HK1086630A - Method and device for electrically programmable display - Google Patents

Abstract

One embodiment includes a display of interferometric modulators having a configurable resolution characteristic. Selected rows and/or columns are interconnected via a switch. The switch can include a fuse, antifuse, transistor, and the like. Depending on a desired resolution for a display, the switches can be placed in an "open" or "closed" state. Advantageously, using the switches, a display can readily be configured for differing modes of resolution. Furthermore, using the switches, a display can be configured to electrically connect certain rows or columns in the display such that the connected rows or columns can be driven simultaneously by a common voltage source.

Description

Method and apparatus for an electrically programmable display

Technical Field

The present invention relates generally to microelectromechanical systems (MEMS).

Background

Microelectromechanical Systems (MEMS) include micromechanical elements, actuators, and electronics. Micromechanical elements may be created using deposition, etching, or other micromachining processes that etch away parts of substrates and/or deposited material layers or that add layers to form electrical and electromechanical devices. These MEMS devices can be used in a wide variety of applications, such as in optical applications and in circuit applications.

One type of MEM device is known as interferometric modulation. An interferometric modulator may comprise a pair of conductive plates, one or both of which may be transparent and/or reflective in whole or part and capable of relative motion upon application of an appropriate electrical signal. One of the plates may comprise a stationary layer deposited on a substrate and the other plate may comprise a metal diaphragm separated from the stationary layer by an air gap. Such devices have a wide range of applications, and it would be beneficial in the art to utilize and/or modify the characteristics of these types of devices so that their performance can be exploited in improving existing products and creating new products that have not yet been developed.

Another type of MEMS device is used as a multi-state capacitor. For example, the capacitor may comprise a pair of conductive plates, at least one of which is capable of relative movement upon application of a suitable electrical control signal. The relative motion changes the capacitance of the capacitor, enabling the capacitor to be used in a wide variety of applications, such as in filter circuits, tuning circuits, phase shifting circuits, attenuation circuits, and the like.

Disclosure of Invention

The system, method and apparatus of the present invention have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this invention, its more prominent features will now be discussed briefly. After reviewing this discussion, and particularly after reading the section entitled "detailed description of certain embodiments" one will understand how the features of this invention provide advantages over other display devices.

One embodiment includes a display. The display may include an array having a plurality of rows and columns of interferometric modulators. The array may also include a plurality of electrical conductors. Each of the electrical conductors is connected to one of the plurality of rows or columns. At least two of the conductors are configured to be selectively electrically interconnected to modify a resolution characteristic of at least one region of the array.

Another embodiment includes a method. The method includes electrically connecting at least two adjacent columns of the display to each other and/or electrically connecting at least two adjacent rows of the display to each other through a switch to modify a resolution characteristic of the display.

Yet another embodiment comprises a system. The system comprises means for displaying an image comprising a plurality of rows and columns of interferometric modulators; a plurality of electrical conductors connected to the plurality of rows and columns; and means for selectively electrically interconnecting at least one pair of the electrical conductors to modify a resolution characteristic of at least one region of the array.

Yet another embodiment includes a method of manufacturing a display system. The method comprises the following steps: fabricating a plurality of electrical conductors, each of said electrical conductors connected to one of said plurality of rows or columns, at least two of said conductors configured to be selectively electrically interconnected by a switch, thereby modifying a resolution characteristic of at least one region of a display; and fabricating the display simultaneously with fabricating the plurality of electrical conductors and switches.

Drawings

The drawings and the associated descriptions herein are intended to illustrate various embodiments and are not intended to limit the invention.

FIG. 1 is an isometric view depicting a portion of one embodiment of an interferometric modulator display in which a movable reflective layer of a first interferometric modulator is in a released position and a movable reflective layer of a second interferometric modulator is in an actuated position.

FIG. 2 is a system block diagram illustrating one embodiment of an electronic device including a 3 × 3 interferometric modulator display.

FIG. 3 is a diagram of movable mirror position versus applied voltage for one exemplary embodiment of an interferometric modulator of FIG. 1.

FIG. 4 is a schematic diagram of a set of row and column voltages that may be used to drive an interferometric modulator display.

Fig. 5A and 5B show an exemplary timing diagram for row and column signals that may be used to write a frame of display data to the 3 x 3 interferometric modulator display of fig. 2.

Fig. 6A is a cross-sectional view of the device of fig. 1.

FIG. 6B is a cross-sectional view of an alternative embodiment of an interferometric modulator.

FIG. 6C is a cross-sectional view of another alternative embodiment of an interferometric modulator.

FIG. 7 is a block diagram of an exemplary display.

FIG. 8 is a block diagram of another exemplary display.

FIGS. 9A-9F are cross-sectional elevation views of a plurality of layers deposited in the process of making the interferometric modulator of FIG. 6A.

FIG. 10 is a flow diagram illustrating an example process for configuring a display.

FIGS. 11A and 11B are system block diagrams illustrating an exemplary embodiment of a display device.

Detailed Description

The following detailed description is directed to certain specific embodiments of the invention. However, the invention can be embodied in a multitude of different ways. In the description, reference is made to the drawings wherein like parts are designated with like numerals throughout. As will be apparent from the following description, the invention may be implemented in any device that is configured to display an image, whether in motion (e.g., video) or stationary (e.g., still image), and whether textual or pictorial. More specifically, the invention may be implemented in or associated with a variety of electronic devices such as, but not limited to, the following: mobile phones, wireless devices, Personal Data Assistants (PDAs), handheld or portable computers, GPS receivers/navigators, cameras, MP3 players, camcorders, game consoles, watches, clocks, calculators, television monitors, flat panel displays, computer monitors, auto displays (e.g., odometer display, etc.), cockpit controls and/or displays, camcorder scene displays (e.g., a rear-view camcorder display for a vehicle), electronic photographs, electronic billboards or signs, projectors, architectural structures, packaging, and aesthetic structures (e.g., a display of images on a piece of jewelry). MEMS devices of similar construction to the MESE devices described herein can also be used in non-display applications such as in electronic switching devices.

The values of the resolution that the display is required to have vary from application to application. By providing a display with sufficient resolution to cover all applications, the cost of the display can be reduced through economies of scale. However, such high resolution may result in unnecessary drive costs for users with low resolution requirements. One embodiment provides an array of modulators in which the leads of each modulator are selectively coupled for actuating groups of sub-pixel elements. This reduces the number of leads at the expense of unnecessary display resolution.

One interferometric modulator display embodiment comprising an interferometric MEMS display element is shown in FIG. 1. In these devices, the pixels are in either a bright or dark state. In the bright on or open state, the display element reflects a large portion of incident visible light to a user. When in the dark (off) or closed (closed) state, the display element reflects little incident visible light to the user. Depending on the embodiment, the light reflectance properties of the "on" and "off" states may be reversed. MEMS pixels can be configured to reflect predominantly at selected colors, allowing for a color display in addition to black and white.

FIG. 1 is an isometric view depicting two adjacent pixels in a series of pixels of a visual display, wherein each pixel comprises a MEMS interferometric modulator. In certain embodiments, an interferometric modulator display comprises a row/column array of these interferometric modulators. Each interferometric modulator includes a pair of reflective layers positioned at a variable and controllable distance from each other to form a resonant optical cavity with at least one variable dimension. In one embodiment, one of the reflective layers is movable between two positions. In a first position, referred to herein as the relaxed, the movable layer is positioned at a relatively large distance from a fixed partially reflective layer. In the second position, the movable layer is positioned closer to the partially reflective layer. Incident light that reflects from the two layers interferes constructively or destructively depending on the position of the movable reflective layer, producing either an overall reflective or non-reflective state for each pixel.

The portion of the pixel array shown in FIG. 1 includes two adjacent interferometric modulators 12a and 12 b. In the interferometric modulator 12a on the left, a movable highly reflective layer 14a is illustrated in a released position at a predetermined distance from a fixed partially reflective layer 16 a. In the interferometric modulator 12b on the right, a movable highly reflective layer 14b is illustrated in an actuated position adjacent to a fixed partially reflective layer 16 b.

The fixed layers 16a, 16b are electrically conductive, partially transparent and partially reflective, and may be fabricated, for example, by depositing one or more layers each of chromium and indium tin oxide on a transparent substrate 20. The layers are patterned into parallel strips and may form row electrodes in a display device, as will be described further below. The movable layers 14a, 14b may be formed as a series of parallel strips of a deposited metal layer or layers (orthogonal to the row electrodes 16a, 16 b) deposited on top of posts 18, and an intervening sacrificial material deposited between the posts 18 after the sacrificial material is etched away, the deformable metal layers 14a, 14b are separated from the fixed metal layers by a defined air gap 19.

When no voltage is applied, the cavity 19 remains between the layers 14a, 16a and the deformable layer is in a mechanically relaxed state as shown by the pixel 12a in FIG. 1. However, after application of a potential difference to a selected row and column, the capacitor formed at the intersection of the row and column electrodes at the corresponding pixel is charged, and electrostatic forces pull the electrodes together. If the voltage is high enough, the movable layer deforms and is forced against the fixed layer (a dielectric material (not shown in this figure) may be deposited over the fixed layer to prevent shorting and control the separation distance), as shown in the right pixel 12b in FIG. 1. The behavior is the same regardless of the polarity of the applied potential difference. It can thus be seen that row/column actuation that can control the reflective vs. non-reflective pixel states is analogous in many ways to that used in conventional LCD and other display technologies.

FIGS. 2-5 illustrate one exemplary process and system for using an array of interferometric modulators in a display application.

FIG. 2 is a system block diagram illustrating one embodiment of an electronic device that may embody aspects of the invention. In the exemplary embodiment, the electronic device includes a processor 21, which may be any general purpose single-or multi-chip microprocessor such as an ARM, Pentium *, Pentium II *, Pentium III *, Pentium IV *, Pentium * Pro, 8051, MIPS *, Power PC *, ALPHA *, or any special purpose microprocessor such as a digital signal processor, microcontroller, or programmable gate array. As is conventional in the art, the processor 21 may be configured to execute one or more software modules. In addition to executing an operating system, the processor may be configured to execute one or more software applications, including a web browser, a telephone application, an email program, or any other software application.

In one embodiment, the processor 21 is further configured to communicate with an array controller 22. In one embodiment, the array controller 22 includes a row driver circuit 24 and a column driver circuit 26 that provide signals to a display array or panel 30. The cross-sectional view of the array shown in FIG. 1 is shown by line 1-1 in FIG. 2. For MEMS interferometric modulators, the row/column actuation protocol may take advantage of the hysteresis properties of these devices shown in FIG. 3. It may require, for example, a 10 volt potential difference to cause a movable layer to deform from the relaxed state to the actuated state. However, when the voltage is reduced from this value, the movable layer will retain its state as the voltage drops back below 10 volts. In the exemplary embodiment of FIG. 3, the movable layer does not relax completely until the voltage drops below 2 volts. Thus, in the example shown in FIG. 3, there is a range of voltage, approximately 3-7 volts, within which there exists a window of applied voltage within which the device is stable in either the relaxed or actuated state. This is referred to herein as the "hysteresis window" or "stability window". For a display array having the hysteresis characteristics of FIG. 3, the row/column actuation protocol can be designed to apply a voltage difference of about 10 volts to the pixels to be actuated in the selected pass and a voltage difference of approximately 0 volts to the pixels to be released during row strobing. After the strobe, the pixels are exposed to a steady state voltage difference of about 5 volts such that they remain in the state they were exposed to by the row strobe. After writing, each pixel sees a potential difference within the "stability window" of 3-7 volts in this example. This characteristic makes the pixel design shown in fig. 1 stable in an existing actuated or relaxed state under the same applied voltage conditions. Since each pixel of the interferometric modulator, whether in the actuated or relaxed state, is essentially a capacitor formed by the fixed and moving reflective layers, this stable state can be held at a voltage within the hysteresis window with almost no power dissipation. Essentially no current flows into the pixel if the applied potential is fixed.

In typical applications, a display frame may be created by asserting the set of column electrodes in accordance with the desired set of actuated pixels in the first row. A row pulse is then applied to the row 1 electrode, actuating the pixels corresponding to the asserted column lines. The asserted set of column electrodes is then changed to correspond to the desired set of actuated pixels in the second row. Thereafter, a pulse is applied to the row 2 electrode, actuating the corresponding pixels in row 2 in accordance with the asserted column electrodes. The row 1 pixels are unaffected by the row 2 pulse, and thus remain in the state they were set to during the row 1 pulse. The above steps may be repeated for the entire series of rows in a sequential manner to form the frame. Typically, the frames are refreshed and/or updated with new display data by continually repeating the process at some desired number of frames per second. A wide variety of protocols for driving row and column electrodes of pixel arrays to produce display frames are also well known and may be used in conjunction with the present invention.

Fig. 4 and 5 show one possible actuation protocol for forming a display frame on the 3 x 3 array of fig. 2. FIG. 4 shows a set of values that can be used for those exhibiting the hysteresis curves shown in FIG. 3Possible row and column voltage levels for the pixels. In the embodiment of FIG. 4, actuating a pixel includes setting the corresponding column to-V_biasAnd sets the corresponding row to + av, which may correspond to-5 volts and +5 volts, respectively. Releasing the pixel is then performed by setting the corresponding column to + V_biasAnd sets the corresponding row to the same + av so as to create a 0 volt potential difference across the pixel. In those rows where the row voltage is held at 0 volts, the pixels are stable in their original state, being at + V with the column_biasOr is-V_biasIs irrelevant. As also shown in FIG. 4, it will be appreciated that voltages of opposite polarity than those described above can be used, e.g., actuating a pixel can include setting the corresponding column to + V_biasAnd sets the corresponding row to- Δ V. In this embodiment, releasing a pixel is by setting the corresponding column to-V_biasAnd the corresponding row to the same-av so as to create a 0 volt potential difference across the pixel.

FIG. 5B is a timing diagram showing a series of row and column signals applied to the 3 × 3 array of FIG. 2, which will result in the display arrangement of FIG. 5A, where actuated pixels are non-reflective. Prior to writing the frame shown in FIG. 5A, the pixels can be in any state, in this example, all the rows are at 0 volts, and all the columns are at +5 volts. Under these applied voltages, all pixels are stable in their existing actuated or relaxed states.

In the frame shown in FIG. 5A, pixels (1, 1), (1, 2), (2, 2), (3, 2) and (3, 3) are activated. To accomplish this, column 1 and column 2 are set to-5 volts, and column 3 is set to +5 volts at a line time in row 1. This does not change the state of any pixels, since all pixels remain within the 3-7 volt stability window. Thereafter, row 1 is strobed with a pulse that rises from 0 volts to 5 volts and then falls back to 0 volts. Thereby actuating the pixels (1, 1) and (1, 2) and relaxing the pixels (1, 3). No other pixels in the array are affected. To set row 2 as desired, column 2 is set to-5 volts, and columns 1 and 3 are set to +5 volts. Thereafter, applying the same strobe to row 2 will actuate pixel (2, 2) and relax pixels (2, 1) and (2, 3). Again, no other pixels in the array are affected. Similarly, row 3 is set by setting columns 2 and 3 to-5 volts, and column 1 to +5 volts. The row 3 strobe sets the row 3 pixels to the state shown in FIG. 5A. After writing the frame, the row potentials are 0, while the column potentials can remain at either +5 or-5 volts, and the display will thereafter be stable in the arrangement shown in FIG. 5A. It will be appreciated that the same procedure can be used for arrays consisting of tens or hundreds of rows and columns. It will also be appreciated that the timing, sequence, and levels of voltages used to perform row and column actuation can be varied widely within the general principles outlined above, and the above example is exemplary only, and any actuation voltage method can be used with the systems and methods described herein.

FIGS. 11A and 11B are system block diagrams illustrating one embodiment of a display device 40. The display device 40 may be a cellular or mobile phone, for example. However, the same components of display device 40 or slightly different components thereof may also illustrate different types of display devices, such as televisions or portable media players.

The display device 40 includes a housing 41, a display 30, an antenna 43, a speaker 44, an input device 48, and a microphone 46. The housing 41 is typically made from any of a number of manufacturing processes well known to those skilled in the art, including injection molding and vacuum forming. Additionally, the housing 41 may be made from any of a variety of materials, including but not limited to plastic, metal, glass, rubber, and ceramic, or a combination thereof. In one embodiment, the housing 41 includes movable portions (not shown) that are interchangeable with other movable portions having different colors or containing different logos, pictures, or symbols.

The display 30 of exemplary display device 40 may be any of a wide variety of displays, including the bi-stable display described herein. In other embodiments, the display 30 comprises a flat-panel display, such as the plasma, EL, OLED, STN LCD, or TFT LCD described above, or a non-flat-panel display, such as a CRT or other tube device, as is well known to those of skill in the art. However, for purposes of describing the present embodiment, the display 30 comprises an interferometric modulator display, as described herein.

FIG. 11B schematically shows components in an embodiment of exemplary display device 40. The exemplary display client 40 shown includes a housing 41 and may include other components at least partially enclosed within the housing 41. For example, in one embodiment, the exemplary display device 40 includes a network interface 27, the network interface 27 including an antenna 43 coupled to a transceiver 47. The transceiver 47 is connected to the processor 21, which processor 21 is in turn connected to conditioning hardware 52. The conditioning hardware 52 may be configured to condition a signal (e.g., filter a signal). The conditioning hardware 52 is connected to a speaker 44 and a microphone 46. The processor 21 is also connected to an input device 48 and a driver controller 29. The driver controller 29 is coupled to a frame buffer 28 and to the array driver 22, which in turn is coupled to a display array 30. A power supply 50 provides power to all components as required by the design of this particular exemplary display device 40.

The network interface 27 includes the antenna 43 and the transceiver 47 so that the exemplary display device 40 can communicate with one or more devices over a network. In one embodiment, the network interface 27 may also have some processing functionality to reduce the requirements on the processor 21. The antenna 43 is any antenna known to those skilled in the art for transmitting and receiving signals. In one embodiment, the antenna transmits and receives RF signals according to the IEEE802.11 standard, including IEEE802.11(a), (b), or (g). In another embodiment, the antenna transmits and receives RF signals according to the Bluetooth (BLUETOOTH) standard. In the case of a cellular telephone, the antenna is designed to receive CDMA, GSM, AMPS or other conventional signals used to communicate in a wireless mobile telephone network. The transceiver 47 pre-processes the signals received from the antenna 43 so that they may be received by and further processed by the processor 21. The transceiver 47 also processes signals received from the processor 21 for transmission from the exemplary client 40 via the antenna 43.

In an alternative embodiment, the transceiver 47 can be replaced by a receiver. In yet another alternative embodiment, network interface 27 can be replaced by an image source, which can store or generate image data to be sent to the processor 21. For example, the image source can be a Digital Video Disc (DVD) or a hard-disc drive that contains image data, or a software module that generates image data.

The processor 21 generally controls the overall operation of the exemplary display device 40. The processor 21 receives data, such as compressed image data, from the network interface 27 or an image source, and processes the data into raw image data or into a format that is readily processed into raw image data. The processor 21 then sends the processed data to the driver controller 29 or to the frame buffer 28 for storage. Raw data generally refers to information that can identify the image characteristics at each location within an image. For example, the image characteristics may include color, saturation, and gray-scale level.

In one embodiment, the processor 21 includes a microcontroller, CPU, or logic unit for controlling the operation of the exemplary display device 40. Conditioning hardware 52 generally includes amplifiers and filters for sending signals to the speaker 44, and for receiving signals from the microphone 46. Conditioning hardware 52 may be discrete components within the exemplary display device 40, or may be incorporated within the processor 21 or other components.

The driver controller 29 takes the raw image data generated by the processor 21 either directly from the processor 21 or from the frame buffer 28 and reformats the raw image data appropriately for high speed transmission to the array driver 22. In particular, the driver controller 29 reformats the raw image data into a data flow having a raster-like format, such that it has a time order suitable for scanning the display array 30. The driver controller 29 then sends the formatted information to the array driver 22. Although a driver controller 29, such as an LCD controller, is typically associated with the system processor 21 as a stand-alone Integrated Circuit (IC), such controllers may be implemented in a number of ways. They may be embedded in the processor 21 as hardware, embedded in the processor 21 as software, or fully integrated in hardware with the array driver 22.

The array driver 22 receives the formatted information from the driver controller 29 and reformats the video data into a parallel set of waveforms that are applied many times per second to the hundreds and sometimes thousands of leads coming from the display's x-y array of pixels.

In one embodiment, the driver controller 29, array driver 22, and display array 30 are appropriate for any of the types of displays described herein. For example, in one embodiment, the driver controller 29 is a conventional display controller or a bi-stable display controller (e.g., an interferometric modulator controller). In another embodiment, the array driver 22 is a conventional driver or a bi-stable display driver (e.g., an interferometric modulator display). In one embodiment, a driver controller 29 is integrated with the array driver 22. Such embodiments are common in highly integrated systems such as cellular phones, watches, and other small area displays. In yet another embodiment, the display array 30 is a typical display array or a bi-stable display array (e.g., a display including an array of interferometric modulators).

The input device 48 enables a user to control operation of the exemplary display device 40. In one embodiment, input device 48 includes a keypad (e.g., a QWERTY keyboard or a telephone keypad), a button, a switch, a touch-sensitive screen, a pressure-or heat-sensitive membrane. In one embodiment, the microphone 46 is an input device for the exemplary display device 40. When the microphone 46 is used to input data to the device, voice commands may be provided by a user to control operation of the exemplary display device 40.

The power supply 50 can include a variety of energy storage devices, as is well known in the art. For example, in one embodiment, the power source 50 is a rechargeable battery, such as a nickel-cadmium battery or a lithium ion battery. In another embodiment, power source 50 is a renewable energy source, a capacitor, or a solar cell, including plastic solar cells and solar-cell paint. In another embodiment, power supply 50 is configured to receive power from a wall outlet.

In some implementations control programmability resides, as described above, in a driver controller, which can be located in several places in the electronic display system. In some cases control programmability resides in the array driver 22. Those skilled in the art will appreciate that the above-described optimization may be implemented in any number of hardware and/or software components and in various configurations.

The detailed structure of interferometric modulators that operate in accordance with the principles set forth above may vary widely. For example, FIGS. 6A-6C show three different embodiments of the moving mirror structure. FIG. 6A is a cross-sectional view of the embodiment of FIG. 1, wherein a strip of metal material 14 is deposited on orthogonally extending supports 18. In FIG. 6B, the moveable reflective material 14 is attached to supports at the corners only, on tethers 32. In FIG. 6C, the moveable reflective material 14 is suspended from a deformable layer 34. This embodiment has several advantages because the structural design and materials used for the reflective material 14 can be optimized with respect to the optical properties, and the structural design and materials used for the deformable layer 34 can be optimized with respect to the desired mechanical properties. The fabrication of various types of interferometric devices is described in a number of published documents, including, for example, U.S. published application 2004/0051929. The above-described structures may be fabricated using a variety of well-known techniques, including a series of material deposition, patterning, and etching steps.

The values of the resolution that the display is required to have vary from application to application. By providing a display with sufficient resolution to cover all applications, the cost of the display can be reduced through economies of scale. However, such high resolution may result in unnecessary drive costs for users with low resolution requirements. One embodiment provides an array of modulators in which the leads of each modulator are selectively coupled for actuating groups of sub-pixel elements. This reduces the number of leads at the expense of unnecessary display resolution.

FIG. 7 shows an exemplary embodiment of a display 700. Display 700 includes an array of interferometric modulators 702. The modulator may comprise any of the interferometric modulators shown in FIGS. 6A, 6B, 6C, or may be other articles of manufacture. M row leads (R1-R4) are provided to select the row of modulators to be written to, and N column leads (C1-C4) are provided to write to the modulators 502 on the selected columns. It should be appreciated that a display comprising any number of rows or columns may be manufactured.

In one embodiment, adjacent row and column leads may be electrically connected through a switch 704. The switches may include fuses, antifuses, jumper pins, transistors, or other types of switching devices. An example of an antifuse is described in "ComparatiVe Study of On-Off Switching Behavior of Metal-Insulator-Metal Antifuses" (IEEE ELECTRON DEVICE LETTERS, Vol. 21, No.6, 6.2000 months) by Li et al. In one embodiment, the switch is in a "closed" state and may be placed in an "open" state by application of an electrical signal (e.g., a large current). For example, if the switch includes a fuse, a large current may short the fuse, thereby creating an open circuit. In another embodiment, the switch is in an "open" state and may be placed in a "closed" state by application of an electrical signal (e.g., a large current). For example, if switch 704 includes an antifuse, the electrical signal may cause the switch to change from an "open" to a "closed" position. Further, in one embodiment, the operation of the switch 704 may be programmatically controlled. In this embodiment, each switch 704 may be connected to a pair of control circuits that are operatively controlled thereby.

By modifying the state of the switch, the resolution characteristics of the display can be configured. A single manufacturing process may be used to form displays that may provide different resolution characteristics. The state of the switch, i.e., open or closed, may be selected after manufacture, before sale to a retailer or customer. In an embodiment, if the switch is programmably controllable, the resolution characteristics of the display may be modified by a controller of the display.

For illustrative purposes, both customers may purchase the display shown in FIG. 7. However, the first client may need to use the full resolution of the display, e.g. 600dpi, for his application, while the second client only wants to use one quarter of the available resolution, in this example 150dpi, for his application. In this case, the first customer may purchase a display in which all of the switches 704 are open. A second customer may be provided with a display in which half of the switches 704 are "closed" (e.g., each pair of adjacent columns or rows are electrically connected together) and the other half are "open," which would provide a quarter number of addressable pixel elements, where each pixel element is four times the size of the pixel element in the maximum resolution display. In the same way, any combination of switches using any array size can be supported. Furthermore, the size or shape of the pixels need not be uniform throughout the array.

In one embodiment, the switches connect non-adjacent columns or rows. For example, as shown in fig. 8, some switches 704 connect several rows or columns-which may be 1, 2, 3. Depending on the embodiment, a selected row or column may be connected to one or more (including all) other rows or columns in the display. Furthermore, in one embodiment, some rows or columns are not connected to other columns or rows through one of the switches 704. For example, referring to fig. 8, it can be seen visually that the top two rows are not connected to the bottom two rows through switches.

FIGS. 9A-9F illustrate aspects of a process flow for fabricating fuses in a process for fabricating interferometric modulators in a display. The examples described below are intended only to facilitate an understanding of the embodiments described herein. Any MEMS structure that uses an air gap and electrostatic attraction can use the methods and structures described herein. In addition, any MEMS structure having a movable element separated from its active layer by a dielectric material, a MEMS structure having a movable element and a movable active layer/element, or a MEMS structure having a movable element in contact with a dielectric layer/element may use the methods and structures described herein.

In fig. 9A, a layer 904 is formed on a transparent substrate 908. In one embodiment, layer 904 may be a metal layer. In one embodiment, the layer 904 may include a Cr layer 912 and an ITO layer 914. Referring now to fig. 9B, a dielectric stack 916 is then deposited over layer 904 and subsequently etched. Fig. 9B shows: after depositing the dielectric stack 916, a sacrificial layer 920 is deposited over the dielectric stack, and the sacrificial layer 920 is then etched to form the hole 922 as shown in FIG. 9C. Fig. 9D shows that a planarization layer 924 has been deposited in the holes 922 in the sacrificial layer. As shown in fig. 9E, a mechanical layer 928 is then formed over sacrificial layer 920 and planarization layer 924. In one embodiment, the mechanical layer 928 may have a reflective surface. In one embodiment, a fuse (switch) 934 is also patterned using the mechanical layer 928. Fuses 934 connect selected rows or columns of the display. It should be noted that the layers below the fuse 934 may comprise any suitable material, for example one or more layers may be fabricated using the deposited materials described above or elsewhere. As can be seen in fig. 9F, a selective etchant is used to remove the sacrificial layer 920, thereby forming a gap 930 below the mechanical layer 928 and above the dielectric stack 916.

FIG. 10 is a flow chart illustrating an exemplary process for configuring a display device to have selected resolution characteristics. Depending on the embodiment, additional steps may be added, other steps deleted, and the order of the steps rearranged. The flow chart shown in fig. 10 is generally used to configure a display in which the switching elements comprise fuses. It should be appreciated that the process flow may be modified for use with displays in which the switches comprise antifuses, transistors, or other elements.

First in step 1000, it is determined which pixels of the display should be independent, i.e., which fuses should remain un-shorted. Proceeding then to step 1004, the fuses that are to be blown (i.e., placed in an "open" state) are identified. Next, in step 1008, a current source is connected to the appropriate row in the display. Proceeding to step 1012, the current source is activated to blow the corresponding fuse. Proceed to a decision step 1016 to determine if all required fuses have been activated. If all required fuses have not been activated, the process returns to state 1004. However, if all required fuses have been activated, the process ends.

Various embodiments have been described above. While described with reference to these specific embodiments, the description is intended to be illustrative and not restrictive. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the invention as defined in the appended claims.

Claims (26)

1. A display system, comprising:

an array comprising a plurality of rows and columns of interferometric modulators; and

a plurality of electrical conductors, each of the electrical conductors connected to one of the plurality of rows or columns, at least two of the conductors configured to be selectively electrically interconnected to modify a resolution characteristic of at least a region of the array.

2. The display system of claim 1, wherein the at least two conductors are respectively connected to rows or columns that are physically close to each other.

3. The display system of claim 1, wherein the at least two conductors are respectively connected to rows or columns that are not physically adjacent to each other.

4. The display system of claim 1, wherein the at least two conductors are connected at least in part by an antifuse.

5. The display system of claim 4, wherein the antifuse is fabricated during a fabrication process of the array of interferometric modulators.

6. A display system as in claim 1, wherein the at least two conductors are connected at least in part by a transistor.

7. The display system of claim 1, further comprising:

a processor in electrical communication with the array, the processor configured to process image data; and

a storage device in electrical communication with the processor.

8. The display system of claim 7, further comprising:

a first controller configured to send at least one signal to the array; and

a second controller configured to send at least a portion of the image data to the first controller.

9. The display system of claim 7, further comprising an image source module configured to send the image data to the processor.

10. The display system of claim 9, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

11. The display system of claim 7, further comprising an input device configured to receive input data and to communicate the input data to the processor.

12. A method of modifying a resolution characteristic of a display comprising electrically connecting at least two adjacent columns of the display to each other and/or at least two adjacent rows of the display to each other through a switch.

13. The method of claim 12, wherein the switch comprises an antifuse.

14. The method of claim 12, wherein the switch comprises a fuse.

15. The method of claim 12, wherein the switch comprises a transistor.

16. The method of claim 12, further comprising fabricating the switch during a fabrication process of the display.

17. A display system, comprising:

means for displaying an image comprising a plurality of rows and columns of interferometric modulators;

a plurality of electrical conductors connected to the plurality of rows and columns; and

means for selectively electrically interconnecting at least one pair of the electrical conductors to modify a resolution characteristic of at least a region of the array.

18. The display system of claim 17, wherein the electrical interconnection means comprises electrically interconnecting at least two adjacent columns of a display and at least two adjacent rows of the display with each other through a switch.

19. The display system of claim 18, wherein the switch comprises a fuse.

20. The display system of claim 19, wherein the switch comprises a transistor.

21. The display system of claim 17 or 18, wherein the display means comprises the plurality of rows and columns of MEMS interferometric modulators.

22. A method of manufacturing a display system, the method comprising:

fabricating a plurality of electrical conductors, each of the electrical conductors connected to one of the plurality of rows or columns, at least two of the conductors configured to be selectively electrically interconnected by a switch, thereby modifying a resolution characteristic of at least an area of a display; and

the display is fabricated at the same time as the plurality of electrical conductors and switches are fabricated.

23. A display system made by the method of claim 22.

24. The display system of claim 23, wherein the switch comprises an antifuse.

25. The display system of claim 23, wherein the switch comprises a fuse.

26. The display system of claim 23, wherein the switch comprises a transistor.