Patent Description:
Methods and systems for providing visual display are known in the art. One technique for providing visual display is called Active-Matrix Liquid-Crystal Display (AMLCD) in which each pixel includes a display element (e.g., liquid crystal) a memory storage for retaining the electrical state of that pixel and a transistor for setting that electrical state.

Reference is now made to <FIG>, <FIG>, <FIG> and <FIG>. <FIG> is a schematic illustration of a conventional AMLCD display, generally referenced <NUM>, which is known in the art. <FIG> are schematic illustrations of a single electrical potential setting section, generally referenced 24AR of display <NUM> of <FIG>, which is known in the art, at different states. <FIG> is a schematic illustration of a specific implementation of a sub-pixel, generally referenced 22AR, of display <NUM> of <FIG>, which is known in the art.

Display <NUM> includes a plurality of pixels 20A, 20B, 20C and 20D. Each of pixels 20A, 20B, 20C and 20D includes three respective sub-pixels 22AR, 22AG, 22AR, 22BR, 22BG, 22BB, 22CR, 22CG, 22CB, 22DR, 22DG and 22DB. It is noted that a typical display such as display <NUM>, may contain any number of pixels, from a few thousands and up to several millions and more, and that <FIG>, provides a mere illustration of a very small portion of a typical display. Each of sub-pixels 22AR, 22AG, 22AR, 22BR, 22BG, 22BB, 22CR, 22CG, 22CB, 22DR, 22DG and 22DB includes a liquid crystal section directed at a predetermined wavelength range such as Red (R), Green (G) and blue (B), a respective capacitor (not shown) and further a respective electrical potential setting section referenced 24AR, 24AG, 24AR, 24BR, 24BG, 24BB, 24CR, 24CG, 24CB, 24DR, 24DG and 24DB. Display <NUM> further includes a select driver <NUM> and a data driver <NUM>. Select driver <NUM> is coupled to each of electrical potential setting sections 24AR, 24AG, 24AR, 24BR, 24BG and 24BB via select line <NUM><NUM> and further to electrical potential setting sections 24CR, 24CG, 24CB, 24DR, 24DG and 24DB via select line <NUM><NUM>. Data driver <NUM> is coupled to each electrical potential setting sections 24AR and 24CR via data line <NUM>1R, to each electrical potential setting sections 24AG and 24CG via data line <NUM><NUM>, to each electrical potential setting sections 24AB and 24CB via data line <NUM>2B, to each electrical potential setting sections 24BR and 24DR via data line <NUM>1R, to each electrical potential setting sections 24BG and 24DG via data line <NUM><NUM> and to each electrical potential setting sections 24BB and 24DB via data line <NUM>2B.

With reference to <FIG>, electrical potential setting section 24AR includes a switch <NUM>. Switch <NUM> is coupled with a capacitor <NUM>, select line <NUM><NUM> and data line <NUM>1R. Select line <NUM><NUM> controls the state of switch <NUM> to be either open (as shown in <FIG>) or closed (as shown in <FIG>). Data line <NUM>1R sets to a certain potential V<NUM>, respective with a desired state of transmittance (e.g., transparent, opaque or various levels of semi- -transparency), for the respective LCD layer (not shown). In <FIG>, capacitor <NUM> exhibits a potential V<NUM>, wherein V<NUM>≠V<NUM>. In <FIG>, select line <NUM><NUM> changes the state of switch <NUM> from open to closed, thereby coupling data line <NUM>1R with capacitor <NUM> and setting capacitor <NUM> to exhibit potential V<NUM>. Capacitor <NUM> induces this potential V<NUM> on to the respective LCD layer which in turn is set to the desired state of transmittance.

With reference to <FIG>, switch <NUM> is implemented in the form of a transistor <NUM>, having a gate electrode <NUM>, a drain electrode <NUM> and a source electrode <NUM>. Gate electrode <NUM> is coupled with select line <NUM><NUM>, source electrode <NUM> is coupled with data line <NUM>1R and drain electrode <NUM> is coupled with capacitor <NUM> and further with LCD element R of sub-pixel 24AR. Select line <NUM><NUM> controls the state of the transistor <NUM>, in time to alternately be in either an open state, a closed/conductive state, a resistive state (i.e., partially/semi-conductive) and the like, coupling between date line <NUM><NUM> and capacitor <NUM>.

Reference is further made to <FIG>, which is a schematic illustration of an electrical potential setting section, generally referenced <NUM>, which is known in the art. Electrical potential setting section <NUM> includes two switches <NUM>A and <NUM>B. Each one of switches <NUM>A and <NUM>B is coupled with a capacitor <NUM>, and further with LCD element R of a sub-pixel (not shown), a select line <NUM> and to a data line <NUM>. Select line <NUM> operates switches <NUM>A and <NUM>B to simultaneously be in the same state, which is either an open state or a closed state. Data line <NUM> simultaneously sets a potential level V<NUM> at one end of switches <NUM>A and <NUM>B. Once select line <NUM> sets switches <NUM>A and <NUM>B to the closed state, <NUM>A and <NUM>B connect data line <NUM> to capacitor <NUM>, thereby charging capacitor <NUM> to potential level V<NUM> and setting it to that potential level.

<CIT>, entitled "Apparatus for aircraft dual channel display" is directed to a display, which includes a pixel matrix, back light illumination and two video channels capable of displaying a video signal on the display panel. Each video channel includes respective column drivers, row drivers, LED drivers, timing controller, backlight controller and a power source. The column and row drives of each channel couples to the columns and rows in the pixel matrix, such as a liquid crystal matrix and drives electrically isolated, interleaved color groups within each pixel. A switch provides for selecting between the two independent video channels to display a video signal on the display. In the display directed to by Bushell et al, each pixel includes two or four color groups of subpixels each group includes a red, a green and a blue subpixel. Each channels drive one color group or a pair of color groups. Such a configuration may provide even distribution of active subpixels upon failure of one of the channels.

<CIT> to Sasaki, titled "Liquid Crystal Display with Reduced Driving Voltage and Separate Driving Circuits for Positive and Negative Voltages" describes a frame inversion technique to prevent degradation of a liquid crystal display (LCD). The architecture separates the drive signal into two, one signal having positive polarity and the other having negative polarity. The positive signal and negative signal are applied to the LCD in a synchronized manner to produce a single alternating signal.

US patent application publication no. <CIT>, entitled "Liquid crystal display apparatus and testing method for liquid crystal display apparatus", is directed to a testing method for a liquid crystal display (LCD) apparatus wherein an accurate comparison can be performed for comparing the voltages between two data lines in the LCD, wherein when voltages retained in paired pixels are read out to two data lines they are compared with each other. The LCD apparatus includes a pixel array section including a plurality of unit pixels disposed in a matrix and each including a pixel transistor, a capacitive element connected to an output electrode of the pixel transistor and a liquid crystal cell configured to display a gradation in accordance with a voltage retained in the capacitive element. A first data line is connected to an input electrode of each unit pixel of a first pixel group in a unit of a pixel column from among the unit pixels of the pixel array section and a second data line is connected to an input electrode of each unit pixel of a second pixel group in a unit of a pixel column from among the unit pixels of the pixel array section. The LCD apparatus also includes a writing unit for writing a first measurement signal into the unit pixels of the first pixel group through the first data lines and for writing a second measurement signal into the unit pixels of the second pixel group through the second data lines, along with a voltage supply control unit for selectively supplying a predetermined DC voltage to the first and second data lines. The LCD apparatus further includes a data line short-circuiting unit for short-circuiting the first data lines and the second data lines after the voltage supply by the voltage supply control unit, a reading out unit for reading out the first and second measurement signals from the unit pixels of the first and second pixel groups into the first and second data lines, respectively, after the first and second data lines are short-circuited to each other by the data line short-circuiting unit. The LCD apparatus finally includes a testing unit for comparing the potentials at the first data lines and the potentials at the second data lines with each other after the reading out by the reading out unit and performing a test of the pixel array section based on a result of the comparison.

US patent application publication no. <CIT>, entitled "Display device and method for controlling the same", is directed to a display device that includes an organic EL element and a capacitor. A driving transistor is connected to an anode of the organic EL element and passes a current to the organic EL element. The current corresponds to a voltage held in the capacitor. A first switch is located between the capacitor and a data line and the data line supplies the voltage to the capacitor. A voltage detector is connected to the data line for detecting an anode voltage applied to the organic EL element. A second switch is located between the anode and the data line. A controller turns on the first switch, causing the organic EL element to emit light, and causing the voltage detector to detect the anode voltage by turning off the first switch and turning on the second switch while the organic EL element is emitting light.

US patent application publication no. <CIT>, entitled "Apparatus for aircraft dual channel display", is directed to a cockpit display including an LCD panel having a liquid crystal matrix and an LED backlight having an array of LEDs for illuminating the liquid crystal matrix. The display includes first and second independent video channels, with each video channel having a row driver operably coupled to and driving the rows in the liquid crystal matrix, a column driver operably coupled to and driving the columns in the liquid crystal matrix, and an LED driver operably coupled to the array of LEDs to control the backlight to the liquid crystal matrix. The display also includes a switch for selecting between the first and second independent video channels to display a video signal on the LCD panel.

It is an object of the disclosed technique to provide a novel method and system for a fault tolerant display (i.e., the presented image is not affected or impaired) that is impervious to at least a single electronic failure in either the image generating electronics, or the driver electronics or the sub-pixel electronic elements or the interconnecting conductors.

In accordance with the disclosed technique, there is provided a display device including a first select driver, a first data driver, a second select driver and a second data driver as well as a plurality of pixels. Each of the pixels includes at least one sub-pixel. Each of the sub-pixels includes a drivable visual segment, a first electrical potential setting section and a second electrical potential setting section. The drivable visual segment is operative to exhibit at least a first visible state and a second visible state and includes an electric potential retentioner selected from the group of a capacitor and a memory element. The first electrical potential setting section includes a first switch which couples the electric potential retentioner of the drivable visual segment with the first select driver and the first data driver. The first switch is operative to drive the drivable visual segment, at least from the first visible state to the second visible state. The second electrical potential setting section includes a second switch which couples the electric potential retentioner of the drivable visual segment with the second select driver and the second data driver. The second switch is operative to drive the drivable visual segment, independently from the first switch, at least from the first visible state to the second visible state. The display device further comprising means configured to determine if the first select driver, the first data driver, or the first electrical potential setting section is malfunctioning. The display device also comprising means configured to cut power from the first select driver and the first data driver, and to provide power to the second select driver and the second data driver in response to a determined malfunction. When the power is provided to the second select driver and the second data driver, the same display instructions provided to the first select driver and the first data driver are provided to the second select driver and the second data driver.

In accordance with another aspect of the disclosed technique there is provided a method for operating a display multi-operation architecture of a multi-pixel display having a first select driver, a first data driver, a second select driver and a second data driver as well as a plurality of sub-pixels. Each of the sub-pixels includes a first switch, a second switch, a first electrical potential setting section, a second electrical potential setting section and a respective drivable visual segment. The drivable visual segment is coupled between the first switch and the second switch and includes a respective electric potential retentioner selected from the group consisting of a capacitor and a memory element. The display multi-operation architecture couples to each one of the electric potential retentioners the first select driver and the first data driver with the respective first switch and the first electrical potential setting section. The display multi-operation architecture further couples to each one of the electric potential retentioners the second select driver and the second data driver with the respective second switch and the second electrical potential setting section. The method includes the procedures of: providing access to the electric potential retentioner respective of a selected one of the at least one of the sub-pixels, by employing the first switch respective of the selected sub-pixel, via the respective first data line and the respective first select line and providing access to the electric potential retentioner respective of the selected one of the at least one of the sub-pixels, by employing the second switch respective of the selected sub-pixel, via the respective second data line and the respective second select line. The method further includes the procedures of determining if the first select driver, the first data driver, or the first electrical potential setting section is malfunctioning and cutting power from the first select driver and the first data driver and providing power to the second select driver and the second data driver in response to a determined malfunction. When the power is provided to the second select driver and the second data driver, the same display instructions are provided to the second select driver and the second data driver as provided to the first select driver and the first data driver.

The disclosed technique overcomes the disadvantages of the prior art by providing a system and a method for redundantly operating pixels in a display unit. In accordance with the disclosed technique there is provided a configuration in which each sub-pixel includes a drivable visual segment (e.g., LCD layer, dynamic mirror), a potential retentioner (e.g., capacitor, a memory element), a first switch, coupled with a first select driver and a first data driver, and a second switch, coupled with a second select driver and a second data driver. Each one of the switches is operative, independently of the other switch, to be operated by the respective select driver, coupled therewith. Each one of the switches is operative, independently of the other switch, to set the capacitor to the potential provided thereto by the respective data driver, coupled therewith.

The following example is provided with respect to a color display, where each full color pixel includes three independently operable sub-pixels, a red sub pixel, a green sub pixel and a blue sub pixel, otherwise known in the art as the RGB chromatic scheme. The disclosed technique can easily apply to any other chromatic schemes, such as:.

Any one of these sub pixels can be set to a plurality of visible states, which are determined by the background illumination illuminating a given sub-pixel, the chromatic filter placed in front of it and the transparency level that the LCD layer is set to. Typically, setting a sub-pixel to a desired visible state (e.g., while refreshing the entire display) is carried out by setting the respective LCD layer to a desired transparency level, which is associated and required for that desired visible state. Transitions between visible states can be discrete (i.e., "jumping" from one visible state to another), gradual or continuous (i.e., "soft") by setting the LCD from one level of transparency to another (e.g., by setting the respective capacitor from a potential level V<NUM> to a potential level V<NUM> all at once or by setting an intermediate level V<NUM> or gradually, respectively. Reference is now made to <FIG>, which is a schematic illustration of the display, generally referenced <NUM>, constructed and operative in accordance with an embodiment of the disclosed technique. Display <NUM> includes a plurality of pixels 120A, 120B, 120C and 120D. Each of the pixels 120A, 120B, 120C and 120D includes three respective sub-pixels 122AR, 122AG, 122AB, 122BR, 122BG, 122BB, 122CR, 122CG, 122CB, 122DR, 122DG and 122DB. It is noted that a typical display such as display <NUM>, may contain any number of pixels (i.e., subject to manufacturing limitations) and further that each such pixel may include one or more sub-pixels, at any desired spectral range arrangement. Each of sub-pixels 122AR, 122AG, 122AB, 122BR, 122BG, 122BB, 122CR, 122CG, 122CB, 122DR, 122DG and 122DB includes a liquid crystal section directed at a predetermined wavelength range such as Red (R), Green (G) and blue (B), a respective capacitor (not shown), a first respective electrical potential setting section referenced 124AR, 124AG, 124AB, 124BR, 124BG, 124BB, 124CR, 124CG, 124CB, 124DR, 124DG, 124DB and a second respective electrical potential setting section referenced 126AR, 126AG, 126AB, 126BR, 126BG, 126BB, 126CR, 126CG, 126CB, 126DR, 126DG, 126DB.

Display <NUM> further includes a first select driver <NUM>, a second select driver <NUM>, a first data driver <NUM> and a second data driver <NUM>.

First select driver <NUM> is coupled to each of electrical potential setting sections 124AR, 124AG, 124AR, 124BR, 124BG and 124BB via select line <NUM><NUM> and further to electrical potential setting sections 124CR, 124CG, 124CB, 124DR, 124DG and 124DB via select line <NUM><NUM>. First data driver <NUM> is coupled to each electrical potential setting sections 124AR and 124CR via data line <NUM>1R, to each electrical potential setting sections 124AG and 124CG via data line <NUM><NUM>, to each electrical potential setting sections 124AB and 124CB via data line <NUM>1B, to each electrical potential setting sections 124BR and 124DR via data line <NUM>2R, to each electrical potential setting sections 124BG and 124DG via data line <NUM><NUM> and to each electrical potential setting sections 124BB and 124DB via data line <NUM>2B.

Second select driver <NUM> is coupled to each of electrical potential setting sections 126AR, 126AG, 126AR, 126BR, 126BG and 126BB via select line <NUM><NUM> and further to electrical potential setting sections 126CR, 126CG, 126CB, 126DR, 126DG and 126DB via select line <NUM><NUM>. Second data driver <NUM> is coupled to each electrical potential setting sections 126AR and 126CR via data line <NUM>1R, to each electrical potential setting sections 126AG and 126CG via data line <NUM><NUM>, to each electrical potential setting sections 126AB and 126CB via data line <NUM>1B, to each electrical potential setting sections 126BR and 126DR via data line <NUM>2R, to each electrical potential setting sections 126BG and 126DG via data line <NUM><NUM> and to each electrical potential setting sections 126BB and 126DB via data line <NUM>2B.

It is noted that each of the above potential setting sections is associated with a respective data terminal and a respective select terminal. Such a respective date terminal is formed from the data line coupled with a given potential setting section and from the respective data driver coupled with that data line. Such a respective select terminal is formed from the select line coupled with a given potential setting section and from the respective select driver coupled with that select line. With reference to <FIG>, the select terminal of potential setting section 124AG includes select line <NUM><NUM> and select driver <NUM>, while the data terminal of potential setting section 124AG includes data line <NUM><NUM> and data driver <NUM>.

Reference is further made to <FIG>, <FIG> and <FIG>. <FIG> is a schematic illustration of first electrical potential setting section 124AR and second electrical potential setting section 126AR, of display <NUM> of <FIG>, constructed and operative in a first mode of operation, in accordance with the disclosed technique. <FIG> is a schematic illustration of first electrical potential setting section 124AR and second electrical potential setting section 126AR, of display <NUM> of <FIG>, constructed and operative in a second mode of operation, in accordance with the disclosed technique. <FIG> is a schematic illustration of first electrical potential setting section 124AR and second electrical potential setting section 126AR, of display <NUM> of <FIG>, constructed and operative in a third mode of operation, in accordance with the disclosed technique. <FIG> is a schematic illustration of first electrical potential setting section 124AR and second electrical potential setting section 126AR, of display <NUM> of <FIG>, constructed and operative in a fourth mode of operation, in accordance with the disclosed technique.

It is noted that first electrical potential setting section 124AR and second electrical potential setting section 126AR, are both associated with sub-pixel 122AR and with a capacitor <NUM>, which serves as an electric potential retentioner, retaining the electric potential which sets the sub-pixel 122AR LCD layer to a desired state of transmittance (e.g., transparent, opaque or various levels of semi-transparency).

Electrical potential setting section 124AR includes a switch <NUM><NUM>. Electrical potential setting section 126AR includes a switch <NUM><NUM>. Switch <NUM><NUM> is coupled with capacitor <NUM>, with first select line <NUM><NUM> and with first data line <NUM>1R. Switch <NUM><NUM> is coupled with capacitor <NUM>, with second select line <NUM><NUM> and with second data line <NUM>1R.

First select line <NUM><NUM> controls the state of switch <NUM><NUM> to be either open (as shown in <FIG> and <FIG>) or closed (as shown in <FIG> and <FIG>). In <FIG>, <FIG>, first data line <NUM>1R is operable to set (i.e., setting only occurs in <FIG> and <FIG>) Capacitor <NUM> to a certain potential V<NUM>, respective with a first desired state of transmittance (e.g., transparent, opaque or various levels of semi-transparency), for the respective LCD layer (not shown).

Second select line <NUM><NUM> controls the state of switch <NUM><NUM> to be either open (as shown in <FIG>) or closed (as shown in <FIG>). Data line <NUM>1R sets to a certain potential V<NUM> (in <FIG> and <FIG>), respective with a second desired state of transmittance (e.g., transparent, opaque or various levels of semi-transparency), for the respective LCD layer (not shown).

Having two complete redundant driving electronics, each sub-pixel of display <NUM> can be driven independently, by either the first select driver <NUM> and first data driver <NUM> or second select driver <NUM> and second data driver <NUM>. Accordingly, power can be toggled between the first driving electronics (i.e., first select driver <NUM> and first data driver <NUM>) and the second driving electronics (i.e., second select driver <NUM> and second data driver <NUM>). If either of first select driver <NUM> and first data driver <NUM> or at least one of the electrical potential setting sections coupled therewith (e.g., 124AR, 124AG, 124AR, 124BR, 124BG, 124BB, 124CR, 124CG, 124CB, 124DR, 124DG, 124DB) is malfunctioning, then power is cut off from first select driver <NUM> and first data driver <NUM> and is provided to second select driver <NUM> and second data driver <NUM>, which in turn operate electrical potential setting sections 126AR, 126AG, 126AR, 126BR, 126BG, 126BB, 126CR, 126CG, 126CB, 126DR, 126DG, 126DB, based on the same display instructions, previously provided to first select driver <NUM> and first data driver <NUM>. Other advantages of the disclosed technique shall be presented further below.

In <FIG>, capacitor <NUM> exhibits a potential V<NUM>, wherein V<NUM>≠V<NUM>≠V<NUM>≠V<NUM>. In <FIG>, second select line <NUM><NUM> maintains an open state for switch <NUM><NUM> while first select line <NUM><NUM> changes the state of switch <NUM><NUM> from open to closed, thereby coupling first data line <NUM>1R with capacitor <NUM> and setting capacitor <NUM> to exhibit potential V<NUM>. Capacitor <NUM> induces this potential V<NUM> on to the respective LCD layer which in turn is set to the first desired state of transmittance.

With reference to <FIG>, when, for example, one or more of first select driver <NUM>, first data driver <NUM> or at least one of the electrical potential setting sections coupled therewith malfunctions, second select driver <NUM>, second data driver <NUM> and the electrical potential setting sections coupled therewith are still operative to set the potential level of the capacitor respective of anyone of the sub-pixels of display <NUM>.

Thus, the display panel may continue to display the full image (i.e., employing all of the pixels in the display panel).

In <FIG>, first select line <NUM><NUM> maintains an open state for switch <NUM><NUM> while second select line <NUM><NUM> changes the state of switch <NUM><NUM> from open to closed, thereby coupling second data line <NUM>1R with capacitor <NUM> and setting capacitor <NUM> to exhibit potential V<NUM>. Capacitor <NUM> induces this potential V<NUM> on to the respective LCD layer which in turn is set to the second desired state of transmittance. It is noted that switch <NUM><NUM> can set capacitor <NUM> to any desired potential, including V<NUM> (e.g., when switch <NUM><NUM> or the electronics driving it are malfunctioning).

In <FIG>, both data lines <NUM>1R and <NUM>1R are set to a potential V<NUM>. First select line <NUM><NUM> changes the state of switch <NUM><NUM> from open to closed thereby coupling first data line <NUM>1R with capacitor <NUM>, while simultaneously second select line <NUM><NUM> changes the state of switch <NUM><NUM> from open to closed, thereby coupling second data line <NUM>1R with capacitor <NUM>. Since both data lines <NUM>1R and <NUM>1R are set to a potential V<NUM> and are hence simultaneously coupled with capacitor <NUM>, they set capacitor <NUM> to exhibit potential V<NUM>, but typically faster than in the configuration disclosed in <FIG> and <FIG> (had second data line been set to a potential V<NUM>), since the current used to charge capacitor <NUM> is the sum of the current I<NUM> flowing through switch <NUM><NUM> and the current I2 flowing thought switch <NUM><NUM> (i.e., I<NUM>+I<NUM>). It is noted that typically current I<NUM> is limited by the material characteristics, which the LCD TFT transistors are made of.

Reference is also made to <FIG> is a schematic illustration of first electrical potential setting section 124AR and second electrical potential setting section 126AR, of display <NUM> of <FIG>, constructed and operative in a further mode of operation, in accordance with another embodiment of the disclosed technique. <FIG> is a schematic illustration of first electrical potential setting section 124AR and second electrical potential setting section 126AR, of display <NUM> of <FIG>, constructed and operative in another mode of operation, in accordance with a further embodiment of the disclosed technique.

In <FIG>, second data line <NUM>1R is further coupled with a potential sensor in the form of a voltmeter <NUM>. In <FIG>, switch <NUM><NUM> is open and switch <NUM><NUM> is closed and hence, voltmeter can measure the potential VC of capacitor <NUM>, uninterrupted by the potential V1, which first data line <NUM>1R sets. In <FIG>, both switches <NUM><NUM> and <NUM><NUM> are closed, and while voltmeter can measure the potential VC of capacitor <NUM>, it can determine if VC has reached potential V<NUM> and thus detect that the mechanism which includes first select line <NUM>1R, first data line <NUM>1R sets and switch <NUM><NUM>, is operating correctly (i.e., when VC=V<NUM>) or exhibits a malfunction (i.e., when VC≠V<NUM>). It is noted that the disclosed technique may utilize any potential measuring device, which can measure potential either directly (e.g., a voltmeter, as in the present example) or indirectly, such as by means of current meter readout integration and optionally further taking into account the characteristics of other components such as the electric potential retentioner. Other types of measurements may replace potential measurement, such as current profile over time, current or potential derivative values and the like. All of the above measurements serve as quality measurements, which may indicate fault/malfunction in the process of setting the desired potential level of one or more potential retentioner. It is noted that a quality measurement unit (e.g., a voltmeter, an ampermeter) may be coupled to one or more of first select terminal, first data terminal, second select terminal and second data terminal. Such a measurement unit can be unique for a selected line, or allocated momentarily to a plurality of lines (i.e., data lines or select lines). In accordance with yet a further embodiment of the disclosed technique, a second data line such as <NUM>1R can be alternatively coupled with a potential source and with a potential sensor, such when the potential sensor detects a malfunction, the potential source coupled with that second data line (i.e., together with second select line and the second switch), can serve as backup for the "first" mechanism that includes the first select line, the first data line and the first switch.

Reference is now made to <FIG>, which is a schematic illustration of a method for operating a redundantly operable display, operative in accordance with a further embodiment of the disclosed technique. In procedure <NUM> a redundantly operable display is provided. The display includes a plurality of pixels, each including at least one sub-pixel. Each sub-pixel includes a drivable visual segment, a first switch and a second switch, the first switch being coupled with a first select driver and a first data driver and the second switch being coupled with a second select driver and a second data driver.

In procedure <NUM>, the transparency state for the drivable visual segment of at least one of the sub-pixels, is set by employing the respective first switch of that sub-pixel. With respect to <FIG>, first electrical potential setting section 124AR, is employed to provide a first potential V<NUM> to the liquid crystal section R of sub-pixel 122AR. First potential V<NUM> corresponds to a desired first transparency level.

In procedure <NUM>, the transparency state for the drivable visual segment of at least another one of the sub-pixels, is set by employing the respective second switch of that sub-pixel. With respect to <FIG>, first electrical potential setting section 124AG, is employed to provide a second potential V<NUM> to the liquid crystal section G of sub-pixel 122AG. Second potential V<NUM> corresponds to a desired second transparency level.

It is noted that procedures <NUM> and <NUM> can be executed either in sequence or simultaneously. When executed simultaneously, procedures reduce the time required to refresh the entire display, by substantially half, since at each given moment, two sub-pixels are refreshed, instead of one. It is further noted that the method of <FIG>, also serves in a situation wherein a certain sub-pixel can no longer be operated by its respective first electrical potential setting section, and is instead being operated by its respective second electrical potential setting section.

Reference is now made to <FIG>, which is a schematic illustration of a method for operating a redundantly operable display, operative in accordance with yet another embodiment of the disclosed technique. In procedure <NUM> a redundantly operable display is provided. The display includes a plurality of pixels, each including at least one sub-pixel. Each sub-pixel includes a drivable visual segment, a first switch and a second switch, the first switch being coupled with a first select driver and a first data driver and the second switch being coupled with a second select driver and a second data driver.

In procedure <NUM>, the transparency state for the drivable visual segment of at least one of the sub-pixels, is set by employing the respective first switch of that sub-pixel. With respect to <FIG>, first electrical potential setting section 126AR, is employed to provide a first potential V<NUM> to the liquid crystal section R of sub-pixel 122AR. First potential V<NUM> corresponds to a desired first transparency level.

In procedure <NUM>, the transparency state for the drivable visual segment of at least another one of the sub-pixels, is set by employing the respective second switch of that sub-pixel. With respect to <FIG>, second electrical potential setting section 126AR, is employed to provide a second potential V<NUM> to the liquid crystal section R of sub-pixel 122AR. Second potential V<NUM> also corresponds to the desired first transparency level.

It is noted that procedures <NUM> and <NUM> can be executed either in sequence or simultaneously. When executed simultaneously, procedures reduce the time required to refresh the entire display, since at each given moment, two electrical potential setting sections are used to set the desired potential for the LCD layer of a given sub-pixel, at a current which exceeds the current provided by a single electrical potential setting section, thereby reducing the time required to charge the respective capacitor of that sub-pixel.

Reference is further made to <FIG>, which is a schematic illustration of a method for operating a redundantly operable display, operative in accordance with yet another embodiment of the disclosed technique. In procedure <NUM>, a display including a plurality of pixels is provided. Each of the pixels includes at least one sub-pixel. Each of the sub-pixels includes a drivable visual segment, a first switch and a second switch. The first switch is coupled with a first select driver and a second data driver. The second switch is coupled with a second select driver and a second data driver. With reference to <FIG>, display <NUM> includes a plurality of pixels 120A, 120B, 120C and 120D, each including sub pixels such as 122AR, 12BB and 122DG, each including a first switch (e.g., <FIG>) a second switch, wherein the first switches are each coupled to a first select driver <NUM> and a first data driver <NUM> and the second switches are each coupled to a second select driver <NUM> and a second data driver <NUM>.

In procedure <NUM>, access to the electric potential retentioner respective of a selected sub-pixel is provided, by employing the first switch respective of that selected sub-pixel, via the respective first data line and the respective first select line. In the example presented in <FIG>, access is provided to capacitor <NUM> by employing switch <NUM><NUM> via first select line <NUM><NUM> and first data line <NUM>1R. The access provided in procedure <NUM> can be provided to a variety of actions such as setting potential to the potential retentioner denoted <NUM>, measuring the potential of the potential retentioner denoted <NUM> and disabling the respective switch <NUM>. In the example presented in <FIG> potential V<NUM> is set for capacitor <NUM>. In the example presented in <FIG> potential V<NUM> is set for capacitor <NUM>. In the example presented in <FIG> although the potential level of capacitor <NUM> is measured via switch <NUM><NUM>, it is noted that a similar technique can be applied for measuring that potential via switch <NUM><NUM>, by coupling a potential measuring unit with switch <NUM><NUM>. Finally, switch <NUM><NUM> can be disabled via either one of select line <NUM><NUM> and first data line <NUM>1R (disabling not shown).

In procedure <NUM>, access to the electric potential retentioner respective of a selected sub-pixel is provided, by employing the second switch respective of that selected sub-pixel, via the respective second data line and the respective second select line. In the example presented in <FIG>, access is provided to capacitor <NUM> by employing switch <NUM><NUM> via first select line <NUM><NUM> and first data line <NUM>1R. The access provided in procedure <NUM> can be provided to a variety of actions such as setting potential to the potential retentioner, as demonstrated in the example presented in <FIG>. Similar to procedure <NUM>, the access provided in procedure <NUM> can be provided to a variety of actions such as setting potential to the potential retentioner denoted <NUM>, measuring the potential of the potential retentioner denoted <NUM> and disabling the respective switch <NUM>.

In procedure <NUM>, access to the electric potential retentioner respective of another selected sub-pixel is provided, by employing the first switch respective of that other selected sub-pixel, via the respective first data line and the respective first select line. It is noted that since the configuration presented in <FIG> is applied for each of the sub-pixels of display <NUM>, the description provided in conjunction with procedure <NUM> can be applied with respective components (not shown) for procedure <NUM>. Similar to procedure <NUM>, the access provided in procedure <NUM> can be provided to a variety of actions such as setting potential to the potential retentioner denoted <NUM>, measuring the potential of the potential retentioner denoted <NUM> and disabling the respective switch <NUM>.

It is further noted that the access provided in procedure <NUM>, the access provided in procedure <NUM> and the access provided in procedure <NUM> can sequential or simultaneous (e.g., depending operational requirements).

Claim 1:
A fault tolerant display device comprising:
a first select driver (<NUM>);
a first data driver (<NUM>);
a second select driver (<NUM>);
a second data driver (<NUM>);
a plurality of pixels (120A, 120B, 120C, 120D), each said pixels including at least one sub-pixel;
each said sub-pixels (122AR) comprising:
a drivable visual segment comprising an electric potential retentioner selected from the group consisting of: a capacitor (<NUM>) and a memory element, said drivable visual segment being operative to exhibit at least a first visible state and a second visible state; a first electrical potential setting section (124AR) comprising a first switch (<NUM><NUM>) coupling said electric potential retentioner of said drivable visual segment with said first select driver (<NUM>) and said first data driver (<NUM>), said first switch (<NUM><NUM>) being operative to drive said drivable visual segment at least from said first visible state to said second visible state; and
a second electrical potential setting section (126AR) comprising a second switch (<NUM><NUM>) coupling said electric potential retentioner of said drivable visual segment with said second select driver (<NUM>) and said second data driver (<NUM>), said second switch (<NUM><NUM>) of said second electrical potential setting section (126AR) being operative independently of said first switch (<NUM><NUM>) to drive said drivable visual segment via said second select driver (<NUM>) and said second data driver (<NUM>), at least from said first visible state to said second visible state; means configured to determine if said first select driver, said first data driver or said first electrical potential setting section is malfunctioning; and
means configured to, in response to a determined malfunction, cut power from said first select driver and said first data driver, and to provide power to said second select driver and said second data driver,
wherein when said power is provided to said second select driver and said second data driver, the same display instructions provided to said first select driver and said first data driver are provided to said second select driver and said second data driver.