Massachusetts Institute of Technology

Other

Ernest R Stern

Richard W Ralston

Richard C Williamson

Barry E Burke

Daniel L Smythe, Jr

Henry Ignatius Smith

John H Cafarella

Abraham Bers

Richard S Withers

Kjell A Ingebrigtsen

A micromechanical panel display driver is shown in which only one driver and control bus are needed for each color. Furthermore, the elements are made with uniform film thicknesses, thereby minimizing the number of steps needed to fabricate the display. Here 6 bits are provided with temporal and aperture weighting. The use of temporal weighting generally requires the activation of most pixels twice/frame, which consumes considerable power. It should also be possible to eliminate temporal weighting by redistributing the contact area into a larger number of aperture weights and by adding a row electrode. Here pixels are activated only in response to a charge in the image. This generally reduces the drive power, since many pixels in a typical image do not change from frame to frame.

Method and apparatus for reducing driver count and power consumption in micromechanical flat panel displays

The invention provides an optical coupling switch and flat panel display including an array of such optical coupling switches. The optical coupling switch includes a light storage plate adapted to set up conditions for total internal reflection such that light injected into the plate is internally reflected. A light tap is disposed proximal to a coupling surface of the light storage plate for coupling internally reflected light out of the light storage plate and into the light tap when the light tap is brought into contact with the light storage plate coupling surface. The light tap is capable of movement in a direction perpendicular to the light storage plate in response to an applied electrostatic force. The optical coupling switch includes a scattering mechanism, such as a scattering surface or scattering medium, for scattering light in the light tap into a viewing volume. With this configuration, the optical coupling switch provides an elegantly uncomplicated geometry that accommodates a range of actuation schemes for efficiently producing high-speed optical switching. Also provided is an optical display in which an array of light taps are disposed proximal to a light storage plate coupling surface. Each light tap is adapted to move in response to an applied electrostatic force in a direction perpendicular to the coupling surface, and each light tap includes a scattering surface for scattering coupled light. A light source is disposed at an edge of the light storage plate for injecting light into the plate. Control circuitry is provided connected to the array of light taps for applying an electrostatic force to selected one or more of the light taps in the array.

Micromechanical optical switch and flat panel display

An optical imaging system for use as a solid-state camera, for example, which includes a plurality of solid-state elements for providing long-term storage of images, such elements being, for example, MNOS chips having a plurality of storage cells, which chips when exposed to an image focussed thereon can store a representation thereof. The chips are at a later time optically addressed, as by a scanning-light beam, to read out the stored image so as to provide an electrical output representing the stored image, such output being usable to provide a visual representation of the image such as on a display screen or in hard copy form.

Solid state imaging technique

A solid state device capable of providing long-term storage of analog signals which in a particular embodiment utilizes a plurality of MNOS storage elements. An input analog signal is applied to a plurality of temporary storage means each associated with an MNOS storage element for temporarily storing a charge proportional to the amplitude of the portion of the input analog signal applied thereto. Storage control means are used to transfer the temporarily stored charges to the long-term MNOS storage elements so that controlled amounts of carrier charges are stored in the nitride layers thereof, such controlled amounts being substantially linearly proportional to the temporarily stored charges associated therewith. In a particular embodiment the input analog signal may be supplied via a surface acoustic wave (SAW) device and coupled to the MNOS device directly or it may be coupled to a charge-coupled device (CCD) and then coupled to the MNOS device.

Analog solid state memory

A solid state device capable of providing long-term storage of analog signals which in a particular embodiment utilizes a plurality of MNOS storage elements. An input analog signal is applied to a plurality of temporary storage means each associated with an MNOS storage element for temporarily storing a charge proportional to the amplitude of the portion of the input analog signal applied thereto. Storage control means are used to transfer the temporarily stored charges to the long-term MNOS storage elements so that controlled amounts of carrier charges are stored in the nitride layers thereof, such controlled amounts being substantially linearly proportional to the temporarily stored charges associated therewith. In a particular embodiment the input analog signal may be supplied via a surface acoustic wave (SAW) device and coupled to the MNOS device directly or it may be coupled to a charge-coupled device (CCD) and thence coupled to the MNOS device.

A solid state device combining the use of a surface-acoustic-wave (SAW) device and a charge-coupled device (CCD) which utilizes an interface means therebetween comprising a plurality of conductive fingers responsive to an acoustic wave on the SAW device. The conductive fingers are electrically connected at at least one end to the CCD substrate and a plurality of temporary storage means are used for temporarily storing a charge proportional to the voltage potential on the associated conductive finger. The temporary stored charges can be transferred to the storage wells of the CCD for storing a replica of the acoustic wave. The SAW-CCD combination is adapted for use as a buffer memory, an accumulating correlator, or as a matched filter device.

Solid state devices combining the use of surface-acoustic-wave devices

A continuously programmable matched filter device using a piezoelectric substrate capable of propagating acoustic wave signals on a selected surface thereof and a semiconductor substrate mounted adjacent and spaced from such surface. Means are provided for altering the conductivity pattern in the semiconductor substrate in accordance with the wave form of a reference wave signal so that a representation of the reference wave is effectively stored therein. Storage of the reference is achieved with electrostatic charge by supplying a plurality of electrons in the spatial region between the substrates or by manipulating the carriers in the semiconductor material into trapping states in order to produce such altered conductivity pattern. A second signal can thereupon be propagated along the piezoelectric substrate to interact with the stored reference conductivity pattern to provide either correlation or convolution operation depending on the direction of propagation thereof along the piezoelectric surface.

Surface wave devices for processing signals

A surface acoustic wave device utilizing a piezoelectric substrate capable of propagating traveling acoustic waves along a surface thereof and a semiconductive substrate positioned adjacent such surface, the latter substrate having an array of Schottky diodes and associated islands of highly resistive material, such as polycrystalline silicon material, disposed in the surface thereof opposite the piezoelectric substrate to form an interaction region. Application of a signal uniformly over the interaction region will charge the diodes uniformly and an acoustic wave traveling along a selected surface of the piezoelectric substrate will interact with the uniformly applied signal to alter the charging pattern of the Schottky diode array in accordance therewith to produce a corresponding altered conductivity pattern stored in the semiconductor substrate and representing the interaction of the uniformly applied signal and the traveling wave signal. A second signal can thereupon be propagated along the piezoelectric substrate to interact with the stored altered conductivity pattern to provide either correlation or convolution operation depending on the direction of propagation thereof along the piezoelectric surface. Improvement in the stored signal to noise ratio can be obtained by applying the signal to be stored and the uniformly applied signal a selected number of times over a selected time interval to maximize the charge on the diodes so that when the stored signal is read out the signal to noise ratio at read-out is also improved. Further, a plurality of signals can be simultaneously stored in substantially the same space in the semiconductor substrate by tilting the direction of propagation thereof or by using coded wavefront patterns thereof to provide orthogonal beams which prevent interaction, or cross-talk, therebetween.

Growing community of inventors

Concord, MA, United States of America

Ernest R Stern