Double substrate reflective spatial light modulator with self-limiting micro-mechanical elements
AssigneeReflectivity, INC
InventorAndrew G. Huibers
Life of this patent
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Abstract
A spatial light modulator includes an upper optically transmissive substrate held above a lower substrate containing addressing circuitry. One or more electrostatically deflectable elements are suspended by hinges from the upper substrate. In operation, individual mirrors are selectively deflected and serve to spatially modulate light that is incident to, and then reflected back through, the upper substrate. Motion stops may be attached to the reflective deflectable elements so that the mirror does not snap to the bottom substrate. Instead, the motion stop rests against the upper substrate thus limiting the deflection angle of the reflective deflectable elements.
Claims55
A spatial light modulator comprising:
- an optically transmissive substrate having an upper surface and a lower surface;
- at least one deflectable element attached to the lower surface of the optically transmissive substrate;
- and
- a circuit substrate positioned below and spaced apart from the lower surface of the optically transmissive substrate, the circuit substrate containing addressing circuitry capable of activation of any set of the at least one deflectable elements.
A process for the fabrication of a spatial light modulator, the process comprising:
- depositing a sacrificial layer over an optically transmissive substrate;
- etching a hole through the sacrificial layer, whereby the hole allows for attachment of subsequent layers to the substrate;
- depositing a reflective layer over the sacrificial layer;
- connecting the reflective layer to the optically transmissive substrate through the hole;
- patterning the reflective layer to define one or more reflective deflectable elements;
- removing the sacrificial layer so that the reflective elements are free and may deflect;
- forming addressing circuitry and electrodes on a circuit substrate;
- and
- aligning and joining the optically transmissive substrate and the circuit substrate, wherein the reflective elements may be selectively actuated by the addressing circuitry and electrodes.
A reflective spatial light modulator comprising:
- an array of electrodes on a circuit substrate;
- an optically transmissive substrate comprising a lower side, the optically transmissive substrate being positioned above and spaced apart from the circuit substrate, the optically transmissive substrate having an array of conducting reflective deflectable elements corresponding to the array of electrodes and attached to the lower side.
The spatial light modulator of claim 40, wherein the memory array comprises a DRAM memory array.
A process for operating a spatial light modulator comprising:
- asserting a bias voltage between addressing circuitry and a reflective deflectable element, the addressing circuitry being contained in a circuit substrate, the reflective deflectable element being attached to a lower surface of an optically transmissive substrate, the circuit substrate disposed below, but separated from, the optically transmissive substrate.
Dependencies are inferred from the claim text.