GB2397720A - Hydrogel acoustic coupling for loudspeakers - Google Patents
Hydrogel acoustic coupling for loudspeakers Download PDFInfo
- Publication number
- GB2397720A GB2397720A GB0400961A GB0400961A GB2397720A GB 2397720 A GB2397720 A GB 2397720A GB 0400961 A GB0400961 A GB 0400961A GB 0400961 A GB0400961 A GB 0400961A GB 2397720 A GB2397720 A GB 2397720A
- Authority
- GB
- United Kingdom
- Prior art keywords
- connection device
- radiating member
- sound
- panel
- vibrational energy
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000000017 hydrogel Substances 0.000 title claims abstract description 12
- 230000008878 coupling Effects 0.000 title abstract description 7
- 238000010168 coupling process Methods 0.000 title abstract description 7
- 238000005859 coupling reaction Methods 0.000 title abstract description 7
- 239000000463 material Substances 0.000 claims abstract description 16
- 239000006260 foam Substances 0.000 claims description 4
- 239000011521 glass Substances 0.000 claims description 4
- 239000007788 liquid Substances 0.000 claims description 4
- 239000002184 metal Substances 0.000 claims description 4
- 239000004033 plastic Substances 0.000 claims description 4
- 229920003023 plastic Polymers 0.000 claims description 4
- 238000000034 method Methods 0.000 claims description 3
- 230000003213 activating effect Effects 0.000 claims description 2
- 229920001169 thermoplastic Polymers 0.000 claims description 2
- 239000004416 thermosoftening plastic Substances 0.000 claims description 2
- -1 1I card Substances 0.000 claims 1
- 230000004913 activation Effects 0.000 abstract description 3
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000010355 oscillation Effects 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000004020 conductor Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000012815 thermoplastic material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/02—Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K13/00—Cones, diaphragms, or the like, for emitting or receiving sound in general
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K9/00—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers
- G10K9/12—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated
- G10K9/13—Devices in which sound is produced by vibrating a diaphragm or analogous element, e.g. fog horns, vehicle hooters or buzzers electrically operated using electromagnetic driving means
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R7/00—Diaphragms for electromechanical transducers; Cones
- H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
- H04R7/04—Plane diaphragms
- H04R7/045—Plane diaphragms using the distributed mode principle, i.e. whereby the acoustic radiation is emanated from uniformly distributed free bending wave vibration induced in a stiff panel and not from pistonic motion
Landscapes
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Multimedia (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- Electromagnetism (AREA)
- Diaphragms For Electromechanical Transducers (AREA)
Abstract
A connection or coupling device 10 offering improved acoustic coupling between a transducer 16 and a panel-form sound-radiating member 14 is described. The connection device 10 is formed of hydrogel material is adapted to couple the voice coil of a voice coil transducer to the panel of a panel-form sound-radiating member. The coupling device 10 also suitably attenuates the output of the transducer to avoid over-driving the panel. An automatic activation system turns on the loudspeaker upon sensing an approaching person.
Description
À:e 2397720 1 Improvements relating to acoustic coupling 3 The invention
relates to improvements relating to 4 acoustic coupling and in particular to a connection device for connecting a sound generator to a panel-form 6 loudspeaker. The invention also relates to apparatus 7 incorporating such a device and a method of operation.
9 Typical display panels currently used in the advertising industry consist of a poster mounted upon a rigid 11 surface. More recently however, display panels have 12 started to appear wherein a number of different posters 13 can be displayed on a single display panel, the different 14 posters are mounted on moving elements such that as the various elements are rotated the different posters are 16 observable at different times.
18 There are also display units available which incorporate 19 sound devices. The sound devices used typically consist of a printable disposable loudspeaker panel made from a 21 low cost material, such as a composite panel or display 22 grade cardboard. A transducer is bonded either to a face e
C
À ese ace ae. .e e À 1 or within the panel itself. The two components are 2 combined in such a way as to form a loudspeaker.
4 These devices have already found use as "Talking Posters" which are used at exhibitions and at point of sale 6 displays. The presently available sound units are 7 produced by permanently gluing the speaker to a board, so 8 that the board becomes the last part of the voice 9 coil/direct linear actuator. The board acts as a diaphragm and generates the required acoustic output.
11 Such devices suffer from the disadvantage that the 12 display panels cannot be attached to and subsequently 13 detached from the panel being used as a speaker.
Unfortunately, such speakers generate only poor quality 16 sound with respect to frequencies in the lower range.
17 Due to this lack of sound quality, such speakers are of 18 only limited use in promotional devices.
One explanation of the poor sound quality achieved with 21 known devices is in appropriate amplitude of acoustic 22 energy transferred to the panel. If low amplitude 23 oscillations are applied to the transducer, the voice 24 coil of the speaker is stressed due to the panel mass, and is unable to reproduce movement of the transducer in 26 the panel with fidelity. If high amplitude oscillations 27 are used, there is enough power to move the panel mass, 28 but the amplitude causes the panel to flex improperly and 29 vibrate inhomogeneously.
31 As a consequence of these problems, overall sales of 32 panel speakers have been low due to the fact that there 33 are no low cost, high quality speaker panels available. À
À t À .. . . . . . À C À C À À À À À À 2 Surprisingly it has now been found that the above 3 problems can be obviated by a first embodiment of the 4 present invention which comprises a connection device which connects an electrically driven vibrational energy 6 generator to an acoustical sound radiating member.
8 It is an object of at least one embodiment of the present 9 invention to provide a connection device suitable for connecting an electrically driven vibrational energy 1I generator to an acoustical sound-radiating member.
13 It is a further object of at least one embodiment of the 14 present invention to provide a connection device that will transform the amplitude of the vibrations from the 16 electrically driven vibrational energy generator to an 17 amplitude appropriate for the acoustical sound radiating 18 member being used.
It is a yet further object of at least one embodiment of 21 the present invention that the connection device can be 22 used with an acoustical sound radiating member comprised 23 of materials such as foam, metal, glass or plastics 24 materials.
26 It is a further object of at least one embodiment of the 27 present invention to provide a connection device for use 28 with an electrically driven vibrational energy generator 29 and an acoustical sound radiating member that can be incorporated into a display unit.
32 According to a first aspect of the present invention 33 there is provided a connection device for use with an À.
I electrically driven vibrational energy generator and an 2 acoustical sound radiating member, wherein the connection 3 device converts electrically generated vibrational energy 4 of one amplitude to a second amplitude suitable for said acoustical sound radiating member, such that in use when 6 an electrically generated vibrational energy acts upon 7 the connection device, the vibrational energy is modified 8 by the device to an amplitude appropriate for the 9 acoustical sound radiating member and transferred from the connection device to the acoustical sound radiating 11 member.
13 Preferably the connection device can be detached and 14 reattached to the electrically driven vibrational energy generator or the acoustical sound-radiating member.
17 Preferably, the connection device is comprised of a 18 hydrogel material.
More preferably, the connection device is comprised of a 21 thermoplastic hydrogel material which has semi-liquid 22 properties.
24 Preferably, the connection device can be used with an acoustical soundradiating member which is comprised of 26 materials such as foam, metal, glass or plastics 27 materials.
29 More preferably, the connection device for use with a electrically driven vibrational energy generator and a 31 acoustical sound radiating member can be incorporated 32 into a display unit, which also comprises an audio unit.
À À # 1 À À À t À C À À
A
À À À À À 1 According to a second aspect of the present invention 2 there is provided a display unit, the display unit 3 incorporating a connection device for use with an 4 electrically driven vibrational energy generator and an acoustical sound radiating member, wherein the connection 6 device converts electrically generated vibrational energy 7 of one amplitude to a second amplitude suitable for said 8 acoustical sound radiating member, such that in use when 9 an electrically generated vibrational energy acts upon the connection device, the vibrational energy is modified 11 by the device to an amplitude appropriate for the 12 acoustical sound radiating member and transferred from 13 the connection device to the acoustical sound radiating 14 member.
16 Preferably, the connection device can be detached and 17 reattached to the electrically driven vibrational energy 18 generator or the acoustical sound-radiating member.
Preferably, the connection device is comprised of a 21 hydrogel material.
23 More preferably, the connection device is comprised of a 24 thermoplastic material which has semi-liquid properties.
26 Preferably, the connection device can be used with an 27 acoustical sound-radiating member which is comprised of 28 materials such as foam, metal, glass or plastics 29 materials.
31 More preferably, the connection device for use with a 32 electrically driven vibrational energy generator and a À 1 À À. . . . . . À. . À . À
I acoustical sound radiating member can be incorporated 2 into a display unit.
4 Preferably, the connection device can be included in a display unit wherein the display unit further comprises 6 an audio unit which may be connected to a sensor such 7 that the approach of a object/person results in 8 activation of the audio unit. The audio unit incorporates 9 an electrically driven vibrational energy generator which is attached to an acoustical sound radiating member by 11 means of the connection device.
13 Preferably, the acoustical sound radiating member 14 comprises a display panel.
16 According to a third aspect of the present invention 17 there is provided a method of using a display panel as a 18 acoustical radiating member comprising the steps: 19 a) a sensor detecting the approach of a person and activating the audio unit; 21 b) upon activation of the audio unit an electrical signal 22 is sent to the electrically driven vibrational energy 23 generator operates so that the vibrational energy thus 24 generated is directed to the connection device; c) the connection device then transforms the amplitude of 26 the vibrational energy to an amplitude suitable for the 27 acoustical radiating member, the vibrational energy being 28 emitted from the connection device to the acoustical 29 sound radiating member; d) the vibrational energy is then emitted by the the 31 acoustical sound radiating member as acoustical sound, 32 the sound radiating member may further comprise a display 33 panel. À
8 À À C, ., , , À À À À 2 An embodiment of the present will now be described by way 3 of example only, with reference to the following diagrams 4 of which: 6 Figure 1 is a schematic cross-sectional view showing 7 the positioning of a connection device between an 8 electrically driven vibrational energy generator and 9 an acoustical sound-radiating member, and; It Figure 2 is a perspective view of a typical 12 arrangement of components for use in a display unit 13 incorporating a connection device suitable for 14 connecting the electrically driven vibrational energy generator and the acoustical sound radiating l6 member.
18 Reference is initially made to Figure 1 of the drawings l9 which is a cross-sectional view illustrating a connection device 10 in accordance with a preferred embodiment of 21 the present invention. The connection device is shown 22 situated in its normal position for use between an 23 electrically driven vibrational energy generator 12 and 24 an acoustical sound-radiating member 14. The electrically driven vibrational energy generator 12 is a 26 transducer and the acoustical sound-radiating member 14 27 is a promotional display board acting as a panel speaker.
29 The transducer 12 is of the moving-coil type, and includes a voice coil 13 and a magnet assembly 11.
32 The voice coil 14 consists of a hollow cylinder with a 33 coil of conducting material secured thereto. Electrical he À À À * À À À À À . À À À À À À I connectors are provided to provide electrical contact 2 with a current source (not shown) via wires. The device 3 is driven by alternating current (AC), and preferably has 4 standard loudspeaker impedance characteristics (4, 6 or 8 S Ohm) with power handling in the range from 0.5 - 100W.
7 The magnet assembly 11 comprises a substantially 8 cylindrical metallic outer sheath, and a circular 9 metallic back plate. The sheath is provided with an l0 inwardly extending lip of lesser inner diameter than the If main body of the sheath. Centrally mounted in the back 12 plate, internally to the sheath, is a cylindrical 13 permanent magnet, mounted to the back plate at one of its 14 ends. On the opposing (lower) end of cylindrical magnet, there is provided an axially extending metallic portion.
16 The axially extending metallic portion comprises a 17 frusto-conical portion, with outer diameter decreasing in 18 a direction moving away from the back plate. The axially 19 extending metallic portion at its free end has a cylindrical portion with greater outer diameter such that 21 a flange is defined.
23 The geometry of the magnet assembly 11 is such that an 24 annular air space separates the inwardly extending lip and the cylindrical portion. The cylindrical portion 26 defines one pole of a permanent magnet (shown as N), and 27 the inwardly extending lip defines the opposing pole of a 28 permanent magnet (shown as S). Magnetic flux is 29 therefore concentrated in the annular region.
31 The connection device 10 contacts the voice coil 13 on a 32 first surface and a panel 14 on a second surface, and ha 33 a surface area greater than that defined by the cross À l r À e, I À À I section of the voice coil 13. The connection device 10 2 is manufactured from a hydrogel that possesses self 3 adhesive properties. This enables detachment and 4 reattachment of the connection device from and to the transducer or panel speaker, without the use of 6 additional adhesive and with no damage to either 7 component. The hydrogel material provides good acoustic 8 coupling between the transducer and the radiating member.
lO Figure 2 is a plan view showing the positioning of the If connection device 10 in relation to a typical set of 12 components that make up a display unit incorporating an 13 audio unit 16 that might utilise a connection device of 14 the type described above.
16 The display unit incorporates a pressure sensitive or 17 infrared sensor 18 which detects the approach of a 18 person. A signal from the sensor activates the audio 19 unit 16, which comprises an electrically operated transducer for converting an electrical signal into 21 vibrational energy.
23 The display unit described further comprises a power 24 source 20 to supply power to the various components.
26 The display panel may be activated by means of an input 27 device such as a keypad 22 and wherein a number of 28 different messages or audio files may be selected by the 29 pressing of different keys.
31 The vibrational energy is transferred to a first surface 32 of the connection device, placed in contact with the 33 transducer. The amplitude of the vibrational energy is . ce r r, À À 1 then converted to an amplitude suitable for the 2 acoustical sound radiating member by the connection 3 device. The modified vibrational energy is transferred 4 from a second surface of the connection device (opposing the first surface) to the panel speaker. The acoustical 6 sound radiating member then emits the vibrational energy 7 as audible sound.
9 The function of the hydrogel is to transform the energy of the voice coil vibrations at the first surface, which 11 are relatively big over a small area, to smaller 12 vibrations on the second surface, over an increased area 13 of the panel. This improves the quality of the sound 14 produced by the panel.
16 The interconnection of the transducer to the panel 17 speaker via the connection device is achieved by pressing 18 the transducer into the connection device and then 19 pressing the combined transducer and connection device onto the panel speaker such that the connection device is 21 contact with the panel speaker.
23 When vibrational energy is applied to the first face of 24 the connection device from a transducer, the semi-liquid properties of the hydrogel used result in modification of 26 the amplitude of the vibrational energy, such that 27 vibrational energy with a modified amplitude appropriate 28 to the panel speaker is then radiated from the second 29 face of the connection device to the panel speaker.
31 The device as described in the present embodiment is flat 32 and has a first surface and a second surface, although in C. 1 C C C C 1 C c c. Àcccec c see
C C
CC C C C
I an alternative embodiment the connection device may be 2 spherical or ovoid in shape.
4 In an alternative embodiment, the connection device may be used to connect a transducer to a computer screen such 6 that the computer screen acts as an acoustical sound 7 radiating device.
9 Various modifications and improvements may be made within the scope of the invention as defined by the appended 11 claims.
Claims (12)
1 ' e À 1 Claims 3 1. A connection device for an audio apparatus 4
comprising a voice coil transducer and a panel-form sound-radiating member, the connection device being 6 adapted to couple the voice coil of the voice coil 7 transducer to the panel of the panel-form sound 8 radiating member, wherein the connection device 9 comprises a hydrogel material.
11
2. A connection device as claimed in Claim 1 comprising 12 a surface for contacting the panel-form sound 13 radiating member panel, wherein the surface area is 14 greater than an area defined by the cross-section of the voice coil.
17
3. A connection device for use with an electrically 18 driven vibrational energy generator and an 19 acoustical sound radiating member, wherein the connection device converts electrically generated 21 vibrational energy of a first amplitude to a second 22 amplitude suitable for said acoustical sound 23 radiating member.
4. The connection device as claimed in any preceding 26 Claim wherein the connection device is operable to 27 be detached and reattached to the electrically 28 driven vibrational energy generator or the 29 acoustical sound-radiating member.
31
5. The connection device as claimed any preceding Claim 32 wherein the connection device comprises a hydrogel 33 material. .
# # À r # , # C 1 1 # # # 8 À # # À À C À C 2
6. The connection device as claimed in Claim 5 wherein 3 the connection device is comprised of a 4 thermoplastic hydrogel material having semi-liquid properties.
7
7. The connection device as claimed in any preceding 8 Claim adapted to be used with an acoustical sound 9 radiating member comprising a material selected from the group consisting of foam, metal, glass, plastic, 1I card, or cardboard.
13
8. The connection device as claimed in any preceding 14 Claim adapted to be incorporated into a display unit.
17
9. Apparatus comprising an audio unit having an 18 electrically driven vibrational energy generator, a 19 sound-radiating member, and a connection device as claimed in any preceding Claim adapted to couple the 21 electrically driven vibrational energy generator to 22 the sound-radiating member.
24
10. A display unit comprising the apparatus of Claim 9.
26
11. Apparatus as claimed in Claim 9 or Claim 10 further 27 comprising a sensor for detecting the approach of an 28 object or person, wherein the audio unit is adapted 29 to be activated in response to a signal from the sensor.
32
12. A method of using a display panel as a sound 33 radiating member comprising the steps of: r
C C
C C C C C C C # C C
C C C C
C C C C C
l a) detecting the approach of a person and activating 2 an audio unit; 3 b) driving a transducer to direct vibrational energy 4 of a first amplitude into a connection device; c) transferring, using the connection device, 6 vibrational energy of a second amplitude to the 7 acoustical radiating member, the second amplitude 8 being less than the first, such that sound is 9 emitted from the display panel.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GBGB0301003.0A GB0301003D0 (en) | 2003-01-16 | 2003-01-16 | Interactive display panel |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0400961D0 GB0400961D0 (en) | 2004-02-18 |
| GB2397720A true GB2397720A (en) | 2004-07-28 |
| GB2397720B GB2397720B (en) | 2006-10-11 |
Family
ID=9951267
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB0301003.0A Ceased GB0301003D0 (en) | 2003-01-16 | 2003-01-16 | Interactive display panel |
| GB0400961A Expired - Fee Related GB2397720B (en) | 2003-01-16 | 2004-01-16 | Improvements relating to acoustic coupling |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GBGB0301003.0A Ceased GB0301003D0 (en) | 2003-01-16 | 2003-01-16 | Interactive display panel |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB0301003D0 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007045908A1 (en) * | 2005-10-21 | 2007-04-26 | Sfx Technologies Limited | Improvements to audio devices |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2102657A (en) * | 1981-07-24 | 1983-02-02 | Nat Res Dev | Ultrasonic transducers |
| US4905700A (en) * | 1985-06-04 | 1990-03-06 | Ed. Geistlich Ag Fur Chemische Industrie | Method of transmitting ultrasound into a body |
| EP0800788A1 (en) * | 1996-04-10 | 1997-10-15 | Lec Tec Corporation | Solid ultrasonic biomedical couplant sheet |
| US5827198A (en) * | 1996-11-21 | 1998-10-27 | Flowscan, Inc. | Low-cost, disposable, polymer-based, differential output flexure sensor and method of fabricating same |
| US6039694A (en) * | 1998-06-25 | 2000-03-21 | Sonotech, Inc. | Coupling sheath for ultrasound transducers |
| WO2002076141A2 (en) * | 2001-03-19 | 2002-09-26 | Newlands Technology Limited | Magnetostrictive actuator |
-
2003
- 2003-01-16 GB GBGB0301003.0A patent/GB0301003D0/en not_active Ceased
-
2004
- 2004-01-16 GB GB0400961A patent/GB2397720B/en not_active Expired - Fee Related
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2102657A (en) * | 1981-07-24 | 1983-02-02 | Nat Res Dev | Ultrasonic transducers |
| US4905700A (en) * | 1985-06-04 | 1990-03-06 | Ed. Geistlich Ag Fur Chemische Industrie | Method of transmitting ultrasound into a body |
| EP0800788A1 (en) * | 1996-04-10 | 1997-10-15 | Lec Tec Corporation | Solid ultrasonic biomedical couplant sheet |
| US5827198A (en) * | 1996-11-21 | 1998-10-27 | Flowscan, Inc. | Low-cost, disposable, polymer-based, differential output flexure sensor and method of fabricating same |
| US6039694A (en) * | 1998-06-25 | 2000-03-21 | Sonotech, Inc. | Coupling sheath for ultrasound transducers |
| WO2002076141A2 (en) * | 2001-03-19 | 2002-09-26 | Newlands Technology Limited | Magnetostrictive actuator |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007045908A1 (en) * | 2005-10-21 | 2007-04-26 | Sfx Technologies Limited | Improvements to audio devices |
| US8204266B2 (en) | 2005-10-21 | 2012-06-19 | Sfx Technologies Limited | Audio devices |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2397720B (en) | 2006-10-11 |
| GB0301003D0 (en) | 2003-02-19 |
| GB0400961D0 (en) | 2004-02-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20110116 |