Spectrally filtered lens producing plural f-numbers with different spectral characteristics

• US 4,687,926 A
• Filed: 12/20/1984
• Issued: 08/18/1987
• Est. Priority Date: 12/20/1984
• Status: Expired due to Term

• Current Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Original Assignee: Polaroid Corporation (PLR IP Holdings LLC)
• Inventors: Plummer, William T.
• Primary Examiner(s): Laroche, Eugene R.
• Assistant Examiner(s): Mis, David
• Application Number:
  US06/684,094
• Time in Patent Office: 971 Days
• Field of Search: 250/216, 250/226, 250/237 R, 350/463, 350/474, 350/475, 350/311, 350/314, 350/315, 350/317, 351/165, 358/55, 354/482
• US Class Current: 250/226
• CPC Class Codes: G01J 1/04 Optical or mechanical part supplementary adjustable parts
• CPC Class Codes: G01J 1/0411 using focussing or collimating elements, i.e. lenses or mirrors; Aberration correction
• CPC Class Codes: G01J 1/0437 using masks, aperture plates, spatial light modulators, spatial filters, e.g. reflective filters
• CPC Class Codes: G01J 1/0492 using at least two different filters

Abstract

A photoresponsive apparatus is disclosed which includes a photoresponsive device that provides an output or response having a characteristic which varies as a function of the radiant power and wavelength incident on a photoresponsive surface thereof. Included is a spectral filtering means associated with an optical assembly so as to provide the assembly with different f-number zones for each of the respectively different proportionalities of wavelengths such that the spectral composition of incident radiation reaching the surface is controlled by the spectral filtering means to effect a desired change in the response of the photoresponsive device.

Claims

1. Apparatus comprising:

a photoresponsive device which provides an output varying as a function of the spectral composition of radiation incident thereon;

an optical assembly structured and arranged to collect scene radiation from a given field of view and direct it onto said photoresponsive device; and

,

spectral filtering means positioned substantially at an aperture stop location of said optical assembly for altering the spectral composition of radiation passing through said optical assembly into at least two spectrally filtered zones having different spectral compositions and different f/numbers and which spectral compositions are then simultaneously directed onto said photoresponsive device by said optical assembly, whereby the spectral composition of radiation reaching said photosensitive device is controlled by said spectral filtering means to effect a desired change in the output of said photoresponsive device.

2. The apparatus of claim 1 including a pair of blades operative to define a scanning radiation transmitting aperture adjacent said aperture stop location and structured and arranged so that a first portion of said aperture defines one of said spectral zones and a second portion of said aperture defines a second of said spectral zones.

3. The apparatus of claim 2 wherein said one spectral zone is unfiltered and said second spectral zone comprises a spectral filter.

4. The apparatus of claim 3 wherein said spectral filter is a blue wavelength pass filter.

5. The apparatus of claim 4 wherein said blue wavelength pass filter is positioned to encircle said unfiltered zone.

6. The apparatus of claim 1 wherein one of said spectral zones is unfiltered and a second of said spectral zones consists of a spectral filter.

7. The apparatus of claim 6 wherein said spectral filter is positioned to encircle said unfiltered spectral zone.

8. The apparatus of claim 6 wherein said spectral filter is a blue wavelength pass filter.

9. A photoresponsive apparatus comprising:

a photoresponsive device which provides an output having a characteristic which varies as a function of the radiant power and wavelength incident on a photoresponsive surface thereof;

an optical assembly structured and arranged in relationship to said device and which collects both coherent and incoherent scene radiation from a given field of view and directs it to said photoresponsive surface; and

,

spectral filtering means associated with the optical assembly for altering simultaneously the composition of coherent and incoherent spectral energy incident on said photoresponsive surface into at least two spatially separated and spectrally filtered zones, each one of which transmits respectively different proportionalities of wavelengths, said filtering means being positioned substantially at an aperture stop location of said optical assembly, whereby said optical assembly is provided with different f-numbers for each of the respectively different proportionalities of wavelengths such that the spectral composition of incident radiation reaching said surface is controlled by said zones to effect a desired change in the resultant output characteristic of said photoresponsive device.

10. The apparatus of claim 9 wherein spectral filtering means includes at least one spectral filter stationarily positioned at the aperture stop, said filter being annular in configuration and which defines the bounds of a non-filtered first or central zone and a second or surrounding zone which surrounding zone includes said annular filter and said central zone.

11. The apparatus of claim 10 wherein said spectral filter transmits substantially exclusively blue wavelengths, while a non-filtered central zone transmits the visual spectral frequencies including blue wavelengths, whereby said second zone has an f-number different from said central zone, such that the red and green wavelengths transmitted through said central zone will in general produce a sharper optical image than the blue wavelengths transmitted through both of said zones.

12. The apparatus of claim 10 wherein said optical assembly includes a portion which is well corrected for aberrations for said central zone and is less well corrected for that portion of said second zone which surrounds said central zone.

13. The apparatus of claim 9 wherein said spectral filtering means includes a shutter blade assembly movable between operative and inoperative positions and having an aperture passing in overlying relationship to said photoresponsive surface and being at an aperture stop position, said filtering means including a spectral filter associated with said blade assembly such that during movement of said blade assembly said filter create a plurality of spectral zones, each of which provides said optical assembly with different f-numbers for each of said spectral zones.

14. The apparatus of claim 9 wherein said spectral filtering means includes a scanning shutter arrangement having a pair of counter reciprocating blades, each of said blades including an aperture and having a spectral filter associated with said apertures, each of said filters being constructed and arranged to cooperate with the other of said apertures so that during counter-reciprocating movement of said blades, said filters cooperate to define a pair of spectral zones, said pair of zones including a generally central first zone and second zone which includes a portion which surrounds said first zone and is inclusive thereof.

15. The apparatus of claim 14 wherein said spectral filters cooperate so that said central zone is not spectrally filtered and said surrounding portion is spectrally filtered and forms a generally annular shape.

16. The apparatus of claim 15 wherein said spectral filter transmits substantially exclusively blue wavelengths.

17. An image enhancing apparatus comprising:

an array of charge-couple devices which provide an output having a characteristic which varies as a function of the radiant power and wavelength incident on photoresponsive surfaces thereof;

an optical assembly structured and arranged in relationship to said device and which collects both coherent and incoherent scene radiation from a given field of view and directs it to said photoresponsive surfaces; and

,

spectral filtering means for filtering simultaneously the composition of coherent and incoherent spectral energy incident on said surfaces into at least two spectrally filtered zones, each one of which transmits respectively different groups of wavelengths, said filtering means being positioned substantially at an aperture stop location of said optical assembly whereby said optical assembly is provided with different f-numbers for each of the respectively different groups of wavelengths such that the spectral composition of incident radiation on said surfaces is controlled by said zones to effect a desired change in the output characteristics of said device.

18. A method of controlling scene radiation incident on a photoresponsive device as a function of the spectral composition of radiation incident thereon;

comprising;

positioning an optical assembly structured and arranged to collect scene radiation from a given field of view and direct it onto said photoresponsive device; and

,

positioning spectral filtering means positioned substantially at an aperture stop location of said optical assembly for altering the spectral composition of radiation passing through the optical assembly into at least two spectrally filtered zones having different spectral compositions and different f/numbers and which are then simultaneously directed onto the photoresponsive device by the optical assembly, whereby the spectral composition of radiation reaching the photosensitive device is controlled by said spectral filtering means to effect a desired change in the output of the photoresponsive device.

19. A method of changing an output characteristic of a photoresponsive device which provides an output having a characteristic which varies as a function of the radiant power and wavelength incident on a photoresponsive surface thereof comprising the steps of:

positioning an optical assembly structured and arranged in relationship to said device so as to collect both coherent and incoherent scene radiation from a given field of view and direct it to said photoresponsive surface; and

,

positioning a spectral filtering arrangement at an aperture stop position of the optical assembly for altering simultaneously the composition of coherent and incoherent spectral energy incident on said photoresponsive surface into at least two (spectral) spectrally filtered zones, each one of which transmits different proportionalities of wavelengths and which provide the optical assembly with correspondingly different f-numbers so as to change the spectral composition incident on the surface so as to effect a desired change in the output characteristics of the photoresponsive device.

20. The method of claim 19 wherein said positioning of said spectral filter includes placing a generally annular spectral filter at said aperture stop position, whereby said filter defines a non-filtered central zone and a second zone which surrounds the central zone and which is spectrally filtered, the second zone also being inclusive of the central zone.

21. The method of claim 20 wherein the spectral filter transmits substantially exclusively blue wavelengths and the central zone transmits substantially all spectral wavelengths such that the central zone transmits red, blue and green wavelengths which tend to be in focus and the blue wavelengths passing the surrounding portion of the second zone are slightly out-of-focus, whereby the signals generated by the out-of-focus blue wavelengths do not affect the human visual response.

22. The method of claim 19 wherein said positioning step includes placing a spectral filter having a predetermined configuration in association with at least one aperture of a movable shutter blade arrangement, said placing step includes placing said filter and said blade for movement along a path which coincides at the aperture stop location of the optical assembly, whereby said filter when passing in overlying relationship to said device defining a non-filtered central zone and a second zone which surrounds the central zone and which is spectrally filtered, the second zone being inclusive of the central zone.

23. The method of claim 22 wherein the spectral filter transmits substantially exclusively blue wavelengths and the central zone transmits substantially all spectral wavelengths such that the central zone transmits red, blue and green wavelengths which tend to form a sharper optical image and the blue wavelengths passing the surrounding portion of the second zone may be slightly blurred, whereby the signals generated by the unsharp blue wavelengths do not affect the human visual response.