Wavelength-controllable voltage-phase photodiode optoelectronic switch ("opsistor")

• US 5,837,995 A
• Filed: 11/25/1996
• Issued: 11/17/1998
• Est. Priority Date: 11/25/1996
• Status: Expired due to Fees

• Current Assignee: Alan Y. Chow
• Original Assignee: Alan Y. Chow
• Inventors: Chow, Alan Y., Chow, Vincent Y.
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US08/755,729
• Time in Patent Office: 722 Days
• Field of Search: 250/214 LS, 250/214.1, 250/214 R, 250/214 SW, 250/551, 257/84, 257/80, 257/432, 257/433, 327/514-517, 327/521
• US Class Current: 250/214.0LS
• CPC Class Codes: H01L 31/08 in which radiation controls flow of current through the device, e.g. photoresistors
• CPC Class Codes: H04B 10/032 using working and protection systems H04J14/0287 takes precedence
• CPC Class Codes: H04N 25/46 by combining or binning pixels
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 25/772 comprising A/D, V/T, V/F, I/T or I/F converters
• CPC Class Codes: H04N 3/1506 with addressing of the image-sensor elements H04N3/1575 takes precedence
• CPC Class Codes: H04N 3/1512 for MOS image-sensors, e.g. MOS-CCD H04N3/1581 takes precedence
• CPC Class Codes: H04N 3/155 Control of the image-sensor operation, e.g. image processing within the image-sensor

Abstract

A wavelength-portion controllable optoelectronic switch ("Opsistor") capable of rapid switch frequencies fabricated as a monolithic integrated circuit is disclosed. The Opsistor is comprised of two inverse parallel photodiodes in close proximity, preferably on a monolithic silicon substrate, such that the anode of one photodiode is electrically connected via a first conductor to the cathode of the second photodiode, and the cathode of the first photodiode is electrically connected via a second conductor to the anode of the second photodiode. The voltage-phase of the Opsistor is determined by the relative illumination to the Opsistor'"'"'s two photodiodes and is rapidly switchable. As a receiving device for data signals, the Opsistor receives programming signals from a transmitter light source. By using different wavelength-portion bandwidth pass filters on each of the two Opsistor photodiodes, a OPS-F device is created, and by using a two-wavelength transmitter light source designated as TM2, a TM2/OPS-F system is created capable of high data transmission rates, and high resistance to signal noise. Applications suitable for the Opsistor and TM2/OPS-F system include high speed optocouplers, linear optical position sensors, edge and target detection sensors, image recognition sensors, the basic subunits of optically based state computers, and high resolution optical encoders.

Claims

1. An optoelectronic switch, comprising:

two photodiodes such that the anode of one photodiode is electrically connected via a first conductor to the cathode of the second photodiode, and the cathode of the first photodiode is electrically connected via a second conductor to the anode of the second photodiode, wherein the voltage-phase of the first conductor and the second conductor of the optoelectronic switch is a function of which of the photodiodes of the optoelectronic switch receives a greater amount of light illumination.

2. The switch of claim 1 wherein the components of the optoelectronic switch are fabricated on a monolithic substrate.

3. The switch of claim 2 wherein the anodes and the cathodes of the switch are fabricated at its surface.

4. The switch of claim 1 further comprising a dielectric light filter layer used to selectively allow only certain bandwidths of light from 450 nm to 1150 nm, to illuminate each of the photodiodes.

5. The switch of claim 4 wherein the dielectric filter layer is deposited directly on the photoactive surfaces of the photodiodes.

6. The switch of claim 4 wherein the dielectric filter layer allows the same bandwidth of the light spectrum to stimulate both photodiodes of the device.

7. The switch of claim 5 wherein the dielectric filter layer allows different bandwidths of the light spectrum to stimulate each of the photodiodes of the switch.

8. An optoelectronic coupler, for coupling a source of light signals to a receiver that can process voltage-phase signals, comprising:

a light transmitter capable of generating light signals of two different first and second bandwidths;

at least one pair of first and second photodiodes to receive light signals from the light transmitter;

a first conductor electrically connecting the anode of the first photodiode to the cathode of the second photodiode;

a second conductor electrically connecting the cathode of the first photodiode to the anode of the second photodiode;

a first light filter disposed on the photoactive surface of the first photodiode that allows the first bandwidth of light to pass;

a second light filter disposed on the photoactive surface of the second photodiode that allows the second bandwidth of light to pass;

whereby the light transmitter signals utilizing the first and second bandwidths can be converted by said photodiodes into voltage-phase signals across the first and second conductors.

9. The optoelectronic coupler of claim 8 further comprising a modulated signal generator for sending data signals to the light transmitter for transmission to the photodiodes, and a signal receiver for receiving and decoding voltage-phase data from across the first and second conductors.

10. The optoelectronic coupler of claim 8 wherein the light transmitter comprises light emitting diodes.

11. The optoelectronic coupler of claim 8 wherein the light transmitter comprises at least one laser.

12. The optoelectronic coupler of claim 8 wherein the coupler is fabricated on a monolithic silicon substrate and wherein the light transmitter comprises amorphous silicon light emitting diodes fabricated on the same monolithic silicon substrate.

13. A state machine comprising:

a plurality of switches each having two photodiodes wherein the anode of one photodiode is electrically connected via a first conductor to the cathode of the second photodiode, and the cathode of the first photodiode is electrically connected via a second conductor to the anode of the second photodiode, wherein the voltage-phase of the first conductor and the second conductor of the optoelectronic switch is a function of which of the photodiodes of the optoelectronic switch receives a greater amount of light illumination;

a dielectric light filter layer used to selectively allow only certain bandwidths of light to illuminate each of the photodiodes and wherein the dielectric filter layer allows different bandwidths of the light spectrum to stimulate each of the photodiodes of the switch, each of the switches disposed on a monolithic silicon substrate wherein each switch has three voltage-phases which are activated rapidly by using a mixture of two bandwidths of light;

a source of two bandwidths of light for programming the switches by activating one of the three voltage phases; and

means to read electronically the combination of voltage states produced by the switches as digital information.

14. The state machine of claim 13 wherein the light source comprises a pair of light emitting diodes for each of the switches, a first member of each light emitting diode pair emitting the first bandwidth of light for programming the plurality of switches, and the second member of each light emitting diode pair emitting the second bandwidth of light for programming the plurality of switches.

15. The state machine of claim 13 wherein the light source comprises a laser.

16. The state machine of claim 15 wherein the laser comprises a tunable laser producing a plurality of different pairs of different wavelengths of light to signal the switches.

17. An optoelectronic position sensor device for determining the location of a light beam, comprising:

a switch having two photodiodes wherein the anode of one photodiode is electrically connected via a first conductor to the cathode of the second photodiode, and the cathode of the first photodiode is electrically connected via a second conductor to the anode of the second photodiode,

wherein the voltage-phase of the first conductor and the second conductor of the optoelectronic switch is a function of which of the photodiodes of the optoelectronic switch receives a greater amount of light illumination;

wherein the components of the switch are fabricated on a monolithic substrate and the anodes and the cathodes of the switch are fabricated at its surface;

a focusing lens system to focus the light beam onto the surface of the switch whereby the switch can sense the position of the focused light beam on its surface by producing a positive voltage-phase, negative voltage-phase, or a null zero-volt voltage phase depending upon the balance of illumination of the focused light beam upon the two photodiode components of the switch; and

means to electronically analyze the produced voltage-phases so as to indicate the linear position of the light beam on the switch'"'"'s surface.

18. An optoelectronic sensor for two-dimensional targeting of an object, comprising:

an upper and lower switch each having two Dhotodiodes wherein the anode of one photodiode is electrically connected via a first conductor to the cathode of the second photodiode and the cathode of the first photodiode is electrically connected via a second conductor to the anode of the second photodiode,

wherein the voltage-phase of the first conductor and the second conductor of each optoelectronic switch is a function of which of the photodiodes of the optoelectronic switch receives a greater amount of light illumination;

wherein the components of the switch are fabricated on a substrate and the anodes and the cathodes of the switch are fabricated at its surface;

a focusing lens system to focus light from the target object onto the surface of the switch whereby the switch can sense the position of the focused light on its surface by producing a positive voltage-phase, negative voltage-phase, or a null zero-volt voltage phase depending upon the balance of illumination of the focused light upon the two photodiode components of the switch; and

means to electronically analyze the produced voltage-phases so as to indicate the linear position of the light on the switch'"'"'s surface;

wherein the upper switch is fabricated from thinned silicon substrate and the upper switch is substantially transparent to the light from the target object and is oriented at 90 degrees rotated from the lower switch, and that the light from the target object also passes through the substantially transparent upper switch onto the lower switch so that together the two switches function as a two-dimensional target sensor;

and means to electronically analyze the produced voltage-phases of the switches so as to indicate the two-dimensional position of the target object being targeted on the target sensor.

19. An optoelectronic encoder, comprising:

a housing;

a slotted rotor disk inside of the housing;

two switches each switch having two photodiodes such that the anode of one photodiode is electrically connected via a first conductor to the cathode of the second photodiode, and the cathode of the first photodiode is electrically connected via a second conductor to the anode of the second photodiode,

wherein the voltage-phase of the first conductor and the second conductor of the switch is a function of which of the photodiodes of the switch receives a greater amount of light illumination;

wherein the components of the switches are fabricated on a monolithic substrate and the anodes and the cathodes of the switch are fabricated at its surface;

and the switches are located inside the housing on one side of the slotted rotor disk;

an encoder light source inside the housing on the other side of the slotted rotor disk;

means for turning the slotted rotor disk, whereby the light pulse signals created from the light source pass through the moving slots of the rotating disk to create voltage-phase changes in the two switches to produce quadrature electrical signals; and

means to electronically read the quadrature electrical signals produced.