Image display dissolve control

Claim 2

Apparatus for controlling image intensity and image change timing of images displayed by a plurality of image display devices, said apparatus comprising: voltage-integrating means for producing at the output thereof a first control voltage the magnitude of which varies as the time integral of a voltage applied to the input thereof; means for applying to the input of said voltage-integrating means a substantially constant voltage of a controlled polarity and of a preselected magnitude which represents a preselected image intensity rate of change; inverter means interconnected with said voltage-integrating means for producing at the output of the inverter means a second control voltage the magnitude of which varies as an inverse function of said first control voltage; first control means, interconnected with said voltageintegrating means, for causing image changing and varying image intensity of images produced by a least one image display device in accordance with said first control voltage; and second control means, interconnected with said inverter means, for controlling image changing and varying image intensity of images produced by a least one further image display device in accordance with said second control voltage whereby image intensity and image change timing of images displayed by said devices are coordinated to cause smoothly dissolving alternating successive display of images.

Claim 3

Apparatus as set forth in claim 1, wherein said voltage-integrating means comprises a differential amplifier and a capacitance interconnected in parallel with a diode between an inverting input terminal and an output terminal of said amplifier, thereby to provide at the output terminal of the amplifier said first control voltage which varies as a ramp function of the magnitude and polarity of said constant voltage applied to the input terminal of said amplifier.

Claim 4

Apparatus as set forth in claim 2, wherein said inverter means comprises a further differential amplifier having an inverting input interconnected with the output terminal of the first-said amplifier, the output terminal of said further amplifier providing said second control voltage which thereby varies as an inverse ramp function of said first control voltage.

Claim 5

Apparatus as set forth in claim 1, wherein said first and second control means are operative to Vary image intensity in direct proportion to said first and second control voltages, respectively.

Claim 6

Apparatus as set forth in claim 4, wherein said first and second control means each comprises: a triggerable semiconductor current switching device including a triggering terminal and a pair of main terminals connectable in a circuit including an a.c. power source with electrically energizable image illumination means of an image display device; and means interconnected with said triggering terminal for triggering said switching device and operative to vary the phase of the triggering as a function of the respective control voltage, thereby to vary the level of energization of said illumination means.

Claim 7

Apparatus as set forth in claim 5, wherein the triggering means comprises a unijunction transistor having a base terminal connected in a circuit with said triggering terminal and an emitter terminal interconnected with a capacitance, the respective control voltage being applied across said capacitance.

Claim 8

Apparatus as set forth in claim 4, wherein said first and second control means are operative to cause image changing at predetermined magnitudes of said first and second control voltages, respectively.

Claim 9

Apparatus as set forth in claim 7, wherein said first and second control means each comprises: a triggerable semiconductor current switching device including a triggering terminal and a pair of main terminals connectible in a circuit with electrically energizable image changing means of an image display device, said switching device becoming conductive when triggered to cause energization of said image changing means; and means for triggering said switching device including a transistor whose state of conduction is controlled by the magnitude of the respective control voltage and which changes at a predetermined magnitude of the respective control voltage, and circuit means responsive to a change in the state of conduction of said transistor for delivering a triggering pulse to said triggering terminal for triggering said switching device.

Claim 10

Apparatus as set forth in claim 1, wherein the voltage-applying means comprises means for reversing the polarity of said constant voltage in response to a momentary control signal input, said first control voltage increasing for one polarity of said constant voltage and decreasing for the opposite polarity, whereby a reversal of polarity of said constant voltage causes said first and second control means to respectively vary image intensity in an opposite direction.

Claim 11

Apparatus as set forth in claim 9, wherein the voltage-applying means further comprises multiplexer means for delivering said constant voltage, said preselected magnitude thereof being dependent upon the presence of control signals at a plurality of inputs of said multiplexer means.

Claim 12

Apparatus as set forth in claim 10, wherein the voltage-applying means further comprises means for continuously generating said control signals in response to respective momentary control signal inputs, each of said control signals representing a stored preselected image intensity rate of change.

Claim 13

Apparatus as set forth in claim 11, wherein said multiplexer means comprises a plurality of voltage-controlled semiconductor devices each having a control terminal and a pair of main terminals between which conductivity is controlled by the presence of a control signal at the control terminal of the device, means for applying different predetermined voltages across respective ones of said pairs of main terminals, conductivity between a pair of main terminals being established to apply the predetermined voltage to the input of said voltage-integrating means whenever a respective control signal is present.

Claim 14

Apparatus as set forth in claim 12, wherein each of said voltage-controlled semiconductor devices comprises a field effect transistor, said main terminals being constituted by the source and drain terminals of said transistor.

Claim 15

ApparaTus as set forth in claim 12, wherein the polarity reversing means comprises a toggle flip-flop having one of its outputs interconnected with a main terminal of each of said pairs of main terminals, the polarity of the voltage appearing at said one of the flip-flop outputs reversing in response to a momentary control signal input to the trigger input of said flip-flop.

Claim 16

Apparatus as set forth in claim 14, wherein the means for applying different preselected voltages comprises voltage divider means interconnected with said one of the flip-flop outputs for dividing the voltage at said one of the outputs to said different preselected voltages.

Claim 17

Apparatus as set forth in claim 15, including diode means interconnected with said one of the flip-flop outputs for clamping the voltage appearing at said one output to a constant absolute value.

Claim 18

Apparatus as set forth in claim 14, wherein said means for continuously generating said control signals comprises a plurality of set-reset flip-flops, one for each of said voltage-controlled semiconductor devices, a corresponding one of the outputs of each of said set-reset flip-flops being connected in a circuit with a control signal input terminal of a respective one of said semiconductor devices.

Claim 19

Apparatus as set forth in claim 17, including a control signal input terminal corresponding to each of the set-reset flip-flops and logic gate means for coupling a momentary control signal input at any one of said terminals to cause setting of the respective set-reset flip-flop corresponding with said one terminal and resetting of set-reset flip-flops other than said respective flip-flops.

Claim 20

Apparatus for controlling image intensity and image change timing of images displayed by first and second image display devices, both of said image display devices being adapted to display images on a single screen space, said apparatus comprising: means for generating a substantially constant voltage of a magnitude which represents a preselected image intensity rate of change; means, interconnected with the constant voltage generating means, for reversing the polarity of said constant voltage at preselected image change timing intervals; a ramp generator interconnected with the constant voltage generating means and having an input to which said constant voltage is applied, for producing a first control voltage the magnitude of which varies as a ramp function of both the magnitude and polarity of said constant voltage; inverter means interconnected with said ramp generator for producing a second control voltage the magnitude of which varies as an inverse ramp function of said first control voltage; first image intensity control means, interconnected with said ramp generator, for varying the energization of image illumination means of said first image display device in accordance with said first control voltage, thereby to vary image intensity; a first voltage-responsive switching circuit interconnected with said ramp generator and operative to energize image-changing means of said first image display device at a predetermined magnitude of said first control voltage; second image intensity control means, interconnected with said inverter means, for varying the energization of image illumination means of said second image display device in accordance with said second control voltage, thereby to vary image intensity; and a second voltage-responsive switching circuit interconnected with said inverter means and operative to energize image-changing means of said second image display device at a predetermined magnitude of said second control voltage whereby image intensity and image change timing of images displayed by said devices are coordinated to cause alternating successive display of images by said devices which images smoothly dissolve one into another.

Claim 21

Apparatus for controlling image intensity and image change timing of images displayed by first and second image display devices, both of said image display devices being adapted to display images on a single screen space, said apparatus comprising: means for generating a substantially constant voltage of a magnitude which represents a preselected image intensity rate of change; means, interconnected with the constant voltage generating means, for reversing the polarity of said constant voltage at preselected image change timing intervals; a ramp generator interconnected with the constant voltage generating means and having an input to which said constant voltage is applied, for producing a first control voltage the magnitude of which varies as a ramp function of both the magnitude and polarity of said constant voltage; inverter means interconnected with said ramp generator for producing a second control voltage the magnitude of which varies as an inverse ramp function of said first control voltage; first image intensity control means, interconnected with said ramp generator, for varying the energization of image illumination means of said first image display device in accordance with said first control voltage, thereby to vary image intensity; a first voltage-responsive switching circuit interconnected with said ramp generator and operative to energize image-changing means of said first image display device at a predetermined magnitude of said first control voltage; second image intensity control means, interconnected with said inverter means, for varying the energization of image illumination means of said second image display device in accordance with said second control voltage, thereby to vary image intensity; and a second voltage-responsive switching circuit interconnected with said inverter means and operative to energize image-changing means of said second image display device at a predetermined magnitude of said second control voltage whereby image intensity and image change timing of images displayed by said devices are coordinated to cause alternating successive display of images by said devices which images smoothly dissolve one into another.