Source: https://patents.google.com/patent/US7986451B2/en
Timestamp: 2019-04-24 20:34:46+00:00

Document:
2010-06-01 Assigned to IDC, LLC reassignment IDC, LLC ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: CUMMINGS, WILLIAM J., GALLY, BRIAN J.
In various embodiments of the invention, an interferometric display device is provided having an external film with a plurality of structures that redirect light from an inactive area of the display to an active area of the display. Light incident on the external film that would normally continue towards an inactive area of the display is either reflected, refracted, or scattered towards an active area of the display comprising moveable and static reflective surfaces that form an optical cavity.
This application is a continuation of U.S. patent application Ser. No. 11/156,162, filed Jun. 17, 2005, issued as U.S. Pat. No. 7,561,323 on Jul. 14, 2009, which claims priority benefit under 35 U.S.C. §119(e) to U.S. Provisional Application Ser. No. 60/613,535, filed Sep. 27, 2004, each of which is incorporated herein by reference in its entirety.
In one embodiment, a display is provided, the display comprising: a light-modulating array comprising a plurality of light-modulating elements, said light-modulating elements including movable reflective surfaces and static reflective surfaces that define active reflector areas of the light-modulating array spaced apart by substantially non-reflective portions; and an optical layer above the light-modulating array, the optical layer including a plurality of optical elements separated by gaps, wherein the gaps between the optical elements are above the active reflector areas and the optical elements are above the substantially non-reflective portions of the light modulating array, the optical elements being configured to re-direct light incident thereon into the active reflector areas of the light-modulating array.
In another embodiment, a method of manufacturing a display is provided, the method comprising: forming a light-modulating array comprising a plurality of light-modulating elements, said light-modulating elements including movable reflective surfaces and static reflective surfaces that define active reflector areas of the light-modulating array spaced apart by substantially non-reflective portions; and forming an optical layer above the light-modulating array, the optical layer including a plurality of optical elements separated by gaps, wherein the gaps between the optical elements are above the active reflector areas and the optical elements are above the substantially non-reflective portions of the light modulating array, the optical elements being configured to re-direct light incident thereon into the active reflector areas of the light-modulating array.
In another embodiment, a display is provided, the display comprising: a light-modulating array comprising a plurality of light-modulating elements, said light-modulating elements including movable reflective surfaces and static reflective surfaces that define active reflector areas of the light-modulating array spaced apart by non-reflective portions; and means for directing light into the active reflector areas of the light-modulating array.
FIG. 8A is side view of a display device with an external film.
FIG. 8B is a side view of an interferometric modulator device configured for displaying information in RGB color.
FIG. 8C is a side view of an interferometric modulator device configured for displaying information in black and white.
FIG. 9 is a side view of an interferometric modulator device configured with a light diffuser on its outer surface.
FIG. 10 is a side view of an interferometric modulator device configured with a light diffuser on its outer surface, where the light diffuser includes diffusing particles.
FIG. 11A is a side view of an interferometric modulator device configured with a grooved front light plate that is separated from the interferometric modulator device by an air gap.
FIG. 11B is a side view of an interferometric modulator device configured with a grooved front light plate connected to the interferometric modulator device.
FIG. 11C is a side view of an interferometric modulator device configured with an external film which has a contoured outer surface so that light provided from a light source is redirected to the interferometric modulator device and reflected out of the interferometric modulator to a viewer.
FIG. 12A is a side view of an interferometric modulator device configured with an external film that includes baffle structures that limit the field-of-view of the interferometric modulator device.
FIG. 12B is a side view of one embodiment of an interferometric modulator device showing how baffle structures contained in the external film limit the direction of the reflected light.
FIGS. 12C and 12D are embodiments of an external film having baffle structures comprising opaque columns.
FIGS. 12E-12G are embodiments of external films having baffle structures comprising opaque portions.
FIG. 12H depicts an external film having baffle structures comprising reflective material.
FIG. 13A is a side view of an interferometric modulator display that includes a touchscreen.
FIGS. 13B-D show different approaches for incorporating a diffusing material.
FIG. 14A is a side view of an interferometric modulator device configured with a touchscreen comprising diffuser material that scatters light from a light source toward the interferometric modulator device.
FIGS. 14B1 and 14B2 show different configurations for delivering light from a light source to the interferometric modulators device.
FIGS. 14C-E demonstrate different approaches for integrating diffusing material into displays for directing light from a light source to the interferometric display device.
FIGS. 15A and 15B are side views of interferometric modulator devices configured with a film that directs at least a portion of light incident on the space between the active reflector areas to the active reflector areas.
FIG. 16A is a side view of an external film having regions that scatter light.
FIG. 16B is a side view of an external film having regions of higher refractive index in a matrix of lower refractive indices material that redirect light.
FIG. 16C is a side view of an external film having a surface having dimpled regions that act as concave lenses.
FIG. 16D is a side view of an external film having a surface comprising Fresnel lenses.
FIG. 16E is a side view of an external film having opposing sloped surfaces configured that refract light in opposite directions.
FIG. 16F is a side view of an external film having sloped surfaces configured to refract light toward one direction.
FIG. 16G is a side view of an external film having sloped surfaces configured to reflect light.
FIG. 17 is a side view of an interferometric modulator device configured with an external film that changes the direction of light that is incident on the external film, to provide the light to active reflector areas of the interferometric modulator device at an angle that is more perpendicular than its incident angle at the external film.
FIG. 18A is a side view of an interferometric modulator device configured with an external film comprising a diffusing element configured to collimate light directed toward the interferometric modulator device.
FIG. 18B is a side view of the interferometric modulator of FIG. 18A showing that the incident light is collimated and redirected to the active reflector areas of the interferometric modulator device.
FIG. 18C is a side view of the interferometric modulator device of FIG. 18A showing that light reflected from the active areas of the interferometric modulator device is diffused by the external film.
In various embodiments of the invention, an interferometric display device is provided having an external film with a plurality of structures that redirect light from an inactive area of the display to an active area of the display. Light incident on the external film that would normally continue towards an inactive area of the display is either reflected, refracted, or scattered towards an active area of the display comprising a moveable and static reflective surfaces that form an optical cavity.
As described above, a picture element (pixel) from a direct-view display may comprise elements such as the one shown in FIGS. 7A-7E. In various embodiments, these modulator elements with the mirror 14 in an undeflected state will be bright, or ‘ON.’ When the mirror 14 moves to its full design depth into the cavity toward the front surface of the cavity, the change in the cavity causes the resulting pixel to be ‘dark’ or OFF. For color pixels, the ON state of the individual modulating elements may be white, red, green, blue, or other colors depending upon the modulator configuration and the display color scheme. In some embodiments using red/green/blue (RGB) pixels, for example, a single color pixel comprises a number of modulator elements that create interferometric blue light, a similar number of elements that create interferometric red light, and a similar number that create interferometric green light. By moving the mirrors according to display information, the modulator can produce full color images.
Various embodiments, include improvements that can be made to an interferometric modulator device using various optical films. The optical films include films that come on rolls or in sheets. The film is attached to or near the interferometric modulator, and positioned so that light reflected from the interferometric modulator passes through the film as it propagates to a viewer. The optical films can also include coatings that are spread, sputtered or otherwise deposited on a surface of the interferometric modulator so that light reflected from the interferometric modulator passes through the film as it propagates to a viewer.
The films are generally disposed on an external surface of the interferometric modulator so that desirable optical characteristics can be achieved without changing the interferometric modulator itself. “External” as used herein refers to a placement of the film outside of the fabricated interferometric modulator, e.g., on the outer surface of the substrate of an interferometric modulator, such that the external film can be applied after fabricating the interferometric modulator display. The external film may be disposed on or near the surface of the interferometric modulator which first receives incident light, which is referred to herein as the outer surface of the interferometric modulator. This outer surface is also the surface that is positioned proximal to a person viewing the interferometric modulator. The external film may be on the layers that form the interferometric modulator or may be formed on one or more layers formed on the interferometric modulator. Although various embodiments are generally described herein as being external to the interferometric modulator display, these types of films can also be fabricated inside the interferometric modulator in other embodiments, and/or characteristics of the external films described can be incorporated into the interferometric modulator, e.g., during fabrication of the interferometric modulator, to achieve a similar effect.
As illustrated in FIG. 8A, one embodiment of a display 100A includes a spatial light modulator 105 and an external film 110 positioned on or near the outer surface 115 of the spatial light modulator 105. The spatial light modulator 105 is a representation of an interferometric modulator device that may include, for example, a substrate, a conductor layer, a partial reflector layer, a dielectric layer and movable reflectors (referred to also as mirrors) configured with a gap between the movable mirrors and the dielectric. The spatial light modulator 105 may be, but is not limited to, a full color, monochrome, or black and white interferometric modulator display device. The design and operation of interferometric modulators are described in detail, e.g., in U.S. Pat. Nos. 6,650,455; 5,835,255; 5,986,796; and 6,055,090, all of which are incorporated herein by reference.
The external film 110 can be fabricated in a variety of ways, including for example, using fabrication techniques where the external film 110 is poured, spun, deposited on or laminated to the display. In some embodiments, the external film 110 is a single film layer, while in other embodiments the external film 110 includes more than one film layer. If the external film 110 comprises more than one film layer, each film layer can have different properties that affect one or more characteristics of light reflecting from the spatial light modulator 105 and propagating through the external film 110. Each layer of a multi-layer external film 110 can be fabricated by the same film fabrication technique or a different film fabrication technique, for example, any single layer can, for example, be poured, spun, deposited on or laminated to an adjacent layer. Other orientations and configurations are also possible.
Referring to FIG. 8B, one embodiment of a display 100B has an external film 110 above an outer surface 115 of an RGB spatial light modulator 105B comprising color interferometric modulators. In this embodiment, the RGB spatial light modulator 105B comprises a substrate 120 above a multilayer 126 comprising, for example, a conductive layer (which is at least partially transmissive), a partially reflecting layer, and dielectric layer, which in turn is above a set of reflectors (e.g. mirrors) that includes red 150, green 160, and blue 170 reflectors, each with a different gap width 175, 180, 190, respectively, that correspond to the colors red, green, and blue. In certain embodiments, the substrate 120 can be between the external film 110 and the reflectors 150, 160, 170, as depicted in FIG. 8B. In other embodiments, the reflectors 150, 160, 170 can be between the external film 110 and the substrate 120.
In other embodiments, the external film may be disposed above the monochrome or black and white interferometric modulator. As illustrated by FIG. 8C, the monochrome or black and white spatial light modulator 105C comprises a substrate 120 above a conductive layer, a partially reflective layer 124, a dielectric layer 125, which in turn is above a set of reflectors (e.g. mirrors) 130, 135, 140. The monochrome spatial light modulator 105C can be fabricated to have reflectors 130, 135, 140 configured with a single gap width 145 between the reflectors 130, 135, 140 and the dielectric layer 125.
In certain embodiments, the external film can diffuse light reflecting from the interferometric modulator display. The light reflecting from the interferometric modulator display may be at least partially diffuse so that the display has an appearance similar to paper (e.g., the display appears diffusely reflecting).
Referring to FIG. 9, a display 300 can include an external diffuse film 305 positioned on the spatial light modulator 105. Light 320 incident on the display 300 is specularly reflected by reflective spatial light modulator 105. As the specularly reflected light 307 propagates from the display 300, diffuse film 305 changes the characteristics of the specularly reflected light 307, which is transformed into diffuse light 330. The diffuser 305 also diffuses light incident on the interferometric modulators.
Diffuse film 305 can be fabricated from a number of materials, and can include one or more layers of diffuse material. The diffuser 305 may include material with surface variation (e.g. corrugations and roughness) or variation in material. This variation can refract or scatter light in different embodiments. A wide variety of diffusers 305 are possible and not limited to those recited herein.
FIG. 10 illustrates an exemplary embodiment of a display 400 that produces diffuse reflected light. The display 400 includes an external film 405 attached to a spatial light modulator 105. The external film 405 includes material 410 comprising scattering features (e.g., particles) that scatter the light 403 reflecting from the spatial light modulator 105 to change the character of the light 407 emitted from the interferometric modulator device from specular to diffuse.
In some embodiments, the external diffuse film 305 includes a material that changes the spectral characteristics of the reflected light 403 and a material that changes the diffuse or specular characteristics of the reflected light. Such material can be included in a single layer of the external film 305, 405 (FIGS. 9 and 10). Alternatively, material that changes the spectral characteristics of the reflected light can be incorporated in one layer of the external film 305 and material that changes the diffuse or specular characteristics of reflected light can be incorporated in a separate layer of external film. In one embodiment, the diffuse material can be included in an adhesive that is used between the external film 305 and the spatial light modulator 105 (FIG. 9).
As mentioned above, some type of diffuser is useful on interferometric modulator displays where it is desired that the display 300, 400 has the appearance of paper rather than the appearance of a mirror. Of course, in some embodiments it can be desirable for the appearance of the display 300, 400 or a portion of the display to be highly reflective or “mirror-like,” and in these embodiments the display may have a diffuse film 305, 405 covering all or only a portion of the interferometric display device 305, 405. In some embodiments, an optically transmissive layer is “frosted” in order to achieve the desired diffusion. For example, the outer surface of the display 105 (FIG. 9) can be frosted to provide diffusion of the reflected light. If the surface is heavily frosted, the light will be diffused more than if the surface is lightly frosted. In some embodiments, the optically transmissive layer that is frosted may comprise a glass or polymer layer.
In some embodiments, it can be advantageous to include a light source (referred to herein as a “front light”) to provide additional light to the interferometric modulator, e.g., for viewing the interferometric modulator in dark or low ambient lighting conditions. Referring to FIG. 11A, one embodiment of a display 500A includes a light source 515 positioned on the side of a front plate 505. This front plate 505 comprises material substantially optically transmissive to light 507 from the light source 515. The front plate 505 may comprise, for example, glass or plastic in some embodiments. The front plate 505 has optical features (e.g., contours such as grooves) configured to disrupt propagation of light in the front plate and redirect the light toward the interferometric modulator display device 105. An air gap 525 separates the contoured/grooved front plate 505 from the spatial light modulator 105. Operationally, the light source 515 provides light 507 into the front plate 505, where the light 520 reflects off the slanted surface features 506 and travels towards the spatial light modulator 105. For ambient light entering the display 500, the air gap 525 reduces the perceived contrast of the display 500A because of the differences in the index of refraction between the air in the air gap 525 and the materials which are used to form the front plate 505 and the spatial light modulator 105.
Referring to FIG. 11B, the display 500B provides for a more efficient transmission of light to the spatial light modulator 105 because it does not have an air gap separating the front plate 505 and the display 105. Instead, the front plate 505 is attached to the spatial light modulator 105. While the configuration of display 500B increases the transmission of light to the spatial light modulator 105, attaching the two pieces is not a good manufacturing practice because the front plate 505 and the spatial light modulator 105 are both relatively expensive pieces, and if either piece exhibits a failure during manufacturing both pieces are lost.
Referring now to FIG. 11C, display 500C illustrates how the problems experienced by the displays 500A, 500B of FIGS. 11A and 11B are overcome using an external film rather than a front plate. As shown in FIG. 11C, the display 500C includes a light source 515 positioned next an edge 531 of spatial light modulator 105 to which is laminated an external film 530, which has a surface 514 comprising optical features such as contouring, e.g., grooves or slanted surface features, configured to redirect light toward the spatial light modulator 105. The light source 515 may, for example, be disposed at an edge of a substrate supporting the interferometric modulator device 105. The external film 530 is attached to the spatial light modulator 105 or laminated onto the spatial light modulator 105. An adhesive may be used. The external film 530 is relatively inexpensive compared to the cost of a grooved front glass plate 505 (FIGS. 11A, 11B), so if the display 105 fails it can be disposed without a large additional loss. Operationally, the external film 530 receives light 511 from the light source 515. As the light propagates through the spatial light modulator 105 (e.g., the substrate of the interferometric modulator device) and the external film 530, the light 511 reflects off of an inner portion of the contoured/grooved surfaces 514 and the reflected light 513 propagates through the substrate of the interferometric modulator device and reflects off mirror surfaces of the interferometric modulators.
Referring now to FIG. 12A, in other embodiments a display 600 may comprise an external film 605 that is attached to the outer surface of the spatial light modulator 105, where the external film comprises a plurality of structures 603 that reduce or minimize the field-of-view of the display. In one embodiment, structures 603 are small vertically aligned obstructions which can be formed in a grid and “sunk” or diffused into the external film 605. In another embodiment, the material of the external film 605 provides the vertically aligned structures 603. These structures 603 may be referred to as baffles. The baffles 603 may be substantially opaque. The baffles 603 may be substantially absorbing or reflective.
FIG. 12B illustrates how light reflected in a substantially non-perpendicular direction 607 is substantially blocked from exiting the external film 605 and how light 609 reflected in a substantially vertical direction is not substantially obstructed by the structures 603. In the embodiment shown in FIGS. 12A and 12B, the field of view is limited depending on the shape (and orientation), size (e.g., length), and spacing of the baffle structures 603. For example, the baffles 603 may have a size, shape, and spacing to provide a field-of-view no more than about 20 degrees or no more than about 40 degrees as measured from a plane 610 normal to a front surface 606 of the display 600. The field-of-view may therefore be between about 20, 25, 30, 35 and 40 degrees or less as measured from the normal. In one exemplary embodiment, the baffles 603 provide the display 600 with a field-of-view of about 30 degrees. As used herein, the term baffle includes but is not limited to the structures 603 depicted in FIGS. 12A and 12B.
The baffle structures 603 may be constructed in accordance with embodiments depicted in FIGS. 12C and 12D. For example, a plurality of substantially vertically aligned columnars features 612 may comprise a transmissive material in the shape of columns having a coating of opaque material on an outer surface 612 a of the column-shaped transmissive material. The columnar features 612 may be bundled together and aligned. The space between the vertically aligned columnars features 612 may be filled with a transmissive material such as polycarbonate, polyethylene terephtalate (PET), acrylic, or polymethylmethacrylate (PMMA) that forms a matrix 613 for these vertically aligned columnars features 612. The matrix 613 having the columnars features 612 disposed therein may be cut perpendicular across line A-A to produce a thin film. A top view of the section cut to form the external film 605 is depicted in FIG. 12D. In this embodiment, the opaque outer surface 612 a of the columnars features 612 substantially block light exiting the external film 605 in substantially non-vertical directions.
The baffle structures 603 may also be constructed in accordance with other embodiments such as described with reference to FIGS. 12E and 12F. In FIG. 12E, a multilayer structure 618 having a plurality of stacked layers is constructed. The multilayer structure 618 has alternating layers of a substantially transmissive material 615 and layers 614 of substantially opaque material. To fabricate this multilayer structure 618, an optically transmissive layer 615 that may comprise a slightly diffuse material is formed and an opaque layer 614 comprising of a substantially opaque material is formed thereon. These steps can be repeated until a desired number of layers have been formed. The multilayer structure 618 can then be cut perpendicular across line A-A. A top view of the section cut to form the external film 605 is depicted in FIG. 12F. The substantially opaque layers 614 form the baffles 603 that substantially block light exiting the external film 605 in a substantially non-vertical direction.
As depicted in FIG. 12G, the external film 605 comprises a two-dimensional grid comprising horizontal opaque layers 616 and vertical opaque layers 617. This two-dimensional grid may be fabricated using a pair of sections cut from the multilayer structure 618 (FIG. 12E) with one section disposed in front of the other such as depicted in FIG. 12F. One of the sections is oriented substantially perpendicular relative to the other external film structure 605. Other orientations and configurations are also possible.
In certain embodiments, the baffle structures 603 shown in FIGS. 12C-12G may comprise reflective material. For example, referring to FIG. 12H, if a portion 625 of the baffle structures 603 nearest to the spatial light modulator 105 is substantially reflective, then light 620 reflected from the spatial light modulator 105 that is incident on the reflective portion 625 of the baffle will not pass through the external film structure 605, but will be reflected back to the spatial light modulator 105. Alternatively, the outer surfaces 603 a and 603 b of the baffle structures 603 may be made of a substantially reflective material, such as a flash coating of substantially reflective material on the baffle structures 603. In this embodiment, the bottom portion 625 of the baffle structures 603 may also be flash coated with the substantially reflective material.
In some embodiments, an interferometric modulator can incorporate a user input device that can also change a characteristic of light reflected from the interferometric modulator. For example, the display 700 in FIG. 13A includes a touchscreen 705 which is connected to the outer surface of spatial light modulator 105. The touchscreen 705 includes an outer touchscreen portion 715 that has an outer touch surface 730 configured to receive touch signals from a user, and a touchscreen inner portion 720 which is attached to the spatial light modulator 105. The touchscreen inner portion 720 and touchscreen outer portion 715 are separated by a space 710 and held apart by spacers 717. For user input, the touchscreen 705 can operate in a manner well known in the art, e.g., a user applies pressure to the touch surface 730 on the other touchscreen portion 715, which makes contact with the touch screen inner portion 720 and activates a circuit which is configured to send a signal when activated. In addition to providing user input functionality, the touchscreen 705 can be configured with a light diffusing material 731 in the touchscreen inner portion 720 and/or a light diffusing material 725 in the touchscreen outer portion 715.
FIG. 13B is a side view of an embodiment of the touchscreen outer portion 715 and/or touchscreen inner portion 720 having a diffusing material. In this embodiment, the diffusing material is a diffusing adhesive 751 between an upper layer 750 a and a lower layer 750 b. The diffusing adhesive 751 may be an adhesive mixed with filler particles 751 a that act as scatter centers for scattering light. Any suitable material that refracts, reflects, or scatters light may be used as the filler particles 751 a. For example, the filler particles 751 a may be made of materials such as, but not limited by, the following polymers: polystyrene silica, polymethyl-methacrylate (PMMA), and hollow polymer particles. In an alternative embodiment the diffusing adhesive 751 is configured to have air bubbles that refract light. In other embodiments, opaque non-reflective particles may be used. The upper 750 a and/or lower 750 b layers may comprise materials such as polycarbonate, acrylic, and polyethylene terephtalate (PET) as well as other materials. FIG. 13C is another embodiment of the touchscreen outer portion 715 and/or touchscreen inner portion 720 comprising a diffusing material, where diffusing material 752 is incorporated in a layer 750 that forms the upper and/or lower portions 715, 720 of the touchscreen. FIG. 13D is an embodiment where diffusing material 753 is between the touchscreen 705 and the spatial light modulator 105. For example, in FIG. 13D, the diffusing material 753 is coated on top of the outer surface 754 of the spatial light modulator 105. In this embodiment, the diffusing material 753 may be patterned on the outer surface 754 of the display 105, where the diffusing material 753 is between the outer surface 754 of the spatial light modulator 105 and the touchscreen 705. In some embodiments, the diffusing material 753 may be spun, e.g., on a glass outer surface of the spatial light modulator 105. In certain embodiments, the diffusing material may comprise scatter features mixed with an ultraviolet epoxy or thermally cured epoxy. When an epoxy is used, the diffusing material 753 may be filler particles mixed with the epoxy, where the filler particles act as scatter centers to scatter light. Other configurations are also possible.
FIG. 14A shows an embodiment of a display 800 that includes a touchscreen 705 with an inner portion 720 attached to a spatial light modulator 105, which includes a substrate, and an outer portion 715 that has a touchscreen surface 730 for receiving user input. Spacers 717 are disposed in a gap 710 between the inner portion 720 and outer portion 715. The display 800 also includes a light source 740 configured to provide light 719 to the touchscreen 705, e.g., the inner portion 720, the outer portion 715, or both. In one embodiment, the touchscreen 705 can include optical structures that redirect the light 719 so that the light is incident on the spatial light modulator 105. In some embodiments, the optical structures comprise inclined or slanted surfaces inside the touchscreen 705. In some embodiments, total internal reflection (TIR) elements may be used. Also, in certain embodiments, the optical elements comprise particles that scatter light such that a portion of the scattered light is incident on the spatial light modulator 105. In some embodiments, the material 745 in the inner portion 720 and/or the material 735 in the outer portion 715 of the touchscreen 705 can include phosphorescent material. This phosphorescent material emits light when activated by the light 719 from the light source 740, providing light directly to the touchscreen 705 and to the spatial light modulator 105, which can then be reflected back to the touchscreen 705.
In other embodiments depicted in FIGS. 14B1 and 14B2, the display 800 with a touchscreen 705 may also include a contoured light guide. For example, in FIG. 14B1, the inner portion 720 of the touchscreen 705 may comprise a plate or layer 760 a with a contoured, e.g., grooved, surface 765. This contoured surface 765 may include a plurality of slanted portions. This surface 765 may have, for example, a sawtooth shape. A transmissive material 760 b may then be placed in the contours or grooves of the surface 765 to form a substantially planer surface 760 c above the plate/layer 760 a. The light source 740 directs light 719 into the plate or layer 760 a, where the light 719 is optically guided. The light propagating in the plate 760 a reflects off the slanted portion of the surface 765 and travels towards the spatial light modulator 105. In the embodiments using the light guiding plate or layer 760 a, or any other suitable light guide, a diffuser material may be incorporated into the display 800 above or below the plate 760 a. For example, the diffusing material may be within the outer portion 715 of the touchscreen 705 or on the outer surface 754 of the spatial light modulator 105.
In an alternative embodiment depicted in FIG. 14B2, the plate or layer 760 a may be placed between the touchscreen 705 and the spatial light modulator 105. In this embodiment, the transmissive material 760 b (FIG. 14B1) is not placed on the surface 765 of the plate 760 a. Rather, air or vacuum occupies a cavity 760 c between the plate/layer 760 a and the touchscreen 705.
In another embodiment illustrated in FIG. 14C, light 719 for the light source 740 may be directed into an edge of the touchscreen 705 and may be guided through at least a portion of the touchscreen 705, and the touchscreen 705 may comprise features that redirect this light toward the spatial light modulator 105. For example, in FIG. 14C, the inner portion 720 of the touchscreen 705 may incorporate particles 770 that scatter the light toward the spatial light modulator 105. As illustrated by FIG. 14D, the inner portion 720 may be a multi-layered with particles 770 mixed in an adhesive between an upper layer 750 a and a lower layer 750 b. The upper 750 a and/or lower 750 b layers may comprise materials such as polycarbonate, acrylic, and polyethylene terephtalate (PET), or other materials. In other embodiments such as depicted in FIG. 14E, scatter features or particles 770 are coated on top of the outer surface 754 of the spatial light modulator 105. These scatter features or particles 770 may redirect light toward the movable reflectors of the interferometric modulators; see for example U.S. patent application Ser. No. 10/794,825, filed Mar. 5, 2004, and entitled “Integrated Modulator Illumination”, issued as U.S. Pat. No. 7,706,050 on Apr. 27, 2010, which is hereby incorporated by reference. In this embodiment, the scatter features or particles 770 may be patterned on the outer surface 754 of the display 105, where the scatter features 770 are between the outer surface 754 of the spatial light modulator 105 and the touchscreen 705. In certain embodiments, the scatter features 770 may be spun on a glass surface of the spatial light modulator 105. In some embodiments, scatter features are mixed with an ultraviolet epoxy or thermally cured epoxy. When an epoxy is used, the scatter features 770 may comprise particles mixed with the epoxy, where the particles act as scatter centers to redirect the light toward the mirrored surfaces of the interferometric modulators.
FIG. 15A is a representation of one embodiment of a display 1100 that uses the light incident on inactive areas between the active reflector areas. As used herein, the term inactive area include but is not limited to the space between the reflective areas (such as the mirrors) of an interferometric modulator. As used herein, the active area includes but is not limited to the reflective areas (such as the mirrors) of an interferometric modulator, for example, that form an optical cavity.
Referring to FIG. 15A, a display 1100 includes a film 1105 connected to the outer surface of a spatial light modulator 105. Red 1121, green 1122, and blue 1123 active reflector areas are shown on the bottom of spatial light modulator 105 and represent the numerous active reflector areas (e.g., resonant optical cavities) of the display 1100. A first space 1110 separates the red active reflector area 1121 from the green active reflector area 1122, which is separated from the blue active reflector area by a second space 1111. The spaces 1110 and 1111 may be between about 2 to 10 microns wide and are spaced apart from each other by about 125 to 254 microns. Similarly, optical features in the spaces 1110 and 1111 in the film 1105 that redirect light may be about 2 to 10 microns wide and are spaced apart from each other by about 125 to 254 microns. Dimensions outside these ranges are also possible.
Generally, without the film 1105, light incident on the areas of the first space 1110 or the second space 1111 may not reach one of the active reflector areas 1121, 1122, 1123. To increase the reflectance of the interferometric modulator 1100, light incident on the inactive areas between the active reflector areas (e.g., first space 1110 and second space 1111) can be redirected to one of the active reflector areas 1121, 1122, 1123. As the location of the inactive areas and the active reflector areas is known, the external film 1105 can be configured to redirect the light incident 1115 on the film 1105 in the inactive areas 1110, 1111 back into the active reflector area 1121, 1122, 1123 (e.g., the optical cavity) as shown by arrow 1120. In some embodiments, the film 1105 includes reflectors to re-direct the light. In some embodiments, the film 1105 is configured with a customized index of refraction in the areas of the spaces 1110, 1111 to re-direct the light. In other embodiments, the film 1105 can contain scattering elements in the areas of the spaces 1110, 1111 so that at least a portion of the light is scattered into and falls onto an active reflector area (e.g., the optical cavity).
In an alternative embodiment depicted in FIG. 15B, the film 1105 may be placed above reflector areas 1121, 1122, 1123 but below the substrate of the spatial light modulator 105. The film 1105 is, thus, in the spatial light modulator 105. In this embodiment, the film 1105 is configured to redirect the light 1115, which is incident on an active area but would normally proceed to an inactive area, to the active reflector areas 1121, 1122, 1123 as shown by arrow 1120.
Referring to FIGS. 16A-H, various embodiments of the external film are illustrated. In FIG. 16A, external film 1205 has scatter regions 1212 that scatter light. As depicted in FIG. 16A, these scatter regions 1212 that scatter light may be interposed with regions 1217 that do not scatter light. The scatter regions 1212 may scatter light, for example, by reflection or refraction. Referring to FIG. 16B, external film 1205 has regions of higher refractive index within a matrix or film comprising material of lower refractive index. This embodiment uses TIR to redirect light. For example, if the spaces of the external film 1205 having a high refractive index are placed over the active regions of an interferometric modulator and the spaces having a low refractive index are placed over the inactive regions of the interferometric modulator, some of the light incident on the low refractive areas of the external film 1205 that would normally pass through to the inactive areas will be redirected to the active areas of the interferometric modulator. Referring to FIG. 16C, external film 1205 may have dimpled regions 1213 on a single surface of the external film that act as concave lenses. Referring to FIG. 16D, the external film 1205 may have Fresnel lenses in the regions 1214. In other embodiments, holographic or diffractive optical elements may be disposed at the regions 1214. These optical elements may scatter or diffract light and may operate as lenses, for example, with negative power that redirect light incident on the lenses toward the active regions. Referring to FIG. 16E, external film 1205 may have opposing sloped surfaces 1215 to refract light in opposite directions toward different active regions. FIG. 16F shows the external film 1205 having surfaces 1215 oriented similarly so as to refract light in the same direction. Referring to FIG. 16G, external film 1205 may have one or more reflecting sloped surfaces 1216 that reflect light toward active regions. Many other configurations are possible that also accomplish the desired redirection of light at the external film 1205.
Referring now to FIG. 17, an interferometric modulator 1200 can include an external film 1205 that is connected to the outer surface of the spatial light modulator 105, where the film 1205 is configured to collect light incident at a wide range of angles and direct the light into at a narrower range of angles onto the light-modulating elements. In FIG. 17, the external film 1205 is configured to receive incident light 1206, 1207 at various angles and substantially collimate the light (represented by arrows 1208, 1209) and direct the light towards the active reflectors 1211. In some embodiments, such as the one shown in FIG. 17, the external film 1205 includes collimating elements 1218 that substantially collimate the light. In some embodiments, the external film 1205 includes a plurality non-imaging optical elements, e.g., compound parabolic collectors, 1218. The non-imaging optical elements, e.g., compound parabolic collectors 1218, collimate at least some of the light 1206 and 1207 that is incident on the external film 1205 at a range of angles. A portion of the light 1208 and 1209 then exits the compound parabolic collectors 1218 at a more normal angle and is directed towards the active reflectors 1211. Some of that light 1208 and 1209 is then reflected by the active reflectors 1211 and exits the display 1200 as light 1210 a and 1210 b egressing from the display 1200 at a limited range of angles. Accordingly, the film 1205 has a limited field-of-view. In some embodiments, at least some of the light 1210 a and 1210 b exits the display 1200 at a cone angle not greater than about 70 degrees from a plane 610 normal to a front surface of the external film 1205. In some embodiments, the cone angle is no more than about 65, 60, 55, 50, 45, 40, 35, 30, 25, or 20 degrees from the plane 610 normal to the front surface of the external film 1205. The collimating elements 1205 effectively limit the field-of-view of the device 1200 because light generally does not egress from the display 1200 at an angle substantially greater than the incident angle. Accordingly, the field-of-view of the external film may be about 70, 65, 60, 55, 50, 45, 40, 35, 30, 25, or 20 degrees or less as measured from the normal. These angles are half-angles. Other values outside these ranges are also possible.
FIGS. 18A-C depicts another embodiment of a display 1300 that includes an optical film 1305 disposed forward of the spatial light modulator 105. The optical film 1305 is configured to receive light incident at a wide range of angles and direct the light into a narrower range of angles onto the light-modulating elements. The optical film 1305 also diffuses light. In certain embodiments, the optical film 1305 is configured to diffuse light such that light incident on the diffuser element is directed to the light-modulating elements more collimated than the incident light.
In one embodiment, the optical film 1305 comprises a holographic diffuser. The holographic diffuser comprises diffractive features arranged to manipulate the light, for example, to produce a heightened intensity distribution over a narrow range of angles. In another embodiment, the optical film 1305 includes a plurality of non-imaging optical elements, e.g., a plurality of compound parabolic collectors such as described above and a thin layer of diffusing material on an upper surface 1340 of the optical film 1305. In another embodiment, the optical film 1305 includes other collimating elements with a film of diffusing material on the outer surface 1340.
Referring to FIG. 18A, the film 1305 is configured to receive incident light 1310. Referring to FIG. 18B, the film is also configured to substantially redirect the incident light 1310 (the substantially redirected light being represented by arrows 1315), which is directed to active reflectors within the spatial light modulator 105, toward the normal to the surface of the active reflectors. For incident light over the range of +/−75 degrees the redirected light can be in the range of +/−35 degrees, wherein the angles are measured from the normal. In this embodiment, the redirected light is substantially collimated. In some embodiments, the reflectors may be at a bottom portion of the spatial light modulator 105. Referring to FIG. 18C, the light 1325 reflected from the active reflectors enters the lower surface 1330 of film 1305. The film 1305 is configured to receive the reflected specular light at its lower surface 1330 and is diffused before it is emitted from the film 1305 as diffuse light. In some embodiments, the light is diffused as it propagates through the film 1305. In other embodiments, the light is diffused at the upper surface 1340 (or lower surface 1330) of the film 1305. Other configurations or values outside the ranges above are also possible.
The foregoing description details certain embodiments of the invention. It will be appreciated, however, that no matter how detailed the foregoing appears in text, the invention can be practiced in many ways. As is also stated above, it should be noted that the use of particular terminology when describing certain features or aspects of the invention should not be taken to imply that the terminology is being re-defined herein to be restricted to including any specific characteristics of the features or aspects of the invention with which that terminology is associated.
wherein the display is a reflective display.
2. The display of claim 1, wherein the redirecting elements are disposed between the light-modulating elements and the substrate.
3. The display of claim 1, wherein the substrate is disposed between the redirecting elements and the light-modulating elements.
4. The display of claim 1, wherein said redirecting elements comprise reflecting surfaces.
5. The display of claim 1, wherein said redirecting elements comprise scatter elements that scatter light incident thereon.
6. The display of claim 1, wherein said redirecting elements comprise lenses.
7. The display of claim 6, wherein said lenses have negative power.
8. The display of claim 7, wherein said lenses comprise concave surfaces that form concave lenses.
9. The display of claim 6, wherein said lenses comprise Fresnel lenses.
10. The display of claim 1, wherein said redirecting elements comprise diffractive optical elements.
11. The display of claim 1, wherein said redirecting elements comprise holographic regions.
12. The display of claim 1, wherein said redirecting elements comprise sloped surfaces.
13. The display of claim 1, wherein said redirecting elements comprise opposing sloped surfaces.
14. The display of claim 1, wherein said redirecting elements comprise total internal reflection elements.
15. The display of claim 1, wherein said redirecting elements have widths between about 2 and 10 microns.
16. The display of claim 1, wherein said redirecting elements are spaced apart by a distance of between about 125 and 254 microns.
20. The display of claim 19, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.
22. The display of claim 1, wherein said light-modulating elements comprise spatial light modulators configured to form an image.
23. The display of claim 1, wherein said light-modulating elements comprise movable reflective surfaces, static reflective surfaces, and optical resonant cavities between the movable reflective surfaces and the static reflective surfaces.
24. The display of claim 23, wherein the active regions include the optical resonant cavities.
25. The display of claim 1, wherein said light-modulating elements comprise electromechanical mirrors.
26. The display of claim 1, wherein said light-modulating elements comprise interferometric light modulators.
27. The display of claim 1, wherein the non-active regions include spaces between adjacent said active regions.
29. The display of claim 28, wherein the supporting means includes a substrate.
30. The display of claim 28, wherein the light-modulating means includes a plurality of light-modulating elements.
31. The display of claim 28, wherein the light-redirecting means includes a plurality of light-redirecting elements.
33. A reflective display manufactured by the method of claim 32.
Amendment and Information Disclosure Statement in U.S. Appl. No. 11/357,702, dated May 5, 2009.
Amendment and Response in U.S. Appl. No. 11/064,143 dated Sep. 25, 2009.
Amendment and Response in U.S. Appl. No. 11/064,143, dated Aug. 27, 2010.
Amendment in U.S. Appl. No. 11/156,162, dated Nov. 28, 2006.
Amendment in U.S. Appl. No. 11/156,162, dated Oct. 30, 2007.
Amendment in U.S. Appl. No. 12/036,958, dated Aug. 31, 2009.
Communication from the Japanese Patent Office in Japanese Application No. 2005-265709 dated Jun. 30, 2009.
Communication in Japanese Patent Application No. 2005-231619 dated Nov. 10, 2009.
Communication in Mexican Patent Application No. Pa/a/2005/009399 dated Mar. 27, 2008.
Extended European Search Report in App. No. 05255638.8 dated May 4, 2006.
Extended European Search Report in App. No. 10178062.5 dated Nov. 11, 2010.
Extended European Search Report in App. No. 10178063.3 dated Nov. 11, 2010.
Extended European Search Report in App. No. 10178067.4 dated Oct. 20, 2010.
Extended European Search Report in App. No. 10178069.0 dated Oct. 20, 2010.
Extended European Search Report in App. No. 10178072.4 dated Nov. 11, 2010.
Interview Summary in U.S. Appl. No. 12/544,184, dated Sep. 22, 2010.
Issued Fee Payment and Amendment in U.S. Appl. No. 11/357,702, dated Aug. 7, 2009.
Notice of Allowance in U.S. Appl. No. 11/156,162, dated Aug. 12, 2008.
Notice of Allowance in U.S. Appl. No. 11/156,162, dated Jan. 29, 2008.
Notice of Allowance in U.S. Appl. No. 11/156,162, dated March 3, 2009.
Notice of Allowance in U.S. Appl. No. 11/357,702, dated May 8, 2009.
Notice of Allowance in U.S. Appl. No. 12/036,958, dated Dec. 31, 2009.
Notice of Allowance in U.S. Appl. No. 12/544,184, dated Feb 15, 2011.
Notice of Allowance in U.S. Appl. No. 12/544,184, dated Nov. 5, 2010.
Office Action in Chinese Application No. 200510103443.4 dated Aug. 7, 2009.
Office Action in U.S. Appl. No. 11/064,143, dated May 27, 2010.
Office Action in U.S. Appl. No. 11/064,143, dated Nov. 15, 2010.
Office Action in U.S. Appl. No. 11/156,162, dated Aug. 28, 2006.
Office Action in U.S. Appl. No. 11/156,162, dated Jul. 31, 2007.
Office Action in U.S. Appl. No. 11/156,162, dated Mar. 14, 2007.
Office Action in U.S. Appl. No. 12/544,184, dated Jun. 28, 2010.
Office Action Response and Applicant Interview Summary in U.S. Appl. No. 12/544,184, dated Sep. 28, 2010.
Official Communication in Chinese Application No. 200510105055 dated Mar. 13, 2009.
Official Communication in Japanese Application No. 2005-265709 dated Mar. 5, 2009.
Official Communication in Japanese Application No. 2005-265709 dated Oct. 21, 2008.
Official Communication in Japanese Application No. 2007-533515 mailed Jun. 8, 2010.
Official Communication in Japanese Application No. 2007-533515, dated Jan. 11, 2011.
Official Communication in U.S. Appl. No. 11/064,143 dated Jun. 26, 2009.
Petition to Withdraw from Issue, Request for Continued Examination, and Information Disclosure in U.S. Appl. No. 11/156,162, dated Nov. 18, 2008.
Request for Continued Examination and Amendment in U.S. Appl. No. 11/064,143, dated Feb. 15, 2011.
Request for Continued Examination and Information Disclosure Statement in U.S. Appl. No. 11/156,162, dated Apr. 28, 2008.
Request for Continued Examination and Information Disclosure Statement in U.S. Appl. No. 11/357,702, dated Apr. 27, 2009.
Requested for Continued Examination and Information Disclosure Statement in U.S. Appl. No. 12/544,184, dated Feb. 4, 2011.
Requested for Continued Examination, Amendment, and Information Disclosure Statement in U.S. Appl. No. 11/156,162, dated May 14, 2007.
Response to Amendment in U.S. Appl. No. 11/357,702, dated Aug. 13, 2009.
Supplemental Amendment and Summary of Interview in U.S. Appl. No. 11/156,162, dated Jul. 24, 2007.
Supplemental Amendment in U.S. Appl. No. 11/156,162, dated Jan. 27, 2009.

References: §119
 Application No. 2005
 Application No. 2005
 Application No. 200510103443
 Application No. 200510105055
 Application No. 2005
 Application No. 2005
 Application No. 2007
 Application No. 2007