HK1201609B - Ultrasonic touch sensor with a display monitor - Google Patents

Description

Ultrasonic touch sensor with display monitor

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. provisional patent application No. 61/594,330, filed on 2/2012.

Technical Field

The present invention relates to an apparatus and method for collecting information about an object in contact with a display.

Background

In the prior art, touch screen monitors are commonly used to assist a user in selecting items displayed on the monitor. Selecting an item is typically performed using a pointing object, such as a stylus or finger. Such touch screen monitors often use capacitive sensors to identify the location at which a pointing object touches the display monitor. The identified location is then compared to the location of the image displayed on the monitor to determine what the user is identifying.

While these prior art touch screen monitors have become reliable and inexpensive, prior art devices do not incorporate any built-in sensing elements suitable for reliably measuring touch events, and while many of these prior art devices work well in dry and clean environments, they often fail in dirty, wet, or adverse conditions.

Disclosure of Invention

The present invention may be embodied as a touch screen display having a display monitor for providing visual images and an ultrasonic device capable of emitting ultrasonic energy waves and capable of detecting reflected ultrasonic energy. The display monitor may comprise light emitting diodes for providing visual images, or a liquid crystal display for providing visual images.

The ultrasound device may comprise a piezoelectric transmitter for emitting ultrasound energy waves. The ultrasonic device may also include a piezoelectric detector, such as a hydrophone array, for detecting the reflected ultrasonic energy. The detector may comprise a thin film transistor receiver for detecting the reflected ultrasonic energy.

The display monitor may be comprised of a plurality of layers of components, and the ultrasound device may be comprised of at least one layer. The ultrasound device may be attached to one or more of the display monitor layers.

The ultrasonic device may include a plurality of receivers for detecting the reflected ultrasonic energy. In one embodiment of the invention, each ultrasonic energy receiver is located within a component of a display monitor that includes pixels.

Drawings

For a fuller understanding of the nature and objects of the present invention, reference should be made to the accompanying drawings and the following description. Briefly, the drawings are:

FIG. 1 is an exploded view of a device according to the present invention in which an on-cell ultrasonic device has been integrated into a backlit LCD display monitor to create a touch screen display.

FIG. 2 is an exploded view of a device according to the present invention in which a top-mount ultrasonic device has been integrated into an OLED display to create a touch screen display.

FIG. 3 is an exploded view of a device according to the present invention in which a built-in ultrasonic device has been integrated into a backlit LCD display to create a touch screen display.

FIG. 4 is an exploded view of a device according to the present invention in which a built-in ultrasonic device has been integrated into an OLED display to create a touch screen display.

The following reference numerals may be found in the drawings and they represent:

1 anti-abrasion glass

2 continuous electrode (e.g., TCF (transparent conductive film, such as IZO, ITO, etc.))

3 PVDF or PVDF-TrFE piezoelectric polymers

5 color Filter glass (5A, 5B and 5C are simple 3 RBG color filters in glass)

6 TFT (thin film transistor) circuit

7 TFT substrate (e.g., glass)

8 piezoelectric emitter

9 polarization filter

10 liquid crystal

11 backlight panel

12 electrode pad (e.g., TCF)

13 continuous electrode (e.g., TCF)

14 optically transparent non-conductive, filling material

Detailed Description

The present invention relates to an ultrasonic scanning device and a display monitor. Information about objects in contact with the display monitor is collected by means of ultrasonic energy. The ultrasonic energy is transmitted toward a surface of a display monitor where a pointing object may contact the display monitor. When ultrasonic energy reaches the pointing object, at least some of the ultrasonic energy is reflected toward an ultrasonic energy receiver. The receiver detects the reflected energy and emits a signal indicative of the reflected energy being sensed. The transmitted signal is used to determine information about the object. The information may include one or more of: (a) a location of the pointing object, (b) information about the texture of the surface of the pointing object, and/or information about the structure of features present in (but not on) the pointing object.

In one embodiment of the present invention, the ultrasound device is attached to a display monitor. For example, the ultrasound device may be laminated to a portion of a display monitor. The combination of the ultrasonic device and the display monitor is referred to herein as a "touchscreen display. The touch screen display may be used to determine the position of a pointing object at a first time, and subsequently determine the position of the pointing object at a second time, in order to track the motion of the pointing object and thereby cause the display of a cursor on the display monitor, in order to identify an image and thereby select an option (e.g., a software application) represented by the identified image.

The pointing object may contain identification characteristics that can be used to identify the owner of the pointing object. For example, the pointing object may be a finger and the identifying characteristic may be a fingerprint. A touch screen display may be used to detect fingerprints to identify a user of the touch screen display. In this way, the touch screen display may be made available only to authorized users, or the touch screen display may be made to display images in a manner believed to be preferred by a particular user. In this way, the touch screen display may be personalized to the preferences of a particular user.

The phrase "built-in" touch screen display as used herein refers to a touch screen display that positions an ultrasound device within a set of elements that collectively make up the pixels of the display monitor. For example, each ultrasonic receiver is located within a component of a display monitor that includes a single pixel.

The phrase "on-top" touchscreen display as used herein refers to a touchscreen that couples an ultrasonic device to a surface that includes one of a plurality of layers of a display monitor. For example, in such an overhead touchscreen display, the layer of the display monitor to which the ultrasound device is attached may be a layer that is typically exposed, or may be an internal layer of the display monitor. For purposes of this disclosure, the phrase "out-cell" touchscreen display is used to refer to a particular type of "over-the-top" touchscreen display whereby an ultrasonic device is attached to a layer of the display monitor that is not internal to the display monitor (except for any protective, wear-resistant surface layer of the display monitor).

The ultrasonic device may be an ultrasonic fingerprint imaging system, such as those that use an ultrasonic sensor to acquire information about a fingerprint (which may then be compared to previously acquired fingerprint information for identification purposes, and/or to display a visual image of the fingerprint). The ultrasonic sensor transmits an ultrasonic pulse or set of pulses and then detects a reflected portion of the transmitted pulse. Such ultrasonic fingerprint imaging systems are relatively simple and reliable. An example of one such system is model 203 manufactured by ultrasonic scanning (Ultra-Scan).

The ultrasound device may use multiple detectors to detect energy reflected by the pointing object. Each detector may be individually calibrated to remove fixed pattern noise effects, which may be characteristics of the components that make up the ultrasound device, the display monitor, or both. These effects may include variations between detectors that may be caused by differences in amplifiers, as well as variations caused by manufacturing processes (e.g., glue, contaminants, etc.). Changes in the attenuation of the ultrasound waves caused by changes between pixels of the display monitor will be detected as non-changing portions of the fixed pattern noise received by the ultrasound sensor, and such fixed pattern noise may be removed during analysis of the signal transmitted by the receiver to indicate reflected energy is sensed by the receiver. Once the fixed pattern noise is removed, a "clean" signal is generated that represents the surface being analyzed by the ultrasonic sensor.

The ultrasound device may include an electronic control system that supplies timing signals. Some of these timing signals may be used to cause the ultrasound device to emit pulses of ultrasound energy. Other of these timing signals may be used in a process commonly referred to as "range gating," in which a determination is made as to which of the reflected ultrasonic energy detected by the ultrasonic device is relevant to indicating a surface on which an object may be placed. Discussion of range gating can be found in many reliable texts on sonar, radar, or ultrasonic non-destructive testing.

The timing signals, initiation of pulse generation, and TFT sensor signal readout may then be further processed into an image of an object in contact with the protective plastic film sheet.

Display monitors on the market today include those that use light emitting diodes and liquid crystal displays to present visual images to a user. Such display monitors are lightweight, thin, flat, reliable, and inexpensive. When such a display monitor is incorporated with an ultrasound device, the resulting touch screen display provides the ability to use a finger to point at the image on the display and provides capabilities similar to those currently provided by touch pads used in conjunction with personal computers and personal digital assistants.

Having provided an overview of the present invention, additional details will now be provided.

It is not required that the resolution of the display monitor must be the same as the resolution of the ultrasound device. This allows for, for example, a system where the resolution of the display monitor may be 100 dots per inch and the ultrasound device may be 10 dots per inch, or any other combination convenient for the application. However, built-in systems place the receivers of the ultrasound device within a 3-color set including color display monitor pixels, and thus adding an ultrasound receiver to a 3-color display pixel assembly typically has a one-to-one receiver-pixel set relationship, but a one-to-one association is not necessary. For example, omitting the ultrasonic receiver set from some display monitor pixels would allow for different pitch distributions of the display monitor and the ultrasonic device.

One embodiment of a top mounted touch display with a piezoelectric imaging system coupled to an LCD display monitor is depicted in FIG. 1. The piezo film emitters 8 are attached to an edge lit backlight panel 11. A TFT6 on the glass substrate 7 is attached on the surface of the backlight panel 11 opposite the piezoelectric radiator 8. Above this is a layer of liquid crystal material 10. Directly above this is a layer 13 of Transparent Conductive Film (TCF) attached to the color filter 5, with a layer of conductive TCF2 on top. Onto this TCF layer 2 is a layer of piezoelectric polymer 3 (or copolymer). The pattern of individual TCF pads 2 is applied to the piezoelectric polymer layer 3 or alternatively the polarizing filter 9 and the outer surface receives a layer of abrasion resistant glass or plastic 1. The resulting touch screen display operates in a manner similar to most LCD displays, and the voltage between the TFT patterned TCF electrode on the TFT (not explicitly shown, but part of the TFT itself) and the continuous common planar electrode 13 allows each display pixel to be turned on or off using a polarizer. If light that has passed through a polarizing filter subsequently passes through a second polarizer oriented at 90 degrees to the first polarizing filter, the light will be completely blocked and will not pass through the second polarizer. LCD displays use a fixed polarizing filter, usually a plastic sheet, and the second polarizing filter is itself a liquid crystal material. If a voltage is applied, it polarizes light to prevent light from being emitted, while if no voltage is applied, light is permitted to pass through. The ultrasonic signature comes into play when the piezoelectric film emitter emits a pulse of ultrasonic energy. The ultrasonic energy pulses travel through the layers to the outward facing surface (in this case, the wear resistant glass or plastic), where at least a portion of the ultrasonic energy pulses are then reflected downward again, carrying information about the ultrasonic impedance of the surface and any objects in contact with the surface. The reflected ultrasonic energy pulses are detected by a hydrophone array consisting of a piezoelectric polymer film 3 and two TCF electrode layers (both continuous electrode 2 and electrode array 12) in contact therewith. Trace conductors interconnect the electrode array 2 with electronics (not shown) to cause the ultrasonic device to generate and transmit signals corresponding to the individual ultrasonic signals associated with each ultrasonic array receiver element of the hydrophone array.

FIG. 2 depicts an alternative embodiment of a top-up touch screen display. In the described embodiment, the display liquid crystal layer 10 and associated TCF electrodes associated with the display monitor are not required. The backlight layer 11 is also not required because the TFT display contains OLED elements which directly illuminate and illuminate the display. In this case, an ultrasonic transmitter may be attached to the back surface of the TFT substrate glass.

Fig. 3 depicts another embodiment of the present invention. In this embodiment, the touch screen monitor is a built-in touch display. The piezo film emitters 8 are attached to an edge lit backlight panel 11. A TFT6 on the glass substrate 7 is attached on the surface of the backlight panel 11 opposite the piezoelectric radiator 8. The TFT6 has many circuits. The individual pixels are groups of three LCD control amplifiers and one ultrasonic receiver circuit. The ultrasonic receiver further has a piezoelectric polymer bonded thereto. Above this is a layer of liquid crystal material 10. Above this is a continuous electrode (TCF)2 which serves as the common electrode for the receiver and as the common electrode for the LCD driver circuitry. This TCF may be attached to the color filter 5. The next layer up in the stack (in figure 3) is a polarisation filter 9 and the final outer surface receives a layer of anti-wear glass or plastic 1. This display operates in a similar manner to most LCD displays, and the voltage between the TFT patterned TCF electrode on the TFT and the continuous common planar electrode 2 allows each display pixel to be turned on or off.

Another embodiment of a built-in touch display according to the present invention is depicted in fig. 4. The piezoelectric film emitter 8 is attached to the back surface of the substrate of the TFT circuit 7. The TFT circuit 7 may be composed of a group of cells constituting individual color pixels, each pixel being composed of three light emitting cells and one ultrasonic sensor cell. Attached to the ultrasonic sensor unit TFT may be a three-layer laminate consisting of a TCF electrode 2, a layer of piezoelectric polymer 3 and another TCF membrane electrode 12 continuous over the TFT. An optically transparent insulating material 14 may be used over the OLEDs (in fig. 4) to isolate them from the light emitting display circuitry and TCF 2. Above this is shown in fig. 4 a color filter glass 5 to allow the red-green-blue to show the color. The wear-resistant surface layer 1 protects the stack from physical abrasion and mechanical damage. It should be noted that although a one-to-one relationship between light pixels and ultrasound sensor pixels is described, the various sensor pixels will be readily omitted to change the resolution of the ultrasound device.

While the invention has been described with respect to one or more specific embodiments, it should be understood that other embodiments of the invention may be made without departing from the spirit and scope of the invention. Accordingly, the invention is to be considered limited only by the following claims and the reasonable interpretation thereof.

Claims (9)

1. A touch screen display, comprising:

a display monitor for providing a visual image; and

an ultrasonic device (6, 8) capable of emitting ultrasonic energy waves and capable of detecting reflected ultrasonic energy,

wherein the display monitor is comprised of a plurality of layers, at least one of the plurality of layers being an interior layer, the ultrasonic device is comprised of at least one layer, and the ultrasonic device is attached to one of the interior layers of the display monitor; and

wherein the ultrasonic receivers (6) of the ultrasonic devices (6, 8) are located within a group of light emitting elements which together constitute a pixel of the display monitor.

2. The touch screen display of claim 1, wherein each pixel comprises a group consisting of an ultrasonic sensor unit and three light emitting units.

3. The touch screen display of claim 1 or 2, wherein the display monitor includes an organic light emitting diode for providing the visual image.

4. The touch screen display of claim 1 or 2, wherein the display monitor includes a liquid crystal display (10) for providing the visual image.

5. The touch screen display of claim 1 or 2, wherein the ultrasonic device comprises a piezoelectric transmitter (8) for emitting the ultrasonic energy waves.

6. The touch screen display of claim 1 or 2, wherein the ultrasonic device includes a piezoelectric hydrophone array for detecting reflected ultrasonic energy.

7. The touch screen display of claim 1 or 2, wherein the ultrasonic device includes a thin film transistor receiver (6) for detecting reflected ultrasonic energy.

8. The touch screen display of claim 1 or 2, wherein the ultrasonic device includes a plurality of receivers for detecting reflected ultrasonic energy.

9. A method of collecting information about an object in contact with a touch screen display according to any of the preceding claims, the method comprising:

causing the ultrasonic device to emit ultrasonic energy waves toward a surface of the display;

reflecting at least a portion of the ultrasonic energy from the surface; and

causing the ultrasonic device to detect the reflected ultrasonic energy,

wherein the display is comprised of a plurality of layers, at least one of the plurality of layers is an inner layer, the ultrasonic device is comprised of at least one layer, and the ultrasonic device is attached to one of the inner layers of the display.