Patent Description:
It will be appreciated that the scope of the invention is in accordance with the claims. Therefore, there is provided a display device as defined in claim <NUM>. Further features are set out in the dependent claims. A display device may comprise a first chassis and a first backlight housing attached to the first chassis, with the first backlight housing including a first wall. A first optical film layer is between a first light guide plate and a first rear polarizer, the first optical film layer comprising a secured end bonded to the first wall. A second chassis is rotatably coupled to the first chassis and includes a second backlight housing comprising a second wall. A second optical film layer is between a second light guide plate and a second rear polarizer, with the second optical film layer comprising a secured end bonded to the second wall.

In the drawings, like reference numerals indicate like parts throughout the various views, except where indicated otherwise.

As noted above some display devices, such as mobile display devices, may include an active display area in which display elements operate to produce visible imagery, and a non-active display area in which displayed imagery is not visible. In some examples electronics that drive operation of the display elements may be disposed in the non-active display area. The non-active display area may occupy a perimeter portion of the display device - e.g., the perimeter portion may surround the active display area. The non-active display area may be defined by a bezel between an outer edge of the active display area and an outer edge of a device chassis.

In some examples, the bezel may include a structure such as a black mask that conceals the non-active display area. To maximize the active display area of a display device, and correspondingly increase the aesthetic qualities of the device, it is desirable to minimize the size of the bezel. However, in some displays a reduction in bezel width may be limited by display component placement, configurations, tolerances and other considerations. For example, in some configurations a cover glass portion and one or more display components extend over and are bonded to an outer edge of the device chassis. These and other configurations may require minimum bezel widths of at least <NUM>. in a single display unit.

In dual-display devices that include two side-by-side displays, such as a hinged dual-display device, such configurations may result in a deadband region between a first active display area edge of the first display unit and a second active display area edge of the second display unit having a width of <NUM>. Such bezel widths and deadband regions can provide a less-than-optimal aesthetic appearance and user experience. Additionally, in some configurations and to account for component assembly tolerances and/or component expansion or shrinkage due to thermal fluctuations, one or more gaps between display components and structural elements may be provided. In some configurations, such gaps may allow for undesirable light leakage from a light source of the display.

Examples are described herein for providing display devices having display component configurations and structures that minimize a bezel width and address light leakage issues. <FIG> schematically illustrates an example of a display device in the form of a mobile computing device <NUM> including a housing <NUM>. As described in more detail below, the housing <NUM> may take the form of two chassis that each surround internal electronics and provide structure for displays, sensors, speakers, buttons, etc. As shown in the examples described below, two side-by-side display units <NUM> may be may be housed in the two chassis that are rotatably coupled via one or more hinges.

The housing <NUM> may include a processor <NUM>, volatile storage device <NUM>, sensor devices <NUM>, and non-volatile storage device <NUM>. The processor <NUM> is configured to execute one or more computer programs <NUM>, which may be an operating system or control program for the mobile computing device, and one or more application programs <NUM> stored on the non-volatile storage device <NUM>, and to enact various control processes described herein.

The sensor devices <NUM> may include a plurality of different sensors, such as, for example, an accelerometer, an ambient light sensor, a forward-facing camera, a microphone, a speaker, a depth camera, etc. The sensor devices <NUM> may also include a capacitive touch sensor, such as a capacitive array that is integrated with each of the one or more display units <NUM>. It will be appreciated that the examples listed above are exemplary, and that other types of sensors not specifically mentioned above may also be included in the sensor devices <NUM> of the mobile computing device <NUM>.

In the example dual-display device illustrated in <FIG>, the sensor devices <NUM> include a forward-facing camera <NUM> and a speaker <NUM>. In some examples, the mobile computing device <NUM> may take the form of a smart phone device. In another example, the mobile computing device <NUM> may take other suitable forms, such as a tablet computing device or other computing device having side-by-side displays.

With reference now to <FIG>, an example dual-display device <NUM> having two separate displays that are rotatably coupled according to examples of the present disclosure is illustrated. In this example and as illustrated in <FIG>, a first chassis <NUM> that houses the right side display <NUM> is rotatably coupled to a second chassis <NUM> that houses the left side display <NUM> via hinges <NUM>, <NUM>. In some examples, the hinges <NUM>, <NUM> are configured to permit the pair of displays <NUM>, <NUM> to rotate about axis <NUM> between angular orientations from a face-to-face angular orientation to a back-to-back angular orientation.

Hinges <NUM>, <NUM> may permit the pair of display <NUM>, <NUM> to rotate relative to one another such that an angle between them can be decreased or increased by the user applying suitable force to the chassis that house the displays. As shown in <FIG> and <FIG>, the first chassis <NUM> and second chassis <NUM> may be rotatably coupled in a manner that enables the right side display <NUM> and left side display <NUM> to be placed side-by-side in a <NUM> degree orientation, such that the two cover glass substrates <NUM>, <NUM> are substantially parallel.

As shown in <FIG>, in this side-by-side orientation the left edge <NUM> of the first chassis <NUM> and the right edge <NUM> of the second chassis <NUM> are abutting along a common axis <NUM>. In this manner, and with reference to <FIG> and the descriptions for this configuration provided below, each of the right side display <NUM> and left side display <NUM> may provide a non-active display area having a bezel width <NUM> of approximately <NUM>. In this manner, the dual-display device <NUM> may provide a deadband region <NUM> between a first active display area edge <NUM> of the right side display <NUM> and a second active display area edge <NUM> of the left side display <NUM> having a width of approximately <NUM>. Advantageously, such a reduced size of the deadband region <NUM> may provide more pleasing user experiences as compared to existing dual-display devices having larger deadband regions, particularly with applications utilizing the two displays in the side-by-side, <NUM> degree orientation.

<FIG> shows a partial sectional view taken along line A-A of <FIG> of a portion of a left side of the right side display <NUM> of the mobile computing device <NUM> according to one example of the present disclosure. In this example, the configuration of the display shown <FIG> may be utilized for the right side display <NUM>, and a mirror image of this configuration may be utilized for the left side display <NUM>. In this example, the chassis <NUM> comprises a bottom portion <NUM> and a left projection <NUM> extending from the bottom portion. It will be appreciated that the chassis <NUM> also includes a right projection (not shown) on the opposite side of chassis <NUM> from the left projection <NUM> that similarly extends from the bottom portion <NUM>. In some examples the right projection may be a mirror image of the left projection <NUM>.

Cover glass substrate <NUM> overlies the components of a display unit <NUM> that are located between the cover glass substrate and a floor <NUM> of the bottom portion <NUM> of the chassis <NUM>. In one example the display unit <NUM> may comprise a liquid crystal display (LCD). In this example, the cover glass substrate <NUM> is bonded to a front polarizer layer <NUM> with an optically clear adhesive layer <NUM>. Below the front polarizer layer <NUM> is a color filter glass substrate <NUM> and a display glass substrate <NUM>. In this example, the display glass substrate <NUM> comprises thin films of an active semiconductor layer, a dielectric layer and metallic contacts deposited over a supporting glass substrate.

In this example, below the display glass substrate <NUM> is a rear polarizer layer <NUM> and a layer of rim tape <NUM>. In other examples a different layer of reflective material may be utilized in place of rim tape <NUM>, such as a layer of film, ink or other reflective coating. In these examples, such reflective material may be provided near the perimeter of the active display area to reflect back light that otherwise may leak from the edge of the display. In other examples, an air gap may be provided in place of rim tape <NUM> to provide margin for component tolerances within the LCD and other display components.

Below the rim tape <NUM> is an upper optical film layer <NUM> and a diffuser substrate <NUM>. A light guide plate <NUM> is positioned below the diffuser substrate <NUM>. In one example, a light source (not shown) is positioned to face the end surface <NUM> of the light guide plate <NUM>. Light emitted by the light source enters the light guide plate <NUM> through the end surface <NUM> and is directed through the upper surface of the light guide plate and the upper optical film layer <NUM> and other layers above to illuminate the display glass substrate <NUM>.

Below the light guide plate <NUM> is a reflective film layer <NUM> and a back plate <NUM> of a backlight unit. The backlight unit may comprise a backlight housing <NUM> that includes a base <NUM> and a projection portion <NUM> extending through an aperture in the back plate <NUM> and comprising an inner wall <NUM>. In some examples the base <NUM> and projection portion <NUM> may comprise an elastomeric material, such as a thermoplastic elastomer. In the example of <FIG>, the base <NUM> of the backlight housing <NUM> comprises a footing <NUM> that is bonded to floor <NUM> of the chassis <NUM> with an adhesive layer <NUM>.

With reference now to <FIG>, in some examples the projection portion <NUM> of backlight housing <NUM> may be heat staked to the back plate <NUM>. In this partial exploded view, the LCD unit <NUM> comprises the front polarizer layer <NUM>, color filter glass substrate <NUM>, display glass substrate <NUM> and rear polarizer layer <NUM>. The upper optical film layer <NUM>, diffuser substrate <NUM>, light guide plate <NUM>, and reflective film layer <NUM> may be contained within the walls <NUM>, <NUM>, <NUM> and <NUM>. In this example, spacings <NUM> are provided between projection portion <NUM> and top portion <NUM>, and between bottom portion <NUM> and outer portion <NUM>, to allow for thermal expansion and contraction of these portions of backlight housing <NUM>.

In other examples the projection portion <NUM> of backlight housing <NUM> may be molded or bonded to the back plate <NUM>. In one example and with reference to <FIG>, the projection portion <NUM>, top portion <NUM>, bottom portion <NUM> and outer portion <NUM> may be injection molded around the back plate <NUM>. A plurality of cuts <NUM> may be formed in these portions to allow for thermal expansion and contraction of the material without deforming or buckling the back plate <NUM>.

With reference again to <FIG>, in this example the projection portion <NUM> of backlight housing <NUM> comprises a shelf <NUM>. The rear polarizer substrate <NUM> extends over and is bonded to the shelf <NUM> of the backlight housing via an adhesive layer <NUM>. Additionally, a secured end <NUM> of the upper optical film layer <NUM> is bonded to the wall <NUM> via another adhesive layer <NUM>. The left ends of each of the diffuser substrate <NUM>, light guide plate <NUM>, and reflective film layer <NUM> also abut the wall <NUM>. In this manner and as described in more detail below, by affixing the rear polarizer substrate <NUM> to the shelf <NUM> and by abutting the left ends of each of the diffuser substrate <NUM>, light guide plate <NUM>, and reflective film layer <NUM> to the wall <NUM>, the non-active display area of bezel <NUM> may be reduced.

In this example, the non-active display area is defined by the bezel <NUM> between the active display area left edge <NUM> and the left edge <NUM> of left projection <NUM> of chassis <NUM>, with the bezel having a width indicated at <NUM>. The active display area left edge <NUM> is aligned with the left ends of each of the diffuser substrate <NUM>, light guide plate <NUM>, and reflective film layer <NUM>. In one example and with reference to <FIG>, the active display area may include those portions of cover glass <NUM> located to the right of active display area left edge <NUM> and continuing to an active display area right edge <NUM> located adjacent to the right end of the right side display <NUM> and aligned with wall <NUM>. Accordingly, by affixing the rear polarizer substrate <NUM> to the shelf <NUM>, abutting the left ends of each of the diffuser substrate <NUM>, light guide plate <NUM>, and reflective film layer <NUM> to the wall <NUM>, and utilizing other structural details described above, the configuration of the display <NUM> of <FIG> may provide a bezel <NUM> with a width <NUM> of approximately <NUM>.

In the example of <FIG>, the bezel <NUM> comprises a thickness <NUM> of the left projection <NUM> of chassis <NUM> and a distance <NUM> from the left ends of components of the display unit <NUM> to the active display area left edge <NUM>. As noted above, in some examples a width <NUM> of bezel <NUM> may be approximately <NUM>, which may comprise a distance <NUM> of approximately <NUM> and a distance <NUM> of approximately <NUM>.

In some examples, the adhesive layer <NUM> between rear polarizer substrate <NUM> and shelf <NUM> may comprise a black or otherwise opaque material to block visibility of the light source, backlight housing <NUM> and/or other components of the display device. Additionally, by abutting the left ends of each of the diffuser substrate <NUM>, light guide plate <NUM>, and reflective film layer <NUM> to the wall <NUM>, this configuration eliminates any gaps between the wall <NUM> and adjacent components. Advantageously, any light leakage that could result from light from the light source bypassing the light guide plate <NUM> is also prevented. Additionally and with this configuration, the cover glass substrate <NUM> may not be affixed to the chassis <NUM>.

With reference now to <FIG>, the upper optical film layer <NUM> includes an unattached end <NUM> opposite to the secured end <NUM>. A gap is provided between the unattached end <NUM> and the wall <NUM> of outer portion <NUM>. Accordingly and with this configuration, by allowing unattached end <NUM> of the upper optical film layer <NUM> to remain free, the optical film layer laterally expands or contracts without buckling or otherwise deforming other components of the display unit <NUM>.

With reference now to <FIG>, another embodiment of a dual-display device <NUM> of the present disclosure is illustrated. In this example, the dual-display device <NUM> utilizes the same components and configurations described above for display device <NUM>. In this example, however, a bottom surface <NUM> of the upper optical film layer <NUM> is bonded to the light guide plate <NUM>. In some examples, the bottom surface <NUM> is bonded to the light guide plate <NUM> with a separate adhesive layer <NUM>. In some examples, adhesive layer <NUM> may be embedded within the diffuser substrate <NUM>.

As with the dual-display device <NUM> described above and illustrated in <FIG>, the upper optical film layer <NUM> includes an unattached end opposite to the secured end <NUM>. The unattached end may be located in a gap that enables the upper optical film layer <NUM> to laterally expand or contract without buckling or otherwise deforming other components of the display unit <NUM>. As with the dual-display device <NUM> described above, the configuration of the left side display <NUM> of the dual-display device <NUM> shown in <FIG> may be a mirror image of the configuration illustrated for the right side display <NUM>. Additionally, the reduced bezel widths and structural configurations to prevent light leakage discussed above are also provided by the configuration of dual-display device <NUM>.

With reference now to <FIG> and <FIG>, another embodiment of a dual-display device <NUM> of the present disclosure is illustrated. In this example, the dual-display device <NUM> utilizes the same components and configurations described above for display device <NUM>. In this example, however, in each of the right side display <NUM> and left side display <NUM>, a biasing element biases the upper optical film layer against the projection portion of the backlight housing. In this manner and as described in more detail below, the upper optical film layer is not bonded to the projection portion <NUM> or light guide plate <NUM> and may expand or contract without wrinkling or buckling. Additionally, one or more other layers/substrates of the display unit <NUM> also may be biased by the biasing element against the projection portion.

As shown in <FIG> and <FIG>, the backlight housing <NUM> comprises inner wall <NUM> of projection portion <NUM> and an outer wall <NUM> of outer portion <NUM>. A biasing element <NUM> is located between the unattached (outer) end <NUM> of the upper optical film layer <NUM> and the outer wall <NUM>. In the example shown in <FIG>, the biasing element <NUM> comprises a foam material that biases the upper optical film layer <NUM> toward inner wall <NUM>. Additionally, resilient properties of the foam material enable the upper optical film layer <NUM> to laterally expand or contract due to thermal variations or other environmental conditions. In this manner, this configuration allows the upper optical film layer <NUM> to experience a variety of environmental conditions without wrinkling or buckling, and without wrinkling or otherwise deforming other components of the display unit <NUM>. In other examples, any other suitable resilient materials, such as elastomeric materials, may be utilized for the biasing element <NUM>. In other examples, biasing element <NUM> may comprise a spring or other elastic object.

In the example of <FIG> and <FIG>, additional layers of the display unit are also biased by the biasing element <NUM> toward and against inner wall <NUM>. For example, the diffuser substrate <NUM> is biased by the biasing element <NUM> against the inner wall <NUM>. In a similar manner, the light guide plate <NUM> and reflective film layer <NUM> are biased by the biasing element <NUM> against the inner wall <NUM>.

As with the dual-display device <NUM> described above, the configuration of the left side display <NUM> of the dual-display device <NUM> shown in <FIG> may be a mirror image of the configuration illustrated for the right side display <NUM> in <FIG>. Additionally, the reduced bezel widths and structural configurations to prevent light leakage discussed above are also provided by the dual-display device <NUM>.

With reference now to <FIG> and <FIG>, another example of a dual-display device <NUM> of the present disclosure is illustrated. In this example, the dual-display device <NUM> utilizes the same components and configurations described above for display device <NUM>, including biasing element <NUM> that biases the upper optical film layer <NUM> toward inner wall <NUM>. In this example, however, instead of bonding the rear polarizer <NUM> to the shelf <NUM> of the projection portion <NUM>, an edge portion of the display glass substrate <NUM> is bonded to the projection portion via an adhesive layer <NUM>.

In the example of <FIG> and <FIG>, additional layers of the display unit <NUM> also are biased by the biasing element <NUM> toward and against inner wall <NUM>. For example, the diffuser substrate <NUM>, light guide plate <NUM> and reflective film layer <NUM> are biased by the biasing element <NUM> against the inner wall <NUM>. In a similar manner, the reflective film layer <NUM> is biased by the biasing element <NUM> the inner wall <NUM>.

As with the dual-display device <NUM> described above, the configuration of the left side display <NUM> of the dual-display device <NUM> shown in <FIG> may be a mirror image of the configuration illustrated for the right side display <NUM> shown in <FIG>. Additionally, the reduced bezel widths and structural configurations to prevent light leakage discussed above are also provided by the dual-display device <NUM>.

<FIG> schematically shows a non-limiting embodiment of a computing system <NUM>. The dual-display devices shown in <FIG>, <FIG>, and <FIG> may include one or more aspects of computing system <NUM>. It is to be understood that virtually any computer architecture may be used without departing from the scope of this disclosure. Computing system <NUM> includes a logic processor <NUM>, volatile memory <NUM>, and a non-volatile storage device <NUM>.

In such a case, these virtualized aspects may be run on different physical logic processors of various different machines.

When included, input subsystem <NUM> may comprise or interface with one or more user-input devices. Example NUI componentry may include a microphone for speech and/or voice recognition; an infrared, color, stereoscopic, and/or depth camera for machine vision and/or gesture recognition; a head tracker, eye tracker, accelerometer, inertial measurement unit, and/or gyroscope for motion detection, gaze detection, and/or intent recognition, electric-field sensing componentry for assessing brain activity, any of the sensors described above with respect to HMD device <NUM>, and/or any other suitable sensor.

Claim 1:
A display device, comprising:
a first chassis (<NUM>);
a first backlight housing (<NUM>) attached to the first chassis and comprising a first wall (<NUM>);
a first optical film layer (<NUM>) between a first light guide plate (<NUM>) and a first rear polarizer (<NUM>), the first optical film layer comprising a secured end (<NUM>) bonded to the first wall (<NUM>);
a second chassis (<NUM>) rotatably coupled to the first chassis (<NUM>);
a second backlight housing attached to the second chassis (<NUM>) and comprising a second wall;
a second optical film layer between a second light guide plate and a second rear polarizer, the second optical film layer comprising a secured end bonded to the second wall;
characterised in that:
the first optical film layer (<NUM>) comprises an unattached end (<NUM>) opposite to the secured end (<NUM>).