Increasing fill-factor on pixelated sensors

• US 20060244851A1
• Filed: 05/02/2005
• Published: 11/02/2006
• Est. Priority Date: 05/02/2005
• Status: Active Grant

• Current Assignee: Andrew G. Cartlidge, Daniel B. Bortnick, Gregory Turocy, Himanshu S. Amin
• Original Assignee: Andrew Cartlidge, Daniel Bortnick, Gregory Turocy, Himanshu Amin
• Inventors: Cartlidge, Andrew G.
• Granted Patent: US 7,738,026 B2
• Time in Patent Office: Days
• US Class Current: 348/281
• CPC Class Codes: G02B 5/021 the diffusion taking place at the element's surface, e.g. by means of surface roughening or microprismatic structures

Abstract

Disclosed are systems, devices, and methodologies that facilitate increasing the effective fill-factor of digital sensors. In general, fill-factor relates to the active area or photosensor region of the sensor with respect to the inactive area/deadzone or space between pixels. By increasing the effective fill-factor, transmission of optical information is increased to the sensor while mitigating information loss between pixels. A digital camera may contain a sensor that is responsive to electromagnetic radiation and a coherent scattering medium between the sensor and a lens that diffuses the electromagnetic radiation with respect to the sensor in order to increase the effective fill-factor.

Claims

1. A digital camera, comprising:

an image transfer medium;

a sensor comprising pixels, each pixel comprising a photosensor region and a deadzone, the pixels having a pixel pitch; and

a coherent scattering medium between the image transfer medium and the sensor, the coherent scattering medium operative to propagate a diffusion pattern of electromagnetic radiation to the sensor, the diffusion pattern at the sensor having a size of at least about 10% of a length of the deadzone between photosensor regions of adjacent pixels in a row of pixels and less than about the pixel pitch.

2. The digital camera of claim 1, the coherent scattering medium comprises a hologram.

3. The digital camera of claim 1, the coherent scattering medium is positioned relative to the sensor via the following equation:

Tan(A)=(P−

D)/(2*S), wherein A represents a diffusion half angle, P represents the pixel pitch, S represents a distance between the coherent scattering medium and the sensor, and D represents a size of an image spot as it contacts the coherent scattering medium.

4. The digital camera of claim 1, the coherent scattering medium is positioned relative to the sensor via the following equation:

Tan (A)=(P/2)/S, wherein A represents a diffusion half angle, P represents the pixel pitch, and S represents a distance between the coherent scattering medium and the sensor.

5. The digital camera of claim 1, the coherent scattering medium comprises at least one selected from the group consisting of polyesters, polycarbonates, polyolefins, polymethyl methacrylates, polystyrenes, polyimides, polyesterimides, polyurethanes, polyamides, polyamideimides, epoxy resins, cellulose acetate butyrate, polyacrylates, urethane acrylates, epoxy acrylates, polyester acrylates, sol-gel glass, quartz glass, fluorine doped silica glass, boron doped silica glass, and phosphorus doped silica glass.

6. The digital camera of claim 1, the diffusion pattern at the sensor having a size of at least about 25% of a length of the deadzone between photosensor regions of adjacent pixels in a row of pixels and about 90% or less of the pixel pitch.

7. The digital camera of claim 1, the diffusion pattern having a shape selected from the group consisting of symmetric ovals, asymmetric ovals, ellipses, squares, rectangles, and hexagons.

8. The digital camera of claim 1, the sensor comprising at least one of a CCD sensor, a CMOS sensor, a CID sensor, and a linear scan sensor.

9. The digital camera of claim 1, further comprising a processor and a memory to receive an output from the pixelated sensor array, the processor storing the output in the memory.

10. The digital camera of claim 1, the image transfer medium comprising at least one lens.

11. A mobile telephone comprising the digital camera of claim 1.

12. The digital camera of claim 1, the coherent scattering medium positioned in contact with the sensor.

13. The digital camera of claim 1, an air void present between the coherent scattering medium and the sensor.

14. A digital video camera, comprising

at least one lens;

a sensor comprising pixels, each pixel comprising a photosensor region and a deadzone, the pixels having a pixel pitch; and

a coherent scattering medium between the at least one lens and the sensor, the coherent scattering medium operative to project a diffusion pattern of electromagnetic radiation to the sensor, the diffusion pattern at the sensor having a size of at least about 10% of a length of the deadzone between photosensor regions of adjacent pixels in a column of pixels and less than about the pixel pitch.

15. The digital video camera of claim 14, the diffusion pattern of electromagnetic radiation comprises a uniform distribution of the electromagnetic radiation.

16. The digital video camera of claim 14, the coherent scattering medium comprises an inorganic glass having a thickness of about 0.01 mm or more and about 20 mm or less or an organic polymer having a thickness of about 0.1 micron or more and about 500 microns or less.

17. A method of making a digital camera, comprising:

positioning a coherent scattering medium between an image transfer medium and a sensor, the sensor having a pixel pitch, the coherent scattering medium operative to propagate a diffusion pattern of electromagnetic radiation to the sensor, the diffusion pattern at the sensor having a size less than about the pixel pitch.

18. The method of claim 17, positioning the coherent scattering medium comprises using at least one of equations:

Tan (A)=(P−

D)/(2*S), wherein A represents a diffusion half angle, P represents the pixel pitch, S represents a distance between the coherent scattering medium and the sensor, and D represents a size of an image spot as it contacts the coherent scattering medium; and

Tan (A)=(P/2)/S, wherein A represents a diffusion half angle, P represents the pixel pitch, and S represents a distance between the coherent scattering medium and the sensor.

19. The method of claim 17, S in either equation is about 0.1 micron or more and about 30 mm or less.

20. The method of claim 17, comprising affixing the coherent scattering medium on the sensor.

21. The method of claim 17, comprising suspending the coherent scattering medium to avoid contact with the sensor.