MOTION PICTURE FADE-OUT AND FADE-IN ARRANGEMENT USING A FLUID CRYSTAL

• US 3,815,982 A
• Filed: 11/13/1972
• Issued: 06/11/1974
• Est. Priority Date: 11/13/1971
• Status: Expired due to Term

• Current Assignee: Eduard Wagensonner
• Original Assignee: Eduard Wagensonner
• Inventors: Wagensonner, Eduard
• Primary Examiner(s): Hayes, Monroe H.
• Application Number:
  US05/305,691
• Time in Patent Office: 575 Days
• Field of Search: 352/91,217 95/53EC 350/16LC
• US Class Current: 352/91.00R
• CPC Class Codes: G03B 19/26 with fade-in and fade-out effects
• CPC Class Codes: G03B 7/085 for control of aperture
• CPC Class Codes: G03B 9/08 Shutters

Abstract

A fluid crystal whose light transmissivity changes as a function of applied voltage is positioned in the path of the light from the objective lens to the film of the camera. Electrical contacts of the fluid crystal are connected to the output and the direction input of an operational amplifier which has an associated timing circuit. Fade-in and fade-out are produced by activation of a switch which alternatively connects the inverting input of the operational amplifier, through a timing resistor, to a battery or to the direct input of one operational amplifier. The fluid crystal is positioned following a standard exposure control circuit in the direction of light propagation towards the film, so that the operation of the exposure control circuit is not affected by the presence of this crystal.

Claims

1. In a motion picture camera having film means and objective lens means, and wherein light travels along a predetermined path from said objective lens means to said film means, a fade-in and fade-out arrangement comprising, in combination, fluid crystal means positioned in said predetermined path of said light, and having a light transmissivity varying in dependence upon an electrical signal applied thereto;

and timing circuit means connected to said fluid crystal means for furnishing a timing signal varying as a predetermined function of time upon external activation, said timing signal constituting said electrical signal, said timing circuit means comprising a source of electrical energy, operational amplifier means having a direct input, an inverting input and an output, a resistor connected to said inverting input, a capacitor connected between said output and said inverting input, and externally operable switch means for connecting said resistor to said source of electrical energy when in a first state and for connecting said resistor to said direct input of said operational amplifier means when in the second state.

2. A motion picture camera as set forth in claim 1, wherein said fluid crystal means has first and second electrical contact means;

further comprising first connecting means for connecting said first electrical contact means to said output of said operational amplifier means and said second electrical contract means to said direct input of said operational amplifier means.

3. A motion picture camera as set forth in claim 2, wherein said source of electrical energy comprises battery means having a battery tap;

further comprising second connecting means for connecting said battery tap to said direct input of said operational amplifier means.

4. A motion picture camera as set forth in claim 2, wherein said first timing element comprises a resistor;

and wherein said second timing element comprises a capacitor.

5. A motion picture camera as set forth in claim 1, wherein said light transmissivity of said fluid crystal means decreases in response to increasing voltages applied thereto.

6. A motion picture camera as set forth in claim 1, further comprising exposure control means positioned in said predetermined path of said light, and wherein said fluid crystal means is positioned in said predetermined path following said exposure control means in the direction of travel of said light.

7. In a motion picture camera having film means and objective lens means, and wherein light travels along a predetermined path from said objective lens means to said film means, a fade-in and fade-out arrangement comprising, in combination, fluid crystal means positioned in said predetermined path of said light, said fluid crystal means having electrical contact means and having a light transmissivity varying in dependence upon variations of an electrical signal applied to said electrical contact means;

timing circuit means having an output connected to said electrical contact means for furnishing said electrical signal thereto, said timing circuit means having a first and second circuit element for controlling the rate of change of said electrical signal in response to a fade-in signal and a fade-out signal applied to said timing circuit means; and

switch means connected to said timing circuit means and externally operable from a first to a second state and from said second to said first state for furnishing, respectively, said fade-in and fade-out signal.

8. In a motion picture camera having film means and objective lens means, and wherein light travels along a predetermined path from said objective lens means to said film means, a fade-in and fade-out arrangement, comprising, in combination, fluid crystal means positioned in said predetermined path of said light, said fluid crystal means having a light transmissivity varying in correspondence to variations in an electrical signal applied thereto;

amplifier means connected to said fluid crystal means for furnishing said electrical signal thereto;

first and second circuit element connected to said amplifier means in such a manner that said electrical signal varies gradually as a predetermined function of time in response to a fade-in and fade-out signal; and

switch means connected to said amplifier means for furnishing said fade-in and fade-out signal in response to external activation.

9. A motion picture camera as set forth in claim 8, further comprising a source of electrical energy;

wherein said amplifier means comprises operational amplifier means having a direct input, an inverting input and an output;

wherein said first circuit element is interconnected between said switch means and said inverting input of said operational amplifier means;

wherein said second circuit elemnt is interconnected between said output and said inverting input of said operational amplifier means; and

wherein said switch means have a first state connecting said first circuit element to said source of electrical energy and a second state connecting said first circuit element to said direct input of said operational amplifier means.

10. In a motion picture camera having film means and objective lens means, and wherein light travels along a predetermined path from said objective lens means to said film means, a fade-in and fade-out arrangement, comprising, in combination, fluid crystal means positioned in said predetermined path of said light, and having a light transmissivity varying in dependence upon an electrical signal applied thereto;

and timing circuit means including a resistor and a capacitor, connected to said fluid crystal means, for furnishing a timing signal varying as a predetermined function of time upon external activation, said timing signal constituting said electrical signal.