Compact optical random access memory having multiple reflections

• US 6,111,776 A
• Filed: 08/27/1998
• Issued: 08/29/2000
• Est. Priority Date: 12/30/1991
• Status: Expired due to Fees

• Current Assignee: RITEK Corporation
• Original Assignee: i-Optics, Incorporated
• Inventors: Russell, James T.
• Primary Examiner(s): Fears, Terrell W.
• Application Number:
  US09/141,335
• Time in Patent Office: 733 Days
• Field of Search: 365/106, 365/120, 365/124, 365/127
• US Class Current: 365/124
• CPC Class Codes: G02B 19/0028 refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• CPC Class Codes: G02B 19/0057 in the form of a laser diode array, e.g. laser diode bar semiconductor laser arrays with beam combining arrangement H01S5/4012
• CPC Class Codes: G02B 19/0066 in the form of an LED array
• CPC Class Codes: G02B 19/0085 for use with both a detector and a source , e.g. in a transceiver, G02B19/009, G02B19/0095 take precedence
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G11C 13/04 using optical elements ; using other beam accessed elements, e.g. electron or ion beam
• CPC Class Codes: G11C 7/005 with combined beam-and individual cell access

Abstract

A compact optical memory is disclosed in which data are stored in an optical data layer capable of selectively altering light such as by changeable transmissivity, reflectivity, polarization, and/or phase. The data are illuminated by controllable light sources and an array of multi-surface diffractive imaging lenslets cause a data image to be projected onto an array of light sensors by multiple reflections of, hence folding the image rays, by surfaces that both reflect and optically modify the light rays to redirect them onto the sensor array. Data are organized into an annular array of patches (called pages). By selective illumination of each data page, one of the lenslets images the selected data page onto a central image plane where the sensor array is located. Light in the data image pattern strikes different ones of the arrayed light sensors, thereby outputting information in the form of electrical data signals.

Claims

1. A collector for retrieving optical data from a record having different data regions illuminated by selectable light sources, the collector comprising:

a sensor having an array of light sensing elements arranged at a common image surface disposed at a predetermined optical path distance from the record for sensing data from light in an image of data from the illuminated record; and

an optical imaging system having a plurality of optical reflective surfaces disposed in substantially opposing relationship, said optical imaging system disposed in said optical path between the record and said sensor and fixed in an opposing relationship to said sensor relative to the record.

2. The optical data system of claim 1, wherein said plurality of optical reflective surfaces are configured in said optical path to cause three reflections of data image rays.

3. The optical data system of claim 2, wherein at least one of said plurality of optical reflective surfaces is formed with a contoured mirror.

4. The optical data system of claim 3, wherein said optical reflective surface formed with a contoured mirror has an optical prescription that includes a combination of spherical and aspherical attributes.

5. The optical data system of claim 4, wherein one of said reflective optical surfaces is proximate the record, and said sensor array is substantially co-axial with said optical imaging system and proximate to the record opposite said optical imaging system.

6. An optical data system comprising:

an optical data object storing data as light altering characteristics;

a controllable light source for selectively illuminating different data regions of said optical data object;

a data imaging lens system having at least a first surface arranged in such proximity to and in optical registration with said data regions on said optical data object such that an image resolving power of said data imaging lens is substantially uniform over the field of view of each said data region;

a sensor having an array of juxtaposed light sensing elements arranged at a common image surface disposed at a predetermined optical path distance from said object for sensing data from light in an image of said data corresponding to one of said selectively illuminated data regions;

a plurality of optical reflective surfaces disposed at a predetermined distance from a side of said object opposite said sensor and in an optical path between said data imaging lens and said common image surface for multiple reflection and redirection of said image of data onto said sensor at said common image surface; and

a data output circuit coupled to said sensor for outputting signals representative of said data.

7. The optical data system of claim 6, wherein at least one of said plurality of optical reflective surfaces is formed with a contoured mirror.

8. The optical data system of claim 7, wherein said plurality of optical reflective surfaces are configured in said optical path to cause three reflections of data image rays.

9. An optical data system comprising:

an optical data object storing data as light altering characteristics in a plurality of data regions;

a controllable light source for selectively illuminating different ones of said data regions;

a data imaging lens arranged in such proximity to and in optical registration with said data regions such that an image resolving power of said data imaging lens is substantially uniform over the field of view of each said data region;

a sensor having an array of juxtaposed light sensing elements arranged at a common image surface disposed at a predetermined distance from said optical data object for sensing data from light in an image of said data corresponding to one of said selectively illuminated data regions;

an image collector including first and second reflective optical surfaces disposed in substantially opposing relation to an optical path between said data imaging lens and said common image surface for multiple reflection and redirection of said image of data onto said sensor at said common image surface; and

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

10. The optical data system of claim 9, said first reflective optical surface further comprising:

an annular reflective optical surface comprising an optical prescription for selectively redirecting data image bits within each data region onto said second reflective optical surface; and

an inner reflective optical surface positioned central of said annular reflective optical surface, said inner reflective optical surface comprising an optical prescription for selectively redirecting said data image bits reflected from said second reflective optical surface onto said common image surface.

11. The optical data system of claim 10, wherein said prescription of said annular reflective optical surface is different from said prescription of said inner reflective optical surface.

12. The optical data system of claim 10, wherein said first reflective optical surface has a non-planar contour to provide each said prescription.

13. The optical data system of claim 9, wherein said first reflective optical surface has an optical prescription that includes a combination of spherical and aspherical attributes.

14. The optical data system of claim 9, wherein said second reflective optical surface is substantially parallel with and spaced away from said data object, and said sensor array is substantially co-axial with said image collector and substantially parallel with and spaced away from said data object opposite said image collector.

15. The optical data system of claim 9, wherein said data regions are arrayed in an annular planar pattern on said optical data object that defines a center open region, and wherein said optical data object is removably disposed relative to said light source and said image collector so that said second reflective optical surface is located in a plane generally parallel to said data regions in substantial registration with said center of said optical data object.

16. The optical data system of claim 9, further comprising at least a first diffractive surface interposed between said light source and said data object to tilt rays that form the data image radially inwardly toward a center of the system.

17. The optical data system of claim 9, wherein said first and second reflective optical surfaces are configured to cause the image rays to reflect at least thrice before striking said sensor array.

18. The optical data system of claim 9, wherein:

said optical data object comprises a data layer for storing said data and at least a first imaging lens surface fixed in a cartridge;

said first and second reflective surfaces are disposed on an optically transparent collector positioned in facing relation to said cartridge; and

said sensor array is disposed substantially co-axially with said image collector and opposite said cartridge.

19. A method for retrieving data from an optical data object having data stored in different data regions as light altering characteristics, the method comprising the steps of:

selectively illuminating different data regions of the optical data object;

projecting data image bits within each data region onto a common surface of an image collector;

multiply reflecting and redirecting said data image bits within said image collector;

disposing a sensor at a predetermined distance from the optical data object, said sensor having an array of light sensing elements arranged at a common image surface;

intercepting said reflected and redirected data image bits on said common image surface of said sensor;

sensing data from light in an image of said data image bits corresponding to one of the selectively illuminated data regions;

converting said sensed data into data signals representing said data image bits; and

outputting said data signals.

20. The method of claim 19, wherein said multiply reflecting and redirecting step includes the steps of:

intercepting said projected data image bits at an annular portion of a reflective optical surface comprising an optical prescription for selectively redirecting said data image bits within each data region downwardly and radially inwardly toward an opposing reflective optical surface;

reflecting and redirecting said data image bits upwardly and radially inwardly toward a reflective surface inner of said annular portion; and

reflecting and redirecting said data image bits downwardly and radially inwardly toward said common image surface of said sensor.