1. A composite film comprising:
an elastic film portion having first and second edges that are substantially parallel, the elastic film portion having a first elasticity; and
a first non-elastic film portion extending along and contacting the first edge of the elastic film portion, the first non-elastic film portion having a second elasticity that is substantially lower than the first elasticity.
2. The composite film of claim 1, further comprising
a second nonelastic film portion extending along and contacting the second edge of the elastic film portion, the second non-elastic film portion having a third elasticity that is substantially lower than the first elasticity.
3. The composite film of claim 1, wherein the elastic film portion includes an elastomer selected from the group consisting of polypropylene (PP), polymethylmethacrylate (PMMA), and polydimethylsiloxane (PDMS).
4. The composite film of claim 1, wherein the first nonelastic film portion includes an engineering plastic selected from the group consisting of acrylonitrile butadiene styrene (ABS), nylon 6, nylon 6-6, polyamides (PA), polybutylene terephthalate (PBT), polycarbonates (PC), polyetheretherketone (PEEK), polyetherketone (PEK), polyethylene terephthalate (PET), polyimides, polyoxymethylene plastic (POMAcetal), polyphenylene sulfide (PPS), polyphenylene oxide (PPO), polysulphone (PSU), polytetrafluoroethylene (PTFETeflon), polyvinyl chloride (PVC), and ultra-high-molecular-weight polyethylene (UHMWPEUHMW).
5. A method of forming a composite film, comprising:
extruding a first melted resin to provide a first extruded resin;
extruding a second melted resin to provide a second extruded resin;
arranging the first and second extruded resins along a first direction such that the first direction crosses the first and second extruded resins;
rearranging the first and second extruded resins along a second direction other than the first direction such that the second direction crosses the first and second extruded resins; and
subsequently extruding the first and second extruded resins arranged in the second direction to produce a film comprising a first film portion and a second film portion such that the second direction crosses the first and second film portions, the first film portion being made of the first extruded resin, and the second film portion being made of the second extruded resin.
6. The method of claim 5, further comprising
melting a first solid resin to provide the first melted resin;
melting a second solid resin to provide the second melted resin;
melting a third solid resin to provide a third melted resin; and
extruding the third melted resin to provide a third extruded resin.
7. The method of claim 6, wherein when extruding the first, second and third melted resins, the method further comprises controlling an extrusion speed of each of the first, second and third melted resins in consideration of a size of the resulting extruded resin produced therefrom.
8. The method of claim 7, wherein when the size of the first melted resin is equal to the size of the second melted resin, and the size of the third melted resin is smaller than the sizes of the first and second melted resins, an extrusion speed of the third melted resin is lower than extrusion speeds of the first and second melted resins.
9. The method of claim 5, wherein the film is produced by cooling the first and second extruded resins.
10. An apparatus for forming a composite film, comprising:
first extruders configured to extrude a first melted resin and a second melted resin to provide a first extruded resin and a second extruded resin;
a feeder configured to arrange the first and second extruded resins along a first direction such that the first direction crosses the first and second extruded resins;
a direction converter configured to arrange the first and second extruded resins along a second direction other than the first direction such that the second direction crosses the first and second extruded resins; and
a second extruder configured to extrude the first and second extruded resins arranged along the second direction to produce a film comprising a first film portion and a second film portion such that the second direction crosses the first and second film portions, the first film portion being made of the first extruded resin, the second film portion being made of the second extruded resin.
11. The apparatus of claim 10, wherein the first extruders include:
a first extruding member configured to melt a first solid resin to extrude the first melted resin;
a second extruding member configured to melt a second solid resin to extrude the second melted resin; and
a third extruding member configured to melt a third solid resin to extrude a third melted resin.
12. The apparatus of claim 11, wherein each of the first, second, and third extruding members includes a screw.
13. The apparatus of claim 11, further comprising:
a controller configured to control extrusion speeds of the first, second, and third melted resins based on the sizes of the first, second, and third melted resins, respectively.
14. The apparatus of claim 13, wherein when the size of the first melted resin is equal to the size of the second melted resin, and the size of the third melted resin is smaller than the sizes of the first and second melted resins, an extrusion speed of the third melted resin is controlled to be lower than extrusion speeds of the first and second melted resins.
15. The apparatus of claim 10, wherein the direction converter includes:
a supply line arranged in the first direction and configured to receive the first and second melted resins arranged in the first direction;
a discharge line arranged in the second direction and configured to discharge the first and second melted resins arranged in the second direction; and
a converting line disposed between the supply line and the discharge line and configured to re-arrange the first and second melted resins, which are arranged in the first direction, in the second direction.
16. The apparatus of claim 10, wherein the first direction corresponds to a thickness direction of the composite film and the second direction corresponds to a transverse direction of the composite film perpendicular to the thickness direction.
17. The apparatus of claim 10, wherein the second extruder includes:
a melted resin supply configured to receive the first and second melted resins arranged in the second direction;
a manifold coupled to the melted resin supply; and
a melted resin extruder coupled to the manifold to extrude the first and second melted resins arranged in the second direction.
18. The apparatus of claim 10, further comprising a cooler configured to cool the first and second extruded resins.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A bias circuit comprising:
a voltage stabilizer connected between a control voltage input terminal through a current limit resistor and a ground;
a bias supply emitter follower with a base connected to a node between the current limit resistor and the voltage stabilizer through a resistor; and
a current limiter connected between the base and an emitter of the bias supply emitter follower.
2. The bias circuit according to claim 1, wherein a base-emitter voltage of the bias supply emitter follower is set by the current limiter.
3. The bias circuit according to claim 2, wherein the current limiter comprises:
a current source having a current value that varies according to a voltage value input through the control voltage input terminal;
a transistor connected between the base of the bias supply emitter follower and the current source and having a base and a collector short-circuited to each other; and
a resistor connected between a node between the transistor and the current source and the emitter of the bias supply emitter follower.
4. The bias circuit according to claim 3, wherein a current flowing to the current source of the current limiter is substantially the same as a current flowing to the voltage stabilizer.
5. The bias circuit according to claim 1, wherein the voltage stabilizer generates a voltage that is set based on a threshold voltage of a power amplifier transistor connected to the bias circuit and a threshold voltage of the bias supply emitter follower.
6. The bias circuit according to claim 1, wherein the voltage stabilizer generates a voltage that is set based on a voltage that is generated based on temperature characteristics of a threshold voltage of a power amplifier transistor connected to the bias circuit and temperature characteristics of a threshold voltage of the bias supply emitter follower.
7. The bias circuit according to claim 1, wherein the bias circuit is connected to an input terminal of a power amplifier transistor.