WO2013134621A1

WO2013134621A1 - Bezel-free display device including an acoustically coupled display cover plate

Info

Publication number: WO2013134621A1
Application number: PCT/US2013/029820
Authority: WO
Inventors: Izhak Baharav; Jacques Gollier
Original assignee: Corning Incorporated
Priority date: 2012-03-09
Filing date: 2013-03-08
Publication date: 2013-09-12

Abstract

A display device comprising a display panel and a display cover plate positioned between the display panel and an observer. The display cover plate is preferably configured to shift an image displayed on the display panel relative to an observer to obscure a bezel surrounding the display panel. In addition, the display cover plate is coupled to an acoustic driver that causes the display cover plate to vibrate and produce sound in response to an electrical signal from an audio circuit of the display device.

Description

BEZEL-FREE DISPLAY DEVICE INCLUDING AN

ACOUSTICALLY COUPLED DISPLAY COVER PLATE

[0001] This application claims the benefit of priority under 35 U.S.C. § 120 of U.S. Application Serial No. 61/608972 filed on March 9, 2012 the content of which is relied upon and incorporated herein by reference in its entirety.

TECHNICAL FIELD

[0002] The present disclosure relates to display devices that appear bezel-free to an observer, and in particular to bezel-free displays that incorporate an acoustic driver coupled to a display cover plate positioned in front of a display panel.

BACKGROUND

[0005] Watching movies on a display device is an experience comprised of image and sound. As used herein, the term display device is intended to encompass all devices capable of displaying visual content, including but not limited to computers, including laptops, notebooks, tablets and desktops; mobile telephones, and; televisions (TV). Each of the foregoing devices includes many component parts including the physical case (i.e. cabinet) in which individual components may reside, circuit boards, circuit elements such as integrated electronic components, and of course the display panel itself. Currently, these display panels are flat display panels comprising liquid crystal display elements, organic light emitting diode (OLED) display elements, or plasma display elements, and of course the glass or plastic substrates on which many of these elements are disposed and/or enclosed by. Typically, the edge portions of the flat display panels and the display device itself are utilized for electrical leads and various other electronic components associated with the operation of the display panel, such as circuits that drive the panel pixels as well as LED illuminators in the case of an LCD display panel. This has resulted in flat display panel manufacturers encasing the edge portions of the display panels within and/or behind a bezel, which bezel serves to conceal the foregoing components, but also obscures the edge portions of the display panel thereby reducing the overall image size.

[0006] For esthetic reasons, flat panel display makers are trying to maximize the image viewing area, and accordingly minimize the size of the bezel surrounding the image. However, there are practical limits to this minimization, and current bezel sizes are in the range of from about 3 mm to 10 mm in width. Moreover, television in particular is rarely viewed without an accompanying audio capability. Thus, in contrast to the desire to reduce the size and overall visual impact of the bezel, the bezel is nevertheless often called upon to house audio components such as speakers.

[0007] In general, many of the speakers for TV's are placed wherever room exists. Yet current television designs consist of virtually nothing visible except the bezel, the display panel and in some cases a stand. Light emitting diode (LED) edge lighted LCD televisions can be less than several centimeters in thickness at the most, and recent announcements regarding OLED televisions have emphasized thicknesses less than 4 mm, leaving little room for conventional speakers capable of room-filling sound. Indeed, very little cabinet space remains in current television designs except for the bezel. Nonetheless, front facing speakers are superior, as the audio power is delivered directly to the observer rather than being bounced from room walls, therefore the visible bezel is an ideal location to position speakers. Thus, manufacturers are faced with competing needs: reducing the size of the bezel while at the same time providing a physical location in which to house audio components. While in some instances auxiliary speakers that are separate stand-alone units may be coupled to the TV audio circuits by electrical cords or even short range radio transmission (e.g. Bluetooth), the vast majority of owners typically rely on the audio equipment supplied with the TV. Unfortunately, insofar as self-contained audio is concerned, the effort to incorporate edge-to- edge visibility of the TV display panel leaves no room for speakers. Therefore, to achieve the ultimate goal of no bezel at all, an optical solution that obscures the bezel and gives the view a perception of edge-to-edge picture should also provide for a front- facing audio capability.

SUMMARY

[0005] According to embodiments of the present disclosure, a display device is described wherein a bezel positioned about a perimeter of a display panel of the display device is concealed by an image generated by the display panel, thus providing an essentially bezel- free appearance to an observer of the image. The bezel-free appearance is facilitated by employing a display cover plate that shifts or stretches the image over the bezel relative to the observer. Moreover, the display cover plate is used to produce sound, wherein the sound can be perceived to come directly from the image. [0006] In one aspect a display device is disclosed comprising a display panel; a display cover plate positioned to form an air gap between the display panel and the display cover plate, the display cover plate comprises a chemically- strengthened glass; and an acoustic driver coupled to the display cover plate and in electrical communication with an audio circuit of the display device. The display panel in the case of an LCD display panel includes, for example, a first substrate, a second substrate sealed to the first substrate, and wherein an LCD material is positioned between the first and second substrates. The substrates are typically formed from glass. The display panel may further comprise various thin film materials deposited on one or both of the substrates, including without limitation thin film transistors, polarizing films, color filter films, transparent conductive films such as ITO (indium tin oxide), antireflection films, spacer elements, and alignment films.

[0007] The display cover plate may comprise an ion-exchanged glass. The display cover plate may further comprise a prismatic array configured to shift an image displayed on the display panel relative to an observer of the image. For example, the prismatic array may be formed in a plastic (polymer) film that is attached to the display cover plate, or the prismatic array may be formed in the glass of the display cover plate such that the individual prisms are glass. In some examples the display cover plate comprises a curved surface. For example, edge portions of the display cover plate may be curved.

[0008] The display device may further comprise one or more rails positioned between the display cover plate and the display panel, and wherein the acoustic driver is positioned on or in at least one of the one or more rails. The acoustic driver may be mechanically coupled to a surface of the display panel. The acoustic driver in some examples comprises an

electromagnetic actuator such as a voice coil. For example, the electromagnetic actuator may comprise a magnet and a wire coil. In other examples the acoustic driver comprises a piezoelectric actuator.

[0009] The display cover plate may comprise one or more piezoelectric actuators

mechanically coupled thereto. For example, at least one of the piezoelectric actuators may be in electrical communication with an electrical circuit configured to energize the piezoelectric actuator for a predetermined time period. Such functionality may be used to remove dust particles from the display cover plate. For example, the piezoelectric actuator may be energized when the display panel is energized and/or de-energized, so that "turning on" the display device or "turning off the display device energizes the piezoelectric actuator for a predetermined time.

[0010] In some embodiments the acoustic driver (e.g. voice coil or piezoelectric actuator) may comprise a transducer such that the acoustic driver is configured as a microphone.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] These and other aspects are better understood when the following detailed description is read with reference to the accompanying drawings, in which:

[0006] FIG. 1 A is a front view of a display device comprising a display panel and a bezel;

[0007] FIG. IB is a front view of a tiled array of display devices;

[0008] FIG. 2 is a front view of a display cover plate including prism regions for concealing a bezel;

[0009] FIG. 3A is a schematic diagram of a portion of a prism region showing individual prisms;

[0010] FIG. 3B is a graph showing the prism angle Θ as a function of position on a display device;

[0011] FIG. 4 schematically illustrates an observer O located far away from a display panel of a display device incorporating a bezel-concealing display cover plate;

[0012] FIG. 5 is an edge view of a portion of a display device wherein a display cover plate positioned in front of the display panel comprises a curved portion and the display cover plate includes an angular filter film adhered to a back surface thereof;

[0013] FIG. 6 is a schematic representation of an acoustic driver coupled to a display panel;

[0014] FIG. 7 is an edge view of an acoustic driver positioned between the rigid structure of a TV display panel and display cover plate;

[0015] FIG. 8 is a graph showing the ratio of air gap AG to bezel width W as a function of prism angle Θ;

[0016] FIG. 9 is a front view of a display cover plate wherein corner portions of the display cover plate are coated with and opaque material, such as black paint;

[0017] FIG. 10 is an edge view of a display panel and a display cover plate attached thereto, and wherein the display cover plate is clamped to a middle portion of the display panel to impart curvature to the display cover plate; [0018] FIG. 11 is an edge view of a display panel and a display cover plate, wherein an acoustic driver is attached to a back surface of the display panel; and

[0019] FIG. 12 is an edge view of a display panel and a display cover plate, wherein a rail is positioned between the display panel and the display cover plate, and an acoustic driver is attached to or within the rail.

DETAILED DESCRIPTION

[0005] Examples will now be described more fully hereinafter with reference to the accompanying drawings in which example embodiments of the disclosure are shown. Whenever possible, the same reference numerals are used throughout the drawings to refer to the same or like parts. However, aspects may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0006] The aesthetics of display devices, such as television display panels, computer monitors, and laptop display panels, are affected by the size and appearance of a bezel that exists around a perimeter of such display devices. The bezel of a display device may be used to house electronics for driving the pixels of the display panel, as well as, in certain instances, to provide backlighting for the display device. For example, an LCD television display panel may include a plurality of backlighting light emitting diodes (LEDs) maintained within the bezel region of the display device.

[0007] The trend over the last few years has been toward smaller and smaller bezels. Current bezel widths are in the order of 3 to 10 mm. However, television models having very large display panels have achieved bezel regions having a width as small as 2 mm on at least two borders and 4 mm on the other two borders. The manufacturing of smaller bezels has come with certain trade-offs, however, and the presence of a bezel, even though small, may still be distracting to some observers, especially when the display devices are assembled in a tiled arrangement to form a very large displayed image. The bezels of such tiled display devices give the undesirable appearance of an image "grid," rather than a cohesive large image without seams. The eye is very sensitive to the presence of a black line separating tiled display devices, which makes such an image unsightly.

[0008] Embodiments of the present disclosure include bezel-concealing display cover plates that conceal the bezel so that its presence is not visible, or at the least not readily noticeable to the observer within a predictable viewing angle. For example, a display cover plate with angular filters in the form of prisms may be used to shift a portion of an image from the display so that it cover plates at least a portion of the bezel behind the display cover plate. In another example, a bezel-concealing display cover plate may include a curved portion at an edge thereof that shifts an image from the display to extend over at least a portion of the bezel. The curved portion of the display cover plate may be, for example, a light bending (refracting) filter layer attached to a curved portion of the display cover plate.

[0009] Referring now to FIG. 1A, a display device 10 configured as a flat display panel television is illustrated. While the following description is primarily in terms of televisions, it should be noted that embodiments of the present disclosure may be suitable for other display devices and therefore are not limited to televisions. The display device 10 comprises a display panel 12 that has a bezel 14 positioned around its perimeter. Bezel 14 comprises bezel portions 14a - 14d. The bezel portions 14a - 14d may enclose display drive electronics, as well as backlighting hardware to backlight the display panel 12, such as edge positioned light emitting diodes (LEDs). The bezel portions 14a - 14d may have a particular width, such as in a range from about 3 mm to about 10 mm, for example. The bezel portions 14a - 14d may be distracting to a viewer, particularly if several display devices are arranged in a matrix in order to view the entire image, as illustrated in FIG. IB.

[0010] Accordingly, FIG. 2 depicts a bezel-concealing display cover plate 16 according to an embodiment of the present disclosure. The bezel-concealing display cover plate 16 of the illustrated embodiment is configured to be mechanically coupled to the display device 10 illustrated in FIG. 1A in a location such that display cover plate 16 is positioned between display panel 12 and the viewer (i.e. observer) of the image. The bezel-concealing display cover plate 16 can be mounted on the display device 10 such that there is an air gap between the bezel-concealing display cover plate 16 and the observer-facing surface of display panel 12. In one example, the bezel-concealing display cover plate 16 may be coupled to the display device 10 by pillars (not shown) at the corners of the bezel- concealing display cover plate 16. In some examples, the mounting pillars may be transparent to reduce their visibility.

[0011] Bezel-concealing display cover plate 16 comprises a prism region including four prism portions 18a - 18d adjacent to the perimeter of the display cover plate. As described in more detail below, prism portions 18a - 18d comprise many prisms arranged in an array that act as an angular filter to the regions of the display panel 12 that are positioned behind the bezel portions 14a - 14d relative to the observer. The display cover plate and the angular filters provided by the prism portions 18a - 18d make it possible to conceal the bezel so that its presence is not visible, or at least not readily apparent, to the observer. The bezel- concealing display cover plate 16 may further comprise a visually transparent central portion 20 bounded by the prism portions 18a - 18d that does not contain any prisms and is therefore substantially flat. The bezel-concealing display cover plate 16 may be made of glass. For example, the glass may be a chemically strengthened glass such as an ion exchanged glass, an acid- washed glass, or both. Prism portions 18a - 18d may, for example, be made from a commercially available angular filter material that can be adhered to the display cover plate, such as Vikuiti image directing film (IDF II) manufactured by the 3M Company. It should be understood that Vikuiti is but one of many possible angular filter solutions, and is presented herein as a non-limiting example only. In another example, angular filters may be incorporated directly into display cover plate 16. For example, prisms may nbe formed directly in the display cover plate material. As described in more detail below, specialized angular filters may be optimized and developed for the purpose of concealing the bezel from an observer. It is noted that an air gap of approximately 2.7 times the desired lateral image shift is needed when using the Vikuiti angular filter.

[0012] Referring now to FIG. 3 A, a portion of a prism region 18 of a bezel-concealing display cover plate 16 according to an embodiment of the present disclosure, such as prism portion 18a, is illustrated. The prism portion comprises many prisms 22 that are triangularly shaped. The prisms 22 include a prism angle Θ that cause the image near the bezel to be shifted. FIG. 3B is a graph showing the prism angle Θ as a function of position on the display device 10. Generally, the prism angle Θ of the prisms 22 should be at a maximum at the edge of the bezel-concealing display cover plate 16 and fall to zero (i.e., no prisms at all) away from the edges of the display cover plate. Accordingly, only a small portion of the image produced by display panel 12 will be shifted. The frequency of the prism array, that is the periodicity of the prisms, should be greater than the frequency of the pixels of the display panel to prevent aliasing in the resulting image. Generally, the prisms should be sized smaller than the pixels. For example, the individual prisms may be as small as 1/10 the size of a single pixel. [0013] Solid curve 24 depicts an embodiment of the present disclosure in which the prism angle Θ of the prisms decreases linearly from the edges of the bezel-concealing display cover plate 16 and falls to zero at the central region over a distance d. Dashed curve 26 depicts an example in which the prism angle Θ of the prisms vary non-linearly over distance d. The more complicated profile of dashed curve 26 may be considered with the aim of avoiding disturbing image discontinuities.

[0014] FIG. 4 schematically illustrates an observer O located far away from a display panel 12 of a display device 10 wherein a bezel-concealing display cover plate 16 is positioned between the display panel and the observer. An air gap AG exists between the bezel-concealing display cover plate 16 and the display panel 12. The simulation traces light rays emitted from the display panel 12 to the observer O and indicates, for a given position XI on the display panel 12, the position X2 where the light ray hits the bezel-concealing display cover plate 16. In one simulation, the prisms face the observer O, and the prism angle of the prisms vary linearly from 32° at the very edge of the bezel-concealing display cover plate 16 (i.e., above a portion of bezel 14) to 0° about 10 mm away from the outer edge of display cover plate 16. The index of refraction of the bezel-concealing display cover plate 16 in the simulation was 1.5, and the air gap AG was about 15 mm.

[0015] It should be noted that the localized angular filters provided by the bezel- concealing display cover plate 16 near the bezel of a display device such as display device 10 may produce some image distortion. Such image distortion may be mitigated, for example, by modifying the pixel position in the display device to compensate for the optical distortion introduced by the prisms. Where the prism angle variation is a linear function, it can be shown that the image distortion causes local magnification of the image, which can then be compensated by using a smaller pixel pitch at the edges of the display device.

[0016] When the observer does not view the display device 10 at normal incidence, bezel 14 may be partly or wholly visible. In particular, when the observer O is located very close to the display device 10, the observer will view all of the edges of the display cover plate at high angles of incidence, which may make all of the bezel portions visible and may give an impression of a television inside a box. [0017] A reduction in the visibility of the bezel at an increased viewing angle may be accomplished by adding a diffusing texture on the prism portions 18a - 18d of the bezel- concealing display cover plate 16. The image may be partially blurred in this region close to the bezel portions 14a - 14d because that part of the image is generated on the bezel- concealing display cover plate 16 itself. However, having a 10 mm blurred area for a large television may not be a significant visual distraction because observers usually fix their attention near the center of the image, and peripheral information is not as significant. In some examples, prism portions 18a - 18d may have prisms on each side of the bezel- concealing display cover plate 16 to enlarge the viewing angle.

[0018] Referring now to FIG. 5, an edge portion of a bezel-concealing display cover plate 16 having a curved portion 28 in close proximity to an edge of the display device 10 and over bezel 14 is illustrated. Curved portion 28 comprises prisms. The shape of the curved portion 28 of the bezel-concealing display cover plate 16 is optimized to conceal bezel 14 over a wider viewing angle. The prisms may be formed directly on display cover plate 16, or on a film 32 attached to display cover plate 16, or other processes may be employed to achieve small prism structures on the display cover plate 16. This may produce an image that is visually bezel-free at a very large viewing angle, for example 45° as a non-limiting example.

[0019] In the embodiment depicted in FIG. 5, the bezel-concealing display cover plate 16 is shown comprising an angular filter film 32 adhered thereto. The display cover plate 16 has a first straight central portion 20 at a height that provides a gap AG between display cover plate 16 and display panel 12 of the display device 10. Display cover plate 16 further comprises a curved portion 28 that connects with central portion 20. Display cover plate 16 may comprise a chemically strengthened glass such as an ion exchanged glass. A glass display cover plate may also be chemically strengthened by acid washing to remove surface defects. The angular filter film 32, which includes the prisms, may be adhered to an underside of display cover plate 16, positioned between display cover plate 16 and display panel 12, and similarly comprises a first flat or straight portion 32a adhered to central portion 20, a curved portion 32b having prisms adhered to curved portion 28, and a second straight portion 32c. In this embodiment, the prisms face display panel 12 such that the smooth flat surface of the angular filter film 32 is adhered to display cover plate 16. In other examples an index-matching adhesive may be utilized to adhere the angled side of the angular filter film 32 to the display cover plate 16, or to adhere an angular filter film that has prisms on each side.

[0020] As described above, the prism angle Θ of the prisms should be at a maximum close to the edge of the display device 10 and falling to a minimum (e.g., zero) at some distance from the edge of the display device 10. It is noted that at some viewing angles, the curved portion 32b may cause the prisms to operate in a total internal reflection regime, thereby causing portions of the bezel-concealing display cover plate 16 look like a mirror. One way to account for total internal reflection, as well as for increasing the viewing angle range, is to optimize the prism angle variation profile of the prisms in the curved portion 32b of the angular filter film 32 (or in the curved portion 28 of display cover plate 16 in embodiments of the disclosure where the prisms are formed directly on the display cover plate, e.g. in the glass of the dsiplay cover plate).

[0021] The preceding example of a bezel-free display using a display cover plate are based on bending light rays, wherein an air gap AG is between the face of the display panel and the display cover plate. One can take advantage of air gap AG to also vibrate the display cover plate and produce sound.

[0022] Referring now to FIG. 6, an acoustic driver 40 may be attached at one surface of display panel 12 and a mass on the other side to efficiently couple energy to the surface of the display panel 12. Acoustic driver 40 may be, for example, an electromagnetic actuator or a piezoelectric actuator. One example of a suitable electromagnetic actuator is a voice coil, such as the voice coil model number HIAX32C20-8 manufactured by HiWave. The electromagnetic actuator such as a voice coil comprises a coil that receives an audio signal from the display device audio circuitry. The audio signal produces a varying electromagnetic field from the coil, and in the presence of a magnetic field supplied by a local magnet, causes the coil to move in relation to the magnet. When the magnet, or the coil, is connected to a suitable diaphragm, the motion is transferred to the diaphragm and the motion of the diaphragm in air produces sound.

[0023] Attaching an acoustic driver comprising such an electromagnetic actuator to a display panel for the purpose of producing sound from the display panel, where the display panel serves as a diaphragm may be undesirable. For example, the actuator is required to cause vibrations in the diaphragm. The heavier and more rigid the diaphragm, the more difficult it is to induce vibration and produce sound. Moreover, the frequency response, which is related to the perceived audio quality produced, depends heavily on the diaphragm structure. In addition, all the circuitry connected to the display panel, which in some instances may be positioned directly on the display panel, will be on a vibrating surface, which may affect reliability of the display panel.

[0024] In the case of a display cover plate positioned in front of a television display panel, a better approach consists of positioning the acoustic driver between the rigid structure of the TV display panel 12 and the relatively flexible TV display cover plate 16 as shown in FIG. 7 so that the display cover plate serves as the diaphragm with the acoustic (audio) driver mechanically and acoustically coupled to the display cover plate.

[0025] When operating acoustic driver 40 away from resonant frequencies, the vibration amplitude, which is related to the acoustic power produced, is a function of the acceleration the acoustic driver can produce, which is inversely proportional to the mass in motion. Therefore, by making the display cover plate very thin, one can minimize the force the acoustic driver needs to produce. In other words, a thin display cover plate can produce a more efficient speaker, and a speaker with better high-frequency response and thus better audio quality. Accordingly, the first resonant frequency of the display cover plate should be also preferred for this reason. For example, the display cover plate thicknesses can be equal to or less than about 1 mm, equal to or less than about 0.7 mm, equal to or less than 0.6 mm, or equal to or less than 0.5 mm.

[0026] One unavoidable chore associated with displays, and in particular televisions, is the removal of accumulated dust from exposed surfaces of the device. For a display device comprising a display cover plate, the dust accumulation may occur on the exposed surface of the display cover plate. Accordingly, display device 10 may include a mechanism by which dust may be removed from display cover plate 16. Dust removal may be accomplished, for example, by coupling a piezoelectric actuator to the display cover plate. The piezoelectric actuator may form a part of an acoustic driver, or the piezoelectric actuator may be separate from the acoustic driver. The piezoelectric actuator associated with dust removal may be in electrical communication with a cleaning circuit configured to energize the piezoelectric actuator at a predetermined time, and for a predetermined length of time. For example, the piezoelectric cleaning circuit may be configured to electrically energize the piezoelectric actuator when the display panel is energized (e.g. the TV is "turned on"), when the display panel is de-energized (e.g. the TV is "turned off), or both. As used herein, energizing or de- energizing the display panel is not to imply energizing or de-energizing the display device (e.g. TV) itself, since at least some circuitry within modern display device typical remain energized. For example, circuitry necessary for continued function of an infrared remote control. Nevertheless, the cleaning circuit may energize the dust removal piezoelectric actuator for a predetermined time period of, for example, less than 10 seconds, less than 8 seconds, or less than 5 seconds. When the piezoelectric actuator is energized, the piezoelectric actuator vibrates the display cover plate at a high frequency, thereby dislodging dust particles from the surface(s) of the display cover plate. The cleaning circuit may be configured with a manual override, wherein on-demand energizing of the piezoelectric actuator may be accomplished, for example, by depressing a button on a remote control device.

[0027] It should be noted that acoustic driver may comprise a transducer wherein, for example, movement of a voice coil in the magnetic field of the magnet generates an electric current. To wit, the acoustic driver may be used as a microphone and be electrically coupled to an electric circuit configured to receive an electric signal from the acoustic driver.

[0028] As described previously, the amount of beam deviation that can be produced by a prism is a function of the prism angle Θ. The graph depicted in FIG. 8 shows the ratio of air gap AG to bezel width W as a function of Θ assuming a refractive index of 1.5 and further assuming the bezel is to remain invisible for a viewing angle of 20 degrees. As an example, by using a prism angle Θ of about 45 degrees, the air gap needs to be at least 4 times the width of the bezel (a ratio of 4), which means a large air gap is unavoidable in such a design.

[0029] Keeping the bezel-free impression at the corners of the display may require bending the prisms, which is a serious design challenge. Therefore, to hide the 4 corners of the TV with opaque areas on the 4 corners of the cover plate glass. For example, the corners 42 may be blackened, such as with paint, thereby providing a location behind which to position drivers 40 as shown in FIG. 9. Also, having drivers at the corners of the display provides sound coming from different locations relative to the image displayed by the display panel.

[0030] With large size TV's, a TV display cover plate as thin as 0.7 mm has extremely low rigidity, and large deformation can be introduced by pushing on the display cover plate with fingers, which gives a very bad tactile impression. To avoid that impression the thickness of the display cover plate may be increased. However, this will considerably increase the weight of the TV, particularly if the display cover plate is formed from glass. Moreover, as the thickness of the display cover plate increases, more acoustic power is required and low frequency response may be impeded.

[0031] The resonant frequencies of a plate can be determined by the following equations:

Eh

D (2)

12(l - v²) '

where p is the density of the plate, h is the thickness, D is the bending stiffness, E is Young's modulus, v is Poisson's ratio, and n and m are mode numbers. Decreasing the thickness of the plate lowers the resonant frequency, thereby providing better low frequency response, but is more likely to result in acoustic breakup, e.g. a chaos of vibrational modes, and decreases high frequency response.

[0032] In the case of a glass display cover plate the rigidity of the glass is proportional to the square of the length. So, by bending the glass of the display cover plate until it touches the display panel at the center, rigidity of the display cover plate will increase by a factor of 4. For example, the display cover plate may be adhered to the front surface of the display panel at a single point.

[0033] In the case where the four edges of the display panel are made to appear bezel-free, the overall shape of a display cover plate constrained at a single point of the display cover, for example near a center of the display cover plate, the shape of the display cover plate will be substantially spherical. Alternatively, where only left and right edges of the display panel are to appear bezel-free, the shape of the display cover plate can be cylindrical and can be obtained, for instance, by clamping down the glass top and bottom at the center with clamps 44 until the display cover plate is in contact with display panel 12 a line at the center of the display panel as illustrated in FIG. 10. In another example, the display cover plate can be adhered to the display panel along a line.

[0034] Where the bezel-free design of the display cover plate is obtained by having sharp curvatures on the right and left sides of the cover plate glass, including light beam bending micro prisms on the back side, rails 46 can be located on the top and bottom sides of the TV. As shown in FIG. 11 showing a portion of an edge of a display device 10, display cover plate 16 is connected to display panel 12 through rail 46. A rigid end cap 48 is attached to rail 46 and is likewise attached to acoustic driver 40. In this embodiment, the one or more acoustic drivers are fixed to the back surface of display panel 12. In another embodiment of the disclosure, shown in FIG. 12, acoustic drivers 40 may be positioning within or on the rail. For example, in the case of an electromagnetic acoustic driver, many voice coils can be connected together and rail 46 attached to either the magnet or the coil, the other part being attached to the display panel 12.

[0035] It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the claimed invention.

Claims

CLAIMS What is claimed is:

1. A display device comprising:

a display panel;

a display cover plate positioned to form an air gap between the display panel and the display cover plate, the display cover plate comprising a chemically-strengthened glass; and an acoustic driver coupled to the display cover plate and in electrical communication with an audio circuit of the display device.

2. The display device according to claim 1, wherein the display cover plate comprises an ion- exchanged glass.

3. The display device according to claim 1, wherein the display cover plate comprises a prismatic array configured to shift an image displayed on the display panel relative to an observer of the image.

4. The glass display cover plate according to claim 3, wherein the prismatic array is formed in the glass of the display cover plate.

5. The glass display cover plate according to claim 3, wherein the prismatic array comprises a polymer film adhered to the display cover plate.

6. The display device according to claim 1, wherein the display cover plate comprises a curved surface.

7. The display device according to claim 1, further comprising a rail positioned between the display cover plate and the display panel, and wherein the acoustic driver is positioned on or in the rail.

8. The display device according to claim 1 , wherein the acoustic driver is mechanically coupled to a surface of the display panel.

9. The display device according to claim 1, wherein the acoustic driver comprises an electromagnetic actuator.

10. The display device according to claim 9, wherein the electromagnetic actuator comprises a magnet and a wire coil.

11. The display device according to claim 1 , wherein the acoustic driver comprises a piezoelectric actuator.

12. The display device according to claim 1 , wherein the display cover plate comprises a piezoelectric actuator mechanically coupled thereto.

13. The display device according to claim 12, wherein the piezoelectric actuator is in electrical communication with an electrical circuit configured to energize the piezoelectric actuator for a predetermined time period.

14. The display device according to claim 13, wherein the piezoelectric actuator is energized when the display panel is energized and/or de-energized.

15. The display device according to claim 1, wherein the acoustic driver comprises a transducer such that the acoustic driver is configured as a microphone.