Local thinned glass and method for producing such a thinned glass

Abstract

Glass (100) with a local thinned region (120, 130, 140) characterised in that the region is thinned by laser ablation. The glass may be display, glass and may have a fingerprint sensor (400) mounted i

Description

5 The present invention relates to a local thinned glass and a method for producing such a thinned glass, e.g. a display cover glass comprising a local sensor and a method for producing such a cover glass. Known thinning methods use grinding and then polishing the glass in a mechanical 10 and / or thermal way. Polishing is an invasive process that can lead to the induction of additional defects in the glass structure, for example, cracks that can propagate over time leading to the destruction of the glass. Furthermore, vibrations during milling can lead to the destruction of the glass, also irregular shapes are very difficult to obtain because the grinding is done with rotary tools and additional the risk of Cyj 15 breakage is high. CN 113149451 A relates to the technical field of glass processing, and in particular relates to a method for preparing anti-glare glass. US 2013273324 A1 relates to strengthened glass articles and, more particularly, strengthened glass articles 20 having etched features, as well as electronic devices incorporating such strengthened glass articles and methods of forming etched features in strengthened glass articles. GB 2569798 A relates to laser based machining and in particular, though not exclusively, to laser based machining using an interlaced raster scanning technique to provide high quality and high efficiency machining of 25 substrates such as fused silica. US 2003006220 A1 relates to a method of ablating a hole in a hard, non-metallic substrate, particularly including glass and ceramics. WO 2014136043 A1 relates to methods for preparing segmented optical structures and more particularly Fresnel lenses. 30 The task of the present invention is the provision of a local thinned glass. The task is reached by a thinned glass with the features of claim. Preferred forms of the invention can be found in the dependent claims. Since the local thinned region is thinned by laser ablation a smooth surface without any grinding tools can be reached. As a result, the stress for the glass is much lower than by the use of any grinding tool and the shape and form of the local thinned can 5 be for example rectangular or even more complex. The thickness of the glass can be locally reduced down from a standard of e.g. 1,3mm or 1.1 mm to 0.25mm. Furthermore, the slope of the walls of the thinned region can easily be controlled. The region is thinned by successive laser ablation. By that the shape of the thinned 10 region will be have less roughness than by a roughness reachable be a single laser ablation. Furthermore, the thickness of the glass can be more reduced. The glass is a display cover glass. By that it may protect the display to which it is mounted. According to the invention, a sensor is mounted in the thinned region. By that one or more additional functions of the glass may be implemented. According to the invention, the sensor is a fingerprint sensor. By that the glass may be used perfectly for a mobile phone or other devices in which a user recognition is 20 required, e. g. for the entry into a conventional car or a self-driving vehicle and / or the use of such a vehicle. According to the invention, the fingerprint sensor and the glass each comprise an upper level and the upper level of the glass and the upper level of the sensor are 25 different. By that a user of the fingerprint sensor can feel with his / her finger the location of the fingertip sensor since he / she feels the hole or elevation of the fingertip sensor and gets in this way a tactile feedback when the finger is the above the fingertip sensor. 30 Since the method for local thinning a glass uses laser ablation, less stress to the glass is provided than with known grinding techniques and as a result possible defects a reduced or even prevented. If the laser ablation is used by a laser spot travelling a path across a surface in a region to be thinned of the glass an easy way to form any desired shape of the thinning can be provided. The thickness of the glass may be further reduced if the laser spot is travelling with consecutive repetitions the path across the surface in the region to be thinned of the glass. 10 If the consecutive repetitions of the laser spot travelling the path across the surface in the region to be thinned of the glass are partly superimposed to the paths travelled by the laser spot before an even more smooth surface of the thinned region or regions may be reached. CO The invention will be exemplarily described with the help of the figures. 15 Fig. 1 shows a first example with glass partly thinned and a laser with a laser spot. Fig. 2 shows an example of a cover glass with an inserted sensor in a cross-section. 25 30 In Fig. 1 is shown a glass 100, a laser 200 with laser beam 210 and a lens 300. The glass 100 comprises an upper level 110, a second level 120 and a third level 130. The laser beam 210 is focused by the lens 300 so that an active laser beam area 211 is created with a lower region 2110 which removes the surface of the glass 100 by successive moving along travel parts (e.g. travel path 220) so that parts of the glass 100 are ablated and originating from the non-ablated upper level 110 of the glass 100 the second level 120 and the third level 130 are reached. Path 220 shows a possible path on which the Laser beam active area 220 travels and ablates in this manner glass on its way creating the different levels 110, 120 of the glass 100. The upper level 110 of the glass 100 is not ablated by the laser beam active area 211. Please note that Fig. 1 only shows the principle of the laser ablation and not the real laser device with is complete construction which is known by the man skilled in the art and therefore not expressly described. By repeated ablation a more lower level can be reached. One possible way is to ablate first completely the required ablated levels to the second level 120 and then starting from there ablating more deeper to the third level 130. A fourth or even fifth level might be possible. A thickness of the remaining glass of about 0.2mm should not be felled below. By only partly superimpose the repeated paths of travel of the laser beam active area 211 a 5 smoother surface 120, 130 can be reached. 02 11 23 In Fig. 2 is shown a glass 100 and a fingertip sensor 400. The glass comprises additional to the upper level 110a fourth level 140, on which the fingertip sensor 400 is mounted. The fingertip sensor 400 comprises an upper level 410. The upper level 10 410 of the fingertip sensor 400 is a little bit lower than the upper level 110 of the glass 100. So a small hole is created above the fingertip sensor 400 so a user can feel the position of the fingertip sensor 400. A similar result could be reached if the fingertip sensor 400 would build a little elevation above the upper level 110 of glass 100 which could be felt by a user, too. If the upper level 110 of the glass 100 and the 15 upper level 410 of the fingertip sensor 400 are in the same level the optical appearance of the glass 100 might be preferred. The second, third and fourth levels 120, 130, 140 of the glass 100 create the region(s) of the local thinned glass. Reference signs glass 100 upper level 110 5 second level 120 third level 130 fourth level 140 laser 200 laser beam 210 10 active laser beam area 211 lower region 2110 Path 220 lens 300 fingertip sensor 400 CO f\i 15 upper level 410

Claims

1. Glass (100) with a local thinned region (120, 130, 140) the region (120, 130, 140) is thinned by laser ablation, wherein the local thinned region (120, 130, 140) is5 thinned by successive laser ablation, wherein the glass (100) is a display cover glass, characterized by a sensor is mounted in a hole of the thinned region (140), the sensor is a fingerprint sensor (400) and the fingerprint sensor (400) and the glass (100) each comprise an upper level, the upper level (110) of the glass (100) and the upper level (410) of the sensor are different.10COCM

Images