ES2363153T3 - LIGHTING SYSTEMS AND PROCEDURES FOR AN INTERFEROMETRIC MODULATOR SCREEN. - Google Patents

Abstract

A reflective display apparatus, comprising: means (300) for providing support; means (310) for modulating the light interferometrically supported by said means for providing support; and means (600) for covering said support means and said modulation means (300), said cover means (600) located in relation to said support means (300) so that there is an air gap (602) between they, said coverage means (600) comprising a first surface facing said support means (300), said coverage means (600) including means for redirecting the light (610), said means for redirecting the light (610) on the first surface and configured to redirect at least a part of the light directed towards the first surface through the air gap (602) on said support means (300).

Description

Background

Field of the Invention

The field of the invention relates to micro electromechanical systems (MEMOS).

Description of related technology

Micro electromechanical systems (MEMS) include micro mechanical elements, actuators and electronics. Micro mechanical elements can be created using deposition, etching and / or other micromachining processes that release parts or substrates and / or deposit layers of materials or that add layers to form electrical and electromechanical devices. One type of MEMS device is called an interferometric modulator. An interferometric modulator may comprise a pair of conductive plates, one or both of which may be transparent and / or totally or partially reflective and suitable for relative movement after the application of an appropriate electrical signal. One plate may comprise a fixed layer deposited on the substrate, the other plate may comprise a metal membrane separated from the fixed layer by an air gap. Such devices have a wide range of applications and it would be beneficial in the art to use and / or modify the characteristics of these types of devices so that their characteristics can be exploited in the improvement of existing products and in the creation of new products that do not have been developed yet.

EP-A-1 271 223 describes an electronic screen, such as a liquid crystal display, in the prior art, the screen is illuminated by ambient light during the day, but at night the screen may be illuminated by a light source located around the periphery of a frontal light. There is a small air gap between the front light and the screen and the front light comprises a light guide that has parallel grooves engraved on its upper surface to redirect the light emitted by the light source towards the screen. The described invention eliminates the air gap by providing an integrated light guide and screen, thereby reducing the overall thickness of the screen.

US-A-2002/0054424 describes a display apparatus with an interferometric modulator. In one embodiment, the supplementary lighting is provided by a light guide with a light source on one side thereof. The light is coupled into the light guide using a collimator so that most of the light is trapped inside the guide by means of total internal reflection. A dispersion pad, which comprises a scraped area of the upper surface of the light guide, reflects the light towards the substrate of the screen apparatus.

EP-A-1 251 454 describes a touch panel that includes an illuminator and a liquid crystal reflective display device, in which a light tube, with an adjacent side light source, is used as an illuminator. In the upper surface of the light pipe are included light output means that face the side of the observer.

US-A-2003/0169385 discloses a lighting device for a color liquid crystal display comprising an LED, and a lighting panel for guiding the light emitted by the LED to illuminate an LCD.

WO-A-01/84228 describes an image display device comprising a light modulation panel, a light conductor arranged in opposition to the light modulation panel and a light source connected to the light conductor . In the described arrangement, the light conductor comprises a striated sheet that reflects a beam of light emitted by the light source and which has a first polarization direction and transmits a beam of light modulated by the light modulation panel and which It has a second polarization direction.

Summary of certain embodiments

The system, procedures and devices of the invention each have various aspects, none of which separately is solely responsible for its desirable attributes. Without limiting the scope of the present invention, its most prominent feature will now be briefly explained. Upon consideration of this explanation and particularly after reading the section entitled "Detailed description of certain embodiments" it will be understood how the features of the present invention provide advantages over other display devices.

One aspect of the invention comprises a reflective screen apparatus, comprising: means for providing support; means for modulating the light by interferometric means on the means for providing support and means for covering said support means and said modulation means, said coverage means located relative to said support means so that there is an air gap among them, said coverage means comprising a first surface facing said support means including said coverage means means to redirect the light, said means for redirecting light on the first surface located and configured to redirect at least a part of the light directed towards the first surface through the air gap on said support means.

Another aspect of the invention comprises a method of manufacturing a reflective screen, which comprises: placing a plurality of interferometric modulators on a first surface of a substrate; the formation of a plurality of light redirectors on or on a cover, the cover having a second surface, the light redirectors being formed on the second surface; and the placement of the cover so that there is an air gap between the second surface and a third surface in the substrate opposite the first surface, the light redirectors configured to redirect at least a part of the light directed towards the second surface Through the air gap.

Brief description of the drawings

Figure 1 is an isometric view depicting a part of an embodiment of an interferometric modulator screen in which a mobile protective layer of a first interferometric modulator is in a relaxation position and a mobile protective layer of a second interferometric modulator is in an acted position.

Figure 2 is a block diagram of the system illustrating an embodiment of an electronic device incorporating a 3x3 interferometric modulator screen.

Figure 3 is a diagram of the position of a moving mirror in relation to the voltage applied for an exemplary embodiment of an interferometric modulator of Figure 1.

Figure 4 is an illustration of a set of row and column voltages that can be used to drive an interferometric modulator screen.

Figure 5A illustrates an example frame of the screen data on the 3x3 interferometric modulator screen of Figure 2.

Figure 5B illustrates an example timing diagram for the row and column signals that can be used to write the plot of Figure 5A.

Figure 6A is a cross section of the device of Figure 1 taken along line 6A-6A of Figure 1.

Figure 6B is a cross section taken along the line corresponding to 6A-6A in Figure 1, but illustrating an alternative embodiment of an interferometric modulator.

Figure 6C is a cross section taken along the line corresponding to 6A-6A in Figure 1, but illustrating an alternative embodiment of an interferometric modulator.

Figure 7 schematically illustrates an interferometric modulator matrix that uses a headlight in conjunction with a light plate to direct the light into the elements of the interferometric modulator.

Figure 8A schematically illustrates an interferometric modulator matrix using a backlight in which the light from the backlight is reflected within the interferometric modulator elements by means of reflective structures located on the post that supports the mirror element.

Figure 8B schematically illustrates another interferometric modulator matrix that uses a backlight in which the light from the backlight that passes through transparent posts is reflected within the interferometric modulator elements by means of reflective structures located in the substrate itself.

Figure 8C schematically illustrates another interferometric modulator matrix that uses a backlight in which light from the backlight that passes through the gaps in the matrix is directed into the elements of the interferometric modulator by reflective structures located in the substrate.

Figure 8D schematically illustrates another interferometric modulator matrix that uses a backlight in which light from the backlight that passes through the gaps in the matrix is directed into the elements of the interferometric modulator by reflective structures located in the film above of the substrate.

Figure 8E schematically illustrates another interferometric modulator matrix that uses a backlight in which light from the backlight passing through the transparent posts is dispersed within the elements of the interferometric modulator by means of scattering centers located in the film above the film. substratum.

Figure 9 schematically illustrates a front light for an interferometric modulator matrix using reflective or light scattering structures fixed to a glass cover according to the invention.

Figure 10 schematically illustrates an interferometric modulator matrix in which the substrate itself is used as a headlight.

Figures 11A schematically illustrate an example of an interferometric modulator matrix in which the use of lateral illumination in combination with angled dispersion centers is used to provide light to the elements of the interferometric modulator in a matrix.

Figure 11B schematically illustrates an example of an interferometric modulator matrix in which lateral illumination is used in combination with angle dispersion elements that align with the direction of the light source to provide light to the interferometric modulator elements.

Figure 12A schematically illustrates an interferometric modulator matrix that uses phosphorescent or fluorescent materials to improve the color scale.

Figure 12B schematically illustrates an interferometric modulator matrix that uses phosphorescent or fluorescent materials to provide light to the matrix that includes a light absorbing material on the surface of the phosphorescent or fluorescent material.

Figures 13A and 13B are block diagrams of the system illustrating an embodiment of a visual display device comprising a plurality of interferometric modulators.

Description of certain embodiments

The following detailed description is directed towards certain specific embodiments of the invention. However, the invention can be carried out in a multitude of different ways. In that description, reference is made to the drawings in which similar parts are designated with similar numbers in all of them. As will be apparent from the following description, the invention can be implemented in any device that is configured to display an image, both moving (for example, video) and still (for example, a still image) and both text and of pictures. More particularly, it is contemplated that the invention may be implemented in or associated with a variety of electronic devices such as, but not limited to, mobile phones, wireless devices, personal data assistants (PDAs), handheld or portable computers, receivers / GPS navigators, cameras, MP3 players, video recorders, game consoles, wrist watches, clocks, calculators, television monitors, flat panel displays, computer monitors, automotive displays (e.g., a odometer display, etc. .), controls and / or screens in the cockpit, screen of vision cameras (for example screens of a rear view camera in a vehicle), electronic photographs, billboards or electronic signage, projectors, architectural structures, packaging and aesthetic structures (for example the visualization of images on a piece of jewelry). MEMS devices of similar structure to those described herein can also be used in non-visualization applications such as electronic switching devices.

An embodiment of an interferometric modulator screen comprising an interferometric MEMS display element is illustrated in Figure 1. In these devices, the pixels are either in a bright state or in a dark state. In the bright state (“on” or “open”), the screen element reflects a large part of the visible light incident to a user. When it is in the dark state (“off” or “closed”), the screen element reflects little of the visible light incident to the user. Depending on the embodiment, the reflection properties of the light in the "on" and "off" states can be reversed. MEMS pixels can be configured to predominantly reflect selected colors, allowing a color screen in addition to black and white.

Figure 1 is an isometric view representing two adjacent pixels in a series of pixels of a display screen, in which each pixel comprises a MEMS interferometric modulator. In some embodiments, an interferometric modulator screen comprises an array of rows / columns of these interferometric modulators. Each interferometric modulator includes a pair of reflective layers positioned at a variable distance and controllable from each other to form a resonant optical cavity with at least one variable dimension. In one embodiment, one of the reflective layers can be moved between two positions. In the first position, referred to herein as a relaxed state, the mobile layer is located at a relatively large distance from a partially reflective fixed layer. In the second position, the mobile layer is located closest to the partially reflective layer. The incident light that is reflected from the two layers interferes constructively or destructively depending on the position of the mobile reflective layer, producing either a global reflective or non-reflective state for each pixel.

The represented part of the pixel matrix in Figure 1 includes two adjacent interferometric modulators 12a and 12b. In the interferometric modulator 12a on the left, a mobile and highly reflective layer 14a is illustrated in a relaxed position at a predetermined distance from a fixed partially reflective layer 16a. In the interferometric modulator 12b on the right, the highly mobile reflective layer 14b is illustrated in an actuated position adjacent to the fixed partially reflective layer 16b.

The fixed layers 16a, 16b are electrically conductive, partially transparent and partially reflective and can be manufactured, for example, by depositing one or more layers each of chromium and indium-tin oxides on a transparent substrate 20. The layers they are drawn in parallel bands and can form row electrodes in a display device as described further below. The mobile layers 14a, 14b can be formed as a series of parallel bands of a deposited metal layer or layers (orthogonal to the rows of electrodes 16a, 16b) deposited on the top of posts 18 and a deposited sacrificial interposition material between posts 18. When the sacrificial material is removed, the deformable metal layers are separated from the fixed metal layers by a defined air gap 19. A highly conductive and reflective material such as aluminum can be used for deformable layers and these bands can form column electrodes in a display device.

Without applied tension, the cavity 19 remains between the layers 14a, 16a and the deformable layer is in a mechanically relaxed state as illustrated by pixel 12a in Figure 1. However, when a potential difference is applied to a row and Selected columns, the capacitor formed at the intersection of the row and column electrodes in the corresponding pixel remains charged and the electrostatic forces pull to join the electrodes. If the voltage is high enough, the movable layer is deformed and forced against the fixed layer (a dielectric material that is not illustrated in this Figure can be deposited on the fixed layer to prevent short-circuiting and to control the separation distance ) as illustrated by pixel 12b to the right of Figure 1. The behavior is the same regardless of the polarity of the potential difference applied. In this way, the row / column performance that can control the states of the reflector pixel with respect to non-reflector is analogous in many ways to that used in conventional LCD and other display technologies.

Figures 2 to 5B illustrate an example process and system for the use of an array of interferometric modulators in a screen application. Figure 2 is a block diagram of the system illustrating an embodiment of an electronic device that can incorporate aspects of the invention. In the exemplary embodiment, the electronic device includes a processor 21 which can be any general purpose microprocessor of a chip or multi chip such as an ARM, Pentium®, Pentium II®, Pentium III®, Pentium IV®, Pentium Pro , an 8051, an MPIS®, a Power PC®, an ALPHA or any special purpose microprocessor such as a digital signal processor, micro controller or an array of programmable doors. As is conventional in the art, processor 21 can be configured to run one or more software modules. In addition to the execution of an operating system, the processor can be configured to run 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 also configured to communicate with a matrix controller 22. In one embodiment, the matrix controller 22 includes a row drive circuit 24 and a column drive circuit 26 that provides signals to a matrix of pixels 30. The cross section of the matrix illustrated in Figure 1 is shown by lines 1-1 in Figure 2. For MEMS interferometric modulators, the row / column actuation protocol can make use of the property of hysteresis of these devices illustrated in Figure 3. For example, a potential difference of 10 volts may be necessary to cause a mobile layer to deform from a relaxed state to the actuated state. However, when the voltage is reduced from that value, the mobile layer maintains its state when the voltage drops back below 10 volts. In the exemplary embodiment of Figure 3, the mobile layer does not relax completely until the voltage drops below 2 volts. There is therefore a voltage range, of approximately 3 to 7 V in the example illustrated in Figure 3, in which there is a voltage window applied within which the device is stable both in the relaxed state and in the state acted This is referred to herein as the "hysteresis window" or the "stability window". For a screen matrix having hysteresis characteristics of Figure 3, the row / column actuation protocol can be designed so that during the strobe impulse in the row, the pixels in the row selected by the strobe impulse that have been If activated, they are exposed to a voltage difference of approximately 10 volts and the pixels to be relaxed are exposed to a voltage difference close to zero volts. After the strobe pulse, the pixels are exposed to a stable state voltage difference of approximately 5 volts so that they remain stable regardless of the state in which the strobe pulse in the row has set them. After they have been written, each pixel sees a potential difference within the 3-7 volt stability window in this example. This feature makes the pixel design illustrated in Figure 1 stable under the same voltage conditions applied in both a pre-existing actuated and relaxed state. Since each pixel of the interferometric modulator, both in the actuated and in the relaxed state, is essentially a condenser formed by the fixed and mobile reflective layers, this stable state can be maintained at a voltage within the hysteresis window without virtually dissipation of power. Essentially, no current flows within the pixel if the applied potential is fixed.

In typical applications, the screen plot can be created by declaring the column electrode set according to the desired set of pixels actuated in the first row. A row pulse is then applied to the electrodes of row 1, the pixels corresponding to the imposed column lines acting. The declared set of column electrodes is then changed to correspond to the desired set of pixels actuated in the second row. A pulse is then applied to the electrode of row 2, the appropriate pixels acting in row 2 in accordance with the declared column electrodes. The pixels of row 1 are not affected by the pulse of row 2 and remain in the state in which they were set during the pulse of row 1. This can be repeated for the entire series of rows in a sequential manner to produce the plot. Generally, frames are refreshed and / or updated with new screen data by continuously repeating this process some desired number of frames per second. A wide variety of protocols for actuating row and column electrodes of pixel matrices to produce screen frames are well known and can be used in conjunction with the present invention.

Figures 4, 5A and 5B illustrate a possible actuation protocol for the creation of a screen frame of the 3x3 matrix of Figure 2. Figure 4 illustrates a possible set of column and row tension levels that can be used for pixels that respond to the hysteresis curves of Figure 3. In the embodiment of Figure 4, the performance of a pixel involves the adjustment of the appropriate column to -Vpolarization and the appropriate row to + ΔV, which may correspond to -5 volts and + 5 volts respectively. Pixel relaxation is carried out by adjusting the appropriate column to + Vpolarization and the appropriate row to it + ΔV, producing a potential difference of zero volts across the pixel. In those rows in which the row voltage is maintained at zero volts, the pixels are stable regardless of the state in which they were originally, regardless of whether the column is at + Vpolarization or at least or -Vpolarization.

Figure 5B is a timing diagram showing a series of row and column signals applied to the 3x3 matrix of Figure 2 that results in the screen layout illustrated in Figure 5A, in which the pixels actuated are not reflectors Prior to writing the plot illustrated in Figure 5A, the pixels can be in any state and in this example, all rows are at 0 volts and all columns are at +5 volts. With these voltages applied, all pixels are stable in their existing actuated or relaxed states.

In the plot of Figure 5A, the pixels (1,1), (1,2), (2,2), (3,2) and (3,3) are actuated. To accomplish this, during a "line time" for row 1, columns 1 and 2 are set to -5 volts, and column 3 is set to +5 volts. This does not change the state of any pixel, because all pixels remain in the 3-7 volt stability window. A strobe pulse is then given to row 1 with a pulse ranging from 0 to 5 volts and back to zero. This acts the pixels (1,1) and (1,2) and relaxes the pixel (1,3). No other pixels in the matrix are affected. To set row 2 as desired, column 2 is set at -5 volts and columns 1 and 3 are set at +5 volts. The same strobe impulse applied to row 2 will then act on the pixel (2,2) and relax the pixels (2,1) and (2,3). Again, no other pixel in the matrix will be affected. Row 3 is set similarly by setting columns 2 and 3 to -5 volts and column 1 to +5 volts. The strobe impulse to row 3 adjusts the pixels in row 3 as shown in Figure 5A. After writing the plot, the row potentials are zero and the column potentials can remain at both +5 and -5 volts and the screen is then stable in the arrangement of Figure 5A. It will be appreciated that the same procedure can be used for matrices of dozens or hundreds of rows and columns. It will also be appreciated that the times, sequences and voltage levels used to perform the performance of rows and columns can be varied widely within the general principles described above and the above example is only an example and any method can be used with the present invention. in the tension of action.

The details of the structure of interferometric modulators that operate in accordance with the principles set forth above can vary widely. For example, Figures 6A-6C illustrate three different embodiments of the moving mirror structure. Figure 6A is a cross section of the embodiment of Figure 1, in which a band of metallic material 14 is deposited on orthogonally extending supports 18. In Figure 6B, the movable reflector material 14 is fixed to the supports in the corners only, on ligatures 32. In Figure 6C, the movable reflector material 14 is suspended from a deformable layer 34. This embodiment has benefits because the structural design and the materials used for the reflector 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 in relation to the desired mechanical properties. The production of various types of interferometric devices is described in a variety of published documents, including, for example, United States Patent Application published 2004/0051929. A wide variety of well-known techniques can be used to produce the structures described above that involve a series of stages of deposition, hatching and engraving of the material.

Generally, the interferometric modulator is used in a highly reflective, direct vision flat panel display. Due to its high reflectivity, the interferometric modulator has little need for lighting in most light conditions. The typical consumer is confident of being able to read electronic screens in certain situations where there is little ambient lighting. As a result, some form of lighting is desirable for the interferometric modulator and other purely reflective space light modulators that typically use ambient lighting.

Typical lighting techniques from the backside used extensively with liquid crystal displays (LCD) do not work for purely reflective space light modulators. A purely reflective spatial light modulator is one through which light cannot be transmitted from the back to the front in such a way that it illuminates the modulator elements. It is possible to leave gaps between the elements of a purely reflective spatial light modulator to allow illumination from the back side that moves through it and emerges on the front of the panel, but the light will not contain any image information, since the Light does not really illuminate the elements, passing them apart as they travel through the screen panel. Therefore, it is desirable to provide illumination directed to the front of the reflector screen elements in the reflector screens.

As written in more detail below, several embodiments of the invention provide light redirectors to redirect the light from a light source located at various locations on a reflecting screen so that the light is directed on the front of the elements of the reflective screen on the reflective screen.

Directed front light

In one example, illustrated in Figure 7, which is not the subject of the claimed invention, a front light directed in conjunction with an array of interferometric modulators is used. A front light plate 200 is attached to the front surface 302 of the substrate 300. Although the front light plate 200 is shown fixed directly to the substrate 300, in other embodiments the light plate 200 can be suspended above the substrate 300 or fixed to a film or other layer that overlaps the substrate.

A light source 100, such as an LED, is connected to the front light plate 200 so that the light 202 emitted by the light source 100 enters the front light plate 200. In the embodiment illustrated in Figure 7 , the light source 100 is connected to a side surface 304 of the front light plate 200. The structure of the front light plate 200 is optimized so that the light 202 passing from the light source 100 inside the plate Front light 200 is redirected inside the elements 310 of the array. Although a single beam of light 202 is depicted in Figure 7 and in subsequent figures, it should be understood that the light source 100 emits a beam of light that has a given divergence and thereby completely fills the front light plate 200 with light. Accordingly, the light that is redirected within the elements 310 will consist of a plurality of beams. Preferably, the light 202 is directed within the elements 310 of the array in beams as narrow as possible. Therefore, as used herein, the term "light 202" represents beams of light illustrating one of the numerous light paths within those beams.

In one example, the light 202 emitted by the light source 100 is held within the front light plate 200 by total internal reflection until the light 202 makes contact with the surfaces 204, from which it is reflected through the substrate 300 and within the elements 310. The light plate 200 may comprise a number of slots 210 that provide surfaces 204 from which the light 202 can be reflected. Advantageously, the light 202 can be redirected within the elements 310 in a beam narrow that is substantially perpendicular to the front surface of the substrate 300. Advantageously, the majority of the light 202 that is directed within the elements 310 is reflected outside the elements 310 and transmitted through the substrate 300 and the light plate 200 without being significantly affected by slots 210.

In one example, the elements 310 are interferometric modulators, the elements may be other optical devices capable of reflecting light of a desired wavelength. By directing the light 202 from the front light 100 directly into the elements of the interferometric modulator 310, the brightness of the screen is increased compared to the use of ambient light only, particularly in situations where there is limited ambient light. In addition, this arrangement allows the use of screens in situations where there is little or no ambient light.

In the example illustrated in Figure 7, because most of the light 202 is reflected out of the elements of the interferometric modulator 310 at an angle substantially perpendicular to the substrate 300 of the front surface, the viewing angle is relatively narrow. However, by changing the depth and spacing of the slots 210 or by using other structures, the angle of incidence of the light 202 within the interferometric modulator elements 310 can be controlled. For example, by changing the side angle inclined 204 of the slots illustrated 210, the angle of the directed light within the interferometric modulator can be controlled. Therefore, the viewing angle can be controlled. In addition to the slots, one skilled in the art will recognize that other structures in the light plate 200 can be used to redirect the light from the light source 100 within the elements 310 at the desired angle. For example, bands of reflective material can be incorporated into the front light plate 200 at a diagonal angle.

A front light plate 200 containing slots 210 can be constructed by injection molding, controlled etching or by another process known to those skilled in the art. The material for use in the front light plate 200 may be any suitable transparent or partially transparent material such as plastic or glass.

In one example, the reflector structures 210 are separated so that the light is directed to the elements 310 and not the gap between the elements 320.

In another example, instead of slots 210, lines of reflective material may be placed inside or on the headlight plate 200 to provide redirection of the light within the elements 310.

In one example, the front light plate 200 can be placed against the substrate 300 as shown in Figure 7. In another example, the front light plate 200 can be positioned so that there is a gap between the plate 200 and the substrate 300.

The light source 100, as well as other light sources described herein, can be any suitable light source known in the art. Non-limiting examples include LED or fluorescent lights such as cold compact fluorescent lights.

Backlit Interferometric Modulator

In another example, which is not the subject of the claimed invention, a backlight is used to provide light to an array of interferometric modulator elements. The use of a backlight to improve the function of an interferometric modulator screen may be desirable, for example, in a device that already uses a backlight, such as a mobile phone.

An example of an interferometric modulator that uses a backlight is illustrated in Figure 8A. A backlight 110 is placed on the opposite side of an interferometric modulator structure from the substrate 300 and is oriented so that its light emitting surface 112 is parallel to and faces towards the substrate 300. A mirror element 370 is suspended below the substrate 300 by posts 400. Because in one example the mirror element 370 is opaque, the light cannot travel from the backlight 110 directly into the cavity of the interferometric modulator 360. Therefore, in this example the posts 400 are constructed of a transparent material

or partially transparent and a light redirector 410 is located at the end of the posts 400 near the substrate 300. The light 202 transmitted from the backlight 110 passes through the posts 400 and is redirected by the light redirector 410 within the cavity 360 of the structure of the interferometric modulator. The light 202 is then reflected outside the mirror 370 and finally leaves the structure of the interferometric modulator through the substrate 300 in the direction of an observer 50.

The light redirector 410 may include a reflective structure, light scattering structures such as a plurality of scattering centers, phosphorescent or fluorescent material or any other suitable feature configured to redirect the light. Transparent posts 400 may be constructed of any suitable transparent or partially transparent material such as a transparent oxide or polymer and may be colorless.

or include a colored ink. In an advantageous example, posts 400 are colorless and transparent. The light redirectors 410 may be incorporated in any desired position within the transparent posts 400 by which the light can be properly directed within the interferometric modulators.

In the example illustrated in Figure 8A, the light redirector 410 comprises diagonally oriented mirrors arranged as a metal pyramid. Other structures that reflect light within the cavity 360 may also be used. For example, a curved structure could be used at the pyramid site to obtain a broader reflection within the cavity 360. Alternatively, a triangular structure could provide the reflection within a simple interferometric cavity. Light redirector 410 can be performed by any process known in the art. For example, it can be constructed by forming a pyramid-shaped channel at the top of the post and subsequently filling the channel with a reflective substance. In one example, the light redirector 410 is constructed of aluminum. In one example, the reflector material (eg, aluminum) can be deposited as a layer on a structure that has the desired shape. For example, a pyramid shape can be created by controlling the etching of silicon or molybdenum followed by a deposition of a layer of aluminum on the pyramid shape.

In an alternative example, the light redirector 410 is located in the substrate 300 rather than in the post 400 (Figure 8B). In the example illustrated in Figure 8B, the light redirectors 410 in the substrate 300 line up above the posts 400. In this case, the light 202 travels from the backlight 110 through the post 400 to the light redirector 410 located in or on the substrate 300 directly above the post 400. The light is reflected outside the light redirector 410 and back to the cavity 360. The light redirector 410 may be, for example, a groove in the glass 300 that is silver or filled with a reflective substance. In another example, the grooves in the substrate 300 can be formed by etching and the groove surfaces can be coated with a reflective material such as aluminum. In another example, the grooves can be filled with polymer containing reflective or dispersing particles. For example, the polymer can be deposited by centrifugal coating.

In another example, the light redirectors 410 can be placed in the substrate 300 above the gaps 320 between the individual elements of the interferometric modulator 310. The light 202 from a backlight 110 can then be passed through very small gaps 320 to light redirectors 410, as illustrated in Figure 8C. The light 202 from the backlight 110 passes through the gaps 320 and is reflected from the light redirectors 410 within the elements of the interferometric modulator 310. As explained above, the light redirectors 410 can be diagonal mirrors formed by the creation of grooves in the substrate and the filling of the grooves with a reflective material. The alternative ways of creating light redirectors 410 for those skilled in the art will be apparent.

In another example, light redirectors 410 are formed above the substrate 300 (Figure 8D). For example, light redirectors 410 can be formed in a film 500 that is applied to the surface of the substrate 300. In one example the film 500 is a diffuser or anti-reflective film. The film 500 can be located on the substrate 300 so that the light redirectors 410 are located directly above the gaps 320 between the elements 310 in the matrix. As in the examples explained above, the light redirectors 410 can be of any shape and material that serves to reflect the light back to the elements of the interferometric modulator 310. In some example, the light redirectors comprise scattering centers or phosphorescent material. or fluorescent deposited within the 500 film. The 500 film can be deposited by lamination, centrifugal coating or any other suitable means.

In an alternative example, light redirectors 410 can be distributed evenly through the low density film 500. Therefore, for example with reference to Figure 8E, a powder of light scattering centers 325 can be distributed throughout the entire film 500. The part of the light distribution centers 325 located above gap 320 or posts 400 can redirecting the light 202 from the backlight 110 into the elements of the interferometric modulator 310. However, because the powder 325 is finely distributed in the film 500, it will not significantly interfere with the ambient lighting of the interferometric modulators 310.

In each of the examples using a backlight described above, the nature of the light redirectors 410 can be manipulated to achieve a desired result, such as by changing the angle of the mirrors diagonally or by using a curved surface instead of a straight mirror. For example, the shape of a reflective surface can be modified to produce a narrower or wider reflected beam of light. A reflective structure that produces a wider reflected beam can be used in situations where a wider viewing angle is necessary, while a structure with a narrower reflected beam can be used in a situation where the maximum is desirable. brightness from a more limited viewing angle.

In addition, in each of the examples an absorbent material can preferably be placed above the light redirectors to form a black mask above. Such a mask would prevent ambient light from being reflected from the light redirectors 410 back towards the observer 50, which could decrease the contrast.

Remote front lighting through the characteristics of the cover glass

In many screen applications, a cover glass or plastic is inserted above the screen to protect the screen (for example, surface plastic on the screen of a mobile phone). Figure 9 represents an embodiment in which the light redirectors 610 can be located on a cover 600 to provide illumination of the receiving screens. There is an air gap 602 between the cover 600 and the substrate 300 of the screen. The light 202 of a light source 100 is directed into a recess 602 and on the lower surface 604 of the cover 600. The light redirectors 610 in or on the cover 600 are used to redirect the light 202 from the light source 100 within the substrate 300 and within the interferometric modulator elements 310 located on substrate 300. In this way, most of the light 202 of the light source 100 enters the elements 310 at an acute angle rather than a flat angle. The light entering and leaving the elements of the interferometric modulator 310 at an acute angle causes the light 202 with the information on the screen to be directed along a line of sight of the typical observer - perpendicular to the screen. In the illustrated embodiment, because most of the light is reflected out of the interferometric modulator elements at a narrow angle, the viewing angle is relatively narrow. Therefore, the brightness of the screen will fall rapidly with larger viewing angles, reducing the observation of the color shift effect, which can typically be observed from the elements of the interferometric modulator from an out-of-angle view.

The light redirectors 610 may be receiving structures, scattering centers, fluorescent or phosphorescent material or any other suitable light redirector. The shape of the light redirectors of the reflective structure can be selected to direct the light 202 in the desired way. The structural characteristics may be reflective or may serve as diffusion scattering centers that scatter light in all directions, including within the elements of the interferometric modulator. By changing the shape and depth of the characteristics, you can adjust the reflection. For example, a diagonal structure will direct the light 202 into the elements 310 along a narrow beam as explained above. However, if a structure with a curved surface (not shown) is used, it will result in a wider reflected beam. A wider beam may be desirable, for example, to achieve a wider viewing angle. However, it may be desirable to narrow the beam scattering angle to limit the observation of the color shift with an angle out of angle. Therefore, in one embodiment, the scattering angle is optimized by adjusting the shape of the light redirectors 610 to provide an optimal balance between the viewing angle and the low observation of the color shift. One skilled in the art will easily understand the type of structure to produce the desired reflection for a given situation.

The light redirectors 610 can be formed on the cover 600 by applying a film or coating comprising the light redirectors 610 to the bottom surface 604 of the cover 600. Thus, the light redirectors 610 can be arranged within a laminate on deck 600. In one embodiment, light redirectors 610 can be etched onto the bottom of deck 600 such as by using photolithography to plot and record features on deck 600. Features may include projections, as illustrated in Figure 9 or depressions such as the grooves described above recorded within the lower surface 604 of the cover 600. In one embodiment, the light redirectors 610 are separated so that the light 202 from the light source 100 it is preferably directed to elements 310 and not to gap 320 between elements 310. In other embodiments, redirect them Light equalizers 610 are distributed evenly over deck 600. Light redirectors 610 can also be formed inside deck 600 by forming slots in deck 600 as described above and adding a layer of material to fill the grooves and protect them from dirt and debris. In this way, the light redirectors 610 (for example slots) can be located near the bottom surface 604 of the cover 600.

The light 202 from the light source 100 is directed to strike the lower surface 604 of the cover 600. Thus, the light source 100 can be located between the substrate 300 and the cover 600 as illustrated in Figure 9 Alternatively, the light source 100 may be located on the side of the substrate 300 or on the side and below the substrate 300, provided that the light 202 continues to strike the lower part of the cover 600.

Preferably, the light 202 is directed within the elements 310 of the array in a beam as narrow as possible. Again, by directing the light 202 from the light source 100 within the interferometric modulator elements 310 at a substantially perpendicular angle, the light 202 with screen information will be directed along a typical line of sight of the observer - perpendicular to the screen. Additionally, a narrow dispersion angle for the beam decreases the observation of the color shift within an out-of-angle angle.

Substrate as front light

In other examples, the transparent substrate 300 itself is used as a headlight. A particular embodiment of this configuration is illustrated in Figure 10. A light source 100, such as an LED, is fixed to a side 304 of the substrate 300. Light 202 from the light source 100 enters the substrate 300 through of lateral 304 and is contained within substrate 300 as a result of a total internal reflection. A film 500 is placed on the front surface 302 of the substrate 300. The refractive index of the film 500 is adjusted to that of the substrate 300 so that the light 202 can be transferred into the film 500 without reflection from the interface between the film 500 and the substrate 300. The film 500 contains grooves 520 on the surface 502 opposite the substrate 300. In the film 500, the light meets the grooves 520, which provide surfaces for internal reflection that direct the light 202 down through the substrate 300 within the elements of the interferometric modulator 310. As explained above, in relation to the slotted faceplate, the shape, depth and separation of the slots 520 can be adjusted to achieve the desired scattering angle of the light beams 202 and therefore the desired reflection cone. In this way, the viewing angle can be adjusted as necessary for a particular application. In other examples, the film 500 may comprise dispersion centers or fluorescent or phosphorescent material to redirect the light 202. The film 500 may be deposited by lamination, centrifugal coating or any other suitable technique.

In some examples, a second film 700 is placed on the first film 500. In one embodiment, the second film 700 has a refractive index that is less than the refractive index of the first film 500 to provide internal receiving surfaces for reflection of the light inside the elements of the interferometric modulator 310. In an advantageous example, the refractive index of the second film 700 is close to the refractive index of the air. The second film 700 protects the first film 500 and in particular the grooves 520, for example by keeping dirt and debris out of the grooves 520.

An alternative example using the substrate 300 as a headlight comprises replacing the slots 520 with a phosphorescent or fluorescent material. In this example, light is redirected through absorption and re-emission by these materials. In a typical case, the light source 100 is a blue / UV LED and the phosphorescent substance will absorb the light at this wavelength and re-emit green or white light.

Side lighting with dispersion centers

Dispersion centers can be used to redirect the light received from a light source located on the side of an interferometric modulator matrix within the interferometric modulator elements. Dispersion centers scatter incident light in multiple directions. These centers may comprise particles, such as metal particles, with uneven surfaces. In the example illustrated in Figure 11A the dispersion centers 800 are located in a film 500 that is fixed to the front surface 302 of the substrate 300. The film can be fixed to the substrate 300 by lamination, centrifugal coating, or any other method suitable.

Light 202 from a side light source 100, such as an LED, is directed along a path that is oblique to the elements of the interferometric modulator and affects the dispersion centers 800. From the dispersion centers 800, the Light 202 is dispersed in multiple directions. Multiple dispersions from the multiple dispersion centers 800 increase the wide distribution of the direction of the light emitted from the film 500. Some of the light 202 is directed through the substrate 300 within the elements of the interferometric modulator 310.

In an alternative example, the dispersion particles 800 have a suitable way to preferably distribute the light in a specific direction. Such particles can be aligned in relation to the direction of the light source 100 and the elements of the interferometric modulator 310, so that such light from the light source 100 is preferably directed within the elements of the interferometric modulator 310 as illustrated in Figure 11B. However, it is not necessary to direct all the light from the light source within the elements. On the contrary, it is sufficient to change the direction of part of the light from the light source 100 so that it enters the elements 310.

In some examples, the angle dispersion centers 800 are located within the film 500. For example, metal chips or particles may be incorporated into the film 500. In other examples, surface features are incorporated into the film 500 which cause the light and that affects the characteristics will disperse. In one example the surface characteristics are scratched areas that cause the light to disperse. In other examples the surface characteristics are geometric structures that produce the scattering of light.

The aligned dispersion centers 800 in Figure 11B can be constructed by rolling successive layers of material with the dispersion material deposited between each layer. The layered material can then be cut at a desired angle to form a thin piece of material having the dispersion material formed within bands oriented at the desired angle. The thin material can then be laminated into the substrate 300.

Alternatively, reflector material or fluorescent or phosphorescent material can be used as light redirectors instead of scattering centers.

Enhanced Color Scale

As explained in the various embodiments and examples above, light redirectors may include phosphorescent or fluorescent material. Such material absorbs the incident light and then re-emits the light on a different frequency. This feature can be used to improve the color scale of the light provided to a reflective screen.

As illustrated in Figure 12A, a phosphorescent material or fluorescent material 630 that emits a particular wavelength of light can be placed on the front surface 302 of the substrate 300. The phosphorescent or fluorescent material 630 is excited by the source light of light 100. Although the illustrated light source 100 is configured as a side light, a light source can be provided in any position so that the light is capable of exciting the phosphorescent or fluorescent material 630. For example, it can be used a light source 103 that provides light 202 directly within the substrate 300. The phosphorescent or fluorescent material 630 absorbs energy from the light 202 and then emits light of a particular wavelength 210 within the elements of the interferometric modulator 310. In general , the light 202 from the phosphorescent or fluorescent material 630 is emitted with a narrower wavelength spectrum than the light 202 of the light source 100, giving greater control of the wavelength of the light that is reflected from the interferometric modulator to the observer 50 and therefore a better color control.

The phosphorescent or fluorescent material 630 is selected to emit light of a desired wavelength. The material may combine a single phosphorescent or fluorescent substance or may comprise a combination of two or more phosphorescent substances, fluorescent substances or a mixture of phosphorescent substances and fluorescent substances. In one embodiment, the material comprises three different materials that emit in three different wavelengths. For example, phosphorescent material 630 may comprise three or more phosphorescent substances to provide red, green and blue light in narrow lines. The particular fluorescent substances or phosphorescent substances to be used can be selected by one skilled in the art based on the desired application. A wide variety of phosphorescent substances and fluorescent substances, including red, green and blue visible light emitters, are well known in the art and are commercially available, for example from the Global Trade Alliance, Inc. (Scottsdale, AZ).

In addition, the light source 100 is preferably selected to provide sufficient excitation of the phosphorescent or fluorescent substances in the material 630 so that the light of the desired wavelength is emitted. In one embodiment the light source 100 is a visible light. In another embodiment, the light source 100 is a source of ultraviolet radiation. In one embodiment, the light source 100 is a light emitting diode (LED). Preferably the LED is a blue LED. In a particular embodiment, the LED emits light with a wavelength between about 300 and about 400 nm.

The phosphorescent and / or fluorescent material 630 can be applied to the surface of a substrate 300 by incorporation into a film 500 that is fixed to the surface of the substrate as illustrated. In other embodiments, the phosphorescent material is fixed directly to a surface of the substrate, either on the upper surface or on the lower surface of the substrate, or incorporated into the substrate itself. Fluorescent or phosphorescent substances can be incorporated into a glass or film substrate by flotation of the material in the glass or film material during manufacturing. As described above, the films can be applied to the substrate by means of a lamination or a centrifuge coating. Those skilled in the art will appreciate other procedures for incorporating fluorescent or phosphorescent substances into a screen.

One skilled in the art will recognize that material 630 can be chosen to also provide illumination of a broad wavelength. Therefore, in some embodiments the material 630 is used to provide the illumination necessary to illuminate a screen in dark or very low ambient light conditions. In a particular embodiment, the light source 103 used to excite the material of a phosphorescent substance 630 is directly coupled to the substrate 300 as illustrated in Figure 12A. In a typical case the light source 100/103 is a blue / UV LED and the material of the phosphorescent substance 630 will absorb the light of this wavelength and re-emit white light. In yet another alternative embodiment, the supplementary lighting is the result of coating the interior of the walls of the screen housing with the material of the phosphorescent substance 630. The screen housing (not shown) maintains the substrate 300 and the elements of the associated interferometric modulator 310. In this embodiment the light source 100 is directed towards the walls of the screen housing rather than towards the front of the screen.

In another embodiment illustrated in Figure 12B, a light absorbing coating 640 can be applied to a part of the surface of the phosphorescent and / or fluorescent material 630. For example, the coating 640 can be preferably applied to the sides of the phosphorescent material and / or fluorescent 630 opposite the light source

100. The coating 640 can absorb the light 202 emitted by the light source 100 and / or the light 210 emitted by the phosphorescent and / or fluorescent material 630. The absorption of the light by the coating 640 results in more directional lighting of the elements of the interferometric modulator 310, thereby improving the contrast. For example, unlike emitting light in all directions, the material 630 with the coating 640 can only emit light towards the elements of the interferometric modulator 310 because the coating 640 will absorb the light emitted from the material 630 in other directions.

The color scale can also be improved by using LED line lighting. In this embodiment, a light source is used that emits a narrow wavelength line or particular wavelengths of light. Because the wavelength of light entering the structure of the interferometric modulator is limited, the color scale is improved. In addition, changes in color with the viewing angle (offset in viewing angle) are minimized. In one embodiment the light source is an LED that emits red, green and blue light in narrow lines.

A light source that emits wavelengths of light defined in conjunction with any of the embodiments described herein can be used to direct the light from a frontal light source within the structure of the interferometric modulator. For example, an LED that emits light of a wavelength can be used

or particular wavelengths such as the light source 100 in the structures illustrated in Figures 7, 9 and 12 described above.

Figures 13A and 13B are system block diagrams illustrating an embodiment of a display device 2040. The display device 2040 may be, for example, a cell or mobile phone. However, the same components of the 2040 display device or slight variations thereof are also illustrative of various types of display devices such as televisions and portable players.

The display device 2040 includes a housing 2041, a display 2030, an antenna 2043, a speaker 2045, an input device 2048 and a microphone 2046. The housing 2041 is generally formed with any of a variety of manufacturing processes as is well known to those skilled in the art, including injection modeling and vacuum formation. In addition, the housing 2041 may be made of any of a variety of materials, including but not limited to, plastic, metal, glass, rubber and ceramics or a combination thereof. In one embodiment, the housing 2041 includes removable parts (not shown) that can be exchanged with other removable parts of different color, or containing different logos, images or symbols.

The screen 2030 of the example display device 2040 may be any of a variety of screens, including flip-flop screens, as described herein. In other embodiments, the display 2030 includes a flat panel display, such as plasma, EL, OLED, STN LCD or TFT LCD as described above or a non-flat panel display, such as a CRT or other tube device, as is well known to those skilled in the art. However, for the purpose of describing the present embodiment, the screen 2030 includes an interferometric modulator screen, as described herein.

The components of an embodiment of the example display device 2040 are schematically illustrated in Figure 13B. The exemplary display device 2040 illustrated includes a housing 2041 and may include additional components at least partially enclosed therein. For example, in one embodiment, the example display device 2040 includes a network interface 2027 that includes an antenna 2043 that is connected to a transceiver 2047. The transceiver 2047 is connected to the processor 2021, which is connected to the conditioning hardware 2052 The conditioning hardware 2052 can be configured to condition a signal (eg filter a signal). The conditioning hardware 2052 is connected to a speaker 2045 and a microphone 2046. The processor 2021 is also connected to an input device 2048 and a controller of the drive 2029. The controller of the drive 2029 is connected to a buffer of the frame 2028 and to the actuation of the matrix 2022, which in turn is connected to a matrix of the screen 2030. A power supply 2050 provides power to all components as required by the particular design of the example display device 2040.

The network interface 2027 includes the antenna 2043 and the transceiver 2047 so that the example display device 2040 can communicate with one or more devices in a network. In one embodiment the network interface 2027 may also have some processing capabilities to release requirements of the processor 2021. The antenna 2043 is an antenna known to those skilled in the art for signal transmission and reception. In one embodiment, the antenna transmits and receives RF signals in accordance with the IEEE 802.11 standard, which includes IEEE

802.11 (a), (b) or (g). In another embodiment, the antenna transmits and receives RF signals in accordance with the BLUETOOTH standard. In the case of a mobile phone, the antenna is designed to receive CDMA, GSM, AMPS or other known signals that are used to communicate within a wireless network of mobile phones. The transceiver 2047 preprocesses the signals received from the antenna 2043 so that they can be received by and further manipulated by the processor 2021. The transceiver 2047 also processes the signals received from the processor 2021 so that they can be transmitted from the example display device 2040 through the antenna 2043.

In an alternative embodiment, transceiver 2047 can be replaced by a receiver. In yet another alternative embodiment, the network interface 2027 can be replaced by an image source, which can store or generate image data to be sent to the processor 2021. For example, the image source may be a digital video disc (DVD ) or a hard disk drive that contains image data or a software module that generates image data.

The processor 2021 generally controls the overall operation of the example display device 2040. The processor 2021 receives data, such as image data compressed from the network interface 2027 or an image source and processes the data in raw image data or within a format that is easily processed in raw image data. The processor 2021 then sends the processed data to the drive controller 2029

or to the buffer memory of frame 2028 for storage. Raw data typically refers to information that identifies the image characteristics at each location within an image. For example, such image features may include color, saturation and grayscale level.

In one embodiment, the processor 2021 includes a micro controller, CPU, or logical unit to control the operation of the example display device 2040. The conditioning hardware 2052 generally includes amplifiers and filters for the transmission of signals to the speaker 2045 and for the Signal reception from the microphone 2046. The conditioning hardware 2052 may consist of discrete components within the example display device 2040 or may be incorporated into the processor 2021 or other components.

The drive controller 2029 takes the raw image data generated by the processor 2021 either directly from the processor 2021 or from the frame memory 2028 and reformats the raw image data appropriately for high speed transmission to the 2022 matrix drive. Specifically, the 2029 drive controller reformats the raw image data into a data stream that has a scan-like format, so that it has an order in time suitable for scanning through the matrix of the display 2030. Then the controller of the drive 2029 sends the formatted information to the drive of the array 2022. Although a driver of the drive 2029, such as an LCD controller, is often associated with the processor of the system 2021 as a Separate integrated circuit (IC), such controllers can be implemented in many ways. They can be integrated into the 2021 processor as hardware, integrated into the 2021 processor as software or fully integrated into hardware with the 2022 matrix drive.

Typically, the matrix drive 2022 receives the information formatted from the controller of the drive 2029 and reformats the video data in a parallel set of waveforms that are applied many times per second to the hundreds and sometimes thousands of output terminals. from the matrix of xy pixels of the screen.

In one embodiment, the driver of the drive 2029, the drive of the array 2022 and the array of the display 2030 are suitable for any of the types of screens described herein. For example, in one embodiment, the drive controller 2029 is a conventional display controller or a bistable display controller (for example, an interferometric modulator controller). In another embodiment, the matrix drive 2022 is a conventional drive or a bistable screen drive (for example, a screen of an interferometric modulator). In one embodiment, a controller of the drive 2029 is integrated with the drive of the array 2022. Such an embodiment is common in highly integrated systems such as cell phones, watches and other small area screens. In yet another embodiment, the screen matrix 2030 is a typical screen matrix or a bistable screen matrix (for example a screen that includes an array of interferometric modulators).

The input device 2048 allows a user to control the operation of the example display device 2040. In one embodiment, the input device 2048 includes a keyboard, such as 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 2046 is an input device for the example display device 2040. When the microphone 2046 is used to enter data to the device, voice commands can be provided by a user for control of operations. of the example display device 2040.

The 2050 power supply may include a variety of energy storage devices as is well known in the art. For example, in one embodiment, the power supply 2050 is a rechargeable battery, such as a nickel-cadmium battery or a lithium-ion battery. In another embodiment, the power supply 2050 is a renewable energy source, a capacitor or a solar cell, including a plastic solar cell and a tinted solar cell. In another embodiment, the 2050 power supply is configured to receive

5 power from a wall outlet.

In some implementations the programmability of the control resides, as described above, in a drive controller that can be placed in various places in the electronic display system. In some cases the programmability of the control resides in the operation of the matrix 2022. Those skilled in the art will recognize that the optimization described above can be implemented in any number of

10 hardware and / or software components and in various configurations.

Although the preceding invention has been described in terms of certain embodiments, other embodiments will be apparent to those of ordinary skill in the art. Additionally, other combinations, omissions, substitutions and modifications will be apparent to those skilled in the art, in view of the disclosure of this document.

fifteen

Claims (31)

1. A reflective screen apparatus, comprising: means (300) for providing support; means (310) for modulating the light interferometrically supported by said means for providing support; and means (600) for covering said support means and said modulation means (300), said cover means (600) located relative to said support means (300) so that there is an air gap (602) between them, said coverage means (600) comprising a first surface facing said support means (300), said coverage means (600) including means for redirecting the light (610), said means located of redirecting the light (610) on the first surface and configured to redirect at least a part of the light directed towards the first surface through the air gap (602) on said support means (300).

2.

The apparatus of claim 1, wherein said support means comprises a substrate (300).

3.

The apparatus of claim 1 or 2, wherein said modulation means comprises a plurality of interferometric modulators (310).

Four.

The apparatus of claim 1, 2 or 3, wherein said covering means comprise a cover (600).

5.

The apparatus of claim 1, 2, 3 or 4, wherein said light redirection means comprise light redirectors (610).

6.

The apparatus of claim 5, wherein said support means (300) have a second surface facing the first surface and said modulation means (310) are disposed on a third surface of the opposite support means (300) to the second surface.

7.

The apparatus of claim 6, wherein said gap (602) is between said first and second surfaces.

8.

The apparatus of claim 5 or 7, wherein said light redirectors (610) are at least partially reflective surfaces.

9.

The apparatus of claim 5 or 7, wherein said light redirectors (610) include dispersion centers.

10.

The apparatus of claim 5 or 7, wherein said light redirectors (610) include fluorescent or phosphorescent material that absorbs said incident light and emits said redirected light at a wavelength different from that of said incident light.

eleven.

The apparatus of claim 10, wherein said incident light (202) has a wavelength that is not visible to a human eye.

12.

The apparatus of claim 5 or 7, wherein said light redirectors (610) comprise grooves in the first surface of said covering means (600).

13.

The apparatus of claim 12, further comprising a filler material in said grooves.

14.

The apparatus of claim 5 or 7, wherein said light redirectors (610) are disposed within a laminate that is disposed on the first surface of said covering means (600).

fifteen.

The apparatus of claim 7, further comprising a light source (100) located between planes defined by said first surface and said second surface, wherein said light source (100) provides said light

(202) directed towards the first surface through the air gap (602).

16.

The apparatus of claim 5 or 7, wherein the light redirectors (610) are disposed within a film or coating on the first surface of said covering means (600).

17.

A method of manufacturing a reflective screen, comprising:

the positioning of the plurality of interferometric modulators (310) on a first surface of a substrate (300); the formation of a plurality of light redirectors (610) on or on a cover (600), the cover having a second surface, the light redirectors (610) being formed on the second surface; and the positioning of the cover (600) so that there is an air gap (602) between the second surface and a third surface on the substrate (300) opposite the first surface, the light redirectors (610) are configured to redirect at least a part of the light directed towards the second surface through the air gap (602).

18.

The method of claim 17, wherein said light redirectors (610) are at least partially reflective surfaces.

19.

The method of claim 17, wherein said light redirectors (610) include scattering centers.

twenty.

The method of claim 17, wherein said light redirectors (610) include fluorescent or phosphorescent material that absorbs said incident light and emits said redirected light at a wavelength different from that of said incident light.

twenty-one.

The method of claim 17, wherein said light redirectors (610) comprise grooves in the second surface of said cover (600).

22

The method of claim 17, comprising filling said slots with a layer of material.

2. 3.

The method of claim 17, wherein said light redirectors (610) are arranged within a laminate that is disposed on the second surface of said cover (600).

24.

The method of claim 17, comprising the application of a cover or film comprising said light redirectors (610) on the second surface of said coverage (600).

25.

The apparatus of Claim 1, further comprising:

a processor that is in electrical communication with said modulation means (310), being configured said processor to process image data; a memory device in electrical communication with said processor.

26.

The apparatus of Claim 25, further comprising a drive circuit configured to send at least one signal to said modulation means.

27.

The apparatus of Claim 26, further comprising a controller configured to send at least a portion of said image data to said drive circuit.

28.

The apparatus of Claim 25, further comprising an image source module configured to send said image data to said processor.

29.

The apparatus of Claim 28, wherein said image source module comprises at least one of a receiver, transceiver and transmitter.

30

The apparatus of Claim 25, further comprising an input device configured to receive input data and to communicate said input data to said processor.

31.

A reflective screen produced by the process of any of claims 17-24.