Precision Grinding and Micro Hot Embossing of the Microgroove 
Lens Array for Light Transmitting and Uniforming

Nowadays several qualified technologies have been established for the manufacturing of precision moulds. The fields of application can mainly be divided into moulds for non-optical and optical components. For optical moulding inserts the development goes from basic rotational symmetric geometries to complex surfaces like steep aspheres and freeforms which can additionally be overlaid with microstructures. The moulded components require a figure accuracy in the (sub-) micrometer and surface roughness in the nanometer range while moulds for replication also need advanced materials with high surface integrity. Here, diamond machining processes, e.g. diamond turning and milling as well as precision grinding and polishing are necessary for the manufacturing of precision moulding inserts from various materials. Depending on the material and application of the applied part to be replicated different replication techniques are used like injection moulding of plastics, hot embossing and precision moulding of optical glasses. For non-optical applications the current technical progress is driven by miniaturized products which are typically produced in mass production by replication techniques like hot embossing or metal forming. Each of these processes requires specific properties of the mould. Therefore, the surface topography and tribological conditions are of particular importance.

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Hot embossing of micro-lens array on bulk metallic glass

Sensors and Actuators A Physical ◽

10.1016/j.sna.2007.10.040 ◽

2008 ◽

Vol 141 (2) ◽

pp. 422-431 ◽

Cited By ~ 53

Author(s):

C.T. Pan ◽

T.T. Wu ◽

M.F. Chen ◽

Y.C. Chang ◽

C.J. Lee ◽

...

Keyword(s):

Metallic Glass ◽

Bulk Metallic Glass ◽

Hot Embossing ◽

Lens Array ◽

Micro Lens Array ◽

Micro Lens

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Development of a Rapid Manufacturing Process for Concave and Convex Lens Arrays

Journal of Engineering and Science Research ◽

10.26666/rmp.jesr.2018.2.6 ◽

2019 ◽

Vol 3 (2) ◽

pp. 38-45

Author(s):

Keyword(s):

Hot Embossing ◽

Steel Ball ◽

Polymer Substrate ◽

Rapid Manufacturing ◽

Lens Array ◽

Pmma Sheet ◽

Array Pattern ◽

Concave Lens ◽

Convex Lens ◽

Small Steel

This paper reports a rapid manufacturing process for the production of concave and convex lens arrays on the polymer substrate. In this method, many small steel balls with highly polished surfaces were placed in a rectangular cavity to form a closely packed small steel ball array. Then, a polymer substrate (PMMA sheet) was placed on top of the small steel ball array, and the stack of the PMMA sheet and the small steel ball array was placed in a hot embossing machine. During the hot embossing process operation, a concave lens array pattern is directly fabricated onto a polymer substrate. In addition, the diameter and depth of the concave lens array can be changed and controlled by adjusting the processing conditions of the hot embossing process. Thus, concave lens arrays with different dimension can be fabricated. Next, the polymer substrate with concave lens array pattern can be used as a mold for rapid replication of polymer convex lens array using vacuum-assisted UV molding process. In this way, various concave and convex lens arrays can be rapid fabricated with high throughput and low cost.

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