The present disclosure relates to touch screen systems. More particularly, the present disclosure relates to touch screens employing a waveguide and usable in a variety of media.
Scuba diving is a unique and enjoyable recreational experience. It is estimated that, every day, over 75,000 persons participate in the sport at thousands of diving resorts and operations worldwide. In addition, various commercial and military operations utilize scuba divers to perform activities such as search and rescue, salvage, underwater construction and repair activities, and military reconnaissance.
Operationally, one aspect of the uniqueness of diving is that the user interface to dive computers and other underwater equipment is less user-friendly and intuitive than land-based equipment. Making push buttons and other controls waterproof is challenging, which limits the number of controls and the types of controls available. Also, traditional capacitive and resistive touch screens do not work underwater because seawater surrounding the device is interpreted by the device as though the entire screen surface is being touched. Other methods of providing a user interface to diver computers and underwater equipment, such as using a gel-filled membrane over capacitive touch screen, or a pressure-controlled, air-filled membrane over capacitive touch screen are bulky, do not work with gloved hands, are vulnerable to membrane ruptures, etc.
Optical touch screens may hold potential for underwater use. However, existing optical touch screens are not designed to work effectively underwater. For example, access is required to the perimeter of the transparent screen for placement of light sources and sensors. This becomes difficult to implement with a practical underwater housing. In other examples, the edge of a transparent screen is required to be patterned (like a Fresnel lens), the screen is required to be multi-layered in order to establish a regular grid of light paths, collimating lenses are required, or solutions to complex systems of equations are required.
Challenges for optical touch screens include providing an implementation that can 1) easily fit in a pressure-tolerant, waterproof housing, 2) tolerate wide variation in ambient light and temperature, 3) tolerate a large difference in the index of refraction for water and air, 4) yield a simple set of algorithms that are not computationally intensive.
Provided is a method for determining location of a touch on a touch-screen which includes emitting a radiation pulse through a waveguide from one or more of a plurality of radiation sources coupled with a lower surface of the waveguide; forming a radiation response profile from the attenuation of each radiation pulse emitted from the plurality of radiation sources, internally reflected through the waveguide and measured at one or more radiation sensors coupled with the lower surface of the waveguide interior to at least one perimeter surface of the waveguide; when a width of the radiation response profile is within a pre-defined range and a magnitude of the radiation response profile meets or exceeds a threshold, determining a response centroid from the radiation response profile; constructing a line equation defining the path between each response centroid and the emitting radiation source such that each line equation extends at an angle relative to every other line equation; calculating points of interception for the line equations; and computing a centroid of the points of interception to establish a valid touch location.
Further provided is a touch screen interface system which includes a waveguide having at least one perimeter surface between an upper surface and an opposite, lower surface; a plurality of radiation sources coupled with the waveguide at the lower surface, interior to the at least one perimeter surface and configured to emit radiation into the waveguide for internally reflected propagation therethrough; a plurality of radiation sensors coupled with the waveguide at the lower surface, interior to the at least one perimeter surface and configured to measure attenuation of radiation internally reflected through the waveguide from one or more of the plurality of radiation sources; and a processor operatively coupled with the radiation sources and the radiation sensors. The processor is configured to cause emission of a radiation pulse from one or more of the plurality of radiation sources through the waveguide; form a radiation response profile from each radiation pulse emitted from the plurality of radiation sources, internally reflected through the waveguide and measured at one or more of the plurality of radiation sensors; determine a response centroid from each radiation response profile having a width within a pre-defined range and a magnitude exceeding a threshold; construct a line equation defining the path between each response centroid and the emitting radiation source such that each line equation extends at an angle to every other line equation; calculate points of interception for the line equations; and compute a centroid of the points of interception to establish a valid touch location.
Also provided is an optical touch screen system which includes a transparent waveguide having a upper touch surface and a lower non-touch surface substantially parallel to the upper touch surface, the surfaces defining therebetween a perimeter having one or more edge surfaces; a plurality of light sources operatively coupled with the waveguide so as to send light into the waveguide through either the upper touch surface or the lower non-touch surface or a combination thereof, such that the light propagates through the waveguide by means of internal reflection; a plurality of light sensors coupled to either the upper touch surface or the lower non-touch surface or a combination thereof, so as to sense intensity of light propagating through the waveguide; wherein with at least one of the plurality of light sources sending light into the waveguide, and in the absence of any touch at the upper touch surface, the light sensors measure relatively large signal strength; wherein with at least one of the plurality of light sources sending light into the waveguide, and in the presence of one or more touches at one or more upper touch surface locations, one or more of the plurality of light sensors measure attenuation in signal strength resulting from escape of some internally reflected light from the waveguide at one of more of the upper touch surface locations; and a processor. The processor is programmed to generate line equations representing attenuated light paths through the waveguide from each of the plurality of light sources to one of the plurality of light sensors or a center location of a group of the plurality of light sensors; and calculate intersections of a plurality of the line equations to relate the one or more of the upper touch surface locations and the sending light sources to determine the upper touch surface touch locations.
The present disclosure sets forth a simple touch screen user interface system that works effectively underwater and on the surface (in air), such that the user can freely move in and out of water while the touch screen continues to work seamlessly in both environments to provide the user a more intuitive interface for underwater equipment.
In accordance with one or more embodiments of the disclosure, a touch screen capable of functioning in air and underwater comprises a waveguide, radiation sources and radiation sensors coupled to a touch or non-touch surface of the waveguide and surrounding a display which presents information to a user. The presence of touch events on the exposed touch surface of the transparent waveguide are observed by measuring attenuations in radiation intensity with the radiation sensors as a result of the touch perturbing internal radiation reflections propagating within the waveguide. Qualified sensor responses are used to generate line equations, which are then used to determine the locations of clustered line intercept points, where touch events occur. Various techniques are implemented to allow the device to be housed in a waterproof case, and to function efficiently, reliably and seamlessly underwater and in air.
In reference to
A plurality of radiation sources 12a, 12b, 12c and 12d and a plurality of radiation sensors 13 are provided adjacent to lower non-touch surface 11b interior to the perimeter defined by one or more perimeter surface 11c. Lower non-touch surface 11b is configured both for coupling radiation emitted from sources 12a, 12b, 12c and 12dinto waveguide 11as well as for coupling radiation from waveguide 11 to radiation sensors 13. In an example, upper touch surface 11a is parallel to lower non-touch surface 11b. Radiation sources 12a, 12b, 12c, 12d may be of any variety configured to emit pulses of radiation detectable by radiation sensors 13 after propagation through waveguide 11. Control of emission of radiation pulses from radiation sources 12 as well as measurement by sensors 13 is provided by a processor 100 operatively coupled thereto.
Referring to
In an example, radiation sources 12a, 12b, 12c and 12d emit light and are provided as infrared light-emitting diodes while radiation sensors 13 measure light intensity and are provided as photo diodes or photo transistors. In an alternative, as light emitters, radiation sources 12a, 12b, 12c and 12d may emit any of a variety of wavelength ranges outside of the infrared spectrum. In another example, radiation sources 12a, 12b, 12c and 12d emit sound the intensity of which, after propagation through waveguide 11, is measurable by radiation sensors 13 which may be, for example, microphones. Neither radiation sources 12a, 12b, 12c and 12d nor radiation sensors 13 are limited to exploiting these example radiation forms.
A display 14 located directly behind waveguide 11 and adjacent to non-touch surface 11b may be used to present information to a user, including icons and other tools with which the user can interact, via touch screen system 10. Radiation sources 12a, 12b, 12c and 12d and radiation sensors 13 may surround display 14 in any of a variety of configurations so that radiation paths connecting the radiation sources 12a, 12b, 12c and 12d and radiation sensors 13 provide adequately dense radiation path coverage over the entire display viewing area and a touch or a plurality of concurrent touches will be detected on upper touch surface 11a. In an example configuration, the radiation paths connecting radiation sources 12a, 12b, 12c and 12d with radiation sensors 13 are adequately dense that a typical finger touch will result in a group of attenuated sensor responses. Some touch screen system embodiments have no display, for example touch pads.
A benefit of providing radiation sources 12 and radiation sensors 13 to lower non-touch surface 11b is that housing the finished assembly in a waterproof case, suitable for underwater use at a range of depths and pressures, is much easier to accomplish than if radiation sources 12 and radiation sensors 13 are located outside the perimeter of the waveguide.
A refractive index-matching material 21 substantially fills in any gaps between sources 12 and waveguide 11 to enable efficient propagation of light therefrom into waveguide 11. Similarly, refractive index-matching material 21 substantially fills in any gaps between waveguide 11 and sensors 13 to enable efficient propagation of light from waveguide 11 to light sensors 13.
Referring to
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As an alternative to refractive index-matching material 21, sources 12 and sensors 13 may be positioned outside perimeter surface 11c of waveguide 11. However, with this arrangement, many light paths between sources 12 and sensors 13 would be direct, and this may complicate detection of touch attenuation. In another alternative, light source(s) 12 and the light sensor(s) 13 may be embedded the in waveguide 11. However, by having the sources and sensors interface to upper touch surface 11a or lower non-touch surface 11b of the waveguide, more light propagating through waveguide 11 undergoes more reflections, and direct light paths between sources and sensors are virtually eliminated. By virtually eliminating the direct light paths in the waveguide, sensors 13 observe a much larger percentage change in signal response between conditions present with an attenuating touch, and conditions when an attenuating touch is not present. Furthermore, with light sources 12 and light sensors 13 coupled to lower non-touch surface 11b of waveguide 11, facilitates accommodation of touch screen 10 within a waterproof housing, and a complex bezel design necessary to withstand water pressure may be avoided.
With light source 12b turned on as shown in
In addition to ambient light effects, thermal sensitivity of sensors 13 and the difference in the indices of refraction for media in which touch screen system 10 is used must also be minimized. Light sensors are inherently sensitive to temperature, which can result in wide variations in measured response 41 when, for example, touch screen system 10 moves between air and water or two other distinct media. Similarly, the indices of refraction for air and water, 1.00 and 1.33, respectively, are quite different, also drastically affecting the measured response 41. To track both temperature sensitivity and the index of refraction for the surrounding medium, as well as to correct for those effects, a measure of average sensor response is tracked by processor 100, in order to dynamically adjust qualification thresholds for sensor response profiles.
In order to distinguish between inadvertent and intentional touches on touch screen 10, in some embodiments, a pre-established range of acceptable, qualified response profile widths are used by processor 100 to determine a valid touch. Since, for a range of gloved and ungloved finger sizes, widths of the response profiles 41x, 41y, 41x′ and 41y′ will vary. For example, a slender finger may result in a fairly narrow response profile width while a wider finger may result in a response profile width that is somewhat greater. Meanwhile inadvertent touches, are most likely narrower than a finger touch or wider than a finger touch in one or more dimensions. Processor 100 is programmed to compare response profile widths to the pre-established range of acceptable widths to further process those response profiles having qualified, acceptable widths and to ignore those response profiles having widths outside the pre-established range.
In an example, once a response profile, such as 41x or 41y, is determined by processor 100 to be of a width within the pre-established range, and the response attenuation is determined by processor 100 to be of a sufficient magnitude (such that it exceeds some threshold), the centroid of the response profile is determined by processor 100 and used to determine a touch location center 42, along a row of sensors. In other embodiments, the response peak, weighted response peak, curve-fitted response peak, or other means can be used to determine the center touch coordinates.
Using a selected means, for example the centroid of the response profile, touch location center 42 is determined for emission from each light source 12a, 12b, 12c or 12d individually. For individual emission from one or more of light sources 12a, 12b, 12c,and 12d, a valid touch may not be found. However, once two or more qualified response profiles have been found for a corresponding number of emitting light sources 12, the location of a single touch event can be determined in two dimensions by processor 100. Then, established location is reconciled and/or matched with an interactive portion of a display coupled to the waveguide adjacent to a lower surface so that the touch affects an interaction between user finger 32 and the display.
Depending on where a touch occurs relative to sources 12a, 12b, 12c and 12d, the widths of response profiles 41 may vary. If a touch occurs close to a source 12, the corresponding response profile 41 will be wider than if the same touch were to occur closer to a corresponding sensor 13. The shadow being cast is larger, as the touch moves toward the source 12. In addition to the shadow getting larger, positional accuracy, as determined by the response profile 41, tends to decrease. By qualifying a response profile 41 based on its width measurements a touch which occurs too close to a light source 12 may be disregarded. In a typical example, only one response out of four, will be discarded, as a result of a touch occurring on the touch surface in a corner of the display area.
Where sources and sensors are arranged as shown in
Using the line equations 62, intercept points 63 (circled) for those line equations are calculated by processor 100. For example, line equation 62a expressed as y=−x+8 and line equation 62b expressed as y=5x/12 have an intercept at a point (96/17, 40/17). In an example, among all calculated intercept points, qualified intercept points may be those identified as being confined, to some envelope of uncertainty. The envelope diameter, which may be defined in accordance with rules programmed into processor 100, relates to accumulated measurement errors caused by such contributors as thermal change effects, ambient lighting effects, various noise sources, electrical circuit settling time, the shape and size of the touch, whether the finger is gloved or not, whether the touch screen is in water, air or in the presence of beads of water, precipitating rain or snow, or other effects. Under a range of such expected operating conditions, not all of the intercept points will coincide exactly, instead there will be some normal distribution of intercept point locations that fall within the above-mentioned envelope of uncertainty and, for example, cluster around a centroid. The multiple points of interception are interpreted collectively or in part as a valid touch location. In one example, to establish a valid touch location, the centroid may be computed from the multiple intercept points. In another example, a single intercept point among a number may simply be chosen as the best representative of a valid touch location.
In cases where the intercept points are broadly distributed, outside the envelope of uncertainty, those intercepts may be interpreted as multiple touch locations or unintentional touches, depending other qualification criteria and rules programmed into processor 100.
Occurrences of false positive touch events and false negative touch events are preferably minimized based on tradeoffs. Such a design may require only two qualified line equations and one intercept point, or perhaps three qualified line equations and three tightly clustered intercept points, or a variety of qualification criteria can be used in determining the two-dimensional location of a valid touch. For example, in reference to
The above discussion focuses on single touch locations on upper touch surface 11a.
Other embodiments such as those represented in
Referring to
While
When a width of any radiation response profile is within a pre-defined range, it is then determined at 94, whether a magnitude of that radiation response profile exceeds a dynamic threshold (based on ambient light levels and source and sensor thermal conditions). If the threshold is not exceeded, process 90 returns to emission of radiation pulses at 91. When a magnitude of the radiation response profile exceeds the threshold, the resulting profile is considered a qualified profile, and a response centroid is determined from the radiation response profile at 95.
At 96, a line equation is constructed to define the path between each response centroid and the emitting radiation source such that each line equation extends at an angle to every other line equation. At 97, points of interception for the line equations are calculated and further evaluated based on the above-mentioned envelope of uncertainty such that interception points within the envelope are retained and those outside the envelope are disregarded. In order to establish the location of one or more valid touch, at 98, a centroid of the interception points is computed. Steps 91 to 98 are only illustrative and other alternatives can also be provided where one or more steps are added, one or more steps are removed, or one or more steps are provided in a different sequence without departing from the scope of the claims herein.
Aspects of touch screen 10, other than the number and locations of light sources, may also be varied. For example, embodiments of a touch screen system described herein may be incorporated into one of many different types of systems that may be used in air or underwater, and that may be utilized by recreational, commercial, industrial and military industries. Aspects of a touch screen system constructed in accordance with the present disclosure may be incorporated into a wrist-mounted, handheld or console dive computer, or may be incorporated into a case used for housing conventional cell phones, tablets or other devices, or may be used in other underwater devices that require a user interface. In an example, processor 100, is a component of the device into which the present system is incorporated.
Those skilled in the art can readily recognize that numerous variations and substitutions may be made to disclosed touch screen systems and components thereof, their use, and their configuration to achieve substantially the same results as achieved by the embodiments described herein. Accordingly, there is no intention to limit the disclosure to the disclosed example forms. Many variations, modifications, and alternative constructions fall within the scope and spirit of the disclosure.
Number | Date | Country | |
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Parent | 14844916 | Sep 2015 | US |
Child | 15091372 | US |