Patent Description:
Ion emitters of charge neutralizers generate and supply both positive ions and negative ions into the surrounding air or gas media. To generate gas ions, the amplitude of the applied voltage must be high enough to produce a corona discharge between at least two electrodes arranged as an ionization cell. In the ionization cell, at least one electrode is an ion emitter and another one may be a reference electrode. <CIT> describes an ion generator for generating air ions. <CIT> describes an ion generating apparatus for generating ionized air. <CIT> describes an apparatus for generating a supersonic jet of gaseous ions.

An apparatus for adaptive charge neutralization are disclosed, substantially as illustrated by and described in connection with at least one of the figures, as set forth more completely in the claims.

Ionizers, or charge neutralizers, emit positive and/or negative ions to discharge static electricity that may be present on a surface or substrate, such as in a manufacturing facility. Disclosed example methods and apparatus for charge neutralization can be used in class <NUM> cleanroom production environments, and are particularly useful for semiconductor chip manufacturing.

Conventional ion emitters are installed into a housing via a receptacle. Due to pressurization within the housing, the ion emitters and/or emitter nozzles holding the emitters are subject to forces that resist installation and/or encourage ejection from the housing. Due to friction forces associated with sealing elements during, installation and replacement of emitter nozzles involving multiple turns of conventional ion emitters could be fatiguing to the operator. Some other conventional ion emitter nozzles are installed using bayonet-type fittings. However, bayonet fittings require substantial insertion force to overcome the resistance from the sealing elements.

In contrast with conventional ion emitter nozzle assemblies, disclosed ion emitter nozzles and receptacles have threaded connections in which the threads have multiple sections. In some such examples, the nozzle receptacle is double threaded and the emitter housing includes cams configured to be threaded into the dual threads. A first section of each thread has a first flank angle (e.g., an angle defined by the pitch with respect to the perpendicular, circumferential line), and each thread terminates into a second section having a lower flank angle. In some such examples, the second section has a pitch angle of zero. The lower flank angle improves locking of the emitter nozzle in the installed position and reduces the likelihood of unintended unwinding or ejection of the emitter nozzle, while improving ease of installation.

The terms "ionization" and "charge neutralization" are used interchangeably in this document.

Disclosed example apparatus for charge neutralization include: an emitter nozzle having an emitter and a housing configured to hold the emitter, in which the housing includes a plurality of cams on an exterior of the housing; and a nozzle receptacle configured to enable insertion and removal of the emitter nozzle, and to hold the emitter nozzle in place during operation of the emitter nozzle, the nozzle receptacle including: a plurality of threads corresponding to the plurality of cams on the emitter nozzle, the plurality of threads having a first flank angle; and a plurality of shelves located at respective distal ends of the plurality of threads, the plurality of shelves having a second flank angle less than the first flank angle.

Some example apparatus further include a power supply, in which the nozzle receptacle is configured to conduct power from the power supply to the emitter nozzle when the emitter nozzle is installed in the nozzle receptacle. In some example apparatus, the housing of the emitter nozzle includes two cams, and the nozzle receptacle comprises a double thread.

In some example apparatus, the plurality of threads include between one-half and one full turn to install the emitter nozzle into the nozzle receptacle. In some example apparatus, the nozzle receptacle includes a seat configured to provide a seal against an exterior of the housing of the emitter nozzle, and the emitter nozzle includes a seal on an exterior of the housing such that the seal abuts the seat. Some such example apparatus further include an ionizer housing having a plurality of nozzle receptacles. In some example apparatus, an interior of the ionizer housing is pressurized with air, and the seat is configured to seal against the air pressure. In some example apparatus, the shelves are configured to prevent unwinding of the emitter nozzle from the nozzle receptacle by the air pressure.

In some example apparatus, the nozzle receptacle is injection molded. In some example apparatus, at least one of the shelves has a second flank angle of <NUM> degrees. In some example apparatus, at least one of the shelves has a protrusion between the threads and the shelves such that one of the cams must traverse the protrusion to reach the corresponding shelf from the thread and to reach the corresponding thread from the shelf. In some example apparatus, at least one of the shelves has a second flank angle of less than <NUM> degrees.

<FIG> illustrates an example AC charge neutralization system <NUM> configured to control an ionization output based on balance voltage feedback. The example AC charge neutralization system <NUM> outputs positive and negative ions <NUM> to neutralize electric charges on a target device or substrate <NUM>.

To generate the ions <NUM>, the example system <NUM> includes one or more ion emitter nozzles <NUM>, which are coupled to one or more power supplies that provide a high voltage, high frequency AC signal for generation of the ions <NUM>. The system <NUM> may include any number of emitter nozzles <NUM> to disperse ions <NUM> to a desired area or size of the target device or substrate <NUM>. By alternating positive and negative ions, the example system <NUM> effectively neutralizes static charge present on the target device or substrate <NUM>, while reducing or avoiding charging the target device or substrate <NUM> with the ions <NUM>.

The system <NUM> of <FIG> alternates positive and negative ions by controlling the output voltage at the nozzles <NUM> to output consecutive pulses of positive ions and consecutive pulses of negative ions. The respective durations of consecutive positive and negative pulses may be controlled based on a desired balance. In contrast with conventional charge neutralization systems, the example system <NUM> achieves a balance voltage within +/- 5V by measuring the balance voltage via an antenna <NUM> and adjusting the ion balance based on the measurements. For example, the system <NUM> may adjust the relative numbers or durations of consecutive positive and negative pulses to adjust the output balance. The antenna <NUM> may be positioned near the target <NUM> such that the antenna <NUM> measures a balance voltage representative of the output of system <NUM>. Using the feedback from the antenna <NUM>, the system <NUM> repeatedly (e.g., constantly) adjusts the balance of positive and negative ions.

The example system <NUM> includes a housing <NUM> that contains the power supply and the nozzles <NUM>, as well as any other components in the system. The nozzles <NUM> may be installed and uninstalled from the system <NUM> to facilitate replacement of the nozzles <NUM> due to wear, contamination, and/or damage.

<FIG> is an exploded view of an example emitter assembly <NUM> that may be used to implement the nozzles <NUM> of <FIG>. In operation, the emitter assembly <NUM> receives a high voltage, high frequency signal from a power supply of the system <NUM>, and outputs positive and negative ions based on the received voltage.

The emitter assembly <NUM> includes an emitter nozzle <NUM> which is configured to be installed into a nozzle receptacle <NUM>. The nozzle receptacle <NUM> may be integral with a housing <NUM> of the system <NUM>, while the emitter nozzle <NUM> is installed and uninstalled in the nozzle receptacle <NUM>. The example nozzle receptacle <NUM> may further facilitate conduction of electrical signals to and/or from the emitter nozzle <NUM>.

The emitter nozzle <NUM> includes an emitter <NUM> and an emitter housing <NUM>. The example emitter <NUM> is removably installed into the emitter housing <NUM>, which positions the emitter <NUM> for proper installation into the nozzle receptacle <NUM>. The emitter housing <NUM> and/or the nozzle receptacle <NUM> may include one or more o-rings, gaskets, and/or other seals to avoid gas leakage between the emitter housing <NUM> and the nozzle receptacle <NUM>.

As disclosed in more detail below, the example emitter nozzle <NUM> is screwed into the nozzle receptacle <NUM>, which includes internal threads and shelves to avoid unintentional unscrewing of the emitter nozzle <NUM> from the receptacle <NUM>. The emitter housing <NUM> includes two cams <NUM>, which are threaded into the internal threads of the receptacle <NUM>. In contrast with conventional emitter nozzles, the example emitter nozzle <NUM> and receptacle <NUM> are resistant to unintentional dethreading due to gas pressure on the emitter nozzle <NUM> from the interior of the housing <NUM>.

<FIG> is a perspective view of the example nozzle receptacle <NUM> of <FIG>. <FIG> is a cross-sectional view of the example nozzle receptacle of <FIG>. The nozzle receptacle <NUM> is threaded to enable screwing in of the emitter housing <NUM> via the cams <NUM>. In the example of <FIG> and <FIG>, the nozzle receptacle <NUM> is double threaded. The threads 302a, 302b have a first flank angle, which may be selected to allow for installation in a quarter-turn, a half-turn, a three-quarter turn, a full-turn, and/or any other number of turns of the emitter nozzle <NUM> into the receptacle <NUM>.

At the distal end of each of the threads 302a, 302b, the thread 302a, 302b includes a shelf portion 304a, 304b which has a reduced flank angle. <FIG> is a more detailed perspective view of the threads 302a, 302b and a shelf 304b of the example nozzle receptacle <NUM> of <FIG>. In the example of <FIG> and <FIG>, the flank angle is reduced to zero at the shelf portion 304a, 304b. When installed, any outward pressure on the emitter housing <NUM> from the nozzle receptacle <NUM> does not result in translation to a dethreading force, even when combined with vibration or other effects that can cause unseating.

<FIG> is a cross-sectional view of the example emitter assembly <NUM> of <FIG> in an installed configuration. As shown in <FIG>, the cams <NUM> are positioned against the shelf portions 304a, 304b of the threads 302a, 302b. In the installed position, the emitter <NUM> extends through the nozzle receptacle <NUM> to make electrical contact with the power supply.

Also illustrated in <FIG> are example seals <NUM>, <NUM>, which are positioned on an exterior of the emitter housing <NUM>. The seals <NUM>, <NUM> abut a seat <NUM> of the nozzle receptacle <NUM> and/or other locations within an interior of the nozzle receptacle. The seals <NUM>, <NUM> reduce leakage of gas around an exterior of the emitter housing <NUM>.

<FIG> is a cross-sectional view of another example nozzle receptacle <NUM> that may be used to implement the nozzle receptacle <NUM> of <FIG>. Similar to the nozzle receptacle <NUM> of <FIG>, the nozzle receptacle <NUM> includes threads 302a, 302b having a shelf portion 304a, 304b. The example nozzle receptacle <NUM> further includes a protrusion <NUM> between the first portion of the thread 302b and the shelf 304b. One or both threads 302a, 302b may include a protrusion.

The example protrusion <NUM> further increases the movement and/or energy required for the cam <NUM> to move from the shelf portion 304b to the thread 302b. Thus, the protrusion <NUM> further reduces the likelihood of unintentional dethreading of the emitter nozzle <NUM> from the receptacle <NUM> without substantially increasing the difficulty of installation and uninstallation.

<FIG> is a cross-sectional view of another example nozzle receptacle <NUM> that may be used to implement the nozzle receptacle <NUM> of <FIG>. Similar to the nozzle receptacle <NUM> of <FIG>, the nozzle receptacle <NUM> includes threads 302a, 302b having a shelf portion 304a, 304b. In the example receptacle <NUM>, the shelf portion 304b has a negative flank angle, in which the shelf portion 304a reverses the thread direction. The example shelf portion 304b with the negative flank angle may have a similar effect as the protrusion <NUM> of <FIG>, which is to increase the movement and/or energy required for the cam <NUM> to move from the shelf portion 304b to the thread 302b. Thus, the shelf portion 304b further reduces the likelihood of unintentional dethreading of the emitter nozzle <NUM> from the receptacle <NUM> without substantially increasing the difficulty of installation and uninstallation.

In the example of <FIG>, both shelf portions 304a, 304b include the negative flank angle for alignment of the emitter <NUM>. The shelf portions 304a, 304b may have a negative flank angle for a portion or the entirety of the length of the shelf portions 304a, 304b.

Any of the example nozzle receptacles <NUM>, <NUM>, <NUM> of the illustrated examples may be constructed using any appropriate technique. Example construction or manufacturing techniques may involve, but are not limited to, injection molding and/or additive manufacturing.

Claim 1:
An apparatus for charge neutralization, the apparatus comprising:
an emitter nozzle (<NUM>) comprising:
an emitter (<NUM>); and
a housing (<NUM>) configured to hold the emitter (<NUM>), the housing (<NUM>) comprising a plurality of cams (<NUM>) on an exterior of the housing (<NUM>); and
a nozzle receptacle (<NUM>, <NUM>, <NUM>) configured to enable insertion and removal of the emitter nozzle (<NUM>), and to hold the emitter nozzle (<NUM>) in place during operation of the emitter nozzle (<NUM>), the nozzle receptacle (<NUM>) comprising:
a plurality of threads (302a, 302b) corresponding to the plurality of cams (<NUM>) on the emitter nozzle (<NUM>), the plurality of threads (302a, 302b) having a first flank angle; and
a plurality of shelves (304a, 304b) located at respective distal ends of the plurality of threads (302a, 302b), the plurality of shelves (304a, 304b) having a second flank angle less than the first flank angle.