The invention relates to electronic devices and more particularly to devices having displays, and methods related thereto.
Privacy filters are well known in the art. Conventional privacy filters are generally passive films that may be placed over a display to restrict the viewing angle for the display.
Various features of the invention will be apparent from the following description of preferred embodiments as illustrated in the accompanying drawings, in which like reference numerals generally refer to the same parts throughout the drawings. The drawings are not necessarily to scale, the emphasis instead being placed upon illustrating the principles of the invention.
In the following description, for purposes of explanation and not limitation, specific details are set forth such as particular structures, architectures, interfaces, techniques, etc. in order to provide a thorough understanding of the various aspects of the invention. However, it will be apparent to those skilled in the art having the benefit of the present disclosure that the various aspects of the invention may be practiced in other examples that depart from these specific details. In certain instances, descriptions of well known devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
Laptop users are familiar with privacy filters that when placed over their displays inhibit individuals sitting nearby from seeing the contents of the display. While effective, traditional privacy filters are cumbersome to install and must be physically removed before the laptop owner can share the contents of his screen with others, for example, as the user may do in a small meeting where no overhead projection system was available.
According to some embodiments of the present invention, an electronic privacy filter enables a user to electronically change the visibility of a display such that the electronic privacy filter inhibits others from seeing the contents of the display when in privacy mode and allows others to see the contents of the display when in public mode. With reference to
Because of the cumbersome nature of existing approaches, passive privacy screens are often not used thereby putting sensitive information at risk when processor-based devices are used in public spaces. Advantageously, an electronic privacy filter, according to some embodiments of the invention, may make the privacy capability a more convenient part of the processor-based device and may result in the more frequent use of the privacy mode, thereby providing better potential to protect sensitive information.
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Advantageously, switching between the two modes may be accomplished electronically by an input device on or connected to the laptop computer (e.g. a button press or a mouse click). In some embodiments of the invention, the electronic privacy filter 24 may provide viewing angles which can be electronically adjusted either discretely or continuously through a range of viewing angles. Accordingly, the user may select the degree of privacy desired through more than just two modes. For example, a dial or scroll wheel may be provided on the laptop computer 20 to accept input from the user to selectively increase or decrease the viewing angle of the display.
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In each of the foregoing examples, the electronic privacy filter may be integrated with the display, or may be added to the device as a retrofit electronic privacy filter. In general terms, the electronic privacy filter is constructed as follows. Where the native display provides a relatively wide viewing angle, the electronic privacy filter is configured to selectively narrow the viewing angle. Where the native display provides a relatively narrow viewing angle, the electronic privacy filter is configured to selectively widen the viewing angle. For example, various liquid crystal materials may be utilized to either increase or decrease the viewing angle. For example, twisted nematics (TN) or super twisted nematics (STN) liquid crystal material may provide a relatively narrow viewing angle, with the degree of twist being voltage controlled. Polymer dispersed liquid crystal (PDLC) material can be electronically switched between a relatively transparent state and a light scattering state. In the light scattering state of the PDLC, the viewing angle of the display may be increased. Various combinations of layers of liquid crystal materials and/or other optical materials with electrically modifiable properties may be utilized to construct an electronic privacy filter, in accordance with the various embodiments of the invention.
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For example, the display 62 includes a multilayer LCD screen consisting of a base set of layers 72, 74, and 76 which provide a native viewing angle. The integrated privacy filter 64 may include an additional layer or set of layers 78 of electronically activated material, which can be electronically activated to adjust the perceived viewing angle for the display 62 to be different from the native viewing angle. For example, the LCD screen may include TN liquid crystal material 72 between two layers of glass 74 and 76, providing a relatively narrow viewing angle. The integrated privacy filter 64 may then include viewing angle enhancement material to selectively increase the perceived viewing angle of the display 62. For example, a PDLC material utilized in the set of layers 78 on the display 62 may provide a dispersive effect on the underlying image to selectively increase the perceived viewing angle for the display 62.
In another example, the LCD screen may include passive films or filters to provide a relatively wide viewing angle. For example, many conventional laptop display include multiple passive layers to increase the perceived viewing angle of the display. The integrated privacy filter 64 may then include viewing angle restrictive material to selectively decrease the perceived viewing angle of the display 62. For example, a TN liquid crystal material utilized in the set of layers 78 on the display 62 may provide a polarizing effect on the underlying image to selectively decrease the perceived viewing angle for the display 62.
The relatively more private and public modes may correspond to the respective viewing angles of the display image. In the private mode, the visibility of the display corresponds to the relatively narrow viewing angle of the underlying base set of layers. In the public mode, the visibility of the display will correspond to a relatively wider viewing angle provided the view angle enhancement material. Because switching between modes is electronically controlled, the user can switch modes without applying external devices to achieve privacy.
Power for the view angle enhancement layer(s) may be drawn from the processor-based device 60. For example, DC power may be provided from the battery of a laptop computer. Alternatively, when the laptop is plugged in for charging, power may be provided from the AC adapter or from the power conversion circuit within the laptop. A set of appropriate electrical contacts or electrodes are provided for the layer(s) as may be required by the particular material utilized for the view angle enhancement. Indium titanium oxide (ITO) is a transparent conductive material that may be suitable for either common electrodes or electrode arrays (e.g. individual electrodes corresponding to pixel locations).
Advantageously, in some embodiments, little or no power is drawn by the electronic privacy filter 64 in private mode. Accordingly, private mode may provide a power savings in many situations where private mode may be preferred, such as when using a laptop computer on battery power in a public place, such as an airport or airplane. Conversely, in some embodiments, public mode may be preferred in situations where AC power is available, such as when using the processor-based device in a meeting at a conference room.
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For example, each pixel 90 may include separate red R, green G, and blue B regions, shown with representative row and columns address lines. Each pixel/line/dot/block may include a separate, selective alignment of the LC material in the affected area (preferably dots which are not black). By constructing the pixel electrode such that the LC aligns along a preferential direction (e.g. in the direction of the illustrated arrows), the viewing angle may be selectively reduced in one direction. The effect would be a relatively wide viewing angle in one direction (e.g. vertical) but a selectively reduced viewing angle in the other direction (e.g. horizontal).
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For example, the display 102 includes a multilayer LCD screen consisting of a base set of layers which provide a relatively narrow viewing angle (e.g. TN liquid crystal material 112 between two layers of glass 111 and 113). The integrated privacy filter 104 includes an additional set of layers including a layer 114 of PDLC between a layer of glass 115 and the layer of glass 113. Advantageously, adding the electronically controlled privacy layers may represent little or no additional cost as compared to conventional flat panel displays with multiple passive layers.
In some examples, the PDLC layer 114 may provide two states including a transparent state and a scattering state. In the transparent state, the light from the LCD pixels may pass through the PDLC material relatively unchanged, providing the relatively more private mode. In the scattering state, the light from the pixels may be scattered, providing the relatively more public mode.
The relatively more private and public modes may correspond to the respective viewing angles of the display image. In the transparent state, the visibility of the display corresponds to the relatively narrow viewing angle of the underlying base set of layers (e.g. the TN material). In the scattering state, the visibility of the display will correspond to a relatively wider viewing angle provided the view angle enhancement of the PDLC material (e.g. the light scattering effect of the PDLC). Because the PDLC state is voltage controlled, switching between public and privates modes can be performed by the user without applying external devices to achieve privacy.
Power for the PDLC layer(s) may be drawn from the processor-based device 100. For example, DC power may be provided from the battery of a laptop computer. Alternatively, when the laptop is plugged in for charging, power may be provided from the AC adapter or from the power conversion circuit within the laptop. For example, for the PDLC layer 114, conductive indium titanium oxide (ITO) layers positioned on both sides of the PDLC material (e.g. on glass layers 113 and 115) may provide suitable electrodes for applying a voltage across the PDLC material.
Advantageously, in some embodiments, little or no power is drawn by the electronic privacy filter 104 in private mode. Accordingly, private mode may provide a power savings in many situations where private mode may be preferred, such as when using a laptop computer on battery power in a public place, such as an airport or airplane. Conversely, in some embodiments, public mode may be preferred in situations where AC power is available, such as when using the processor-based device in a meeting at a conference room.
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The foregoing and other aspects of the invention are achieved individually and in combination. The invention should not be construed as requiring two or more of such aspects unless expressly required by a particular claim. Moreover, while the invention has been described in connection with what is presently considered to be the preferred examples, it is to be understood that the invention is not limited to the disclosed examples, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and the scope of the invention.