysis, a severe degradation of the average pixel luminosity levels can be observed as a result of the annealing and accelerated aging phases. The results show that the dispersion of the pixel luminosity remained relatively unvarying during the whole study. Also, regardless the observed degradation of the pixel luminosity levels due to aging effects, the luminous uniformity along the OLED surface is maintained.






7.2 Functional defects analysis results From the pixel-level optical inspection data, an analysis of the occurrence of functional defects, with respect to the radiation dose and to thermal processing time (annealing and accelerated aging phases), was performed. The only type of defects found, on both biased and unbiased OLEDs, was isolated inoperative pixels. No inoperative groups of pixels (clusters), display lines or columns defects were found in any phase of the study. The numbers of isolated pixel defects detected in each OLED display for each phase of the study are shown in Figure 38 and Figure 39. The number of detected defects refer to the center quarter of each OLED’s emitting area, which includes 120 000 pixels. As shown in Figure 38 and Figure 39, the occurrence of dead pixels is generally very low (~ 40 ppm) and does not vary with respect to the increase of radiation dose. However, because a dedicated image analysis software was used, the number of detected defects on a particular device sometimes can increase and afterwards decrease, due to slight variations of image acquisition conditions. Moreover, when pixel luminosity degradation occurs in the thermal processing phases, several pixels (with particularly weak luminosity) are not detected as so, and are classified as defects by the software. Thus, due to lack of pixel luminosity in the annealing and accelerated aging phases, the number of detected defects rises significantly. Although this happens for both biased and unbiased devices, the effect on the biased devices appears to be stronger.

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Figure 38 – Isolated pixel defects in eMagin biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time. The defects count refer to the centre of the OLED emitting

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Figure 39 – Isolated pixel defects in eMagin unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time. The defects count refer to the centre quarter of the

OLED emitting area, which includes 120 000 pixels.






7.3 Electrical analysis results As previously mentioned in Section 5.1.1, the electrical characterization of eMagin OLEDs included the measurement of the following electrical currents: IDD (analog and logic power supply); Ian (input power for pixel array); Icommon (common electrode bias); Ibl and Ibh (references for the pixel driver circuitry). The variation of these parameters with radiation dose and with thermal processing time (annealing and accelerated aging phases) are shown in Figure 40 to Figure 44 for the case of eMagin biased OLEDs (CBMJR, CBML6, CBMKX, CBMK8 and CBMLA) and, in Figure 45 to Figure 49 , for the unbiased devices (CBMJW, CBMKS, CBML4, CBMKP and CBMJX). The behaviour of both Ian and Icommon curves show the changes in electrical consumption due to changes in the pixel matrix luminosity. Therefore, the Ian and Icommon curves roughly exhibit the same behaviour of the ones of luminous intensity. In contrast, since Vbl and Vbh voltages constitute reference inputs for the pixel intensity control circuitry, the corresponding Ibl and Ibh currents should and did not vary significantly during the study. If fact, both Ibl and Ibh currents remained relatively constant, at about 0.18 mA.

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Figure 40 – Variation of IDD current in eMagin biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 41 – Variation of Ian current in eMagin biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






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Figure 42 – Variation of Icommon current in eMagin biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 43 - Variation of Ibl current in eMagin biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 44 – Variation of Ibh current in eMagin biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






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Figure 45 – Variation of IDD current in eMagin unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 46 – Variation of Ian current in eMagin unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 47 – Variation of Icommon current in eMagin unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






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Figure 48 – Variation of Ibl current in eMagin unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 49 – Variation of Ibh current in eMagin unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






8. Results of the Pictiva OLED testing In this section, the results of the Pictiva OLEDs are reported

8.1 Luminous intensity analysis results The luminous intensity of the OSRAM-Pictiva OLED devices was analysed, using the results from both display-level and pixel-level optical inspections. Using display-level results, the overall luminosity of each OLED sample was characterized (full white image loaded condition) and from the pixel-level optical inspection, the resultant pixel’s luminosity statistics was used to characterize the average luminous intensity and its non-uniformity along the OLED surface.

8.1.1 Overall light emission analysis The variation of overall luminous intensity, with respect to radiation exposure dose and to thermal processing time (annealing and accelerated aging phases), for the 5 OSRAM-Pictiva OLEDs which were biased during the radiation exposure process (devices A07, A08, A09, A10 and A11) is shown in Figure 50. The results concerning the 5 OSRAM-Pictiva OLEDs, which were not biased during the radiation exposure process (devices A02, A03, A04, A05 and A06), are shown in Figure 51. As previously mentioned, only the A07/A08 and A02/A03 devices (respectively biased and unbiased) were subjected to the annealing and accelerated aging thermal processing phases. Moreover, the A02 OLED device (unbiased) could not be tested for the 2nd stage of the accelerated aging process, because it suffered an “electrical accident” and became inoperative during this phase.

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Figure 50 – Variation of overall luminous intensity of OSRAM-Pictiva biased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

On the charts concerning the luminosity vs. radiation dose, the first points (optical inspection at LusoSpace premises, before the radiation exposure campaign) show significantly lower levels, because the image acquisition conditions were changed in order to take a higher advantage of the imaging system’s dynamic range. Namely, the used F-Number of the camera was changed from F/6.6 (used on the photos taken before the radiation) to F/3.7 (photos during radiation and after). Moreover, if a linear relationship between the used F-Number and the obtained results is roughly assumed (level inversely proportional to F/#), a correction factor of 6.6/ 3.7 ≈ 1.78 would shift the levels of the first points from about 130 to about 231, “in-line” with the remaining points.






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Figure 51 – Variation of overall luminous intensity of OSRAM-Pictiva unbiased OLED sample(s), as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

As shown in the charts, there was not a significant change in the luminous intensity level as a result of the increase in the radiation exposure dose. On the other hand, both the annealing and the accelerated aging phases appear to have an impact on the luminous intensity of the OLEDs, although relatively weak when compared with the case of eMagin OLEDs. Degradation on the luminosity levels as a result of the “thermal processing” can be noticed, although a slight recover appears after the first accelerated aging phase (24 h at 60ºC). What concerns the results from the conditions were an all-black image pattern was loaded onto the OSRAM-Pictiva OLEDs, no luminous intensity was detected in any image, from any device, either before, during or after the radiation exposure campaign. Therefore, for these conditions, all pixels remained completely OFF, without “leaks” or incorrect behaviours, during the study.

8.1.2 Pixel-level luminous intensity statistics The average pixel luminous intensity in each OSRAM-Pictiva OLED and its non-uniformity along the respective emitting surface, as a function of radiation dose and thermal processing time (annealing and accelerated aging phases), are shown in Figure 52 and Figure 53 for the 5 biased devices (A07, A08, A09, A10 and A11). In Figure 54 and Figure 55, the results for the 5 OLEDs which were not biased during the radiation exposure process (devices A02, A03, A04, A05 and A06) are shown. As previously mentioned, only the A07/A08 and A02/A03 devices (respectively biased and unbiased) were subjected to the annealing and accelerated aging thermal processing phases. Also, the A02 OLED (unbiased) could not be tested for the 2nd stage of the accelerated aging, because it became inoperative (due to an accident) during this phase. Furthermore, difficulties were found in processing some of the photos (about 10 photos out of a total of 192) concerning the pixel-level analysis of OSRAM-Pictiva OLEDs, because in these photos the OLED pixels were out of focus. Therefore, the results from these photos were considered invalid and were not taken into account in the analysis. Both the average pixel intensity and the non-uniformity of luminosity were calculated using the same method described for the case of eMagin OLEDs.






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Figure 52 – Average pixel intensity in OSRAM-Pictiva biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 53 – Pixel luminosity non-uniformity in OSRAM-Pictiva biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

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Figure 54 - Variation of pixel’s average luminous intensity, in OSRAM-Pictiva unbiased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






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Figure 55 - Variation of pixel’s luminosity non-uniformity, in OSRAM-Pictiva unbiased OLED samples, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

As in the case of the results for overall luminous intensity (obtained from the display-level optical inspection), the luminosity vs. radiation dose charts reveal significant lower values for the first points (inspection before the radiation exposure campaign). As previously explained, this was due to different image acquisition conditions and a rough correction (multiplying by 1.78, as explained before) would shift these points to the levels of the subsequent points. This also had an effect in the non-uniformity, which appears to increase for lower pixel luminosity values. Nevertheless, and apart from the “first point anomaly”, the results show that both pixel intensity and non-uniformity values remained relatively unvarying with respect to the radiation exposure phase. The annealing and accelerated aging phases caused a considerable effect in the pixel luminosity values, although the non-uniformity remained relatively unchanged.

8.2 Functional defects analysis results In the case of OSRAM-Pictiva OLEDs, there was not any functional defect, on any OLED device, during the whole duration of this study. That is to say, all the pixels were ON when it should be ON.






8.3 Electrical analysis results The results from the electrical measurements performed on the OSRAM-Pictiva OLEDs, namely the IDD (logic supply) and ICC (OLED supply) currents, are presented in Figure 56 and Figure 57 for the case of biased devices. In Figure 58 and Figure 59, the results for the unbiased OLEDs are shown.

a)

0,0

0,1

0,2

0,3

0 200 400 600 800 1000Dose (rad)

Cur

rent

(mA

)

A07A08A09A10A11

b)

0,0

0,1

0,2

0,3

0 50 100 150 200 250 300 350 400Tim e (hours)

Cur

rent

(mA

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A07A08

Figure 56 – Variation of IDD current in OSRAM-Pictiva biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

a)

15

16

17

18

19

20

0 200 400 600 800 1000Dose (rad)

Cur

rent

(mA

)

A07A08A09A10A11

b)

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18

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0 50 100 150 200 250 300 350 400Tim e (hours)

Cur

rent

(mA

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A07A08

Figure 57 – Variation of ICC current in OSRAM-Pictiva biased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

a)

0,0

0,1

0,2

0,3

0 200 400 600 800 1000Dose (rad)

Cur

rent

(mA

)

A02A03A04A05A06

b)

0,0

0,1

0,2

0,3

0 50 100 150 200 250 300 350 400Time (hours)

Cur

rent

(mA

)

A02A03

Figure 58 – Variation of IDD current in OSRAM-Pictiva unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.






a)

15

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0 200 400 600 800 1000Dose (rad)

Cur

rent

(mA

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A02A03A04A05A06

b)

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0 50 100 150 200 250 300 350 400Tim e (hours)

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rent

(mA

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A02A03

Figure 59 – Variation of ICC current in OSRAM-Pictiva unbiased OLEDs, as a function of a) radiation exposure dose and b) annealing/ accelerated aging time.

As in the case of the luminous intensity analysis, the results from electrical measurements do not shown variation in the electrical consumption, with respect to the increase of the radiation dose, on OSRAM-Pictiva OLEDs. Also, the effect of the annealing and accelerated aging steps does not greatly influence these devices, when compared with its effect on the eMagin OLEDs.

9. Conclusions The result shows that the OLED technology is not sensitive to radiation up to 1000 rad. This is compatible with Astronaut expected environment. However, there was some degradation for the eMagin OLEDs, due to the annealing and accelerating aging. The real cause seems to be the temperature applied on the devices, although inside the specifications given by the manufacturer. However, this is not a big concern because it is likely that this technology will be used on a controlled environment for human survival. If this technology is to be used in a display tool for Astronauts, a full qualification campaign is necessary. This includes much more than the radiation effect. However, this one was of more concern, taking into account that there was no information about the behaviour of OLED when subjected to this kind of environment. It is expected that the OLED devices will have high probability to be successfully qualified for space applications (for a human compatible environment).






10. ANNEX I - Technical specifications of test objects In this ANNEX, the OLED’s technical specifications are presented.

10.1 eMagin SVGA+ OLED The diagram bellow shows the functional block diagrams of the eMagin OLED microdisplay. The video signal can be provided by a RGB signal or a Composite Monochrome. The R, G, B input signals are dc-coupled analog signals with external vertical and horizontal synchronization signals, compatible with the VESA VSIS standard. The I2C serial interface provides for user adjustments such as contrast, brightness, PLL parameters, display orientation. The OLED logic (low voltage CMOS technology) is powered by a 3.3 V and the OLED material is powered by a -3.0 V (cathode) and 4.0 V.

Figure 60 – Microdisplay’s functional block diagram

The table bellow lists the pin-out of the eMagin OLED. The electrical current, of the logic power supply, should be measured in PIN 1 and the current of the OLED power supply should be measured in PIN 9 or PIN 10.






Table 13 - EMagin OLED microdisplay pin out.

The SVGA+ color can work in the video formats listed in the table bellow.

Table 14 - SVGA+ Video forma s. The power-up default is a non-interlaced Zoom 60Hz mode. t






• Electrical characteristics

Table 15 - Absolute maximum ratings

Table 16 - Recommended ope ating conditionsr

Table 17 - DC Characteristics






Table 18 - AC Characteristics

• Analog RGB characteristics

Table 19 - Input characteristics






10.2 OSRAM Pictiva OLED The OLED display is controlled by a “Solomon SSD0323” driver. This microprocessor is built-in a flexible cable. The block diagram and specifications of this OLED display are presented in the figure bellow. The display communicates with external devices through an 8-bit parallel interface.

Figure 61 - Pictiva OLED block diagram The table bellow lists the pin-out of the OSRAM-Pictiva OLED. The electrical current, of the logic power supply, should be measured in PIN 16 and the current of the OLED power supply should be measured in PIN 17.

Table 20 - OSRAM OLED microdisplay pin out .

• Electrical properties

Table 21 - Absolute maximum values.






Table 22 - Recommended DC ope a ing conditions r t

Table 23 - Typical powe consumption r

• Parallel protocol characteristics

Table 24 - Parallel communications characteristics






• Power Up Sequence: 1. Power Up VDD 2. Send display off command 3. Power Up VCC 4. Delay 100ms (when VCC is stable) 5. Send Display on command

Figure 62 - Power up diag am r

• Power Down Sequence:

1. Send Display off command 2. Power down VCC 3. Delay 100ms (when VCC is reach 0 and panel is completely discharges) 4. Power down VDD

Figure 63 Power Down diagram -

• Power connection One ground and two power connections are required to operate Atlanta module. The logic power, VDD, is 3 volts, the OLED driver power, VCC, is 13 volts and the ground is common for both logic and analog.

• Tail connector The flex tail is terminated with an 18-pin pad designed to mate with a 0.5 mm pitch ZIF connector. Recommended mating connectors: Molex: 52893-1890, HIROSE: FH12(A)-18S-0.5SH






• Initialization The Pictiva module requires certain commands to be executed upon a power up for its proper operation. Failure to execute these commands may lead to shortened display lifetime, poor image quality, and incorrect image display. The following table lists the commands that must be executed during an initialization after a power up.

Table 25 - Recommended initialization commands






• Mechanical characteristics

Figure 64 - Pictiva Mechanical Characteristics






• Qualification tests

Figure 65 - Manufacturer Qualification tests
