1. A ladder-type elastic wave filter comprising:
a piezoelectric substrate formed of a material with a negative temperature coefficient;
a first series elastic-wave resonator formed on the piezoelectric substrate and connected in series between an input terminal and an output terminal, the first series elastic-wave resonator having a first capacitance;
a second series elastic-wave resonator connected in series between the input terminal and the output terminal and having a second capacitance, the first capacitance of the first series elastic-wave resonator being higher than the second capacitance of the second series elastic-wave resonator;
a parallel elastic-wave resonator formed on the piezoelectric substrate and connected in parallel between the first series elastic-wave resonator and a ground terminal; and
a dielectric film formed on the piezoelectric substrate the dielectric film covering the first series elastic-wave resonator and the second series elastic-wave resonator, the dielectric film formed of a material with a positive temperature coefficient, a thickness of the dielectric film being thicker than a film thickness with which a frequency-temperature coefficient of a passing characteristic of the first series elastic-wave resonator becomes 0.
2. The ladder-type elastic wave filter of claim 1,
wherein the thickness of the dielectric film is formed thicker than a film thickness with which respective frequency-temperature coefficients of the passing characteristic of the first series elastic-wave resonator and the second series elastic-wave resonator become 0.
3. A duplexer comprising:
the ladder-type elastic wave filter of claim 1; and
a filter through which a signal with a frequency higher than a passband of the ladder-type elastic wave filter passes.
4. The ladder-type elastic wave filter of claim 1 wherein a passband of the first series elastic-wave resonator shifts to a high frequency side as temperature rises.
5. The ladder-type elastic wave filter of claim 1 wherein the ladder-type elastic wave filter is configured to pass signals in a transmission band between 1.85 GHz and 1.91 GHz and suppress signals in a reception band between 1.93 GHz and 1.99 GHz.
6. The ladder-type elastic wave filter of claim 5 further comprising a reception filter configured to suppress signals in a transmission band between 1.85 GHz and 1.91 GHz and pass signals in a reception band between 1.93 GHz and 1.99 GHz.
7. The ladder-type elastic wave filter of claim 6 wherein the ladder-type elastic wave filter is a WCDMA standard compliant filter.
8. The ladder-type elastic wave filter of claim 1 further comprising an antenna terminal connected to an output terminal of the ladder-type elastic wave filter.
9. The ladder-type elastic wave filter of claim 1 wherein the parallel elastic-wave resonator is electrically connected between the first series elastic-wave resonator and the second series elastic-wave resonator.
10. The ladder-type elastic wave filter of claim 1 wherein the dielectric film includes a protrusion part formed on a top surface of the dielectric film.
11. The ladder-type elastic wave filter of claim 1 wherein the dielectric film includes silicon dioxide.
12. A ladder-type elastic wave filter comprising:
a piezoelectric substrate formed of a material with a negative temperature coefficient;
a series elastic-wave resonator formed on the piezoelectric substrate and connected in series between an input terminal and an output terminal;
a first parallel elastic-wave resonator formed on the piezoelectric substrate and connected in parallel between the series elastic-wave resonator and a ground terminal, the first parallel elastic-wave resonator having a first capacitance;
a second parallel elastic-wave resonator connected between the series elastic-wave resonator and the ground terminal and having a second capacitance, the first capacitance of the first parallel elastic-wave resonator being lower than the second capacitance of the second parallel elastic-wave resonator; and
a dielectric film formed on the piezoelectric substrate, the dielectric film covering the first parallel elastic-wave resonator and the second parallel elastic-wave resonator, the dielectric film formed of a material with a positive temperature coefficient, a thickness of the dielectric film being thinner than a film thickness with which a frequency-temperature coefficient of a passing characteristic of the first parallel elastic-wave resonator becomes 0.
13. The ladder-type elastic wave filter of claim 12
wherein the thickness of the dielectric film is formed thinner than respective film thicknesses with which respective frequency-temperature coefficients of the passing characteristic of the first parallel elastic-wave resonator and the second parallel elastic-wave resonator become 0.
14. A duplexer comprising:
the ladder-type elastic wave filter of claim 12; and
a filter through which a signal with a frequency lower than a passband of the ladder-type elastic wave filter passes.
15. The ladder-type elastic wave filter of claim 12 wherein the ladder-type elastic wave filter is configured to pass signals in a transmission band between 1.85 GHz and 1.91 GHz and suppress signals in a reception band between 1.93 GHz and 1.99 GHz.
16. The ladder-type elastic wave filter of claim 15 further comprising a reception filter configured to suppress signals in a transmission band between 1.85 GHz and 1.91 GHz and pass signals in a reception band between 1.93 GHz and 1.99 GHz.
17. The ladder-type elastic wave filter of claim 12 wherein a passband of the first parallel elastic-wave resonator shifts to a low frequency side as temperature increases.
18. The ladder-type elastic wave filter of claim 12 further comprising a second series elastic-wave resonator formed on the piezoelectric substrate and connected in series with the first series elastic-wave resonator between the first parallel elastic-wave resonator and the second parallel elastic-wave resonator.
19. The ladder-type elastic wave filter of claim 12 wherein a resonance frequency of the first parallel elastic-wave resonator shifts as temperature rises.
20. The ladder-type elastic wave filter of claim 19 wherein a resonance frequency of the second parallel elastic-wave resonator does not shift as temperature rises.
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. An illumination apparatus, comprising:
a base; and
a CU-shaped spiral fluorescence tube disposed on the base and having a first spiral part, a second spiral part and a CU-shaped bending part, wherein one end of the first spiral part connects to one end of the CU-shaped bending part, the other end of the first spiral part is disposed with an electrode, one end of the second spiral part connects to the other end of the CU-shaped bending part, and the other end of the second spiral part is disposed with another electrode.
2. The illumination apparatus according to claim 1, wherein the first spiral part and the second spiral part are spirally wreathed with at least one spiral radius, and the CU-shaped bending part has a curvature radius smaller than the spiral radius.
3. The illumination apparatus according to claim 1, further comprising:
a housing covering the CU-shaped spiral fluorescence tube and assembled with the base.
4. The illumination apparatus according to claim 1, wherein the first spiral part and the second spiral part are disposed between the base and the CU-shaped bending part.
5. The illumination apparatus according to claim 1, wherein the first spiral part and the second spiral part are spirally wreathed in parallel, and each of the first spiral part and the second spiral part has a plurality of circles.
6. The illumination apparatus according to claim 1, wherein the CU-shaped bending part is disposed between the first spiral part and the second spiral part, and the second spiral part is disposed between the base and the CU-shaped bending part.
7. The illumination apparatus according to claim 1, wherein the first spiral part and the second spiral part are spirally wreathed toward opposite directions, and each of the first spiral part and the second spiral part has a plurality of circles.
8. The illumination apparatus according to claim 1, wherein the CU-shaped spiral fluorescence tube further has a third spiral part disposed between the base and the first spiral part, and a fourth spiral part disposed between the base and the second spiral part, the spiral radius of the first spiral part is smaller than that of the third spiral part, and the spiral radius of the second spiral part is smaller than that of the fourth spiral part.
9. The illumination apparatus according to claim 1, wherein the CU-shaped spiral fluorescence tube further has a third spiral part disposed between the base and the first spiral part, and a fourth spiral part disposed between the base and the second spiral part, the spiral radius of the first spiral part is greater than that of the third spiral part, and the spiral radius of the second spiral part is greater than that of the fourth spiral part.
10. The illumination apparatus according to claim 1, wherein the lengths of the first spiral part and the second spiral part are different.
11. The illumination apparatus according to claim 1, further comprising:
a driving circuit disposed at the substrate.
12. The illumination apparatus according to claim 11, wherein the driving circuit is disposed on the base, and the electrodes are electrically connected with the driving circuit.
13. The illumination apparatus according to claim 1, further comprising:
an electronic element disposed on the substrate, wherein the electronic element is a converter or a coil.
14. The illumination apparatus according to claim 1, further comprising:
a reflective element, wherein the CU-shaped spiral fluorescence tube is disposed around the reflective element.
15. The illumination apparatus according to claim 1, further comprising:
a supporting element, wherein the CU-shaped spiral fluorescence tube is disposed around the supporting element.
16. The illumination apparatus according to claim 15, further comprising:
a sensing unit disposed on the supporting element.
17. The illumination apparatus according to claim 15, further comprising:
a wireless transmission unit disposed on the supporting element.
18. A manufacturing method of an illumination apparatus, comprising the steps of:
bending a linear fluorescence tube to form a CU-shaped fluorescence tube, wherein the CU-shaped fluorescence tube has a first part, a second part and a CU-shaped bending part, and two ends of the CU-shaped bending part are connected with the first part and the second part, respectively; and
bending the first part and the second part from the CU-shaped bending part to shape the first part and the second part in spiral.
19. The method according to claim 18, further comprising a step of:
sealing the CU-shaped fluorescence tube.
20. The method according to claim 18, wherein the CU-shaped fluorescence tube is a cold cathode fluorescent (CCF) tube.