JP5518764B2 - Method and apparatus for processing colors in a display - Google Patents

Description

  The present invention relates to a microelectromechanical system (MEMS).

  Microelectromechanical systems (MEMS) include micromechanical elements, actuators, and electronics. Micromechanical elements can be deposited, etched, and / or otherwise formed by etching or removing a portion of the substrate and / or deposited material layer or adding material layers. It can be manufactured using a microfabrication process. One type of MEMS device is called an interferometric modulator (). As used herein, the term interferometric modulator or interferometric light modulator refers to a device that selectively absorbs and / or reflects light using optical interference principles. In some embodiments, the interferometric modulator comprises a pair of conductive plates, one or both of these plates being wholly or partially transparent and / or reflective, suitable When an electric signal is applied, relative movement is possible. In a particular embodiment, one plate comprises a stationary layer deposited on a substrate and the other plate comprises a metal film separated from the stationary layer by an air gap. As described in more detail herein, the position of the other plate with respect to one plate can change the optical interference of light incident on the interferometric modulator. These devices have a very wide range of applications, and those skilled in the art can take advantage of the features of these types of devices when modifying existing products and when creating new products that have not yet been developed. It would be beneficial to utilize and / or modify the characteristics of these types of devices to ensure that

  Each of the systems, methods, and devices of the present invention has several aspects, and no single aspect is solely responsible for ensuring the desired attributes. In the following, the more prominent features of the present invention will be outlined without limiting the scope of the present invention. Those skilled in the art will understand how the features of the present invention are superior to other display devices after reviewing this description and particularly after reading the section entitled “Best Mode for Carrying Out the Invention”. Will.

  One embodiment includes a display. The display includes a plurality of pixels. Each of the pixels includes at least one red sub-pixel comprising at least one interferometric modulator configured to output red light, and at least one interferometer configured to output green light. Outputting colored light, at least one green sub-pixel comprising a metric modulator, at least one blue sub-pixel comprising at least one interferometric modulator configured to output blue light, and And at least one white sub-pixel comprising at least one interferometric modulator configured as described above.

  Other embodiments include a display. The display includes a plurality of interferometric modulators. The plurality of interferometric modulators includes at least one interferometric modulator configured to output red light, at least one interferometric modulator configured to output green light, and blue At least one interferometric modulator configured to output light and at least one interferometric modulator configured to output white light. The at least one interferometric modulator configured to output white light outputs white light having a standardized white point.

  Other embodiments include a display. The display includes a plurality of display elements. Each of the display elements includes a reflective surface configured to be disposed at a distance from the partially reflective surface. The plurality of display elements are at least one of the plurality of display elements configured to output colored light and at least one of the plurality of display elements configured to output white light in an interference manner. And one.

  Other embodiments include a method of manufacturing a display. The method includes forming a plurality of display elements. Each of the plurality of display elements includes a reflective surface configured to be disposed at a point at a distance from the partially reflective surface. Each of the distances is configured such that at least one of the plurality of display elements outputs colored light, and at least one other of the plurality of display elements outputs white light in an interfering manner. Selected to be configured.

  Other embodiments include a display comprising means for displaying an image. The means for displaying comprises means for reflecting light and means for partially reflecting light. The means for reflecting is arranged to be located at a distance from the means for partially reflecting. The means for displaying comprises first means for outputting colored light and second means for outputting white light in an interference manner.

  Other embodiments include a display. The display includes a plurality of pixels each including a red, green, and blue interferometric modulator configured to output red light, green light, and blue light, respectively. Each of the pixels is configured to output green light having a higher intensity than red light when each of the interferometric modulators is set to output red light, green light, and blue light. It is configured to output green light having a higher intensity than the light.

  Other embodiments include a method of manufacturing a display. The method includes forming a plurality of pixels. Forming the plurality of pixels includes forming an interferometric modulator configured to output red light and forming an interferometric modulator configured to output green light; Forming an interferometric modulator configured to output blue light. Each of the pixels is configured to output green light having a higher intensity than red light when each of the interferometric modulators is set to output red light, green light, and blue light. It is configured to output green light having a higher intensity than the light.

  Other embodiments include a display. The display includes a plurality of pixels. Each of the pixels includes a red, green, and blue interferometric modulator configured to output red light, green light, and blue light, respectively. Each of the pixels is configured to output green light having a higher intensity than red light, and further configured to output green light having a higher intensity than blue light. At least one of an interferometric modulator configured to output red light and an interferometric modulator configured to output blue light is configured to compensate for the higher intensity green light. It is configured to output light having a selected wavelength.

  Another embodiment comprises a display comprising a plurality of means for outputting red light, a plurality of means for outputting green light, and a plurality of means for outputting blue light. The means for outputting red, green and blue forms means for displaying pixels. Each of the means for displaying the pixels outputs green light having a higher intensity than the blue light when the means for outputting red, green and blue is set to output red light, green light and blue light. Configured.

  Other embodiments comprise a display comprising a plurality of display elements. The plurality of display elements include at least one color display element configured to output color light and at least one display element configured to output white light. The at least one display element configured to output white light outputs white light having a standardized white point.

  Another embodiment comprises a display comprising means for displaying an image. The means for displaying comprises means for outputting colored light and means for outputting white light. The means for outputting white light outputs white light having a standardized white point.

  Another embodiment forms a plurality of display elements comprising forming at least one color display element configured to output color light and at least one display element configured to output white light. A display manufacturing method. The at least one display element configured to output white light is configured to output white light having a standardized white point.

FIG. 5 is an isometric view depicting a portion of one embodiment of an interferometric modulator display, wherein the movable reflective layer of the first interferometric modulator is in an open position and the movement of the second interferometric modulator The possible reflective layer is in the operating position. FIG. 2 is a system block diagram illustrating one embodiment of an electronic device incorporating a 3 × 3 interferometric modulator display. FIG. 2 is a schematic diagram illustrating the relationship between movable mirror position and applied voltage for one exemplary embodiment of the interferometric modulator of FIG. 1. FIG. 6 illustrates a set of row and column voltages that can be used to drive an interferometric modulator display. FIG. 3 illustrates one exemplary display data frame within the 3 × 3 interferometric modulator display of FIG. 2. FIG. 5B is an exemplary timing diagram for row and column signals that can be used to write the frame of FIG. 5A. FIG. 3 is a system block diagram illustrating an embodiment of a visual display device comprising a plurality of interferometric modulators. FIG. 3 is a system block diagram illustrating an embodiment of a visual display device comprising a plurality of interferometric modulators. FIG. 2 is a cross-sectional view of the device of FIG. FIG. 6 is a cross-sectional view of an alternative embodiment of an interferometric modulator. FIG. 6 is a cross-sectional view of another alternative embodiment of an interferometric modulator. FIG. 6 is a cross-sectional view of yet another alternative embodiment of an interferometric modulator. FIG. 6 is a cross-sectional view of an additional alternative embodiment of an interferometric modulator. FIG. 4 is a side cross-sectional view of a typical interferometric modulator showing the spectral characteristics of output light by placing movable mirrors within a range. FIG. 3 is a diagram illustrating the spectral response of one embodiment including cyan and yellow interferometric modulators for generating white light. FIG. 6 is a side cross-sectional view of the interferometric modulator showing different optical paths through which the different colored light will be reflected through the interferometric modulator. 1 is a side cross-sectional view of an interferometric modulator having a material layer for selectively transmitting light of a specific color. FIG. FIG. 6 is a diagram illustrating the spectral response of one embodiment including a green interferometric modulator and a “magenta” filter layer for generating white light. 2 is a schematic diagram illustrating two pixels of a typical pixel array 30. FIG. Rows 1 to 4 and columns 1 to 4 form one pixel 120a. FIG. 4 is a chromaticity diagram illustrating colors that can be produced by a typical color display including red, green, and blue display elements. FIG. 3 is a chromaticity diagram illustrating colors that can be generated by a typical color display including red, green, blue, and white display elements.

Detailed Description of the Invention

  The following detailed description is directed to certain specific embodiments of the invention. However, the present invention can be embodied in a great many different ways. In this description, reference is made to the drawings, and the same components are denoted by the same reference numerals throughout the drawings. As will become clear from the following description, each embodiment is further a text or a picture, regardless of whether it is a moving image (video, etc.) or a still image (still image, etc.). Regardless, it can be implemented in any device that is configured to display images. More specifically, each embodiment includes various electronic devices, such as, without limitation, mobile phones, wireless devices, personal data assistants (PDAs), portable computers, portable computers, GPS receivers / navigators, Camera, MP3 player, camcorder, game console, watch, wall clock, calculator, TV monitor, flat panel display, computer monitor, automobile display panel (odometer display panel, etc.), cockpit control panel and / or display panel , In camera displays (rear view camera displays in vehicles, etc.), electronic photographs, electronic billboards or signs, projectors, building structures, packaging, aesthetic structures (image display on gems, etc.) or Can be implemented in connection with these electronic devices It is contemplated that way. Furthermore, a MEMS device having a structure similar to that of the MEMS device described in this specification can be used in applications other than display such as an electronic switchgear.

  One embodiment is a display in which each pixel comprises a set of display elements, each of which may comprise one or more interferometric modulators. The set of display elements includes display elements configured to output red light, green light, blue light, and white light. In one embodiment, the “white light” display element outputs white light having a broader and higher intensity spectral response than the combined spectral response of the “red”, “green”, and “blue” display elements. . In one embodiment, the display includes a driver circuit configured to activate a “white light” display element when data is provided to drive the pixels. Further, some embodiments include the color display configured to increase the percentage of output light intensity in the green portion of the visible spectrum to increase the perceived brightness of the color display.

  One interferometric modulator display embodiment comprising an interferometric MEMS display element is shown in FIG. In these devices, the pixels are either bright or dark. In the bright (“on” or “open”) state, the display element reflects a large portion of incident visible light to a user. In the dark (“off” or “closed”) state, the display element reflects little incident visible light to the user. The light reflection characteristics of the “on” state and “off state” can be reversed and depend on the embodiment. MEMS pixels can be configured to reflect primarily in selected colors, taking into account color displays 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, each pixel comprising a MEMS interferometric modulator. In some embodiments, the interferometric modulator display comprises a row / column array of these interferometric modulators. Each interferometric modulator includes a pair of reflective layers. The pair of reflective layers are disposed at a variable and controllable distance from each other to form a resonant optical cavity having at least one variable dimension. In one embodiment, one of the reflective layers can be moved between two positions. In a first position, referred to herein as the release position, the movable reflective layer is disposed at a distance relatively far from the fixed partially reflective layer. In the second position, referred to herein as the actuated position, the movable reflective layer is positioned closer to the partially reflective layer. Incident light reflected from these two layers interferes constructively or destructively depending on the position of the movable reflective layer, creating an overall reflective or non-reflective state for each pixel.

  In FIG. 1, the depicted portion of the pixel array includes two adjacent interferometric modulators 12a and 12b. In the left interferometric modulator 12a, the movable reflective layer 14a is released at a position at a predetermined distance from the optical stack 16a that includes the partially reflective layer. In the right interferometric modulator 12b, the movable reflective layer 14b is in an operating position adjacent to the optical stack 16b.

  The optical stacks 16a and 16b referred to herein (collectively referred to as optical stack 16) typically include an electrode layer, such as indium-tin oxide (ITO), and a partially reflective layer, such as chromium. , Transparent dielectrics, and several melt layers. Thus, the optical layer 16 is electrically conductive, partially transparent, and partially reflective, for example manufactured by depositing one or more of the above layers on the transparent substrate 20. can do. In some embodiments, these layers are patterned in parallel strips to form row electrodes in the display device as described below. The movable reflective layers 14a, 14b were deposited as and between the columns 18 as a series of parallel strips of one or more deposited metal layers (perpendicular to the row electrodes 16a, 16b) deposited on top of the columns 18. It can be formed as an intervening sacrificial material. When the sacrificial material is removed by etching, the movable reflective layers 14a and 14b are separated from the optical stacks 16a and 16b by a defined gap 19. A highly conductive reflective material, such as aluminum, can be used for the reflective layer 14, and these strips can form column electrodes in the display device.

  As illustrated by pixel 12a in FIG. 1, when no voltage is applied, cavity 19 remains between movable reflective layer 14a and optical stack 16a, and movable reflective layer 14a is mechanically coupled. It is in a released state. However, when a potential difference is applied to the selected row and column, the capacitor formed at the intersection of the row electrode and the column electrode in the corresponding pixel is charged, and the electrostatic force attracts these electrodes. If the voltage is high enough, the movable reflective layer 14 is deformed and pressed against the optical layer 16. A dielectric layer (not shown in this figure) in the optical layer 16 prevents short circuit between layers 14 and 16 and controls the separation distance, as shown by the right pixel 12b in FIG. can do. This behavior is the same regardless of the polarity of the applied potential difference. Thus, row / column operation that can control the state of reflective vs. non-reflective pixels is similar in many ways to that used in conventional LCD and other display technologies.

  2-5B illustrate one exemplary process and system for using an interferometric modulator ray in a display application.

  FIG. 2 is a system block diagram illustrating one embodiment of an electronic device that may incorporate aspects of the invention. In this exemplary embodiment, the electronic device includes a processor 21 that can be any general purpose single-chip or multi-chip microprocessor, such as ARM, Pentium®, Pentium II®, Pentium III (registered trademark), Pentium IV (registered trademark), Pentium (registered trademark) Pro, 8051, MIPS (registered trademark), PowerPC (registered trademark), ALPHA (registered trademark), etc., or any dedicated microprocessor, for example, It can be a digital signal processor, microcontroller, programmable gate array, etc. As is conventional in the art, the processor 21 can be configured to execute one or more software modules. In addition to running the operating system, the processor 21 may be configured to run one or more software applications, such as a web browser, a phone application, an email program, or any other software application. it can.

  In one embodiment, the processor 21 is also configured to communicate with the array driver 22. In one embodiment, the array driver 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 section of the array shown in FIG. 1 is indicated by line 1-1 in FIG. In MEMS interferometric modulators, the row / column operation protocol can take advantage of the hysteresis characteristics of these devices shown in FIG. For example, a potential difference of 10 volts is required to transform the movable layer from the released state to the activated state. However, when the voltage is reduced from the same value, the movable layer maintains its state as the voltage drops and again drops below 10 volts. In the exemplary embodiment of FIG. 3, the movable layer is not fully released until the voltage is below 2 volts. Thus, in the example shown in FIG. 3, there is a voltage range of about 3-7V, and there is a window of applied voltage that is stable when the device is released or activated. . This window is referred to herein as a “hysteresis window” or “stable window”. In the case of the display array having the hysteresis characteristic of FIG. 3, during the row strobe, the actuated pixel in the strobed row is exposed to a voltage difference of about 10 volts, and the released pixel is brought to a voltage difference of about zero volts. A row / column operating protocol can be designed to be exposed. After the strobe, the pixel is exposed to a steady state voltage difference of about 5 volts, and therefore remains in any state placed by the roast strobe. In this example, each pixel is exposed to a potential difference within a “stable window” of 3-7 volts after being written. This feature will stabilize the pixel design shown in FIG. 1 under the same applied voltage condition, whether it is in the active state or the pre-existing released state. Since each pixel of the interferometric modulator is essentially a capacitor formed by a fixed reflective layer and a movable reflective layer, whether it is in an activated state or a released state, this stable state is It can be held at one voltage in the hysteresis window with almost zero power dissipation. Essentially, no current flows into the pixel when the applied potential is fixed.

  In a typical application, a display frame can be manufactured by selecting a set of column electrodes according to the desired set of working pixels in the first row. Next, a row pulse is applied to the row 1 electrode, actuating the pixels corresponding to the selected column line. Next, the selected set of column electrodes is changed to correspond to the desired set of working pixels in the second row. Next, a pulse is applied to the row 2 electrode to actuate the corresponding pixel in row 2 according to the selected column electrode. The row 1 pixels are not affected by the row 2 pulse and remain in the state set during the row 1 pulse. This process can be repeated sequentially for the entire series of rows to produce the frame. In general, these display frames are refreshed by repeating the process continuously and / or updated with new display data at some desired number of frames per second. It is well known that the protocols for driving the row and column electrodes of the pixel array to produce a display frame are very varied and can be used with the present invention.

4, 5A and 5B illustrate one operational protocol that can be used to fabricate a display frame on the 3 × 3 array of FIG. FIG. 4 shows a set of column / row voltage levels that can be used for a pixel that exhibits the hysteresis curve of FIG. In the embodiment of FIG. 4, actuating the pixels involves setting the appropriate column to −V _bias and setting the appropriate row to + ΔV, these voltages being −5 volts and Each corresponds to +5 volts. Pixel release is accomplished by setting the appropriate column to + V _bias and the appropriate row to the same + ΔV, creating a zero volt potential difference at the pixel. In a row where the row voltage is held at zero volts, the pixel is stable in its original position regardless of whether the column is + V _bias or -V _bias . Also in FIG. 4, the ability to use a voltage of the opposite polarity to the above voltage, eg, actuating a pixel includes setting the corresponding column to + V _bias and setting the corresponding row to −ΔV. You will understand that you can. In this embodiment, pixel release is accomplished by setting the relevant column to -V _bias and the relevant row to the same -ΔV, creating a zero volt potential difference at 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, resulting in the display arrangement shown in FIG. Is non-reflective. Prior to writing the frame shown in FIG. 5A, the pixels can be in any state, and in this example, all rows are 0 volts and all columns are +5 volts. In a state where these voltages are applied, all the pixels are stable in an activated state or a released state before application.

  In the frame of FIG. 5A, pixels (1,1), (1,2), (2,2), (3,2) and (3,3) are activated. To accomplish the operation, during the “line time” for row 1, columns 1 and 2 are set to −5 volts and column 3 is set to + 5V. In this case, since all the pixels remain within the stable window of 3 to 7 volts, the state of any pixel is not changed. Row 1 is then strobed with a pulse, rising from 0 to a maximum of 5V and back to 0. This action activates pixels (1, 1) and (1, 2) and releases pixel (1, 3). Other pixels in the pixel array are not affected. To set row 2 as desired, column 2 is set to -5V and columns 1 and 3 are set to + 5V. The same strobe applied to row 2 now activates pixel (2, 2) and releases pixels (2, 1) and (2, 3). Again, the other pixels in the pixel array are not affected. Similarly, row 3 is set by setting columns 2 and 3 to -5V and column 1 to + 5V. The row 3 strobe sets the row 3 pixels as shown in FIG. 5A. After writing the display frame, the row potential is zero and the column potential can remain at either +5 or -5 volts, thus stabilizing the display in the arrangement of FIG. 5A. It will be understood that this procedure can be employed for arrays of dozens of rows and columns, as well as arrays of hundreds of rows and columns. In addition, the timing, sequence, and voltage levels used to perform row and column operations can vary widely within the general principles described above, and the above example is a typical example. It will also be appreciated that any operating voltage method can be used with the systems and methods described herein.

  6A and 6B are system block diagrams illustrating an embodiment of the display device 40. The display device 40 can be, for example, a mobile phone. However, the same components of display device 40, or slight variations thereof, also indicate that it can be various types of display devices such as televisions and portable media players.

  The display device 40 includes a housing 41, a display 30, an antenna 43, a speaker 45, an input device 48, and a microphone 46. The housing 41 is typically molded from any of a variety of manufacturing processes well known by those skilled in the art and includes injection molding and vacuum molding. Further, the housing 41 can be manufactured from any of a variety of materials including, but not limited to, plastic, metal, glass, rubber, ceramic, or combinations thereof. In one embodiment, the housing 41 includes a removable portion (not shown) that is compatible with other removable portions of different colors, or other removable portions that include different logos, pictures, or symbols.

  The display 30 of the exemplary display device 40 can be any of a variety of displays, including the bistable display display described herein. In other embodiments, the display 30 is a flat panel display such as a plasma, EL, OLED, STN LCD, or TFT LCD, or a non-flat panel display, such as a CRT or well known to those skilled in the art. Includes other picture tube devices. However, for purposes of describing the present embodiment, display 30 includes an interferometric modulator display as described herein.

  The components of one embodiment of exemplary display device 40 are schematically illustrated in FIG. 6B. The illustrated exemplary display device 40 includes a housing 41 and may include additional components at least partially contained within the housing. For example, in one embodiment, the exemplary display device 40 includes a network interface 27 that includes an antenna 43 coupled to a transceiver 47. The transceiver 47 is connected to the processor 21, and the processor 21 is connected to the conditioning hardware 52. Conditioning hardware 52 may be configured to condition the signal (eg, filter the signal). The conditioning hardware 52 is connected to the speaker 45 and the microphone 46. The processor 21 is also connected to the input device 48 and the driver controller 29. Driver controller 29 is coupled to frame buffer 28 and array driver 22, and array driver 22 is coupled to display array 30. The power supply 50 provides power to all components required by the particular design of the typical display device 40.

  The network interface 27 includes an antenna 43 and a 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 have several processing capabilities to reduce processor 21 requirements. 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 IEEE 802.11 standard, including IEEE 802.11 (a), (b), or (g). In another embodiment, the antenna transmits and receives RF signals according to the BLUETOOTH® standard. In the case of a cellular phone, the antenna is designed to receive CDMA, GSM®, AMPS or other known signals that are used to communicate within a wireless cellular network. The transceiver 47 preprocesses the signal received from the antenna 43 so that it can be received by the processor 21 and further processed. The transceiver 47 also processes the signal received from the processor 21 so that it can be transmitted from the typical display device 40 via the antenna 43.

  In an alternative embodiment, the transceiver 47 can be replaced by a receiver. In still other embodiments, the network interface 27 can be replaced with an image source that can store or generate image data that is sent to the processor 21. For example, the image source can be a digital video disk (DVD) or hard disk 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, eg, compressed image data, from the network interface 27 or an image source and processes the data into raw image data, or in a format that can be easily processed into raw image data. To do. Next, the processor 21 sends the processed data to the driver controller 29 or sends it to the frame buffer 28 for storage. Raw data is typically information that identifies the characteristics of an image at each location within an image. For example, these features for the image can include color, saturation, and grayscale level.

  In one embodiment, the processor 21 includes a microcontroller, CPU, or logic device for controlling the operation of the exemplary display device 40. Conditioning hardware 52 generally includes amplifiers and filters for transmitting signals to speaker 45 and for receiving signals from microphone 46. Conditioning hardware 52 may be a separate component within typical display device 40 or may be incorporated within processor 21 or other components.

  The driver controller 29 receives the raw image data generated by the processor 21 directly from the processor 21 or from the frame buffer 28 and reformats the raw image data suitable for high-speed transmission to the array driver 22. Against. Specifically, the driver controller 29 reformats the raw image data into a data flow having a format similar to a raster. For this reason, the data flow has a temporal order suitable for scanning the entire display array 30. Next, the driver controller 29 sends the formatted information to the array driver 22. A driver controller 29, such as an LCD controller, is often associated with the system processor 21 as a stand-alone integrated circuit (IC), but these controllers can be implemented in a number of ways. These controllers can be embedded in the processor 21 as hardware, embedded in the processor 21 as software, or completely embedded in hardware together with the array driver 22.

Typically, the array driver 22 receives formatted information from the driver controller 29 and reformats the video data into a parallel set of waveforms. These waveforms are applied many times per second to hundreds and sometimes thousands of leads coming from the xy pixel matrix of the display.
In one embodiment, driver controller 29, array driver 22, and display array 30 are suitable for any type of display described herein. For example, in one embodiment, driver controller 29 is a conventional display controller or a bi-stable display controller (such as an interferometric modulator controller). In other embodiments, the array driver 22 is a conventional driver or a bi-stable display display driver (interferometric modulator display, etc.). In one embodiment, the driver controller 29 is integrated with the array driver 22. This embodiment is a common embodiment in highly integrated systems such as mobile phones, watches, and other small displays. In yet other embodiments, the display array 30 is a typical display array or a bi-stable display display array (such as a display that includes an interferometric modulator array).

  Input device 48 allows the user to control the operation of exemplary display device 40. In one embodiment, the input device 48 includes a keypad, such as a QWERTY keyboard or telephone keypad, buttons, switches, touch screen, pressure sensitive film, and heat sensitive film. In one embodiment, the microphone 46 is an input device for the exemplary display device 40. When using the microphone 46 to enter data into the device, the user can provide voice commands to control the operation of the exemplary display device 40.

  The power supply 50 can include a variety of energy storage devices that are 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 other embodiments, the power source 50 is a renewable energy source, a capacitor, or a solar cell that includes a plastic solar cell and a solar cell paint. In other embodiments, the power supply 50 is configured to receive power from an outlet.

  In some implementations, control programmability resides in a driver controller that can be located in several places in the electronic display system, as described above. In some cases, control programmability resides in the array driver 22. One skilled in the art will recognize that the optimization described above can be implemented in any number of hardware and / or software components and in various configurations. The details of the structure of interferometric modulators that operate according to the above principles can vary greatly. For example, FIGS. 7A-7E show five different embodiments of the movable reflective layer 14 and its support structure. FIG. 7A is a cross section of the embodiment of FIG. 1, with an elongated strip of metal material 14 deposited on an orthogonal support 18. In FIG. 7B, the movable reflective layer 14 is attached only on the corners of the support (on the tether 32). In FIG. 7C, the movable reflective layer 14 is suspended from a deformable layer 34 that can comprise a flexible metal. The deformable layer 34 connects directly or indirectly to the substrate 20 around the deformable layer 34. These connections are referred to herein as support posts. The embodiment shown in FIG. 7D has a support post plug 42 on which the deformable layer 34 rests. The movable reflective layer 14 is suspended above the cavity, as in FIGS. 7A-7C, but the deformable layer 34 is formed by filling the hole between the deformable layer 34 and the optical stack 16. Do not form support pillars. Rather, the support column is formed by a planarizing material used to form the support column plug 42. The embodiment shown in FIG. 7E is based on the embodiment shown in FIG. 7D, but can be adapted to work with any embodiment shown in FIGS. 7A-7C and additional embodiments not shown. . In the embodiment shown in FIG. 7E, an additional metal or conductive material layer is used to form the bus structure 44. This use allows the routing of signals along the backside of the interferometric modulator and eliminates some electrodes that otherwise had to be formed on the substrate 20.

  In an embodiment such as that shown in FIG. 7, the interferometric modulator functions as a direct view device, and the image is viewed from the front side of the transparent substrate 20 opposite the side where the interferometric modulator is located. It can be seen. In these embodiments, the reflective layer 14 optically shields some portions of the interferometric modulator on the side of the reflective layer opposite the substrate 20 including the deformable layer 34 and the bus structure 44. . This occlusion allows you to configure and work with occluded areas without adversely affecting image quality. This separable modulator structure allows the structural design and materials used for the electromechanical and optical aspects of the modulator to be selected and to function independently of each other. In addition, the embodiment shown in FIGS. 7C-7E has the additional benefit obtained by decoupling the optical properties of the reflective layer 14 from the mechanical properties performed by the deformable layer 34. This allows the structural design and materials used for the reflective layer 14 to be optimized for optical properties, and the structural design and materials used for the deformable layer 34 to be optimized for desired mechanical properties. To.

  As described above with reference to FIG. 1, modulator 12 (ie, both modulators 12a and 12b) includes mirrors 14 (ie, mirrors 14a and 14b) and 16 (ie, mirrors 16a and 16b). Including an optical cavity formed therebetween. The characteristic distance of the optical cavity, ie the effective optical path length d, determines the resonant wavelength λ of the optical cavity and thus of the interferometric modulator 12. The peak resonant visible wavelength λ of the interferometric modulator 12 generally corresponds to the perceived color of the light reflected by the modulator 12. Mathematically, the optical path length is equal to 1 / 2Nλ, where N is an integer. Accordingly, a predetermined resonance wavelength λ is reflected by the interferometric modulator 12 having an optical path length d such as ½λ (N = 1), λ (N = 2), 3 / 2λ (N = 3), or the like. The The integer N can be called the interference order of the reflected light. As used herein, the order of the modulator 12 also refers to the order N of the light reflected by the modulator 12 when the mirror 14 is in at least one position. For example, the first order red interferometric modulator 12 may have an optical path length d of about 325 nm, corresponding to a wavelength λ of about 650 nm. Accordingly, the second order red interferometric modulator 12 may have an optical path length of about 650 nm. In general, higher order modulators 12 reflect light at a narrower range of wavelengths, for example, to produce colored light that has a higher “Q” value and is therefore more saturated. The degree of saturation of the modulator 12 with color pixels affects the properties of the display, such as the color gamut and white point of the display. For example, a display using a second order modulator 12 has a different central peak optical wavelength in order to have the same white spot or color balance as a display including a first order modulator that reflects the same general color of light. A second order modulator 12 can be selected.

  FIG. 8 is a side cross-sectional view of an exemplary interferometric modulator 12 showing the spectral characteristics of the light output by placing the movable mirror 14 in a range of positions 61-65. The exemplary modulator includes a conductive layer 52 of indium-tin oxide (ITO) that functions as a column electrode. In the exemplary modulator, the movable mirror 14 includes a low conductor.

  Each of the particular groups of positions 61-65 of the movable mirror 14 is indicated by an arrow extending from the fixed mirror 16. Each arrow point indicates a specific position among the positions 61 to 65 of the movable mirror. The color of light reflected from the interferometric modulator is determined by the optical path length d between the movable mirror 14 and the fixed mirror 16. The distances 61 to 65 are selected to take into account the thickness and refractive index of the dielectric layer 54 at the optical path length d. Accordingly, the movable mirrors 14 disposed at different ones of the positions 61 to 65 each corresponding to a different distance d result in different colors of incident light being reflected by the modulator 12. A modulator 12 is obtained that outputs light having a corresponding different spectral response to a viewing position 51. Furthermore, at position 61, the movable mirror 14 is a mirror at which the influence of interference is negligible and the modulator 12 reflects substantially all colors of incident visible light substantially equally, for example as white light. It is arranged at a distance sufficiently close to the fixed mirror 16 so as to function as The effect of this broadband mirror is due to the short distance d being too small for optical resonance to occur in the visible band. Therefore, the mirror 14 simply functions as a reflective surface for visible light.

  With the mirror 14 positioned at position 62, the modulator 12 exhibits a gray tint as the gap distance between the mirrors 14 and 16 gradually increases to reduce the reflectivity of the mirror 14. At position 63, the distance d is a distance that reflects substantially no visible wavelength since the cavity operates in an interferometric manner but the resonant wavelength is outside the visible range.

  As the distance d increases further, the peak spectral response of the modulator 12 moves into the visible wavelength. Thus, when the movable mirror 14 is at position 64, the modulator 12 reflects blue light. When the movable mirror 14 is in position 65, the modulator 12 reflects green light. When the movable mirror 14 is in the undeflected position 66, the modulator 12 reflects red light.

  When designing a display using the interferometric modulator 12, the modulator 12 can be formed in a manner that increases the color saturation of the reflected light. The degree of saturation means the intensity of hue of colored light. A hue with a high degree of saturation has a clear and intense color, and a hue with a low degree of saturation looks plain and gray. For example, lasers that produce a very narrow range of wavelengths produce light that is highly saturated. Conversely, typical incandescent bulbs generate white light having an unsaturated red or blue color. In one embodiment, the modulator 12 is formed at a distance d corresponding to a higher interference order, eg, a second or third order, to increase the saturation of the reflected color light.

  A typical color display includes red, green, and blue display elements. Other colors are produced in the display by changing the relative intensity of the light produced by these red, green and blue elements. Such a mixture of primary colors such as red, green and blue is perceived as other colors by the human eye. The relative values of red, green, and blue in the color system can be referred to as tristimulus values related to stimuli of a part that feels red, green, and blue of the human eye. In general, the higher the saturation of these primary colors, the wider the range of colors that can be generated by the display. In other embodiments, the display may include a modulator 12 having a set of colors that define other color systems with respect to a set of primary colors other than red, green, and blue.

  Another consideration in the design of a display incorporating the interferometric modulator 12 is the generation of white light. “White” light generally refers to light perceived by the human eye as light that does not contain a particular color, ie, white light is not associated with hue. Black means no color (ie, light), while white means light that includes a broad spectral range where a particular color is not perceived. White light refers to light having a broad spectral range of visible light of approximately uniform intensity. However, because the human eye feels certain wavelengths of red, green, and blue light, white is one or more perceived as “white” by the human eye by mixing colored light of multiple intensities. Can be produced by generating light having a spectral peak of The color gamut of the display is the range of colors that the device can reproduce by mixing, for example, red light, green light, and blue light.

  In reflective displays, white light generated using a saturated interferometric modulator is viewed because only a small range of incident wavelengths is reflected at a relatively high intensity to form the white light. For humans, they tend to have relatively low strength. In contrast, broadband white light, such as a mirror that reflects substantially all incident wavelengths, has greater intensity because a larger range of incident wavelengths is reflected. Therefore, designing a reflective display that produces white light using a combination of primary colors is generally a matter of either between color saturation and color gamut and white light brightness output by the display. It will be sacrificed.

  In one embodiment, the movable mirror 14 is such that the modulator 12 does not reflect visible light in the first position (eg, position 63 in FIG. 8) and the movable mirror 14 and fixed mirror in the second position. Since the distance to 16 is too small for interferometric modulation of incident visible light, the mirror 14 is arranged to reflect broadband white (eg, position 61 in FIG. 8). In said embodiment, the movable mirror 14 reflects incident light having a broad and relatively uniform spectral response over the entire visible spectrum. If the incident light comprises white light, the light reflected by the modulator 12 in the second position will be substantially similar white light. The spectral response of the “white” reflection state of the modulator 12 can generally be uniform across the visible spectrum. In one embodiment, the spectral response is fine tuned by modulator material selection. For example, different materials, such as aluminum or copper, can be used for the reflective surface of the movable mirror 14 to fine tune the spectral response of the modulator 12 in the white reflection state. In other embodiments, a filter can be used to selectively absorb a certain wavelength of reflected or incident light so as to affect the output of the broadband white modulator.

  In one embodiment of the pixel array 30, each pixel reflects one or more color modulators 12, eg, modulators configured to reflect red light, green light, and blue light, and white light. One or more “white” modulators 12 configured. In the embodiment, the light from the red, green, and / or blue modulators 12 in each reflection state is combined to output colored light. The light from the white modulator 12 can be used to output white light or gray light. Using white in combination with color can increase the brightness or intensity of the pixel.

  The white point of a display is a hue that is generally considered neutral (gray or colorless). The white spot of a display device can be characterized based on a comparison of the white light generated by the device and the spectral content of light emitted by a black body at a particular temperature (“black body radiation”). A blackbody radiator is an idealized object that absorbs all incident light and re-emits light having a spectrum that depends on the temperature of the blackbody. For example, a black body spectrum at 6,500 ° K can be referred to as white light having a color temperature of 6,500 ° K. The color temperature, i.e., the white spot of about 5,000 to 10,000 ° K, is generally identified by sunlight.

The International Commission on Illumination (ICE) has promulgated a standardized white spot for light sources. For example, “d”, which is a light source designation symbol, means sunlight. In particular, standard white points D ₅₅ , D ₆₅ , and D ₇₅ that correlate with color temperatures of 5,500 ° K, 6,500 ° K, and 7,500 ° K are standard sunlight white points.

  A display device can be characterized by a white point of white light generated by the display. Like white light from other light sources, human perception of a display is determined, at least in part, by the perception of white light from the display. For example, a display or light source with a lower white spot, eg, D55, is perceived by the viewer as having a yellow hue. A display with a higher temperature white spot, eg, D75, is perceived by the user as a “more calm” or display with a blue tone. Users generally respond more favorably to displays with higher temperature white spots. Thus, controlling the white point of the display can desirably control to some extent the reaction of the viewer. Embodiments of the interferometric modulator ray 30 are configured to generate white light in such a way that a white point is selected that matches the standardized white point under one or more expected lighting conditions. be able to.

  White light can be generated by the pixel array 30 by including one or more interferometric modulators for each pixel. For example, in one embodiment, the pixel array 30 includes pixels of a group of red, green, and blue interferometric modulators 12. As described above, the color of the interferometric modulator 12 can be selected by selecting the optical path length d using the relationship d = 1/2 Nλ. Further, the color balance, or relative proportion, produced by each pixel in the pixel array 30 is relative to each of the interferometric modulators 12, eg, the red, green, and blue interferometric modulators 12. May be further affected by the static reflection area. Furthermore, since the modulator 12 selectively reflects incident light, the white point of the reflected light from the pixel array 30 of the interferometric modulator 12 generally depends on the spectral characteristics of the incident light. In one embodiment, the white point of the reflected light can be configured to be different from the white point of the incident light. For example, in one embodiment, the pixel array 30 can be configured to reflect D75 when used in D65 sunlight.

In one embodiment, the distance d and area of the interferometric modulator 12 in the pixel array 30 is such that the white light generated by the pixel array 30 is expected to be in an illumination state, such as sunlight, fluorescent light, or pixel array. 30 is selected to correspond to a specific standardized white spot in the frontlight arranged to illuminate 30. For example, the white point of the pixel array 30 can be selected to be D ₅₅ , D ₆₅ , or D ₇₅ in a particular illumination state. Further, the light reflected by the pixel array 30 may have a white point that is different from the light of the expected or configured light source. For example, a particular pixel array 30 can be configured to reflect D75 light when viewed in D65 sunlight. More generally, the white point of the display can be selected for an illumination source configured with the display, such as a front light, or for a particular viewing condition. For example, the display has a white point selected when viewed under an expected or typical illumination source, such as an incandescent light source, a fluorescent light source, or a natural light source, such as D55, D65, or D75. It can be constituted as follows. More specifically, a display for use in, for example, a portable device can be configured to have a selected white spot when viewed in daylight conditions. Alternatively, a display for use in an office environment can be configured to have a white point, eg, D75, selected when illuminated by a typical office fluorescent lamp. In various embodiments, different distances d and areas of the modulator 12 can be selected to generate other standardized white point settings for different viewing environments. Furthermore, the red, green and blue modulators 12 are reflected or non-reflected for different amounts of time and the relative balance of reflected red, green and blue light, and thus the white point of the reflected light. It is also possible to control to further change. In one embodiment, the ratio of the reflective area of each color modulator 12 can be selected to control the white point in different viewing environments. In one embodiment, the optical path length d is greater than or equal to two or more visible resonance wavelengths, eg, red, green, such that the interferometric modulator 12 reflects white light characterized by three visible peaks in the spectral response. , And blue first order, second order, or third order peaks, may be selected to correspond to common multiples. In the embodiment, the optical path length d can be selected so that the generated white light corresponds to the standardized white point.

  In addition to the group of red, green, and blue interferometric modulators 12 in the pixel array 30, other embodiments include other white light generation methods. For example, one embodiment of the pixel array 30 includes a cyan and yellow interferometric modulator 12, eg, an interferometric modulator 12 having a respective separation distance d to generate cyan and yellow light. The combined spectral response of the cyan and yellow interferometric modulator 12 produces light having a broad spectral response perceived as “white”. These cyan and yellow modulators are placed next to each other so that the viewer perceives the combined response. For example, in one embodiment, the cyan and yellow modulators are arranged in adjacent rows of the pixel array 30. In other embodiments, the cyan and yellow modulators are arranged in adjacent columns of the pixel array 30.

  FIG. 9 is a diagram illustrating the spectral response of one embodiment including cyan and yellow interferometric modulators 12 for generating white light. The horizontal axis indicates the wavelength of the reflected light. The vertical axis represents the relative reflectance of light incident on the modulator 12. Trace line 80 shows the response of the cyan modulator and is a single peak centered in the cyan portion of the spectrum, eg, between blue and green. Trace line 82 shows the response of the yellow modulator and is a single peak centered in the yellow part of the spectrum, for example between red and green. Trace line 84 shows the combined spectral response of a pair of cyan and yellow modulators 12. Trace line 84 has two peaks at cyan and yellow wavelengths, but is sufficiently uniform over the entire visible spectrum that the reflected light from modulator 12 is perceived as white.

In general, the color of light reflected by the interferometric modulator 12 shifts when the modulator 12 is viewed from a different angle. FIG. 10 is a side cross-sectional view of the interferometric modulator 12 showing the different optical paths through the modulator 12. The color of the light reflected from the interferometric modulator 12 can change at different incident angles (and reflection angles) with respect to the axis AA, as shown in FIG. For example, with respect to interferometric modulators 12 illustrated in Figure 10, when the traveling light along the off-axis path A _1, the light interferometric incident on the interferometric modulators on a first angle Reflects from the metric modulator and travels towards the viewer. The viewer perceives the first color when the light reaches the viewer as a result of optical interference between a pair of mirrors in the interferometric modulator 12. Viewer has changed the ie the location movement, thus changing the angle of observation, sometimes, the light perceived by the viewer, different axis path A ₂ corresponding to the second different angles of incidence (and reflection angle) Proceed along. The optical interference in the interferometric modulator 12 depends on the optical path length d of the light propagated in the modulator. Thus, different optical path lengths for different optical paths A ₁ and A ₂ produce different outputs from the interferometric modulator 12. As the viewing angle increases, the effective optical path of the interferometric modulator 12 decreases according to the relation 2d cosβ = Nλ, where β is the viewing angle (the angle between the normal to the display and the incident light). is there. As the viewing angle increases, the peak resonance wavelength of the reflected light decreases. Thus, the user perceives different colors depending on his viewing angle. As described above, this phenomenon is called “color shift”. This color shift is typically identified with respect to the color produced by the interferometric modulator 12 when viewed along axis AA.

  In one embodiment, the pixel array 30 includes a first order yellow interferometric modulator and a second order cyan interferometric modulator. When the pixel array 30 is viewed from a gradually increasing off-axis angle, the light reflected by the first order yellow modulator is shifted toward the blue end of the spectrum. For example, a constant angle modulator has an effective d equal to the angle of the first order cyan. In parallel, the light reflected from the second order cyan modulator is shifted to correspond to the light from the first order yellow modulator. Thus, the overall combined spectral response is broad even when the relative peak of the visible spectrum is shifted and is relatively uniform throughout the visible spectrum. Accordingly, the pixel array 30 generates white light over a relatively wide range of viewing angles.

  In one embodiment, a display having a cyan modulator and a yellow modulator can be configured to produce white light having a standardized white point selected under one or more viewing conditions. For example, the spectral response of the cyan and yellow modulators can be determined as D55, D65, D65, D65, or D75 under selected lighting conditions where the reflected light includes D55, D65, or D75 light, eg, sunlight for a display suitable for outdoor use. It can be selected to have a D75 white spot, or other suitable white spot. In one embodiment, the modulator can be configured to reflect light having a white point different from the incident light from the expected or selected viewing state.

  FIG. 11 is a side cross-sectional view of an interferometric modulator 12 having a material layer 102 for selectively transmitting light of a particular color. In the exemplary embodiment, layer 102 is on substrate 20 opposite the modulator 12. In one embodiment, material layer 102 comprises a magenta filter in which green interferometric modulator 12 is seen. In one embodiment, material layer 102 is a dyed material. In one embodiment, the material is a dyed photoresist material. In one embodiment, the green interferometric modulator 12 is a first order green interferometric modulator. The filter layer 102 is configured to transmit magenta light during illumination with uniform white light over a wide range. In the exemplary embodiment, light is incident on the layer 20, and the filtered light from the layer 20 is transmitted to the modulator 12. Modulator 12 reflects the filtered light back through layer 102. In the embodiment, the light passes through layer 102 twice. In the embodiment, the thickness of the material layer 102 can be selected to compensate and utilize this double filtering. In other embodiments, a front light structure can be disposed between layer 102 and modulator 12. In this embodiment, the material layer 102 only affects the light reflected by the modulator 12. In the embodiment, the layer 102 is appropriately selected.

  FIG. 12 shows the spectral response of one embodiment including a green interferometric modulator 12 and a “magenta” filter layer 102. The horizontal axis indicates the wavelength of the reflected light. The vertical axis shows the relative spectral response of light incident on the green modulator 12 and filter layer 102 over the entire visible spectrum. Trace line 110 shows the response of green modulator 12, which is a single peak located in the middle of the green portion of the spectrum, eg, near the center of the visible spectrum. Trace line 112 shows the response of the magenta filter formed by material layer 102. Trace line 112 has two relatively flat portions on either side of the center u-shaped minimum. Thus, trace line 112 represents the response of a magenta filter that selectively transmits substantially all red and blue light while filtering light in the green portion of the spectrum. Trace line 114 shows the combined spectral response of the green modulator 12 and filter layer 102 pair. Trace line 114 indicates that the spectral response of the coupling is at a lower reflection level than green modulator 12 due to light filtering by filter layer 102. However, this spectral response is relatively uniform throughout the visible spectrum, so that the reflected light from the green modulator 12 and magenta filter layer 102 is perceived as white.

  In one embodiment, a display having a green modulator 12 with a magenta filter layer 102 can be configured to produce white light having a standardized white point selected under one or more viewing conditions. . For example, the spectral response of the green modulator 12 and the magenta filter layer 102 can be determined to be D55, D65, D65, D65, or D75 under selected lighting conditions, where the reflected light includes D55, D65, or D75 light, eg, sunlight for a display suitable for outdoor use. It can be selected to have a D75 white spot, or other suitable white spot. In one embodiment, the modulator 12 and the filter layer 102 can be configured to reflect light having a white point that is different from the incident light from the expected or selected viewing state.

FIG. 13 is a schematic diagram illustrating two pixels of a typical pixel array 30. Rows 1 to 4 and columns 1 to 4 form one pixel 120a. Rows 5 through 8 and columns 1 through 4 form a second pixel 120b. Each pixel 120a and 120b includes at least one modulator 12 configured to reflect red light (column 1), green light (column 2), blue light (column 3), and white light (column 4). Each pixel of the exemplary pixel array 30 forms “4 bits” per color display that can output 2 ⁴ = 16 shades of red, green, blue, or white / gray each for a total of 2 ¹⁶ shades. In order to do so, four display elements of red, green, blue and white are included.

  FIG. 14A is a chromaticity diagram illustrating the colors that can be produced by a typical color display including red, green, and blue display elements. In the display, a wide range of colors is generated by changing the relative intensity of the light generated by the red, green and blue elements. The chromaticity diagram shows how to control the display to produce a mixture of primary colors such as red, green, and blue that are perceived as other colors by the human eye. The horizontal and vertical axes in FIG. 14 define a chromaticity coordinate system that can represent color values. In particular, point 130 indicates the color of light reflected by typical red, green, and blue interferometric modulators. A triangular trace line 133 surrounds a region 134 corresponding to the range of colors that can be generated by mixing the light generated at point 120. This color range can be referred to as the color gamut of the display. As a principle of operation, each of the red, green and blue display elements in the pixel is controlled to produce different mixtures of red, green and blue light that combine to form each color in the color gamut. Can do.

  As shown in FIG. 13, in one embodiment, a typical display 30 includes pixels having red, green, blue, and white subpixels. One embodiment of a scheme for driving the display defines three different color gamuts: (i) red, green, and white; (ii) red, blue, and white; and (iii) blue, green, and white. Define each color displayed by a pixel with respect to a combination of chromaticity values. In the operating principle of the embodiment, when the display controller decides to set a particular pixel in the color values represented by red, green, and blue, the display controller: (i) red, green, and white, The color value is converted to a value represented by one of (ii) red, blue, and white, and (iii) blue, green, and white.

  FIG. 14B is a chromaticity diagram illustrating colors that can be generated by the color display. The overall color gamut of the display is defined by the area defined by the trace lines 140 connecting each of the points 130 corresponding to the display primaries red, green and blue chromaticities. Furthermore, the point 130a corresponds to the chromaticity of the light emitted by the white subpixel. This point 130a can exist at other positions depending on the white generated by the white subpixel. Trace lines 144a, 144b, and 144c connect point 130a corresponding to the white subpixel to each of points 130 corresponding to red, blue, and green, respectively. Along trace line 140, trace lines 144a, 144b, and 144c are (i) red, green, and white, (ii) red, blue, and white, and (iii) blue, green, within the color gamut of the display. And three regions 136a, 146b, and 146c corresponding to colors that can be generated by the white and white display elements, respectively. Thus, conceptually, one embodiment of a drive scheme for the display includes identifying which of the three regions 146a, 146b, or 146c the color desired to be displayed falls into. The input color represented as red, green, and blue values can then be converted to a new chromaticity. This chromaticity coordinate falls within one of the three identified regions 146a, 146b, or 146c. The new output value is then the value of each of the three identified display elements at the boundary of the region that contains the desired chromaticity coordinates: (i) red, green, and white of the pixel, (ii) red. , Blue and white, or (iii) blue, green and white display elements can be used to output the desired light color.

  In one embodiment, when the chromaticity value is within a selected distance (eg, in the chromaticity diagram) from the white display element point 130a, a color display to produce a brighter output from the pixel with respect to the color. Both the element and the white display element are activated.

  In other embodiments, in order to drive a pixel array as described above, when the overall hue of the pixel data is below a threshold, for example when the pixel data is gray or substantially gray, the driver The circuit sets the white modulator in column 4 to the corresponding reflective state. In one embodiment, red, green, and blue modulators can also be in their respective reflective states. When the overall hue for the pixel data exceeds a threshold, for example, the pixel data is not substantially gray, the driver circuit sets the white modulator in column 4 to its respective non-reflective state, and columns 1 through 3 The color modulator inside is set to the reflective state.

  In some embodiments, the white display element can be activated in combination with the color display element to increase brightness. For example, when a pixel outputs red light, all red display elements in the pixel can be activated. In addition, one or more of the white display elements can be activated to generate other color combinations.

  In some embodiments, the driver circuit provides a color balance for a display such as that described above (although the display is enhanced in terms of relative lightness) that is substantially unchanged by the white reflective area. The input data can be adjusted to produce additional images to compensate for the additional white surface area.

  In one embodiment, the white interferometric modulators are grouped together with the other white interferometric modulators, for example, in the additional column shown in FIG. In other embodiments, white interferometric modulators are interlaced between, for example, red, green, and blue display elements that are uniformly distributed throughout the pixel. Furthermore, in some embodiments, the number of white display elements in each pixel is different from, for example, the number of red, green, or blue display elements.

  In addition to using an additional interferometric modulator configured to reflect white light to increase the intensity of the reflected white light, the pixel array increases the overall apparent brightness of the system by other means Thirty embodiments can be formed. For example, the human eye is more sensitive to green light than other hues. Thus, in one embodiment, the apparent brightness of the interferometric modulator system is increased by using an additional green interferometric modulator in every pixel. For example, in some embodiments, there are an equal number of green, red, and blue interferometric modulators per pixel. In one embodiment similar to the embodiment shown in FIG. 13, a second column of green interferometric modulators may be included. In other embodiments, the pixel array 30 can include a fourth column, such as the column shown in FIG. 13, where some of the display elements reflect white light and some reflect green light.

  In one embodiment, the additional green interferometric modulators can be grouped together with other green interferometric modulators, for example, in the additional column shown in FIG. In other embodiments, additional green interferometric modulators can be uniformly distributed throughout the pixel, eg, interlaced between red, green, and blue display elements. Further, in some embodiments, the number of additional green elements in each pixel can be different from the number of red, green, or blue display elements, for example. In one embodiment, these display elements are interferometric modulators in which the optical path length d of the red and blue modulators is selected to compensate for the additional green pixels in the color balance of the display. is there. Furthermore, in one embodiment, the optical path length d of one or both of the red and blue display elements can be selected to produce a more saturated color. In one such embodiment, the optical path length d of the red or blue display element can be selected to produce a higher order reflected light (second order or higher). The second order corresponds to an optical path length d equal to 1 × λ. Because interferometric modulators with higher saturation responses reflect a smaller portion of the incoming light, the modulators tend to have lower (darker) output intensity. However, such a display can be configured to appear brighter to the viewer by increasing the relative intensity of the reflected green light. In one embodiment, the area ratio of red to blue is 1 to 1, and the area ratio of green to red (or blue) is greater than 1 to 1. For example, in one embodiment, 33 to 50% of the pixels are green when expressed as a percentage of the total reflection area of each pixel. In one embodiment, 38 to 44% of the pixels are provided.

  In one embodiment, to increase the perceived brightness, the ratio of the green interferometric modulator surface area to the total reflection area of the pixel is greater than the surface area ratio of the red and blue interferometric modulators. be able to. In other embodiments, the time that the green interferometric modulator is in the reflecting state is increased to increase the green color with respect to the duration of the other color producing interferometric modulators. In one embodiment, the blue and red interferometric modulators are fine tuned in the direction of the green spectrum to increase the appearance of green and thereby increase the perceived lightness in the system. As will be appreciated by those skilled in the art, the driver circuit is substantially configured with an additional green reflective area when the display as described above is (although the display is enhanced in terms of relative brightness). The input data can be adjusted to compensate for the additional green surface area to produce an image with a color balance that remains unchanged. In one embodiment, the additional green display element is used in a display mode where brightness is more important than color accuracy, for example, in text display.

  While the above description displays, describes, and points out novel features of the present invention that apply to various embodiments, those skilled in the art will be able to illustrate the devices or processes illustrated without departing from the spirit of the present invention. It will be understood that various omissions, substitutions, and changes in form and detail may be made. As will be appreciated, the invention may be embodied in a manner that does not provide all of the features and benefits described herein, as several features may be used or practiced separately from one another. can do. The scope of the invention is indicated by the appended claims rather than by the foregoing description. All changes that come within the meaning and range of equivalency of the claims are embraced within the scope of the claims.

Claims (25)

A display comprising a plurality of pixels each comprising a red, green, and blue interferometric modulator configured to output red light, green light, and blue light, respectively, each of the pixels When each of the interferometric modulators is set to output red light, green light, and blue light, the interferometric modulator is configured to output green light having a higher intensity than red light, and further outputting green light having a higher intensity than blue light. Configured to output ,
At least one of the interferometric modulators configured to output red light or at least one of the interferometric modulators configured to output blue light is more saturated than the green light. A display that is configured to output light of high color .   Each of the interferometric modulators of each of the plurality of pixels has a reflective area, and the green interferometric modulator of each pixel is larger than the red interferometric modulator of each pixel, and each The display of claim 1, having a total reflection area that is greater than the blue interferometric modulator of a pixel.   2. Each of the plurality of pixels comprises a greater number of interferometric modulators configured to output green light than interferometric modulators configured to output blue light. Display.   2. Each of the plurality of pixels comprises a greater number of interferometric modulators configured to output green light than interferometric modulators configured to output red light. Display.   The interferometric modulator configured to output red light is characterized by an optical path length, and the optical path length of the interferometric modulator configured to output red light is a second order red The display of claim 1, wherein the display is substantially equal to about one wavelength λ associated with red light to produce a reflection of.   The interferometric modulator configured to output blue light is characterized by an optical path length, and the optical path length of the interferometric modulator configured to output blue light is a second order blue. The display of claim 1 wherein said display is substantially equal to about one wavelength λ associated with blue light to produce a reflection of. A processor in electrical communication with the plurality of pixels, the processor configured to process image data;
The display of claim 1, further comprising a memory device in electrical communication with the processor.   The display of claim 7, further comprising a driver circuit configured to send at least one signal to the display.   The display of claim 8, further comprising a controller configured to send at least a portion of the image data to the driver circuit.   The display of claim 7, further comprising an image source module configured to send the image data to the processor.   The display of claim 10, wherein the image source module comprises at least one of a receiver, a transceiver, and a transmitter.   The display of claim 7, further comprising an input device configured to receive input data and to communicate the input data to the processor. A method of manufacturing a display comprising:
Forming a plurality of pixels, wherein forming the plurality of pixels is configured to form an interferometric modulator configured to output red light and to output green light Forming an interferometric modulator and forming an interferometric modulator configured to output blue light, wherein each of the pixels includes a red light for each of the interferometric modulators. Configured to output green light having higher intensity than red light when configured to output green light and blue light, and configured to output green light having higher intensity than blue light ,
At least one of the interferometric modulators configured to output red light or at least one of the interferometric modulators configured to output blue light is more saturated than the green light. A method configured to output light having a high color .   Each of the interferometric modulators of each of the plurality of pixels has a reflective area, and the green interferometric modulator of each pixel is larger than the red interferometric modulator of each pixel, and each 14. The method of claim 13, having a total reflection area that is greater than the blue interferometric modulator of a pixel.   14. Each of the plurality of pixels comprises a greater number of interferometric modulators configured to output green light than interferometric modulators configured to output blue light. the method of.   14. Each of the plurality of pixels comprises a greater number of interferometric modulators configured to output green light than interferometric modulators configured to output red light. the method of.   A display manufactured by the method according to claim 13. A display comprising a plurality of pixels each comprising a red, green, and blue interferometric modulator configured to output red light, green light, and blue light, respectively, each of the pixels being red Of the interferometric modulators configured to output green light having higher intensity than light and configured to output green light having higher intensity than blue light, and configured to output red light . At least one or at least one of the interferometric modulators configured to output blue light is configured to output light having a color that is more saturated than green. ,display.   And further comprising a circuit configured to drive each of the red, green, and blue interferometric modulators over a respective time period, wherein the time associated with the green interferometric modulator comprises the red and green interferometric modulators. 19. The display of claim 18, wherein the display is longer than each of the times associated with a blue interferometric modulator. The at least one of the interferometric modulator configured to output red light, display of claim 18 associated with the reflection of the red secondary number, and outputs light having a wavelength λ . 19. A display according to claim 18, wherein the at least one of the interferometric modulators configured to output blue light outputs light having a wavelength [lambda] associated with a second order blue reflection. . A plurality of means for outputting red light;
A plurality of means for outputting green light;
A plurality of means for outputting blue light, wherein the means for outputting red, green, and blue forms means for displaying a pixel, and each of the means for displaying the pixel includes the red, green, , And means for outputting blue when configured to output red light, green light, and blue light, and configured to output green light having a higher intensity than blue light,
At least one of the interferometric modulators configured to output red light or at least one of the interferometric modulators configured to output blue light is more saturated than the green light. A display that is configured to output light of high color .   The display of claim 22, wherein the means for displaying the pixel comprises a pixel.   24. The means for outputting red, green, and blue comprises a red, green, and blue interferometric modulator configured to output red light, green light, and blue light, respectively. display.   The total reflection area of the green interferometric modulator of each pixel is greater than the total reflection area of the red interferometric modulator of each pixel, and the total reflection area of the green interferometric modulator of each pixel 25. The display of claim 24, wherein is greater than the total reflection area of the blue interferometric modulator of each pixel.

Images