Projection TV with improved micromirror array
First Claim
1. A rear or front projection TV, comprising:
- an array of micromirrors, wherein the micromirrors comprise micromirror plates that are connected via hinges to a substrate, and wherein the substrate, micromirror plates and hinges are disposed in different planes;
a light source for providing light to the array of micromirrors;
a screen on which an image to be viewed is displayed;
wherein light from the light source is incident on the array of micromirrors during operation and directed as the image to be viewed on the screen;
wherein the micromirrors are capable of movement between an OFF state and an ON state by pulse width modulation to form the image on the screen; and
wherein the micromirror array is rectangular with four sides, and wherein each micromirror of the array has no micromirror plate sides that are parallel to any of the four sides of the micromirror array, and wherein light from the light source incident on the array of micromirrors is a) substantially perpendicular to a side of the micromirror array, b) substantially perpendicular to an axis of rotation of the micromirrors, and c) not perpendicular to any micromirror plate sides of the micromirrors.
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Accused Products
Abstract
In order to minimize light diffraction along the direction of switching and more particularly light diffraction into the acceptance cone of the collection optics, in the present invention, micromirrors are provided which are not rectangular. Also, in order to minimize the cost of the illumination optics and the size of the display unit of the present invention, the light source is placed orthogonal to the rows (or columns) of the array, and/or the light source is placed orthogonal to a side of the frame defining the active area of the array. The incident light beam, though orthogonal to the sides of the active area, is not however, orthogonal to any substantial portion of sides of the individual micromirrors in the array. Orthogonal sides cause incident light to diffract along the direction of micromirror switching, and result in light ‘leakage’ into the ‘on’ state even if the micromirror is in the ‘off’ state. This light diffraction decreases the contrast ratio of the micromirror. The micromirrors of the present invention result in an improved contrast ratio, and the arrangement of the light source to micromirror array in the present invention results in a more compact system. Another feature of the invention is the ability of the micromirrors to pivot in opposite direction to on and off positions (the on position directing light to collection optics)-, where the movement to the on position is greater than movement to the off position. A further feature of the invention is a package for the micromirror array, the package having a window that is not parallel to the substrate upon which the micromirrors are formed. One example of the invention includes all the above features.
168 Citations
52 Claims
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1. A rear or front projection TV, comprising:
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an array of micromirrors, wherein the micromirrors comprise micromirror plates that are connected via hinges to a substrate, and wherein the substrate, micromirror plates and hinges are disposed in different planes; a light source for providing light to the array of micromirrors; a screen on which an image to be viewed is displayed; wherein light from the light source is incident on the array of micromirrors during operation and directed as the image to be viewed on the screen; wherein the micromirrors are capable of movement between an OFF state and an ON state by pulse width modulation to form the image on the screen; and wherein the micromirror array is rectangular with four sides, and wherein each micromirror of the array has no micromirror plate sides that are parallel to any of the four sides of the micromirror array, and wherein light from the light source incident on the array of micromirrors is a) substantially perpendicular to a side of the micromirror array, b) substantially perpendicular to an axis of rotation of the micromirrors, and c) not perpendicular to any micromirror plate sides of the micromirrors. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52)
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Specification