Reactive Mesogens Brighter, Clearer Communication
Statement Merck is the world leader in manufacturing and marketing liquid crystals (LCs). The anisotropic optical behaviour of LCs is the fundamental underlying mechanism of any LC display and of various optical elements or optical films. 2 3
What Is RM? RMs are polymerizable liquid crystals. The liquid crystalline monomers carry, for example, reactive acrylate end groups, which polymerize with one another in the presence of photo-initiators and UV light to form a rigid network. The orientation of the liquid crystal molecules is frozen due to mutual polymerization of their ends. This makes RMs an interesting material also for the non-display industry which is manipulating light in large and small size applications. Posssible Alignments Of RM Films Exposure To UV Light Transforms The Liquid Reactive Mesogen Mixture Into A Film Solvent UV Splayed Twisted Biased Twisted Vertical Aligned What Is RM? Optical Film RM Broadband Twisted Planar Patterned 4 5
RM How It Works The diverse anisotropic optical properties of Reactive Mesogens (RMs) and the polymer films formed from them, make them well suited to many different applications including, but not limited to, flat panel displays. Reactive Mesogen Solutions can either be coated onto flexible plastic substrates by a roll-to-roll coating process, or be used inside the display to form incell optical elements, either as patterned or monolithic retarders. As a world-leading supplier of electro-optical liquid crystal mixtures which are being promoted and sold under licristal, Merck have used the in-depth experience to develop a range of ready-to-use Reactive Mesogen formulations which are being promoted under the name licrivue. Roll To Roll Processing Of RM Solutions RM Solution Oven, Heat Ultraviolet Lamps RM How It Works Plastic Substrate RM Solution Film Liquid Crystal Film Polymer Film Wet Film Coated from Solution Drying Annealing Aligning LC UV Cure 6 7
Application Examples Typical applications and optical elements which can be materialised with RMs include: 3D displays Quarter and half wave retarders in consumer electronics and anti-reflection circular-polarizers for OLED displays PA Layer Process Polarized UV (-45 ) Polarized UV (+45 ) Patterned Retarder To Make The Third Dimension Visible Bringing the third dimension to the home is one of the most exciting technology trends for digital displays. licrivue reactive mesogen materials have enabled 3D displays which can be watched with passive polarizer glasses, just like those found in cinemas around the globe. The 3D enabling layer, a selective polarizer called the patterned retarder, consists of reactive mesogen materials coated and processed on either glass or film substrates. And there is even more with licrivue materials. Selective Polarization By Patterned RM Films PA ~ 50 400 nm 1) Coating the PA Layer 2) PUV Mask Exposure 3) PUV Flood Exposure RM Layer Process UV Exposure (non-polarized) RM ~ 1 2 µm Application Examples LCD Pixel Patterned Retarder Passive Glasses TV-Set / Imaging 1) Coat RM on PA Layer 2) RM Annealing Step 3) RM Polymerisation Separation / Encoding by Polarization Decoding Thanks to the anisotropic optical properties of reactive mesogens and of the polymer films formed by them, licrivue can be used in a wide range of optical elements. Don t be surprised if your next generation, glasses-free, 3D display uses licrivue materials. 8 8 9
RM Anti-Reflection Films For OLED Lens On State Autostereoscopic Although 3D experience with patterned retarder is very well established, glasses free, autostereoscopic viewing experience is considered as an essential milestone towards an even larger adoption of 3D TV. Various technical approaches are making use of the unique properties and possibilities inherent with RMs to make glasses free 3D. One already realized approach is based on a film with integrated micro lenses made of RMs. Due to the optical anisotropy of the RMs, incoming light will be focussed or not depending on its polarization state. This allows switching between 2D and 3D mode by simply changing the polarization state. Lens Off State RM QWF HWF Polarizer OLED Display Reverse Or Negative Dispersion s/w off Subpixel Polarization Substrate Polarization Activated Micro Lens Polarization Switch (TN) Polarizer Polarization Subpixel s/w on RM and LC LC or OLED RM ND-QWF Polarizer OLED Display Retardation (nm) 180 160 Standard Dispersion (SD) 140 120 100 Negative Dispersion (ND) 80 60 40 20 0 400 450 500 550 600 650 700 Wavelength (nm) QWF For OLED Organic light emitting diode (OLED) displays are expected to become the next generation flat panel display technology. For this display technology it is essential to reduce unwanted reflections in order to sustain high contrast in bright ambient light, a vital requirement for technology used in mobile applications. Two approaches to anti-reflection films can be proposed both based on achromatic quarter wave retarders. The first is a two layer solution, comprised of a half wave retardation plate and a quarter wave retardation plate aligned with correct relative orientation. With thinner film thickness requirements, licrivue high birefringence RM materials are ideally suited for the production of thin half wave retardation plates. An alternative approach is a single layer solution comprised of reverse dispersion materials from Merck, resulting in a simplified optical stack. 10 11
What Is Your Application For RM? RMs are polymerizable liquid crystalline materials. They are often processed on a plastic film but there are many more possibilities such as anisotropic RM particles possessing both shape and optical anisotropy. What Is Your Application For RM? Is this the RM material for your application? 12 13
Notes Contacts Merck KGaA, Germany Frankfurter Straße 250 64293 Darmstadt Germany Phone +49 (0) 6151 72-0 Fax +49 (0) 6151 72-2000 E-mail liquid.crystals@merckgroup.com Merck Display Technologies Ltd., Taiwan No. 39, Ching Chien 1 Road, Kyanyin Ind. Park Taoyuan 32853 Taiwan Phone +886-3-483-6521 Fax +886-3-416-0440 E-mail display.materials-taiwan@merckgroup.com Merck Ltd., Japan LC Division Arco Tower 5F 8-1, Shimomeguro 1-chome Meguro-Ku, Tokyo 153-8927 Japan Phone +81 (0)3 5434-4700 Fax +81 (0)3 5434-4705 E-mail MJ_LC-service@merckgroup.com Merck Chemicals Ltd., United Kingdom Chilworth Technical Centre University Parkway Southampton SO16 7QD United Kingdom Phone +44 (0) 23 8076 3300 Fax +44 (0) 23 8076 3380 E-mail reactive.mesogens@merckgroup.com Merck Advanced Technologies Ltd., Korea 1173-2, Wonjeong-ri, Poseung-myun 451-822 Pyungtaek-shi, Kyungki-do South Korea Phone +82-2-2185-3800 Fax +82-2-2185-3900 E-mail pmkorea@merckgroup.com EMD Chemicals an affiliate of Merck KGaA, Darmstadt, Germany 300 2nd Avenue, 2nd floor Waltham, MA 02451-1102 Phone +01-781-533-5800 Fax +01-781-533-5876 E-mail liquidcrystals@emdchemicals.com www.emd4displays.com Design and typesetting: Merck Graphic Design Studio, Kadja von Coester 14 15
Merck KGaA Germany Frankfurter Str. 250 D-64293 Darmstadt www.merckgroup.com Liquid Crystals Business Unit: