US-12619143-B2 - Apparatus and process for replicating a texture

US12619143B2US 12619143 B2US12619143 B2US 12619143B2US-12619143-B2

Abstract

A process is for replicating a texture. A method continuously produces a flex stamp and applies the flex stamp in texturing a resin by combination of a roll-to-plate and a plate-to-roll process. An apparatus is suited for the continuous process.

Inventors

Alexander Sebastiaan Kommeren
Jan Matthijs Ter Meulen
Bram Johannes Titulaer

Assignees

MORPHOTONICS HOLDING B.V.

Dates

Publication Date: 20260505
Application Date: 20210716
Priority Date: 20200731

Claims (14)

1 . A method of continuously replicating a texture comprising: (a) providing a a first resin and a second resin; (b) providing a master comprising a textured surface to be replicated wherein the master is treated with an anti-stick agent prior to being provided, and wherein the textured surface of the master has a surface free energy of at most 35 mN/m; (c) applying the second resin to the carrier and/or the textured surface of the master, wherein the second resin has antistick properties; (d) providing a carrier on a belt moving in a first direction past a first roller; (e) following steps (a)-(d), bringing the master and the carrier into contact while moving over the first roller in the first direction with the second resin between the master and the carrier thereby texturing the second resin on the carrier by applying a plate-to-roll process; (f) the textured the second resin to form an imprint texture on the carrier; (g) following steps (e)-(f), providing a substrate; (h) applying the first resin to the substrate, which first resin differs from the second resin; (i) following steps (g)-(h), texturing the first resin on the substrate by the imprint texture of the carrier while the carrier on the belt and the substrate are moving over the first roller in the first direction by applying a roll-to-plate process; and (i) consolidating the first resin on while the first resin is in contact with the imprint texture, wherein: steps (g)-(j) are repeated without interruption plural times, each time with a different substrate, to produce multiple imprinted products, each imprinted product comprising a substrate with a textured and consolidated first resin thereon; and during texturing of the second resin in step (e), the master is moving in said first direction in a first plane, and during texturing of the first resin in step (i), the substrate is moving in said first direction in said first plane.
2 . The method of claim 1 , wherein the master has a surface free energy of at most 15 mN/m.
3 . The method of claim 1 , wherein: step (e) includes bringing the master and the carrier into contact via movement of the carrier on the belt and movement of the master by a sliding means in the first direction, such that the master and the carrier move together; and step (f) includes consolidating the textured second resin to form an imprint texture on the carrier while the master and the carrier move together in step (e).
4 . The method of claim 1 , wherein: step (i) includes bringing the substrate and the carrier into contact via movement of the carrier on the endless-belt and movement of the substrate by a sliding means in the first direction, such that the substrate and the carrier move together; and step (j) includes consolidating the first resin on the substrate while the substrate and the carrier move together in step (i).
5 . The method of claim 1 , wherein the at least one first roller is used for the plate-to-roll process and for the roll-to-plate process.
6 . The method of claim 1 , wherein: the texturing of the second resin on the carrier in step (e) occurs at an imprint speed between 0.1 m/min and 10 m/min; and the texturing of the first resin on the carrier in step (i) occurs at an imprint speed between 0.1 m/min and 10 m/min.
7 . The method according to claim 1 , wherein the belt on which in step (d) the carrier is provided is an endless belt.
8 . The method according to claim 1 , wherein in step (b) the master is provided on a sliding means for sliding the master underneath the first roller, and wherein a gap is defined between the sliding means and the first roller.
9 . The method according to claim 8 , wherein in step (g) the substrate is provided on the sliding means moving in the first direction.
10 . The method of claim 8 , wherein the first roller is displaceable relative to the sliding means.
11 . The method of claim 8 , wherein the sliding means is a conveyor belt or a sliding plate.
12 . The method according to claim 1 , wherein in step (f) the second resin is consolidated via UV radiation from a UV radiation source.
13 . The method according to claim 1 , wherein in step (j) the first resin is consolidated via UV radiation from a UV radiation source.
14 . The method according to claim 1 , wherein in step (i), the imprint texture is directly applied to the first resin in the roll-to-plate process.

Description

CROSS-REFERENCE TO RELATED APPLICATION(S) This application is a National Stage Application of PCT/EP2021/070042, filed 16 Jul. 2021, which claims benefit of Ser. No. 20/188,855.9, filed 31 Jul. 2020 in Europe, and which applications are incorporated herein by reference. To the extent appropriate, a claim of priority is made to each of the above disclosed applications. The invention pertains to a method and an apparatus for replicating a texture as well as to products obtained using the process according to the application. The use of functional textured layers on devices is an important topic. The smart usage of such layers can enhance performance, reduce cost or improve the visual appearance of the product. For example, diffusing layers are used in displays, enabling the use of thinner LED backlight concepts and illuminating the display from the sides. Other new high-tech possibilities are the integration of functional textured layers into solar panels improving their efficiency or integration in organic light-emitting diode (OLED) lighting panels to extract more light. Functional textured layers can be made by use of UV imprinting. In this case the substrate, or stamp, or both are coated with a lacquer (also called resin or resist). After pressing the stamp on the substrate with lacquer in between, the textured lacquer is cured to a solid phase. The curing method can be thermal or by use of UV light. Already in 1978, this technology was mentioned in U.S. Pat. No. 4,128,369. Further pioneering work was done by Chou in 1995. He demonstrated that by use of a rigid stamp sub-25 nm textures could be replicated at high throughput for mass production (U.S. Pat. No. 5,772,905 or in an article by Stephen Y. Chou, Peter R. Krauss, Preston J. Renstrom (Appl. Phys. Lett. 67 (1995) 3114-3116)). Later-on the use of a roller to apply pressure on either a rigid stamp or a bended thin metal sheet to replicate textures was demonstrated (article Hua Tan, Andrew Gilbertson, Stephen Y. Chou, J. Vac. Sci. Technol., B 16 (1998) 3926-3928). Many institutes and companies continued this work, resulting in different techniques. In the semiconductor industry plate-to-plate imprinting is applied by using a rigid stamp in combination with a transfer process, materials and precise positioning as described in U.S. Pat. No. 6,334,960, US Patent Application 2004/0065976 and U.S. Pat. No. 8,432,548. The roll-to-roll imprinting technique uses textured rollers in combination with flexible substrates to texture foils or films in a continuous process as described in e.g. the U.S. Pat. No. 8,027,086. The above-mentioned plate-to-plate technique is designed for the precise, wafer-scale, imprinting of small textures (feature size of sub-100 nm) on uniform flat wafers with high position accuracy. But as described in the Chinese Patent Application CN 103235483, this technology is difficult to scale to a larger area. By use of the roll-to-roll technology textured foils can be made continuously at high production speeds. These textured foils can be used as substrates for flexible applications or can be laminated onto rigid substrates. However, the latter comes at additional cost of an intermediate adhesive layer to adhere the textured flexible foil to the rigid substrate or product. Therefore, a third new technology is being developed: direct roll-to-plate imprinting. Hereby the functional textured layer is directly applied on the discrete substrate without the use of an auxiliary film that has an additional intermediate adhesive layer of tens to hundreds of microns thickness. In contrast to the plate-to-plate technology the imprint is made by use of rollers which are textured or by use of textured foils, also called flexible stamps, wound around rollers. In contrast to most rigid stamps and imprinting rollers which are usually made of metal, flexible stamps have a shorter lifetime as they are less resistant against mechanical stress for the softness of the polymeric materials they normally consist of. As flexible stamps are normally in contact with the lacquer or resin during the curing or consolidation process they are also exposed to radiation and/or thermal stress which lowers the lifetime of their chemical structure. This requires that flexible stamps have to be replaced more often compared to rigid stamps and imprinting rollers which are often of metal and have a more or less infinite lifetime. This implies that flexible stamps have to be produced much more often and that there is thus a necessity for fast and efficient processes for production thereof. Typically, flexible stamps are produced by replicating a texture from a rigid master which may consist of wear-resistant materials such as metal, glass or quartz. This master is typically covered with a resin, with a carrier placed on top of the master and the resin is consolidated either thermally or by UV light, the consolidated and the textured resin layer is separated from the master, furthe