The greenhouse effect is becoming increasingly serious, and sustainable buildings are being taken seriously. Too much unnecessary energy is consumed in lighting equipment during the day. Use nanoimprint molding technology to produce sunlight guide grating structural plates to save energy. The sunlight that shines into the room passes through the sunlight guide structure, so that the light shines evenly into the room, reducing the power consumption of lighting equipment during the daytime. Imprinting technology is used to produce large-area daylight light guide plates to increase production capacity and reduce production time. However, during the preparation process, sunlight guide plates are spliced into large areas and are prone to structural resist overflow defects at the splicing joints. Therefore, the purpose of this research is to use a dispensing machine to distribute droplets on UV resist materials, draw patterns based on the volume, position parameters and graphic parameters of the droplets, design the droplet distribution pattern, and imprint a large-area microstructure that can be spliced. The imprinted area is formed in a single pass, and finally 4 × 4 large-area splicing imprinting is completed with multiple droplet distribution patterns.

This study has three parts. The first part is the design and production of the imprint device; the second part is to use the triangular grating microstructure PDMS imprint stamp to imprint the droplets after distributing them through the dispensing machine and explore the optimization of imprinting experimental parameters. It is expected that during imprinting Achieve no resist overflow and imprint it into a quasi-rectangular area; finally, explore whether the imprinted area of the UV resist droplet distribution pattern is suitable for the splicing process.

In the design of the imprinting device, the processing error of the imprinting device can easily lead to low uniformity of film thickness after imprinting, and excessive residual layer thickness differences can easily occur during splicing. In addition, during the splicing process, machine accuracy issues can easily cause the angles of the grating structures to be different for different imprints. Therefore, in this study, floating joints were added to improve the uniformity of the film and provide rotatability, so that the direction of the grating structure can be self-adjusted when the stamp is spliced to keep it consistent. Without adding floating joints, the thickness difference of the residual layer at the four corners of the single imprinting result is 77.1 μm. After adding floating joints, the thickness difference drops to 9.9 μm. After splicing, the grating angles of different imprinting results can also remain consistent.

During the splicing process, in order to avoid resist overflow and make the forming area close to a rectangular shape while having a lower residual layer thickness and better residual layer uniformity, the above problems are solved by selecting appropriate imprinting parameters. Experimental results show that when the holding time is 30 s, the imprinting force is 15 N, and the imprinting speed is 0.005 mm/s, a single imprint has the lowest average residual layer thickness of 4.1 μm. In the imprinted area, the larger the imprinted inscribed rectangular area is, the more conducive to splicing large areas. After imprinting the six spoked asterisk droplet distribution pattern, the largest inscribed rectangular area can be obtained is 483.6 mm2.

A 28 mm × 28 mm PDMS stamp was spliced 4 × 4 times to obtain a large-area daylight light guide grating structure with an area of 93.2 mm × 87.8 mm. The structural size change rate of the daylight light guide grating structure between the splicing and non-splicing locations is 2%. Linear defects were found at the splicing area. It is speculated that this defect is a microstructural misalignment caused by the PDMS stamp alignment problem, that is the grating structure merging of different PDMS imprinting areas. During the splicing process, the overlapping sides of two imprinted areas will produce a thicker residual layer thickness, but the residual layer difference is only less than 7.6 μm; and the overlap of four imprinted areas, due to the single stamping area of 4 The corners are rounded, so during the splicing process, too much UV resist does not overlap in this area, causing the thickness of the residual layer to increase.