US 6,150,645 A · Radiation control system

Abstract

A control system for a blind microwave radiation tool a workpiece is described. The controlled system automatically tunes the cavity containing the workpiece. The control system automatically controls the temperature of the workpiece according to a predetermined temperature versus time schedule. Control system automatically determines when the workpiece has reached a particular predetermined physical condition. To achieve these results the control system automatically monitors applied power, reflected power or current temperature and automatically controls the microwave cavity volume and shape and launch structure including antennae location, cavity short location, cavity diameter, coupling loop position, etc. in order to maintain the cavity in resonance and to determine when to exit without operator intervention. Control system can run on a small computer or an embedded controller and is useful for automatically curing polyamic acid to polyimide to a predetermined percent cure, processing preimpregnated glass cloth in a continuous manner which can be used in circuit boards and drying and partial curing of web-like materials automatically without operator intervention.

Claims31

Dependent claims

A system for controlling the application of radiation to a workpiece in a cavity comprising:

time tracking means for tracking current times;
means for receiving a forward power signal indicative of the applied intensity of said radiation;
means for receiving a reflected power signal indicative of the reflected intensity of said radiation;
wherein a predetermined .alpha. value is determined by calculating the ratio of the forward power signal received indicative of the applied intensity of said radiation divided by the reflected power signal indicative of the reflected intensity of said radiation received, and wherein a current value of .alpha. corresponds to a current time;
means for receiving a temperature signal indicative of the temperature of said workpiece;
minimizing means for causing .alpha. to be less than a predetermined .alpha. value;
minimizing means in which .alpha. is minimizing by moving a movable launch device, said device being selected from the group consisting of a movable antenna, movable coupling loop, and a movable stub;
and a movable volume, said movable volume being selected from the group consisting of a moving short and a moving sidewall;
temperature control means for producing an intensity signal indicative of the forward power signal indicative of the applied intensity of said radiation to control said temperature to be substantially equal to a desired temperature;
means for determining the physical condition of said workpiece;
means for setting desired temperature based on current physical condition of said workpiece.

8 more elements

A system for controlling the application of radiation to a workpiece in a cavity comprising:

time tracking means for tracking current time;
means for receiving a forward power signal indicative of the applied intensity of said radiation;
means for receiving a reflected power signal indicative of the reflected intensity of said radiation;
wherein a predetermined .alpha. value is determined by calculating the ratio of the received forward power signal indicative of the applied intensity of said radiation divided by the received reflected power signal indicative of the reflected intensity of said radiation, and wherein a current value of .alpha. corresponds to said current time;
means for receiving a temperature signal indicative of the temperature of said workpiece;
.alpha. minimizing means for causing a to be less than a predetermined .alpha. value;
means for producing an intensity signal indicative for each the reflected intensity and the applied intensity of said radiation to control said temperature to be substantially equal to a predetermined temperature;
means for determining when said workpiece has achieved a final predetermined physical condition;
and
means for producing a signal indicative of whether said workpiece has achieved said final predetermined physical condition;
means to vary said predetermined temperature to achieve predetermined physical condition;
said .alpha. minimizing means which produces signals to control the location of a launch device and a variable volume device, comprises:
means for receiving a signal indicative of said current value of .alpha.;
means for generating a position signal indicative of an updated location of one member of the group consisting of said launch device and said variable volume device with respect to the position of said workpiece;
means for transmitting said position signal to said one member of the group consisting of said launch device and said variable volume until said current value of .alpha. is at a local minimum;
when said local minimum is reached, said means for transmitting said position signal transmits said position signal to the other member of the group consisting of said launch device and said variable volume device;
wherein said launch device is in said cavity and is selected from the group consisting of a movable antenna, a movable coupling loop, and a movable stub;
wherein said variable volume device is achieved by one of the group consisting of a moving short, and a moving sidewall;
and
when said current value of .alpha. is less than said predetermined .alpha. value, said current value of .alpha. is minimized;
temperature control means, which controls said temperature to be substantially in agreement with a predetermined temperature versus time schedule, comprises:
temperature hold determining means for producing a temperature hold signal when said temperature is to be held constant in accordance with said schedule and for producing a temperature test signal when said temperature is not to be held constant according to said schedule;
temperature test means for receiving said temperature test signal and for producing a temperature duration signal when said temperature is greater than a next hold temperature according to said schedule and for producing a heating rate determine signal when said temperature is not greater than said next hold temperature;
means for receiving said temperature duration signal and for producing a signal indicative of a temperature hold condition;
means for receiving said signal indicative of a temperature hold condition and for producing an initial time record signal;
means for receiving said initial time record signal and for receiving said temperature hold signal and for producing a temperature hold continue signal when said current time is in a region of said schedule indicative of holding said temperature constant and for producing a temperature hold discontinue signal when said current time is in a region of said schedule indicative of not holding said temperature constant;
means for receiving said temperature hold continue signal and for producing a temperature different than desired signal when said temperature is different than indicated by said schedule for said current time and for producing a temperature not different than desired signal when said temperature is not different than desired;
means for receiving said temperature different than desired signal and for increasing said applied intensity when said temperature is lower than that indicated by said schedule and for decreasing said intensity when said temperature is greater than when indicated by said schedule, and for producing a temperature equal to desired signal;
means for receiving said heating rate determining signal and for determining a current heating rate and for producing a temperature rate compare signal, means for receiving said temperature rate compare signal and for producing a temperature rate equal to expected signal when said temperature rate is substantially equal to that indicated by said schedule for said current time and for producing a temperature rate not equal to expected signal when said temperature rate is not equal to that indicated by said schedule for said current time;
means for receiving said temperature rate not equal to expected signal and for producing a signal indicative of increasing said intensity when said heating rate is less than indicated by said schedule for said current time and for producing a signal indicative of decreasing said intensity when said heating rate is greater than indicated by said schedule for said current time and for producing a second temperature rate equal to expected signal when said temperature rate is substantially equal to said rate indicated by said schedule for said current time;
and
means for determining when said current time is substantially equal to an end time of said schedule and for receiving said temperature equal to desired signal and for receiving said temperature not different than desired signal and for receiving said temperature hold discontinue signal and for producing a schedule end signal when said current time is not less than said end time and for producing a schedule not ended signal when said current time less than said end time;
said means for determining when said workpiece has achieved a final predetermined physical condition comprises:
means for generating a signal to place said .alpha. value in a nonminimized condition to determine a current Q value for said workpiece, wherein Q value is the ratio of the measure of energy stored in said cavity divided by the average power loss therein;
means for executing said .alpha. minimizing means to return said .alpha. value to a minimum;
means for determining from said current Q value and said current temperature whether said workpiece has achieved said predetermined physical condition.

33 more elements

A method for controlling the application of radiation to a workpiece in a cavity comprising:

tracking current times;
measuring a forward radiation intensity applied to said workpiece at said current time;
measuring a reflected intensity reflected from said workpiece at said current time;
determining a predetermined .alpha. value by calculating the ratio of the forward radiation intensity divided by the reflected intensity of said radiation and wherein a current value of .alpha. corresponds to a current time;
employing means to minimize .alpha.;
wherein said .alpha. minimizing means includes varying the position of a movable launch device in said cavity, said device is selected from the group consisting of a movable antenna, movable coupling loop, and a movable stub;
and varying the position of a movable volume device, said movable volume device being selected from the group consisting of a moving short and a moving sidewall;
measuring a temperature of said workpiece at said current time;
controlling said measured temperature to be substantially equal to a predetermined temperature;
determining whether said workpiece has achieved a final predetermined physical condition;
and
adjusting said forward radiation intensity if said workpiece has not achieved said final predetermined physical condition.

9 more elements

A system for controlling an application of radiation to a workpiece in a cavity comprising:

time tracking means for tracking current time;
means for receiving an applied power signal indicative of a magnitude of an applied intensity of said radiation;
means for receiving a reflected power signal indicative of a magnitude of a reflected intensity of said radiation;
means for receiving a phase signal indicative of the phase of the said radiation means for receiving a temperature signal indicative of a magnitude of a temperature of said workpiece;
minimizing means coupled to said time tracking means, for causing .alpha. to be less than a predetermined value, .alpha. is a ratio of said magnitude of said reflected intensity over said magnitude of said applied intensity and coupled to said phase signal to provide a signal corresponding to signal a current value of .alpha. signal corresponding to said current time;
said minimizing means being coupled to said time tracking means, to said means for receiving said applied power signal indicative of said magnitude of said applied intensity, to said means for receiving said reflected power signal indicative of said magnitude of said reflected intensity and to said means for receiving said temperature signal indicative of said magnitude of said temperature of said workpiece;
temperature control means coupled to said time tracking means, for producing an intensity signal indicative of said magnitude of said applied intensity of said radiation to control said temperature of said workpiece to be substantially equal to a predetermined temperature;
means for determining when said workpiece has achieved a final predetermined physical condition;
said means for determining is coupled to said time tracking means;
and means for producing an end signal to end operation of said system when said workpiece has achieved said final predetermined physical condition;
said means for producing is coupled to said time tracking means.

8 more elements

A system for controlling an application of radiation to a workpiece in a cavity comprising:

time tracking means for tracking current time;
means for receiving an applied power signal indicative of a magnitude of an applied intensity of said radiation;
means for receiving a reflected power signal indicative of a magnitude of a reflected intensity of said radiation;
means for receiving a temperature signal indicative of a magnitude of a temperature of said workpiece;
minimizing means coupled to said time tracking means, for causing .alpha. to be less than a predetermined value, .alpha. is a ratio of said magnitude of said reflected intensity over said magnitude of said applied intensity and to provide a signal corresponding to signal a current value of .alpha. signal corresponding to said current time;
said minimizing means being coupled to said time tracking means, to said means for receiving said applied power signal indicative of said magnitude of said applied intensity, to said means for receiving said reflected power signal indicative of said magnitude of said reflected intensity and to said means for receiving said temperature signal indicative of said magnitude of said temperature of said workpiece;
said minimizing means is achieved by moving a movable volume element and a movable launch device;
where said movable launch device in said cavity is selected from the group consisting of a movable antenna, movable coupling loop, movable stub and;
where said movable volume is achieved by one of the group of a moving short, a moving sidewall;
temperature control means coupled to said time tracking means, for producing an intensity signal indicative of said magnitude of said applied intensity of said radiation to control said temperature of said workpiece to be substantially equal to a predetermined temperature;
means for determining when said workpiece has achieved a final predetermined physical condition;
said means for determining is coupled to said time tracking means;
and
means for producing a signal to control said predetermined temperature if said workpiece has not achieved said final predetermined physical condition;
said means for producing is coupled to said time tracking means.

12 more elements

A system for controlling an application of radiation to a workpiece having a position in a cavity comprising:

time tracking means for tracking current time;
means for receiving a forward power signal indicative of a magnitude of an applied intensity of said radiation;
means for receiving a reflected power signal indicative of a magnitude of a reflected intensity of said radiation;
means for receiving a temperature signal indicative of a magnitude of a temperature of said workpiece;
minimizing means for causing .alpha. to be less than a predetermined a value, wherein .alpha. is a ratio of said magnitude of said reflected intensity over said magnitude of said applied intensity and wherein a current value of a corresponding to said current time;
said minimizing means being coupled to said timetracking means, to said means for receiving said applied power signal indicative of said magnitude of said applied intensity, to said means for receiving said reflected power signal indicative of said magnitude of said reflected intensity and to said means for receiving said temperature signal indicative of said magnitude of said temperature of said workpiece;
wherein said minimizing means is accomplished by moving movable volume element and movable launch device;
means for producing an intensity signal indicative of an intensity of said radiation to control said temperature to be substantially equal to a predetermined temperature;
means for determining when said workpiece has achieved a final predetermined physical condition;
and
means for producing a signal to control said predetermined temperature if said workpiece has not achieved said final predetermined physical condition;
said minimizing means which produces signals to control a location of a short and an antenna in said cavity comprises:
means for receiving a signal indicative of a current value of .alpha.;
means for generating a position signal indicative of an updated location of one member of the group consisting of said antenna and said short with respect to a position of said workpiece, said one member being a selected member and the other member being an unselected member;
means for transmitting said position signal indicative of an updated location to said one member of the group consisting of said antenna and said short until said current value of .alpha. is at a local minimum;
when said local minimum is reached, said means for transmitting said position signal indicative of an updated location transmits said position signal indicative of an updated location to said unselected member of the group consisting of said movable sidewall and said movable launch device, selected from the group consisting of a movable stub, movable coupling loop and movable antenna;
when said current value of .alpha. is less than said predetermined a value, said current value of .alpha. is minimized;
a temperature control means, which controls a temperature to be substantially in agreement with a predetermined temperature versus time schedule, comprises:
temperature hold determining means for producing a temperature hold signal when said temperature is to be held constant in accordance with said schedule and for producing a temperature test signal when said temperature is not to be held constant according to said schedule;
temperature test means for receiving said temperature test signal and for producing a temperature duration signal when said temperature is greater than a next hold temperature according to said schedule and for producing a heating rate determine signal when said temperature is not greater than said next hold temperature;
means for receiving said temperature duration signal and for producing a signal indicative of a temperature hold condition;
means for receiving said signal indicative of a temperature hold condition and for producing an initial time record signal;
for receiving said initial time record signal and for receiving said temperature hold signal and for producing a temperature hold continue signal when said current time is in a region of said schedule indicative of holding said temperature constant and for producing a temperature hold discontinue signal when said time is in a region of a schedule indicative of not holding said temperature constant;
means for receiving said temperature hold continue signal and for producing a temperature different than desired signal when said temperature is different than indicated by said schedule for said time and for producing a temperature not different than desired signal when said temperature is not different than desired;
means for receiving said temperature different than desired signal and for increasing said applied intensity when said temperature is lower than that indicated by said schedule indicative of not holding said temperature constant and for decreasing said intensity when said temperature is greater than when indicated by said schedule;
indicative of not holding said temperature constant, and for producing a temperature equal to desired signal;
means for receiving said heating rate determining signal and for determining a current heating rate and for producing a temperature rate compare signal,
means for receiving said temperature rate compare signal and for producing a temperature rate equal to expected signal when said temperature rate is substantially equal to that indicated by said schedule for said current time and for producing a temperature rate not equal to expected signal when said temperature rate is not equal to that indicated by said schedule for said current time;
means for receiving said temperature rate not equal to expected signal and for producing a signal indicative of increasing said intensify when said heating rate is less than indicated by said schedule for said current time and for producing a signal indicative of decreasing said intensity when said heating rate is greater than indicated by said schedule for said current time and for producing a second temperature rate equal to expected signal when said temperature rate is substantially equal to said rate indicated by said schedule for sad time;
and
means for determining when said current time is substantially equal to an end time of said schedule and for receiving said temperature equal to desired signal and for receiving said temperature not different than desired signal and for receiving said temperature hold discontinue signal and for producing a schedule end signal when said current time is not less than said end time and for producing a schedule not ended signal when said current time less than said end time;
said means for determining when said workpiece has achieved a final predetermined physical condition comprises:
means for generating a signal to place said a value in a nonminimized condition to determine a current Q value for said workpiece;
means for executing said a minimizing means to return said a value to a minimum;
means for determining from said current Q value and said current temperature whether said workpiece has achieved said predetermined physical condition wherein said Q is the ratio of energy stored to energy lost in said cavity.

32 more elements

A system for controlling an application or radiation to a workpiece in a cavity comprising:

time tracking means for tracking current time;
means for receiving an applied power signal indicative of the applied intensity of said radiation;
means for receiving a reflected power signal indicative of a magnitude of a reflected intensity of said radiation;
means for receiving a temperature signal indicative of a magnitude of a temperature of said workpiece;
a minimizing means coupled to said time tracking means for causing .alpha. to be less than a predetermined value, wherein .alpha. is a ratio of said magnitude of said reflected intensity over said magnitude of said applied intensity;
said minimizing means being coupled to said timetrack aid means for receiving said applied power signal indicative of said magnitude of said applied intensity, to said means for receiving said reflected power signal indicative of said magnitude of said reflected intensity and to said means for receiving said temperature signal indicative of said magnitude of said temperature of said workpiece;
temperature control means for producing an intensity signal indicative of a magnitude of an intensity of said radiation to control said temperature to be substantially equal to a predetermined temperature from a predetermined temperature versus time schedule;
means for determined when said workpiece has achieved a final predetermined physical condition, said means for determining is operatively connected to said time tracking means;
means for producing a signal to modify said predetermined temperature if said workpiece has not achieved said final predetermined physical condition, said means for producing is operatively connected to said time tracking means;
said minimizing means comprises:
means for generating a signal to modify said cavity to vary a value of .alpha.;
means for determining in response to said varying said value of .alpha. if said value of .alpha. is increasing or decreasing;
and
means for generating a signal in response to a determination of whether said current value of .alpha. is increasing or decreasing, for modifying said cavity to minimize said current value of .alpha.;
means for varying position of variable launch device, selected from the group movable coupling loop and movable stub and movable volume element selected from the group consisting of a movable sidewall and a movable short;
said temperature control means comprises:
means for receiving specific temperature values of said temperature signal corresponding to specific time values of said current time;
means for producing a heating rate signal in response to determining a heating rate from said specific temperature values and said specific time values;
means for producing a comparison signal in response to comparing said heating rate signal with said predetermined temperature versus time schedule;
and
means for producing a signal to modify said applied power signal indicative of the applied intensity in response to said comparison signal;
said means for determining when said workpiece has achieved a final predetermined physical condition comprises:
means for determining a current Q for said cavity wherein said current Q;
and
means for comparing said current Q and said current temperature with a predetermined Q, and temperature versus degree of workpiece physical condition schedule wherein said Q is the ratio of energy stored to energy lost in said cavity.

22 more elements

Dependencies are inferred from the claim text.

Radiation control system

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Radiation control system

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Abstract

Claims31