Display systems, such as projection type devices, may include one or more optical modulators. The modulators may each include a plurality of reflective devices, such as movable micromirrors, wherein each micromirror corresponds to a pixel or a sub-pixel of the modulator. A display system may function by reflecting light from pixels or sub-pixels of the one or more modulators in accordance with the individual positions of the pixels or sub-pixels.
Support base 26 may be manufactured from any suitable material, and in the embodiment shown, may be manufactured from a silicon based material, such as glass. Mirrors 24 may be manufactured from any reflective material, and in one exemplary embodiment, may be manufactured from an aluminum coating formed on a movable, rigid plate, such as by deposition techniques. Sensing devices 14 may also be a micromirror device, such as an aluminum coating formed on a rigid plate by deposition techniques. In the embodiment shown, sensing devices 14 are movably mounted on base 26.
Activation device 16 may be an electron beam generator that may generate an electron beam 28 directed toward support base 26 having mirrors 24 and sensing devices 14 mounted thereon. Housing 18 may define a vacuum therein such that electron beam generator 16, electron beam 28, sensing devices 14 and movable mirrors 24 are all housed within a vacuum. In one embodiment, electron beam generator 16 may sweep beam 28 sequentially across each of mirrors 24a and 24b and sensing devices 14a and 14b to control the position of the mirrors, such as controllably moving the imaging mirrors 24 between first or inactive position 24a and second or active position 24b. In first position 24a, an imaging mirror may be positioned with its front reflective surface 30 positioned parallel to a plane 32. In second position 24b, a mirror may be positioned with its front reflective surface 34 positioned at an angle 36 with respect to plane 32, wherein angle 36 may be in a range of −90 to +90 degrees. In other embodiments, the “off” position of mirrors 24 may be angled and the on position may be parallel with respect to plane 32, or both the on and the off positions may be angled with respect to plane 32.
Similarly, in the embodiment wherein sensing devices 14 are movable mirrors, electron beam generator 16 may sweep beam 28 sequentially across each of sensing devices 14 to controllably move ones of the sensing device mirrors between a sensing position 14b wherein light is reflected from the sensing device mirror 14b to a sensor 38 and a non-sensing position 14a wherein light is reflected from sensing device mirror 14a to light dump 22. In sensing position 14b, a mirror may be positioned with its front reflective surface 50 positioned at an angle 52 with respect to plane 32, wherein angle 52 may be in a range of −90 to 90 degrees, as measured in an opposite direction from the measurement of angle 36 of mirror 24b for example. In other words, sensing devices 14 may be mounted on one or more supports that tilt sensing devices 14 in a direction different from imaging mirrors 24. In other embodiments, the nonsensing position of sensing devices 14 may be angled and the sensing position may be parallel with respect to plane 32, or both the sensing and the nonsensing positions may be angled with respect to plane 32. In some embodiments, the sensing devices may be tilted in the same direction as the imaging mirrors but at a different angle. For example, in such an embodiment the imaging mirrors may be tilted at +45 degrees and the sensing device mirrors may be tilted at +60 degrees, for example. Accordingly, even though sensing device 14 and imaging mirrors 24 may tilt in different directions with respect to base 26, sensing device 14 and imaging mirrors 24 may be manufactured in the same manner as one another on base 26.
Sensing devices 14 may be placed throughout array 12 at strategic locations such that sensing devices 14 are interspersed with movable imaging mirrors 24. Accordingly, activation device 16 may sweep electron beam 28 over the entire array to activate both movable mirrors 24 and sensing devices 14 in the same sweeping action of beam 28.
Display device 10 may further include a light source 40 that produces a light beam 42 directed toward sensing devices 14 and movable mirrors 24 mounted on support base 26. Light source 40 may generate light beam 42 having a wavelength in a range of 380 nm to 780 nm. However, any suitable type of light may be generated by an appropriate light source as may be utilized for a particular application. Moreover, in one embodiment, light source 40 may produce a first beam of light 42a, having a first wavelength and being directed toward imaging mirrors 24, and a second beam of light 42b, having a second wavelength and being directed toward sensing devices 14. In still another embodiment, light source 40 may include two separate light generation devices that may each produce a light beam 42a and 42b, respectively, having a unique wavelength. The use of two different wavelengths of light may allow a visible light to be reflected by imaging mirrors 24 to imaging region 20 and invisible light to be reflected by sensing device 14 to sensor 38 such that the two wavelengths of light do not interfere with one another during simultaneous operation of imaging region 20 and sensor 38.
In operation of one exemplary embodiment, display device 10 may function as follows. Electron beam generator 16 scans array 12 with beam 28 to activate individual ones of movable mirrors 24 to the on/activated state 24b and other individual ones of movable mirrors 24 to the off/unactivated state 24a, such that the activated mirrors 24b may be angled at angle 36 with respect to plane 32, and such that the unactivated mirrors 24a may be positioned parallel to plane 32. Light beam 42a may be directed toward micromirror array 12. A portion of light beam 42a that is directed toward activated mirrors 24b will be reflected by mirrors 24b toward imaging region 20 and a portion of light beam 42a that is directed toward unactivated mirrors 24a will be reflected by mirrors 24a toward light dump 22. The light received by imaging region 20 may form an image thereon that may be projected to or viewed directly by a viewer (not shown). The process may then be repeated again and again with different individual ones of micromirrors 24 being activated and/or deactivated such that different images are sequentially formed on imaging region 20 to produce a desired single or motion, color or black and white, picture image. During this repetitive process, undesirable light reflected by unactivated mirrors 24a may be reflected to light dump 22 such that the undesirable light is not reflected to imaging region 20 and is not viewed by a viewer.
During, before or after forming images on imaging on region 20 from mirrors 24, light 42b may be projected from light source 40 to sensing devices 14. In one embodiment, sensing devices 14 may be immovably positioned in a sensing position wherein light 42b may be reflected from one or more of sensing devices 14 to sensor 38. The light received by sensor 38 from one or more sensing devices 14 may be utilized to align the position of light source 40 with respect to array 12. In particular, sensing devices 14 may be strategically positioned on array 12, such as in an edge region 44 of array 12, and more particularly, at each of the four corners 46 (only one corner is shown for ease of illustration in
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Controller 48 may be connected to sensor 38 and may include software or code so as to determine when light is received at sensor 38 from individual ones of device 14. Accordingly, sensor 38 may indicate to controller 48 of system 10 that light is not detected at one or more of sensors 38 from one or more of sensing devices 14. The light detection, or lack of light detection, information received by controller 48 from sensor 38 may then be utilized to move activation device 16, or to change the size or pattern of beam 28, so that beam 28 is correctly aligned and patterned with respect to array 12. In other words, if activation device 16 is misaligned or incorrectly patterned or sized with respect to array 12, some of sensing devices 14 may not be activated and therefore may not reflect light to sensor 38. Controller 48 may utilize its software or code to deduce this information and correct the position and/or size/pattern of light source 40 and/or activation device 16 such that the entirety of array 12 is illuminated by light source 40 and/or is within the activation path of activation device 16, including each corner 46 and all of edge regions 44 of array 12. Accordingly, one or more sensing devices 14 may be utilized to align and/or size/pattern light source 40 and/or activation device 16 with respect to array 12 by reflecting light from sensing devices 14 to sensor 38 and by use of that information by controller 48. The alignment and/or size/pattern correction of light source 40 and/or beam 28 of activation device 16 may occur on an ongoing or continuous feedback basis during use of display 10 such that a full and focused image on imaging region 20 is actively maintained.
Similarly, if controller 48 determines that activation devices 16a or 16b are not properly aligned and/or electron beam 28 is not properly sized/patterned with respect to corresponding array 12, controller 48 may move and/or change the size or pattern of electron beam 28 of activation device 16a and/or 16b with respect to its corresponding array 12. In particular, controller 48 may utilize software or code to determine if activation device 16 produces an activation beam 28 that defines a pattern 58 that activates an array 12. For example, as shown in
Light information detected at sensor 38 may also be utilized by controller 48 to determine if arrays 12a and 12b, or more, such as arrays 12c (not shown), etc., are aligned with respect to one another, and/or if activation devices 16a and 16b, or more, such as 16c, etc. (not shown), are aligned with respect to one another. For example, controller 48 may use light information from sensors 38a and/or 38b to determine if an axis 60a of array 12a is positioned parallel to an axis 60b of array 12b. If not, controller 48 may position one or more of arrays 12 to align the axes 60 of each array in a parallel manner. In the embodiment shown, axis 60 may be a vertical axis of array 12. However, controller 48 may be utilized to align the axes of plural arrays 12, wherein the axis 60 may be a rotational axis, a horizontal axis, or any other type of alignment axis or plane about which an array may be aligned. Additionally, controller 48 may use light information from sensors 38a and/or 38b to determine if an axis 62a of activation device 16a is positioned parallel to an axis 62b of activation device 16b. If not, controller 48 may position one or more of activation devices 16 to align the axes 62 of each activation device in a parallel manner.
Sensing mirrors 14 may be fabricated on array 12 along with imaging mirrors 24 without substantially increasing the process costs of manufacturing array 12. The sensing mirrors 14 may be utilized to align multiple arrays 12 with respect to one another. The sensing mirrors 14 may also be utilized to align one or more arrays 12 with respect to one or more light sources 40. Sensing mirrors 14 may also be utilized to align and/or size and/or pattern an electron beam from one or more electron beam generation devices with respect to one or more arrays and with respect to another beam generation device.
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The foregoing description of embodiments of the invention have been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and modifications and variation are possible in light of the above teachings or may be acquired from practice of the invention. The embodiment was chosen and described in order to explain the principles of the invention and its practical application to enable one skilled in the art to utilize the invention in various embodiments and with various modification as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.