WO2015088453A1

WO2015088453A1 - Touch screen for underwater use

Info

Publication number: WO2015088453A1
Application number: PCT/SI2014/000075
Authority: WO
Inventors: Oskar Marko MUSIĆ
Original assignee: Emmedi Software Engineering S.R.L.
Priority date: 2013-12-12
Filing date: 2014-12-11
Publication date: 2015-06-18
Also published as: SI24585A

Abstract

Subject of the invention is a transparent touchscreen, which is placed over the existing capacitive touchscreen [11) of the electronic - mobile device (17) and is used for direct and unobstructed input of touch in conditions of elevated pressure and under water. It is possible to use the invention with protective equipment such as gloves in a dry or wet environment. The device can be used independently or in combination with a dedicated watertight housing (14). The touchscreen according to the invention comprises of: a bottom film (6,) which is metalized in such a manner that it forms fields (4), a frame (13), which combines the bottom film (6) and the top film (3) and contains a medium (18), spacers (12) between the bottom film (6) and the top film (3) whereby the spacers (12) are glued to the bottom of the top film (3) or to the top of the bottom film (6), or to both, and the top film (3), which is metalized in such a manner that it forms a grid (1).

Description

TOUCH SCREEN FOR UNDERWATER USE

The invention relates to a touchscreen for underwater use, that is, a transparent screen that is placed over an existing touchscreen, of electronic - mobile devices, which is preferably of the capacitive type and is used for direct and unobstructed entry of touch in conditions of elevated pressure and under water. It is possible to use protective equipment, for example the gloves, in a dry or wet environment. The device may be used independently or in combination with a dedicated housing, which is watertight. The screen according to the invention is applicable for mobile devices, preferably phones and tablet computers, which use capacitive screen.

There are at least two known solutions for using a capacitive touchscreen underwater. According to the patent US20120256867, with the use of two layers of transparent film between which a liquid with a low dielectric coefficient is trapped, and according to patent US20130027849, with the use of a flexible transparent film over the capacitive display connected to a housing in which the internal pressure can be equalized with the ambient pressure.

The described solutions do not allow touchscreen usage in case the user wears protective equipment, such as gloves, which is very common by diving and other activities. These devices do not offer a solution with their own electrically conductive element to activate the screen.

There are several types of protective gloves with conductive threads, which solve the problem on land but in the underwater environment due to the nature of the operation of a capacitive screen these solutions are not taken into account because they do not work.

According to the patent US20130113755 an invention is described in which a transparent metalized film is installed over the capacitive touchscreen and is connected to the housing in which the internal pressure can be equalized with the ambient pressure. The capacitive touchscreen is capable of detecting touch, through the use of protective equipment, by pressing onto a transparent metalized film, which activates the capacitive touchscreen. Using a metalized layer an electrically conductive element is made.

The described solution uses a uniform metalized film and is thus not sufficiently precise and thus hinders the use of the user interface and the capacitive touchscreen. The film, in its initial state, due to its own electrical influence, has to be put relatively far away from the existing capacitive touchscreen and thus prevents reliable and accurate user input. By pressing it, the metalized film approaches the capacitive touchscreen with several conductive fields, which give rise to unintended operation in the wrong places.

There are many known solutions, which activate the capacitive touchscreen without electrical connections to a human finger or skin. According to the patent US20080238879 a device is formed by several capacitors deposited over or in proximity to the capacitive touchscreen, which are connected to electronic circuitry, which simulates the electrical characteristics of the human body. The activation circuit triggers operation of the screen independently of the user. After subsequent patent US20120326998 the same principle is used, with the possibility of activation via a light signal. According to the patent WO2013141762 a method and a mechanical device is described with two plates forming a capacitor directly above the capacitive touchscreen, which triggers the capacitive touchscreen once the plates come in contact via a separate mechanical button.

The described solutions do not satisfy the need for a device that would enable direct input by pressing over the existing capacitive touchscreen. In addtition to that, they do not solve the problem in environments where water or increased ambient pressure is present.

The objective of the invention is to enable the use of a conventional capacitive touchscreen in a way that it is sensitive to any kind of input of the user, by any kind of object. More specifically, this means that the touchscreen can be used in conditions of elevated ambient pressure and under water or by wearing protective equipment in such a manner that the user can directly and smoothly input touch via the existing touchscreen of the capacitive type. At the same time the invention must guarantee the ease of activation, a high accuracy of entries, by generating touch only at the site of the pressure or input, and a high transparency, consequently minimizing the thickness and quantity of elements, which overlap the existing display.

According to the invention, the problem is solved by using two transparent metalized films, separated by spacers and merged with a frame. The metalized layers on the film are treated in such a way that a bottom film, which is in contact with the capacitive touchscreen, forms fields and a top film, forms a grid. The sensitivity of the touchscreen is determined from the distance between the films and a surface area of the metalized components. For use in situations of moderate ambient pressure, a medium with a low dielectric coefficient is added between the films. In conditions of high ambient pressure, instead of the bottom film, which forms the fields, a solid metalized plate of an arbitrary thickness, which is metalized in such a way that it connects the fields on both sides of the plates, is added. The user operates the capacitive touchscreen of the electronic - mobile device by directly pressing onto the top film without using an additional source of charge in the form of a battery or the like.

The invention will be described in the embodiment and the drawings, which show:

Fig. 1 a device in axonometric projection - exploded

Fig. 2 a device supplemented with a watertight housing

Fig. 3 a device during operation in cross-section

Fig. 4 a top film with the metalized grid

Fig. 5 a top film with the metalized grid in cross-section

Fig. 6 a bottom film with metalized fields

Fig. 7 a bottom film with metalized fields in cross-section Fig. 8 a metalized plate with passage openings in cross-section

Fig. 9 a metalized plate with links in cross-section

Fig. 10 metalized fields with links

Fig. 11 spacers in the form of spacer lines

Fig. 12 a spacer in the form of a spacer line in cross-section

Fig. 13 implementation with magnets

Fig. 14 diagonal links

Fig. 15 a device for use in dry conditions

A capacitive touchscreen 11 and an electronic - mobile device 17 are pre-existing and available in standard version. According to the invention they are supplemented with a touchscreen for underwater use, which is mounted over the existing touchscreen of the electronic - mobile device. Embodiment with a watertight housing 14 is shown in FIG. 2.

A touchscreen for underwater use in accordance with FIG. 1 consists of a bottom film 6 and a top film 3, which are separated by spacers 12 and joined with a frame 13. A top side of the bottom film 6 and a bottom side of the top film 3 are metalized in such a way that on the bottom film 6 metalized fields 4 are formed and on the top film 3 a metalized grid 1 is formed.

By adjusting the distance between the bottom film 6 and the top film 3, and by adjusting the area of facing surfaces of the metalized parts of the grid 1 and the fields 4, the sensitivity to inputs of the user is determined.

In situations of moderate ambient pressure a medium 18 with a low dielectric coefficient is added between the bottom film 6 and the top film 3. In conditions of elevated ambient pressure, the bottom film 6 is replaced by a transparent metalized plate 8 of an arbitrary thickness, which is treated in such a way that it connects the appropriate fields 4 on both sides of the metalized plate 8. As shown in FIG. 13, a possible embodiment for the usage in conditions of elevated ambient pressure is represented, in which an additional plate 25 is glued on a top side of the top film 3 along its edge, so as to form an additional space between the top film 3 and the additional plate 25, within which small magnets 26 are located and glued to the top side of the top film 3 and simulate a pressure 22 at the approach of a large magnet 27.

The fields 4 and the grid 1 are transparent and electrically conductive. The electrically conductive and transparent material, which provides the characteristics of transparence and electrical conductivity, is preferably indium tin oxide by the abbreviation ITO, but conductive nanotubes or any other electrically conductive and transparent material may be used. The fields 4 are electrically insulated by a gap 5. The surface area of one field 4 shall not be smaller than the surface area of the smallest icon in the user interface of the electronic - mobile device 17. The gap 5 should be as narrow as possible but must still provide electrical insulation of the fields 4. The top surface of the bottom film 6 is coated with a transparent and electrically non-conducting film, which is no thicker than 50μπι and offers additional protection of the electrically conducting elements on the bottom film 6 against wear.

The gap 5 on the bottom film 6 and the grid 1 on the top film 3 are technically carried out by the removal of the electrically conductive and transparent material by well-known and available methods of etching, laser ablation and the like.

In the presented embodiment the gap 5 is less than 30μηι and was carried out by a laser ablation of electrically conductive and transparent material. The grid 1 on the top film 3 is defined by lines 28. When forming the grid 1 on the top film 3 by removing the electrically conductive and transparent material left and right of the lines 28, voids 2 are formed. It is not necessary that the electrically conductive and transparent material in the void 2 is completely removed, it is important that the electrically conductive and transparent material is completely removed only left and right of the lines 28 and that the un-removed area does not come into contact with the lines 28. The amount of un- removed surface within the voids 2 is determined only experimentally by observing the continuity of operation of the device according to the invention over the existing capacitive touchscreen 11.

The fields 4 and the grid 1 overlap in such a way that when a pressure 22 is applied on the top film 3, the grid 1 comes as close as possible or touches the fields 4. According to FIG. 3 the pressure 22 can be executed at any place and with any blunt object as long as the grid 1 can come closer or touches the fields 4. In order to carry out its functions the underwater touchscreen according to the invention does not require an additional source of electrical power.

The grid 1 is transparent and electrically conductive between all points. To ensure a smooth transition of a touch, the grid 1 covers a certain area over the capacitive touchscreen 11. According to the presented embodiment the grid 1 covers a surface area of 40mm² above the standard capacitive touchscreen 11 with a surface area of 4000mm². The optimal ratio between the surface area of the capacitive touchscreen 11 and the surface area of the grid 1 is experimentally determined. In case the electronic - mobile device 17 detects too much noise and does not respond, the surface area of the voids 2 is increased, that is, the surface area of the grid 1 is decreased, and vice versa, if the electronic - mobile device 17 barely detects the pressure 22, the surface area of the voids 2 is decreased, that is, the surface area of the grid 1 is increased. The surface area of the grid 1 above the capacitive touchscreen 11 must be smaller than the surface area of the fields 4 above the capacitive touchscreen 11.

Voids 2 are preferably rectangular in shape but they can form an arbitrary geometric shape with corners. As shown in FIG. 14, in the presented embodiment, the voids 2 are implemented as a set of four triangles with the bottom side of each of the triangle being one side of a square and the sides of the square represent the lines 28, which define the grid 1. In this case, the void 2 is formed in such a manner that the lines 28, which define the grid 1, are connected with diagonal links 31, which are interrupted from the center outwards. In the case that the capacitive touchscreen 11 is significantly larger than that described above, the grid 1 is divided into groups that are electrically insulated and each of these groups overlap the surface of the capacitive touchscreen 11 in a ratio that has been experimentally determined beforehand. The bottom surface of the top film 3 is coated with a transparent and electrically nonconducting film, which is not thicker than 50μπι and offers additional protection of the electrically conducting elements on the top film 3 against wear.

Spacers 12 are arranged in such a manner as not to overlap the grid 1 or lines 28, which define the grid 1. When a solution without overlapping is technically not feasible the overlapping should be minimal. Spacers 12 are preferably spherical in shape and have a diameter of less than 3mm. Spacers 12 are completely transparent or partially transparent or opaque. In case that the spacers 12 have an upper surface curved in such a way as to form a plan convex lens, a partially transparent or non-transparent material is used as the lens interferes with the view onto the display of the electronic - mobile device 17. In case that the spacers 12 consist of two plan parallel surfaces they can be completely transparent. The height of the spacer 12 does not exceed 1 mm. The spacers 12 are lower than the frame 13. Spacers 12 are glued to the top side of the bottom film 6 or on the bottom side of the top film 3. In case that the spacers 12 are glued to the top film 3 and the bottom film 6 at the same time, they are of the same height as the frame 13. In the embodiment of the device according to the invention, spacers 12 of height of 0.2 mm and of a diameter of 2 mm that were cut from acrylic adhesives are used. Spacers 12 may be an integrated part of the bottom film 6 and the top film 3 in such a way that the bottom film 6 and the top film 3 already have protrusions in the form of spacers 12. Spacers 12 are printed with a silk-screen printing process or with the use of digital printers, which enable a coating of paint or varnish in the form of dots. According to FIG. 11 spacers 12 are implemented as spacer lines 24, which overlap the gap 5. The spacer lines 24 are made so that they do not overlap and are of uniform height. Spacer lines 24 are set at an angle of 45^Q in relation to the orientation of the capacitive touchscreen 11. The surface of spacer lines 24 is plan parallel or curved. In the case that the spacer lines 24 have an upper surface curved in such a way as to form a plan convex lens, a partially transparent or non-transparent material is used as the lens interferes with the view onto the display of the electronic - mobile device 17. The height of the spacer lines 24 is determined in the same way as the height of the spacer 12.

The top film 3 and the bottom film 6 are no thicker than 300 μπι. In the presented embodiment the bottom film 6 and the top film 3 in the thickness of ΙΟΟμηι are used. There are several known materials available for the bottom film 6 and the top film 3 having electrically conductive layers on one side. The bottom film 6 and the top film 3 are equipped with different colors, symbols, logos and other design accessories via printing processes.

In case the electronic - mobile device 17 is very sensitive to the noise related to immersion in water, an additional protection against noise is used above the top film 3. This protection is achieved by increasing the thickness of the top film 3 or by adding materials over the top film 3 or by using an additional metalized film in which a metal layer must be as far away from the grid 1.

Enclosed within the bottom film 6, the top film 3 and the frame 13 is a medium 18, which is transparent and has a low dielectric coefficient. In situations of ambient pressure between 0.5 bars and 2 bars, the medium 18 is preferably air or an inert gas such as helium. In conditions of elevated ambient pressure above 2 bars, the medium 18 is preferably incompressible fluid in the form of silicone oil or transformer mineral oil or a similar fluid with a low dielectric coefficient.

The frame 13 is sticky and enables a hermetical seal of the space between the bottom film 6 and the top film 3. The frame 13 is at least as high as the spacers 12. The frame 13 may be cut from an electrically conductive material and is covered with an adhesive on both sides as to provide electrical insulation.

According to FIG. 8, in conditions of extremely elevated pressure such as by diving with scuba diving equipment, in addition to the medium 18, in the form of an incompressible fluid, the bottom film 6 is replaced with a metalized plate 8 with passage openings 9 and a conductor 7 that connects the fields 4. The metalized plate 8 is preferably transparent and rigid and is metalized on both sides with an electrically conductive and transparent material, whereby on both sides of the metalized plate 8 there are fields 4 with a gap 5 made according to one of the above described methods, that is, by removing the electrically conductive and transparent material with well-known and accessible procedures of etching, laser ablation and the like. In the embodiment the metalized plate 8 is made from acrylic glass. With the introduction of a rigid and transparent metalized plate 8 the possibility of damage to the electronic - mobile device 17, which could arise due to increased external pressure, is reduced. Passage openings 9 have a broad of maximum of 0.5 mm. In the embodiment the conductor 7 is preferably made from a coating of conductive and transparent nanotubes but may also be made from a thin conductive wire. Over the bottom face of the metalized plate 8 a thin self-adhesive transparent film 19 is placed and this film prevents the penetration of the medium 18 through the passage openings 9. The self-adhesive transparent film 19 is electrically non- conductive and no thicker than ΙΟΟμηι.

According to FIG. 13, in conditions of elevated pressure above 2 bars, an embodiment with the magnets is shown. Small magnets 26 have a maximum diameter of 3 mm and a maximum height of 5 mm. The small magnets 26 are glued to the top surface of the top film 3. The small magnets 26 are equally oriented with respect to their polarization. The small magnets 26 are glued at a density not denser than five times the number of the voids 2. Small magnets 26 are glued in geometric patterns around the spacer 12. With the approaching of a large magnet 27 the pressure 22 is simulated wherein the bottom surface of the large magnet 27 and the top surface of small magnets 26 repel. Above the top film 3 an additional plate 25 is mounted. The mounting of the additional plate 25 is made by an additional spacer 29. The additional spacer 29 is sticky on both its surfaces and is installed above the frame 13. The height of the additional spacer 29 is at least the same as the height of a small magnet 26. Additional plate 25 is waterproof glued to a groove 32 of watertight housing 14. According to FIG. 9 an embodiment of the metalized plate 8 with a link 10 is shown. The function of the link 10 is the same as of the conductor 7, in both cases connecting the fields 4. A transparent film 23 is applied over the links 10, which prevents the convergence of the grid 1 to the link 10 thus reducing the chance of an accidental touch. Link 10 is preferably a coating of conductive nanotubes or another conductive material that is sufficiently transparent and does not obstruct the view on the display of the electronic - mobile device 17.

When the device according to the invention is used in conditions of elevated pressure or under the water, the bottom side of the bottom film 6 is in direct contact with the capacitive touchscreen 11 through the frame 13, which engages tightly in the groove 32 made in the housing 14.

For use in dry conditions or when the use of protective equipment is foreseeable, preferably gloves, or the use with prosthesis of a user who inputs touches through the prosthesis, the device according to the invention includes an adhesive film, with which the device is attached on the electronic device. The adhesive film has on a side with which it is attached to the electronic device a layer of silicone or polyurethane adhesive, or any other adhesive having similar properties, preferably of a silicone or a polyurethane composition, which enables its repeated removal or installation onto the electronic device. On the side facing towards the bottom film 6 a layer of adhesive for attachment onto the bottom film 6 is used. The adhesive film is positioned on the bottom side of the bottom film 6 in such a way that it covers the entire bottom surface of the bottom film 6 or is positioned on the bottom side of the bottom film 6 under the frame 13 in its whole circumference or in spots. The installment of the device according to the invention onto the electronic device can be done through openings 30, which are located on the bottom film 6 in an area under the frame 13. In this case the adhesive film on the side facing the bottom film 6 does not include an additional layer of adhesive, since the frame 13 is itself sticky. Instead of the adhesive film an adhesive mass can be used which is applied to the bottom side of the bottom film 6 with a screen-printing process or another known process for the application of a silicone or polyurethane mass. The adhesive film and the adhesive mass have a thickness of less than 1mm.

In this case the device is designed in such a way that it does not overlap a speaker 33, a microphone 34, cameras 35, lamps 36, proximity sensors 37 and buttons 38 or other sensoric and image elements of the electronic - mobile device 17. If the execution without overlapping is not possible the overlap should be minimal. The device according to the invention is sticked to the back of the electronic - mobile device 17, where it is stored for a time when not in use, as shown in FIG. 15.

Electrically conductive elements of the grid 1 and the fields 4 absorb the electromagnetic radiation of the electronic - mobile device 17.

In conditions where there is a risk of water intrusion or damage due to the rise in pressure, the device according to the invention is used in combination with a watertight housing 14. The watertight housing 14 is formed around the electronic - mobile device 17 in such a way that it enables its closure by a hood 16 and creates a watertight seal through a seal 15 and the frame 13.

Claims

1. A touchscreen for underwater use, that is, a transparent screen that is placed over an existing touchscreen which is of the capacitive type, wherein the touchscreen according to the invention is used for touch input in conditions of elevated pressure, under water or with use of protective equipment such as gloves and the touchscreen according to the invention does not have a source of electrical power, wherein said touchscreen is in the direction outward of a capacitive touchscreen [11] comprised of at least:

- a bottom film (6], which is metalized with an electrically conductive and transparent material in such a manner that it forms fields (4),

- a frame (13] that joins a bottom film (6) and a top film (3) and contains a medium (18),

- spacers (12] between the bottom film (6) and the top film (3], whereby the spacers (12) are glued to the bottom side of the top film (3) or to the top side of the bottom film (6) or to both,

- a top film (3), which is metalized with an electrically conductive and transparent material in such a manner that it forms a grid (1).

2. The touchscreen according to claim 1, wherein the fields (4) are transparent, electrically conductive and electrically isolated by a gap (5) and the grid (1) is preferably transparent and electrically conductive between all points, and the electrically conductive and transparent material is indium tin oxide with the acronym ITO.

3. The touchscreen according to claim 1, wherein the fields (4) and the grid (1) overlap in such a way that when a pressure (22) is applied on the top film (3), the grid (1) comes as close as possible or touches the fields (4), and that a surface area of the grid (1) above the capacitive touchscreen (11) is smaller than a surface area of the fields (4) above the capacitive touchscreen (11).

4. The touchscreen according to claim 1, wherein the grid (1) is defined by lines (28), and voids (2) are formed by removing the electrically conductive and transparent material left and right of the lines (28), whereby the electrically conductive and transparent material is completely removed only left and right of the lines (28), and an un-removed area is not in contact with the lines (28).

5. The touchscreen according to claim 1, wherein the voids (2) and the gap (5) are oriented horizontally or at an angle of 45⁹ with respect to the orientation of the capacitive touchscreen (11).

6. The touchscreen according to claim 1, wherein the spacers (12) are lower in height than the frame (13) and are preferably in circular shapes of smaller diameters, or the spacers (12) are an integrated part of the. bottom film (6) and the top film (3) in such a way that the bottom film (6) and the top film (3) already have protrusions in the form of the spacers (12).

7. The touchscreen according to claim 6, wherein the spacers (12) are implemented as spacer lines (24) covering the gap (5) and the spacer lines (24) are made so that they do not overlap.

8. The touchscreen according to claim 1, wherein between the bottom film (6), which forms fields (4), the top film (3), which forms the grid (1) and the frame (13), a medium (18) is enclosed which is preferably transparent with a low dielectric coefficient.

9. The touchscreen according to claim 8, wherein, for usage in conditions of ambient pressures between 0.5 bars and 2 bars, the medium (18) is preferably air, and for usage in conditions of elevated ambient pressure, above 2 bars, the medium (18) is replaced with an incompressible fluid, preferably a silicone or transformer mineral oil.

10. The touchscreen according to claim 1, wherein, for usage in conditions of very high ambient pressure, the bottom film (6) is replaced with a metalized plate (8) with passage openings (9) and conductors (7), which connect the fields (4) and a thin transparent self- adhesive film (19) is applied over the bottom surface of the metalized plate (8), which prevents the penetration of the medium (18) via passage openings (9), and the conductor (7) is preferably a coating of conductive nanotubes.

11. The touchscreen according to claim 10, wherein the metalized plate (8) is fitted with links (10), which connect the fields (4), and a transparent film (23) is applied over the links (10) and links (10) are preferably a coating of conductive nanotubes.

12. The touchscreen according to claim 1, wherein, for usage in conditions of elevated pressure, an additional plate (25) above the top film (3) is mounted, smaller magnets (26) of a diameter less than 3 mm and a maximum height of 5 mm are glued to the top side of the top film (3) and are all facing the same way with respect to their polarization and are glued in geometric patterns around the spacer (12) at a density that is no denser than five times the number of voids (2).

13. The touchscreen according to claim 1, wherein an adhesive film or an adhesive mass is applied on the bottom side of the bottom film (6) so that it covers the entire bottom surface of the bottom film (6), or is applied below the whole circumference of the frame (13), or is applied in spots below the frame (13), whereby the adhesive film or the adhesive mass has a layer of, preferably, a silicone or a polyurethane adhesive on the side with which is attached to the display of the electronic device, and a layer of adhesive for attachment to the bottom film (6) on the side facing toward the bottom film (6), and the thickness of the adhesive film or the adhesive mass is less than 1mm.

14. The touchscreen according to claim 13, wherein the bottom film (6) has openings (30) in the area below the frame (13), and the adhesive film or the adhesive mass on the side facing the bottom film (6) do not include an additional layer of adhesive as the frame (13) itself is sticky.

15. The touchscreen according to previous claims, wherein, where there is a risk of water intrusion and damage due to the rise in pressure, a watertight housing (14) is used which is formed around an electronic - mobile device (17) in such a way that it allows its closure by a hood (16) and creates a watertight seal with a seal (15) and the frame (13).