Electro-optical control of light attenuation in the optical path of a camera
First Claim
1. In a camera comprising a taking lens for focusing light entering said camera, an optical sensor for receiving said light entering said camera, an iris, located between said taking lens and said optical sensor, said iris having an adjustable diameter aperture for restricting the amount of said light entering said camera and controlling depth of field, an apparatus for compensating for an increase or decrease in the amount of light entering said camera when said aperture diameter of said iris is changed to adjust said depth of field, said apparatus comprising:
- an electrochromic neutral density (ND) filter, located between said iris and said taking lens; and
ND control means coupled to said ND filter for applying a ND control current to said ND filter, said ND filter having a light transmission characteristic that is varied by applying said ND control current to said ND filter, such that the amount of light reaching said optical sensor may be maintained constant by darkening or lightening said ND filter.
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Accused Products
Abstract
A camera which has an electrochromic neutral density filter. The neutral density filter is placed in the optical path of the camera. The filter changes the amount of light which may pass through it when a voltage is applied thereby regulating the amount of light which may enter the camera. By controlling the amount of light which passes through the electrochromic filter, the camera operator can control incoming light to maintain desired density (depth of field). In another embodiment, a color video camera has a color separator which separates the light into red, green and blue components. Electrochromic filters are placed between the color separator and red and blue light sensors of the camera to control the amount of light reaching the red and blue sensors. By controlling the amount of light which passes through the electrochromic filters, the camera operator can control incoming light to correct color.
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Citations
65 Claims
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1. In a camera comprising a taking lens for focusing light entering said camera, an optical sensor for receiving said light entering said camera, an iris, located between said taking lens and said optical sensor, said iris having an adjustable diameter aperture for restricting the amount of said light entering said camera and controlling depth of field, an apparatus for compensating for an increase or decrease in the amount of light entering said camera when said aperture diameter of said iris is changed to adjust said depth of field, said apparatus comprising:
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an electrochromic neutral density (ND) filter, located between said iris and said taking lens; and ND control means coupled to said ND filter for applying a ND control current to said ND filter, said ND filter having a light transmission characteristic that is varied by applying said ND control current to said ND filter, such that the amount of light reaching said optical sensor may be maintained constant by darkening or lightening said ND filter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. In a color video camera comprising a taking lens for focusing light entering said camera, an optical separator for separating said light entering said camera into red, green and blue light beams, a red sensor which receives said red light beam from said optical separator and converts said red light beam into an R video signal, a green sensor which receives said green light beam from said optical separator and converts said green light beam into a G video signal, a blue sensor which receives said blue light beam from said optical separator and converts said blue light beam into a B video signal, an apparatus for providing color correction comprising:
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an electrochromic red filter, located between said optical separator and said red sensor; red light control means for applying a red light control current to said red filter, said red light control means coupled to said red filter, said red filter having a light transmission characteristic that is varied by applying said red light control current to said red light filter; an electrochromic blue filter, located between said optical separator and said blue sensor; blue light control means for applying a blue light control current to said blue filter, said blue light control means coupled to said blue filter, said blue filter having a light transmission characteristic that is varied by applying said blue light control current to said blue light filter; such that the amount of red and blue light reaching said respective red and blue sensors may be adjusted by darkening or lightening said red and blue filters to compensate for a respective increase or decrease in the amount of light entering said color video camera, thereby providing color correction. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21)
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22. In a color video camera comprising a taking lens for focusing light entering said camera, an optical separator for separating said light entering said camera into red, green and blue light beams, an iris, located between said taking lens and said optical separator, said iris having an adjustable diameter aperture for restricting the amount of said light entering said camera and controlling depth of field, a red sensor which receives said red light beam from said optical separator and converts said red light beam into an R video signal, a green sensor which receives said green light beam from said optical separator and converts said green light beam into a G video signal, a blue sensor which receives said blue light beam from said optical separator and converts said blue light beam into a B video signal, an apparatus for controlling the amount of light reaching said red, green and blue sensors comprising:
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an electrochromic neutral density (ND) filter, located between said iris and said optical separator; ND control means for applying a ND control current to said ND filter, said ND control means coupled to said ND filter, said ND filter having a light transmission characteristic that is varied by applying said ND control current to said ND filter such that the amount of light reaching said optical separator may be maintained constant by darkening or lightening said ND filter, whereby an increase or decrease in the amount of light entering said camera is compensated for when said aperture diameter of said iris is changed to adjust said depth of field; an electrochromic red filter, located between said optical separator and said red sensor; red light control means for applying a red light control current to said red filter, said red light control means coupled to said red filter, said red filter having a light transmission characteristic that is varied by applying said red light control current to said red light filter; an electrochromic blue filter, located between said optical separator and said blue sensor; blue light control means for applying a blue light control current to said blue filter, said blue light control means coupled to said blue filter, said blue filter having a light transmission characteristic that is varied by applying said blue light control current to said blue light filter; such that the amount of red and blue light reaching said respective red and blue sensors may be adjusted by darkening or lightening said red and blue filters to compensate for a respective increase or decrease in the amount of light entering said camera, thereby providing color correction. - View Dependent Claims (23, 24, 25)
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26. In a camera comprising a taking lens for focusing light entering said camera, an optical sensor for receiving said light entering said camera, an iris, located between said taking lens and said optical sensor, said iris having an adjustable diameter aperture for restricting the amount of said light entering said camera and controlling depth of field, a method for controlling the amount of light reaching said sensor comprising the steps of:
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providing an electrochromic neutral density (ND) filter between said iris and said optical sensor, said ND filter having a light transmission characteristic that is varied by applying a ND control current to said ND filter; if the diameter of said aperture of said iris is increased to decrease said depth of field, applying said ND control current to said ND filter to darken said ND filter and thereby decrease the amount of light reaching said optical sensor; if the diameter of said aperture of said iris is decreased to increase said depth of field, applying said ND control current to said ND filter to lighten said ND filter and thereby increase the amount of light reaching said optical sensor; such that the amount of light reaching said optical sensor may be maintained constant by darkening or lightening said ND filter as the diameter of the aperture increases or decreases, whereby an increase or decrease in the amount of light entering said camera is compensated for when said aperture diameter of said iris is changed to adjust said depth of field. - View Dependent Claims (27, 28, 29, 30, 31, 32, 33, 34)
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35. A camera comprising:
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a taking lens for focusing light entering said camera; an optical sensor for receiving said light entering said camera and for converting said light into a video signal; an iris, located between said taking lens and said optical sensor, said iris having an adjustable diameter aperture for restricting the amount of said light entering said camera and controlling depth of field; and an apparatus for compensating for an increase or decrease in the amount of light entering said camera when said aperture diameter of said iris is changed to adjust said depth of field, said apparatus comprising; an electrochromic neutral density (ND) filter, located between said iris and said optical sensor; and ND control means coupled to said ND filter for applying a ND control current to said ND filter, said ND filter having a light transmission characteristic that is varied by applying said ND control current to said ND filter, such that the amount of light reaching said optical sensor may be maintained constant by darkening or lightening said ND filter. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. In a camera comprising a taking lens for focusing light entering said camera, an optical sensor for receiving said light entering said camera, an iris, located between said taking lens and said optical sensor, said iris having an adjustable diameter aperture for restricting the amount of said light entering said camera and controlling depth of field, an apparatus for compensating for an increase or decrease in the amount of light entering said camera when said aperture diameter of said iris is changed to adjust said depth of field, said apparatus comprising:
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an electrochromic neutral density (ND) filter, located between said iris and said optical sensor; and ND control means coupled to said ND filter for applying a ND control current to said ND filter, said ND filter having a light transmission characteristic that is varied by applying said ND control current to said ND filter, said ND control means comprising a light sensor which measures the amount of light reaching said optical sensor and generates a value to cause the ND filter to proportionately change to maintain constant light output from the ND filter such that an amount of lightening or darkening of said ND filter is controlled automatically by said ND control means and the amount of light reaching said optical sensor may be maintained constant by darkening or lightening said ND filter. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55)
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56. In a camera comprising a taking lens for focusing light entering said camera, an optical sensor for receiving said light entering said camera, an iris, located between said taking lens and said optical sensor, said iris having an adjustable diameter aperture for restricting the amount of said light entering said camera and controlling depth of field, an apparatus for compensating for an increase or decrease in the amount of light entering said camera when said aperture diameter of said iris is changed to adjust said depth of field, said apparatus comprising:
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an electrochromic neutral density (ND) filter, located between said iris and said optical sensor; and ND control means coupled to said ND filter for applying a ND control current to said ND filter, said ND filter having a light transmission characteristic that is varied by applying said ND control current to said ND filter, an amount of lightening or darkening of said ND filter being controlled automatically by said ND control means such that the amount of light reaching said optical sensor may be maintained constant by darkening or lightening said ND filter. ND control means coupled to said ND filter for applying a ND control current to said ND filter, said ND filter having a light transmission characteristic that is varied by applying said ND control current to said ND filter, said ND control means measures the amount said iris is opened or closed and generates a value to cause the ND filter to proportionately change to maintain constant light output from the ND filter such that an amount of lightening or darkening of said ND filter is controlled automatically by said ND control means and the amount of light reaching said optical sensor may be maintained constant by darkening or lightening said ND filter. - View Dependent Claims (57, 58, 59, 60, 61, 62, 63, 64, 65)
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Specification