Optical random access memory

• US 5,696,714 A
• Filed: 06/28/1994
• Issued: 12/09/1997
• Est. Priority Date: 12/30/1991
• Status: Expired due to Fees

• Current Assignee: RITEK Corporation
• Original Assignee: Information Optics Corporation
• Inventors: Russell, James T.
• Primary Examiner(s): Fears, Terrell W.
• Application Number:
  US08/256,202
• Time in Patent Office: 1,260 Days
• Field of Search: 365/106, 365/235, 365/120, 365/127
• US Class Current: 365/106
• CPC Class Codes: G11C 11/56 using storage elements with more than two stable states represented by steps, e.g. of voltage, current, phase, frequency
• CPC Class Codes: G11C 13/04 using optical elements ; using other beam accessed elements, e.g. electron or ion beam
• CPC Class Codes: G11C 13/041 using photochromic storage elements G11C13/042 takes precedence
• CPC Class Codes: G11C 7/005 with combined beam-and individual cell access

Abstract

An optical memory (10) is disclosed in which data is stored in an optical data layer (19) capable of selectively altering light such as by changeable transmissivity, reflectivity, polarization, and/or phase. The data is illuminated by controllable light sources (15) and an array of multi-surface imaging lenslets (21) project the image onto a common array of light sensors (27). Data is organized into a plurality of regions or patches (called pages) and by selective illumination of each data page, one of the lenslets (21) images the selected data page onto the light sensors (27). Light in the data image pattern strikes different ones of the arrayed light sensors (27), thereby outputting a pattern of binary bits in the form of electrical data signals. By selectively and sequentially illuminating different ones of the data regions (pages) on the data layer (19), correspondingly different data patterns are imaged by the corresponding lenslets (21) onto the common sensor array (27), thereby enabling many stored data pages to be retrieved by multiplexing at electro-optical speed.

Claims

1. An optical data sensor for sensing optical data imaged on a sensing plane, comprising:

an array of solid state light sensor elements disposed for receiving imaged data; and

a plurality of adaptive threshold sensing circuit means for providing a variable, adaptive light sensing threshold to data at each sensor element in response to receipt of light on adjacent sensor elements.

2. The optical data sensor of claim 1 wherein said array of light sensor elements comprises a plurality of charge coupled devices.

3. The optical data sensor of claim 1 wherein said array of light sensor elements comprises photosensing diodes.

4. The optical data sensor of claim 3 wherein at least one of said photosensing diodes is a PIN diode.

5. The optical data sensor of claim 1 further comprising a plurality of solid state light emitters disposed substantially in juxtaposition with said light sensor elements, and means for selectively energizing said light emitters.

6. The optical data sensor of claim 1 wherein said plurality of adaptive threshold sensing circuit means comprises variable level comparator means, said variable level comparator means connected to receive sensor output signals from predetermined subgroups of said sensor elements for changing a threshold sensing level at each said variable level comparator means as a function of the amount of light incident on said subgroups of said sensor elements.

7. The optical data sensor of claim 1 wherein said array of solid state light sensor elements and said adaptive threshold sensing circuit means are fabricated as an integrated solid state circuit.

8. A method of sensing optical data imaged on a sensing plane, comprising:

forming a light image of a data pattern on an array of photo sensitive elements;

outputting data from each element when light in said pattern that is incident on one of said elements has a predetermined intensity threshold; and

changing said intensity threshold in response to light incident on elements adjacent to said one of said elements.

9. An optical data system comprising:

an optical data means for storing data as light altering characteristics and being organized into a plurality (P) of juxtaposed data regions each having capacity to store (B) bits of data;

controllable light source means for selectively illuminating at least one of said data regions of said optical data means;

data imaging lens system having a plurality of juxtaposed lenslet subsystems each being formed of multiple elements and so shaped and arranged in such proximity to and in optical registration with a different one of said juxtaposed data regions so that the image resolving power thereof is substantially uniform over the field of view of that data region to form an image thereof on a common image surface spaced from said data means and data imaging lens system and wherein at least one element is diffractive for imaging an associated data region, and at least one element is an anomalous lens means for achromatizing the imaging rays;

sensor means having a plurality (S) of juxtaposed light sensors arranged at said image surface for sensing data as a light image corresponding to an illuminated data region; and

data signal output means coupled to said sensor means for outputting data signals representing said data of an illuminated and imaged data region.

10. The system of claim 9, wherein said anomalous lens means comprises an optical medium containing a buried refractive surface formed by a preselected dye that has an anomalous dispersion selected to cancel out color aberration caused by dispersion in the diffractive element.

11. The system of claim 9, wherein said anomalous lens means is in the configuration of a Fresnel lens.

12. The system of claim 9, wherein said anomalous lens means is characterized by an optical medium having embedded therein an optical material exhibiting a predetermined sharp change in index of refraction as a function of wavelength.

13. The system of claim 9, wherein said anomalous lens means is formed by at least two optical media that exhibit a predetermined net dispersion such that the optical power introduced thereby substantially affects color aberration.

14. An optical data system comprising:

an optical data means for storing data as light altering characteristics and being organized into a plurality (P) of juxtaposed data regions each having capacity to store (B) bits of data;

controllable light source means for selectively illuminating at least one of said data regions of said optical data means;

data imaging lens system having a plurality of juxtaposed lenslet subsystems each being formed of multiple elements and so shaped and arranged in such proximity to and in optical registration with a different one of said juxtaposed data regions so that the image resolving power thereof is substantially uniform over the field of view of that data region to form an image thereof on a common image surface spaced from said data means and data imaging lens system and wherein at least one element is diffractive for imaging an associated data region, and at least one element is a gradient index lens means;

sensor means having a plurality (S) of juxtaposed light sensors arranged at said image surface for sensing data as a light image corresponding to an illuminated data region; and

data signal output means coupled to said sensor means for outputting data signals representing said data of an illuminated and imaged data region.

15. The system of claim 14, wherein said gradient index lens means is formed by a gradient of anomalous dispersion dye varying the index of refraction longitudinally of the optical axis.

16. The system of claim 14, wherein said gradient index lens means is formed by a gradient of anomalous dispersion dye varying the index of refraction radially of the optical axis.

17. An optical data system comprising:

an optical data means for storing data as light altering characteristics and being organized into a plurality (P) of juxtaposed data regions each having capacity to store (B) bits of data;

controllable light source means for selectively illuminating at least one of said data regions of said optical data means;

data imaging lens system having a plurality of juxtaposed lenslet subsystems each being formed of multiple elements and so shaped and arranged in such proximity to and in optical registration with a different one of said juxtaposed data regions so that the image resolving power thereof is substantially uniform over the field of view of that data region to form an image thereof on a common image surface spaced from said data means and data imaging lens system;

sensor means having a plurality (S) of juxtaposed light sensors arranged at said image surface for sensing data as a light image corresponding to an illuminated data region and having adaptive threshold sensing circuit means for providing a variable, adaptive light sensing threshold to data images incident on each of said sensors wherein said adaptive threshold sensing circuit means comprises an integrated circuit sensor array having a plurality of subarrays of grouped sensor cells for detecting a single light image bit and sensor processing means for detecting data bits from said light image bits; and

data signal output means coupled to said sensor means for outputting data signals representing said data of an illuminated and imaged data region.

18. The optical data system of claim 17,

wherein each of said data regions has fiducial data stored thereon for registering the light image on said sensor means, and

wherein said adaptive threshold sensing circuit comprises processing means for reading said fiducial data and controlling addressing of said data signal output means for adapting the reading of data from said sensor means according to said fiducial data.

19. An optical data system comprising:

an optical data means for storing data as light altering characteristics and being organized into a plurality (P) of juxtaposed data regions each having capacity to store (B) bits of data;

controllable light source means for selectively illuminating at least one of said data regions of said optical data means;

data imaging lens system having a plurality of juxtaposed lenslet subsystems each being formed of multiple elements and so shaped and arranged in such proximity to and in optical registration with a different one of said juxtaposed data regions so that the image resolving power thereof is substantially uniform over the field of view of that data region to form an image thereof on a common image surface spaced from said data means and data imaging lens system;

sensor means having a plurality (S) of juxtaposed light sensors arranged at said image surface for sensing data as a light image corresponding to an illuminated data region and means for submultiplexing data from each of said data regions so as to cause portions of each of said regions to be selectively imaged on said sensor means; and

data signal output means coupled to said sensor means for outputting data signals representing said data of an illuminated and imaged data region.

23. The optical data system of claim 19, wherein said controllable light source means comprises at least one light guide means for jointly illuminating a subset of said data regions, and electrically controlled shutter means disposed in a data image path between said light guide and said sensor means for shuttering image light from certain but not all of said subset of said data regions.

20. An optical data system comprising:

an optical data means for storing data as light altering characteristics and being organized into a plurality (P) of juxtaposed data regions each having capacity to store (B) bits of data;

controllable light source means for selectively illuminating at least one of said data regions of said optical data means;

data imaging lens system having a plurality of juxtaposed lenslet subsystems each being formed of multiple elements and so shaped and arranged in such proximity to and in optical registration with a different one of said juxtaposed data regions so that the image resolving power thereof is substantially uniform over the field of view of that data region to form an image thereof on a common image surface spaced from said data means and data imaging lens system and a field flattener lens means for correcting spherical aberration of said light image incident on said sensor means;

sensor means having a plurality (S) of juxtaposed light sensors arranged at said image surface for sensing data as a light image corresponding to an illuminated data region; and

data signal output means coupled to said sensor means for outputting data signals representing said data of an illuminated and imaged data region.

21. An optical data system comprising:

an optical data means for storing data as light altering characteristics and being organized into a plurality (P) of juxtaposed data regions each having capacity to store (B) bits of data;

controllable light source means for selectively illuminating at least one of said data regions of said optical data means;

data imaging lens system having a plurality of juxtaposed lenslet subsystems each being formed of multiple elements and so shaped and arranged in such proximity to and in optical registration with a different one of said juxtaposed data regions so that the image resolving power thereof is substantially uniform over the field of view of that data region to form an image thereof on a common image surface spaced from said data means and data imaging lens system, and a focal plane lens array after said plurality of juxtaposed lenslet subsystems and proximate said common image surface for refocusing each imaged data region onto said common image surface;

sensor means having a plurality (S) of juxtaposed light sensors arranged at said image surface for sensing data as a light image corresponding to an illuminated data region; and

data signal output means coupled to said sensor means for outputting data signals representing said data of an illuminated and imaged data region.

22. An optical data recording and retrieval system comprising:

read light source array means;

optical data record means disposed proximate to said read light source array means for being illuminated thereby;

lens array means comprising a plurality of substantially similar lenslets arrayed in a lens structure disposed proximate and affixed to said optical data record means, each said lenslet forming a distal image of a portion of said optical data record means illuminated by said read light source array means;

light sensor array means disposed to receive said image of said portion of said optical data record means illuminated by said read light source means, said sensor array means responding to said image to output data; and

recording light data composer means for producing a recording light data pattern and imaging same onto said optical data record means for storing said data pattern, wherein said recording light data composer means comprises ultrasonic lens means for controllably directing said data pattern and imaging it onto said optical data record.

24. An optical data reading system comprising:

at least one of an optical data storage medium with juxtaposed data regions thereon;

a controllable light source means for selectively illuminating a data region on said data storage medium;

a data imaging lens means having a plurality of juxtaposed lenslets proximate said data storage medium being shaped and arranged to form an image of an associated data region on a common image surface; and

a sensor means having a plurality of juxtaposed light sensors arranged at said common image surface for sensing data as a light image corresponding to an illuminated data region, wherein the relative positions of said optical data storage medium, said controllable light source means, said data imaging lens means and said sensor means are controllably moveable in substantially parallel planes.

25. An optical data reading system comprising:

a substantially planar optical data storage medium with juxtaposed data regions thereon wherein said data storage medium is controllably movable within a first planar area occupied by it;

a plurality of juxtaposed lenslets proximate a first side of said data storage medium being shaped and arranged to form an image of an associated data region on a common image surface spaced from said first side;

a controllable light source means for selectively illuminating a data region of said data storage medium wherein said controllable light source means is controllably moveable within a second plane parallel to said first plane, and

a substantially planar sensor means having a plurality of juxtaposed light sensors arranged at said common image surface for sensing data as a light image corresponding to an illuminated data region wherein said sensor means is cooperatively connected to said light source means.

26. An optical data system comprising:

an optical data means for storing data as light altering characteristics and being organized into a plurality (P) of juxtaposed data regions each having capacity to store (B) bits of data, said optical data means defining a plane;

controllable light source means for selectively illuminating at least one of said separate data regions of said optical data means;

data imaging lens means having a plurality of juxtaposed lenslets each being shaped and arranged in such proximity to and in optical registration with a separate one of said juxtaposed data regions so that the image resolving power thereof is substantially uniform over the field of view of that data region to form an image thereof on a common image surface spaced from said data means and lens means;

sensor means having a plurality (S) of juxtaposed light sensors arranged at said image surface for sensing data as a light image corresponding to an illuminated data region;

data signal output means coupled to said sensor means for outputting data signals representing said data of an illuminated and imaged data region; and

registration adjustment means being controlled by a control signal for adjusting the position of said optical data means within said plane for maintaining optical registration of said light image and said sensor means.

27. An optical data cartridge reading system comprising:

a cartridge including a housing,

said housing suspending in its interior a data array of substantially planar optical data storage medium with juxtaposed data regions thereon,

said data array including a plurality of juxtaposed lenslets proximate a first side of said data array being shaped and arranged to form an image of an associated data region on a common image surface spaced from said first side,

a reading unit including a controllable light source means for selectively illuminating a data region from a second side of said data array wherein said light source means is supported by said reading unit in a plane parallel to said data array,

said reading unit further including a sensing array of substantially planar sensor means having a plurality of juxtaposed light sensors arranged at said common image surface for sensing data as a light image corresponding to an illuminated data region wherein said sensing array is supported by said reading unit in a plane parallel to said data array

a clamping means including registration means mounted within said reading unit for clamping said data array and said plurality of lenslets between said light source means and said sensing array.

28. An optical data sensor for sensing optical data imaged on a sensing plane, comprising:

an array of solid state light sensor elements disposed for receiving imaged data; and

a plurality of adaptive threshold sensing circuit means for providing a variable, adaptive light sensing threshold to data at each sensor element in response to receipt of light on adjacent sensor elements wherein said plurality of adaptive threshold sensing circuit means comprises variable level comparator means, said variable level comparator means connected to receive sensor output signals from predetermined subgroups of said sensor elements for changing a threshold sensing level at each said variable level comparator means as a function of the amount of light incident on said subgroups of said sensor elements.