SCREEN PROTECTOR FOR A MOBILE ELECTRONIC DEVICE WITH A TOUCH SCREEN

Abstract

A screen protector (5) for a mobile electronic device with a touch screen. The screen protector comprises a flat laminated film comprising a layer (2) of polyethylene terephthalate (PET) bonded to one face of a layer (3) of thermoplastic urethane (TPU) and a layer (4) of adhesive on the opposite side of the TPU layer. The PET layer is less than 50 μm thick and wherein the adhesive layer provides a tack force of greater than 5 g/cm.sup.2. The relatively thin layer of PET with the relatively high tack force adhesive provides a screen protector particularly suited to a device with a curved screen.

Claims

1. A screen protector for a mobile electronic device with a touch screen, the screen protector comprising a flat laminated film comprising a layer of polyethylene terephthalate (PET) bonded to one face of a layer of thermoplastic urethane (TPU) and a layer of adhesive on the opposite side of the TPU layer; wherein the PET layer is less than 50 μm thick and wherein the adhesive layer provides a tack force of greater than 5 g/cm.sup.2.

2. A screen protector according to claim 1, wherein the PET layer is less than 40 μm thick.

3. A screen protector according to claim 1, wherein the PET layer is less than a half of the thickness of the TPU layer.

4. A screen protector according to claim 2, wherein the PET layer is less than a third of the thickness of the TPU layer.

5. A screen protector according to claim 1, wherein the PET layer is less than twice the thickness of the adhesive layer and is preferably less than 1.5 times the thickness of the adhesive layer and most preferably less than the thickness of the adhesive layer.

6. A screen protector according to claim 1, wherein the thickness of the TPU is greater than two thirds of the total film thickness.

7. A screen protector according to claim 1, wherein the film thickness is less than 250 μm and is preferably less than 220 μm.

8. A screen protector according to claim 1, wherein the tack force is greater than 6 g/cm.sup.2 and is more preferably greater than 7 g/cm.sup.2.

9. A screen protector according to claim 1 further comprising a second PET layer between the TPU layer and the adhesive.

10. A combination of a screen protector according to claim 1, a first release layer removable to expose the layer of adhesive prior to application of the protector to the device, and a second release layer is removable to expose the top surface of the screen protector once the protector has been applied to the device such that it protects it during transportation and installation.

11. A method of applying a screen protector according to claim 1, the method comprising laying the laminated film onto the screen of the device to bring the adhesive layer into contact with the screen and bending the edges of the film over the edges of the screen and adhering them in place.

12. A combination of a mobile electronic device with a touch screen which is curved along its longitudinal edges and a screen protector according to claim 1 adhered to the touch screen including the curved edges.

Description

[0019] An example of a screen protector in accordance with the present invention will now be described with reference to the accompanying drawings, in which:

[0020] FIG. 1 is a schematic diagram of the screen protector of the prior art;

[0021] FIG. 2 is a similar view of a screen protector of the present invention;

[0022] FIGS. 3A and 3B are schematic end views showing the application process of the screen protector onto the mobile electronic device; and

[0023] FIG. 4 is a schematic cross-section showing the protector between two release layers.

[0024] FIG. 1 shows the screen protector currently marketed by the applicant as the Impact Shield screen protector. This screen protector is a laminate of three primary layers, namely an upper layer of PET 100 μm thick, a central layer of TPU (known as BulletShield®) 150 μm thick and a bottom layer of silicon adhesive 30 μm thick. This adhesive has a tack force of 1.5 g/cm.sup.2 (10 g/inch.sup.2). The PET and TPU layers are bonded with an adhesive. Optional anti-glare, scratch-resistant and self-healing coatings are applied to the top of the PET. The overall thickness of the screen protector is 280 μm.

[0025] FIG. 2 shows a corresponding view of the screen protector according to the present invention. This uses the same TPU layer, but the PET layer has been reduced to 25% of its original thickness such that it is now 25 μm thick. The same thickness of adhesive is used, but this has been substituted with a much stronger adhesive which has a tack force of 9.3 g/cm.sup.2 (60 g/inch.sup.2). The screen protector is made using the same technique as before just using a reduced thickness of PET and the different adhesive. This means that the screen protectors can be quickly and cheaply produced by cutting them from a sheet of laminate. No subsequent shaping of the sheet is then required.

[0026] As previously described, the screen protector may have adhesive between the PET and TPU layers and many of the previously described coatings.

[0027] As shown in FIG. 4, the screen protector 5 is supplied to a user sandwiched between two release layers 9 and 10 both of which have a conventional construction. The lower layer 9 is adhered to the adhesive layer 8 and is removed first by a user before applying the protector to a mobile electronic device D as shown in FIG. 3A. The upper release layer is provided with a pair of tabs 11, one on either side of the release layer which enable the user to handle the screen protector for accurate placing on the screen of the device.

[0028] Prior to application, the screen may be cleaned with water and a detergent or with alcohol to remove stains and grease from the screen.

[0029] The screen protector 5 is initially placed flat on the screen of the device D and may, at that point, be scraped in order to remove any bubbles. Alternatively, this may be done later. The two side edges of the screen protector are then pressed onto the curved edges E of the screen S in a position shown in FIG. 3B. Again, bubbles may be pushed out at this stage. From a comparison of FIGS. 1 and 2, the degree to which the PET layer in the vicinity of the edges generates an “unpeeling” is greatly reduced. This is because the PET is relatively stiff. A thick layer when bent out of the neutral plane will generate a higher restoring force than a thinner one.

[0030] It will be appreciated from FIG. 3B, the present invention provides a layer of strong adhesive providing a strong bond between the screen protector 5 and the screen S in the regions where it is needed most. It will be appreciated from FIG. 3B that the motion of a thumb or finger around the edge of the device will tend to cause a peeling action on the edge of the screen protector and this is strongly resisted by the screen protector of the present invention.