Laser damage detection mechanisms for safety interlock and fault detection

An apparatus includes a substrate and first and second electrical connectors. The apparatus also includes at least one first conductive trace positioned in, on, or over the substrate. The at least one first conductive trace forms an electrical connection between the first and second electrical connectors. The at least one first conductive trace is configured to be damaged by laser energy to break the electrical connection between the first and second electrical connectors. The apparatus further includes an indicator electrically coupled to the at least one first conductive trace. The indicator is configured to generate feedback based on whether the electrical connection between the first and second electrical connectors has been broken.

TECHNICAL FIELD

This disclosure generally relates to high-energy laser systems. More specifically, this disclosure relates to laser damage detection mechanisms for safety interlock and fault detection.

BACKGROUND

High-energy laser systems are being developed for a number of commercial and defense-related applications. Unfortunately, it is not uncommon for a high-energy laser beam (or a portion thereof) to escape a high-energy laser system. This can be caused by a number of factors, such as misalignment of optical elements in the laser system. As a result, physical barriers are often positioned around a high-energy laser system (such as in a laboratory, test area, or other setting) or incorporated into the high-energy laser system itself (such as in a housing). Stray laser energy can strike the barriers and be converted into heat, which helps to protect nearby personnel from injury and helps to protect nearby equipment from damage. These barriers are often formed from materials such as graphite, aluminum, plastic, or steel.

SUMMARY

This disclosure provides laser damage detection mechanisms for safety interlock and fault detection.

In a first embodiment, an apparatus includes a substrate and first and second electrical connectors. The apparatus also includes at least one first conductive trace positioned in, on, or over the substrate. The at least one first conductive trace forms an electrical connection between the first and second electrical connectors. The at least one first conductive trace is configured to be damaged by laser energy to break the electrical connection between the first and second electrical connectors. The apparatus further includes an indicator electrically coupled to the at least one first conductive trace. The indicator is configured to generate feedback based on whether the electrical connection between the first and second electrical connectors has been broken.

In a second embodiment, a system includes one or more laser damage detectors each configured to detect stray laser energy from a laser. Each laser damage detector includes a substrate, first and second electrical connectors, at least one first conductive trace, and an indicator. The at least one first conductive trace is positioned in, on, or over the substrate. The at least one first conductive trace forms an electrical connection between the first and second electrical connectors. The at least one first conductive trace is configured to be damaged by the stray laser energy to break the electrical connection between the first and second electrical connectors. The indicator is electrically coupled to the at least one first conductive trace. The indicator is configured to generate feedback based on whether the electrical connection between the first and second electrical connectors has been broken. The system also includes a laser controller configured to shut down operation of the laser in response to breaking of the electrical connection between the first and second electrical connectors in at least one of the one or more laser damage detectors.

In a third embodiment, a method includes passing an electrical current through at least one first conductive trace of a laser damage detector. The at least one first conductive trace is positioned in, on, or over a substrate. The at least one first conductive trace forms an electrical connection between first and second electrical connectors. The method also includes generating feedback as the electrical current passes through the electrical connection between the first and second electrical connectors. The method further includes, in response to damage of the at least one first conductive trace by laser energy, stopping generation of the feedback, where the damage breaks the electrical connection between the first and second electrical connectors.

In a fourth embodiment, an apparatus includes a substrate and first and second electrical connectors. The apparatus also includes at least one first conductive trace positioned in, on, or over the substrate. The at least one first conductive trace forms an electrical connection between the first and second electrical connectors. The at least one first conductive trace is configured to be damaged by laser energy to break the electrical connection between the first and second electrical connectors.

DETAILED DESCRIPTION

As noted above, it is often possible for a high-energy laser beam (or a portion thereof) to escape a high-energy laser system, such as when mirrors, lenses, or other optical elements in the system are misaligned. Barriers can be positioned around a high-energy laser system or incorporated into the high-energy laser system so that stray laser energy strikes the barriers, which helps to protect nearby personnel and equipment. Unfortunately, these barriers are typically very heavy and thick, so it can be difficult and expensive to incorporate these barriers into or around a laser system. Also, these barriers typically block viewing into an enclosed volume, which can prevent personnel from viewing the laser system itself. Because of this, it is often difficult or impossible for personnel to know if and when there is a misalignment or other fault that allows laser energy to escape a laser system.

In one approach, “burn strips” can be positioned around a laser system. Each burn strip generally includes a material that, when exposed to laser energy, changes color or is removed to expose a lower material having a different color or brightness. This allows the burn strips to be used to identify (after the fact) that laser energy escaped a laser system. However, burn strips are prone to failure and typically cannot be used to identify where a fault lies within a laser system. Also, burn strips cannot be used to automatically shut down a laser system when there is a fault, so operation of the laser system can continue even after stray laser energy strikes the burn strips.

In another approach, one or more infrared-sensing cameras can be used to sense when laser energy escapes a laser system. However, infrared-sensing cameras can often receive a significant amount of scattered light, which can interfere with proper operation of the infrared-sensing cameras. As a result, infrared-sensing cameras are often prone to generating “false positives,” meaning the cameras detect stray laser energy when there is none. Because of this, there often needs to be a human operator monitoring the infrared-sensing cameras in order to verify whether stray laser energy has actually been detected and to shut down a laser system at an appropriate time. This can sometimes result in significant delays between the release of the stray laser energy and shutdown of the laser system.

This disclosure provides various laser damage detection mechanisms that can be used for safety interlock, fault detection, or other functions. Each laser damage detection mechanism generally includes one or more conductive traces formed in, on, or over a substrate. The substrate can represent a thin film, a fabric, a wall panel, a laser housing, or other suitable structure configured to carry or incorporate one or more conductive traces. For example, the conductive traces can be formed on panels that are mountable to walls or other structures around a given area, or the conductive traces can be integrated into or positioned around a laser housing. As particular examples, the conductive traces can be formed using three-dimensional (3D) printing on polyimide films or other substrates, or the conductive traces can be overlaid onto or inlayed into different portions of a laser housing. The one or more conductive traces can be wired in series with one or more light emitting diode (LED) indicators or other indicator or sensing devices that can generate visual feedback or other feedback.

When a high-energy laser beam (or a portion thereof) strikes a laser damage detection mechanism, the beam energy can burn through or melt at least one conductive trace of the laser damage detection mechanism. This interrupts or alters an electrical circuit formed using the conductive trace. In some embodiments, while the electrical circuit of a laser damage detection mechanism is intact, the LED indicator can generate illumination, or another indicator or sensing device can generate other feedback. This feedback allows personnel to know that the laser damage detection mechanism has not been damaged by laser energy. Damage from laser energy can break the electrical circuit, causing the illumination or other feedback to stop. The loss of feedback allows personnel to know that a fault has occurred and that the laser damage detection mechanism has been damaged by the laser energy. Also, interruption or alteration of the electrical circuit can be quickly detected by a control mechanism for the laser system, which can then shut down the laser system using an appropriate safety interlock. In addition, a bypass mechanism can be used in a damaged detection mechanism to restore current flow through the damaged detection mechanism, which allows other laser damage detection mechanisms coupled in series to continue operation.

In this way, one or more laser damage detection mechanisms can be used to support the shutdown of a laser system in response to detecting damage caused by stray beam energy. This can occur automatically and in an ultra-fast manner without requiring human intervention. Also, the size and pattern of the conductive traces in the laser damage detection mechanisms can be easily configured to prevent beams of certain diameters from escaping a given volume, which allows for easy tailoring of the laser damage detection mechanisms to support their use with various laser systems. Further, when conductive traces are formed on film or fabric substrates or other thin flexible substrates, the resulting structures are lightweight and easily conformed to match the surfaces of a laboratory, test area, or other area. Moreover, laser damage detection mechanisms implemented in this manner can be quickly and easily manufactured in various shapes and sizes, and they may be easily and cheaply replaced depending on the implementation. In addition, the LED indicators or other indicator or sensing devices can be used to quickly and easily identify where laser energy strikes laser damage detection mechanisms, and diagnostics can be performed to identify the conductive traces that failed for rapid troubleshooting.

FIGS. 1 and 2illustrate example systems100and200having laser damage detection mechanisms for safety interlock and fault detection in accordance with this disclosure. As shown inFIG. 1, the system100includes a high-energy laser102, which generally operates to produce at least one high-energy laser beam104. The laser102represents any suitable source configured to generate at least one high-energy beam. In some embodiments, for example, the laser102can be implemented as described in U.S. Patent Application Publication Nos. 2017/0353005 and 2018/0013256 (both of which are hereby incorporated by reference in their entirety). However, any other suitable high-energy laser102(now known or later developed) can be used in the system100. The beam104represents any suitable high-energy laser beam having any suitable cross-sectional size and power level. In general, a “high-energy” beam can represent a beam having about ten kilowatts of power or more.

The laser102can be used in a number of commercial and defense-related applications. For example, the high-energy laser102can find use in commercial mining applications, such as in drilling, mining, or coring operations. For instance, the high-energy laser102can be used to soften or weaken an earth bed prior to drilling through the earth bed using drill bits. This can allow for fewer drill bit changes and extended lifetimes and reliabilities of the drill bits. Here, free-space propagation of the high-energy laser beam104from an output window of the laser102may be used, allowing deeper penetration at further distances compared to conventional fiber lasers.

The high-energy laser102can also find use in remote laser welding, cutting, drilling, or heat treating operations, such as in industrial or other automation settings. The use of a high-power and high-beam quality system100allows the processing of thicker materials to occur at larger working distances from the system100while minimizing the heat-affected zone and maintaining vertical or other cut lines. Among other things, this helps to support welding or cutting operations where proximity to the weld or cut site is difficult or hazardous. It also helps to protect the system100and possibly any human operators from smoke, debris, or other harmful materials.

The high-energy laser102can further find use in construction and demolition operations. Example operations can include metal resurfacing or deslagging, paint removal, and industrial demolition operations. The high-energy laser102can be used to ablate material much faster and safer compared to conventional operations. As a particular example of this functionality, the high-energy laser102can be used to support demolition of nuclear reactors or other hazardous structures. Here, the high-energy laser102can be used to cut through contaminated structures like contaminated concrete or nuclear containment vessels or reactors from long distances. This helps to avoid the use of water jet cutting or other techniques that create hazardous waste, such as contaminated water. It also provides improved safety since human operators can remain farther away from contaminated structures being demolished.

A number of additional applications are possible. For example, the high-energy laser102can find use in power beaming applications, where high-power laser beams104are targeted to photovoltaic (solar) cells of remote devices to be recharged. The high-energy laser102can also find use in hazardous material (HAZMAT) applications, where the laser102is used to heat and decompose hazardous materials into less harmful or non-harmful materials. Note that all of the above applications are for illustration only and do not limit this disclosure to any particular applications of the system100.

The laser102is typically contained within a housing106. The housing106generally encases and protects the components of the laser102. The housing106also typically includes an opening, window, or other structural feature that allows passage of the beam104from the laser102out of the housing106. The housing106can be formed from any suitable material(s) and in any suitable manner. The housing106can also have any suitable size, shape, and dimensions.

A laser controller108generally controls the operation of the laser102. For example, the laser controller108can control whether the laser102is actively generating the beam104or is in a standby state ready to generate the beam104. The laser controller108can also control whether the laser102is generating a continuous beam104or an intermittent beam104and the power/energy level of the beam104. The laser controller108includes any suitable structure for controlling operation of a laser102. For instance, the laser controller108can include one or more processing devices, such as one or more microprocessors, microcontrollers, digital signal processors, field programmable gate arrays, application specific integrated circuits, or discrete logic devices. The laser controller108can also include one or more memories configured to store instructions or data used, generated, or collected by the processing device(s). The laser controller108can further include one or more interfaces configured to facilitate communications with other components or systems. Note that while the laser controller108is shown here as being separate from the laser102, the laser controller108can be incorporated into the laser102inFIG. 1.

In the example shown inFIG. 1, the laser102is surrounded by one or more laser damage detection mechanisms110. As described in more detail below, each laser damage detection mechanism110includes at least one conductive trace in, on, or over a substrate. The substrate represents a thin film, a fabric, a wall panel, or other suitable structure configured to be positioned around or near the laser102. For example, wall panels incorporating the laser damage detection mechanisms110can be mounted on walls of a laboratory, test area, or other area in which the laser102is being tested or otherwise used. As another example, films incorporating the laser damage detection mechanisms110can be placed around the laser102and conformed to walls of the housing106or walls of a laboratory, test area, or other area.

Each laser damage detection mechanism110also includes at least one LED or other feedback device configured to generate visual feedback or other feedback. The conductive trace(s) of each laser damage detection mechanism110can form an electrical circuit with the associated LED(s) or other feedback device(s). If the high-energy beam104(or a portion thereof) strikes a laser damage detection mechanism110, the energy in the beam104can burn through at least one conductive trace of the laser damage detection mechanism110, which interrupts or alters an electrical circuit formed using that conductive trace. In some embodiments, when a laser damage detection mechanism110is undamaged, its LED or other feedback device generates feedback to indicate no laser damage has occurred. When damage occurs to the conductive trace(s) of a laser damage detection mechanism110, its LED or other feedback device stops generating feedback to indicate that laser damage has occurred.

Moreover, control feedback associated with the electrical circuit formed using one or more laser damage detection mechanisms110can be provided to the laser controller108. For example, a sensor (such as a current sensing or measuring device) can be used to detect a loss of current flowing through the laser damage detection mechanism110or to detect a change in the current flowing through the laser damage detection mechanism110. If and when damage occurs to a laser damage detection mechanism110, the laser controller108can detect the interruption or alteration of the current caused by the damage using the control feedback. The laser controller108can therefore use this control feedback to determine whether a fault has occurred, automatically shut down the laser102using a safety interlock function, trigger an alarm, or perform any other suitable function.

In some embodiments, the laser controller108can receive control feedback associated with each individual laser damage detection mechanism110. In other embodiments, multiple laser damage detection mechanisms110can be coupled together, such as in series, and the laser controller108can receive control feedback associated with the group of laser damage detection mechanisms110. In particular embodiments, multiple laser damage detection mechanisms110can be coupled together in series, and each laser damage detection mechanism110can include a bypass mechanism. Each bypass mechanism allows current to flow through a laser damage detection mechanism110even when at least one conductive trace of the laser damage detection mechanism110has been interrupted. This allows the LED or other feedback device of the damaged detection mechanism110to stop working (allowing personnel to identify the damaged detection mechanism110) while allowing the current to flow through the other laser damage detection mechanisms110. In some embodiments, this also allows the current flowing through the entire collection of laser damage detection mechanisms110to be sensed or measured, which allows the laser controller108to detect damage to one or more of the laser damage detection mechanisms110based on changes in the current.

Each laser damage detection mechanism110includes any suitable structure containing at least one conductive trace that can be damaged or otherwise interrupted by laser energy. Each conductive trace can be formed from any suitable conductive material(s), such as copper or aluminum. Each conductive trace can also be formed in any suitable manner, such as 3D printing onto a substrate or by depositing conductive material and patterning/etching the conductive material.

As shown inFIG. 2, the system200includes a high-energy laser202, which generally operates to produce at least one high-energy laser beam204. The laser202is typically contained within a housing206, and a laser controller208generally controls the operation of the laser202. These components202-208can be the same as or similar to the corresponding components102-108described above. Note that while the laser controller208is shown here as being separate from the laser202, the laser controller208can be incorporated into the laser202inFIG. 2.

The system200also includes one or more laser damage detection mechanisms210, each of which can include at least one conductive trace in, on, or over a substrate as described above. In this example, however, the laser damage detection mechanisms210are positioned inside or incorporated into the housing206of the system200. For example, the laser damage detection mechanisms210can be implemented using one or more films, fabrics, or other small or flexible substrates that are placed on or within the housing206. As another example, the laser damage detection mechanisms210can be implemented using conductive traces formed on surfaces of the housing206or embedded within the surfaces of the housing206. As particular examples, the conductive traces can be formed on the surfaces of the housing206by using 3D printing or by depositing conductive material and patterning/etching the conductive material. As another particular example, the conductive traces can be formed as embedded traces within the housing206during manufacturing of the housing206.

Each laser damage detection mechanism210also includes at least one LED or other feedback device that produces feedback or that does not produce feedback based on whether at least one conductive trace of the laser damage detection mechanism210has been damaged. This can occur in the same manner discussed above. Also, control feedback associated with the electrical circuit formed using one or more laser damage detection mechanisms210can be provided to the laser controller208, and the laser controller208uses the control feedback to determine whether a fault has occurred or to automatically shut down the laser202using a safety interlock function. Again, this can occur in the same manner discussed above.

In some embodiments, the laser controller208can receive control feedback associated with each individual laser damage detection mechanism210. In other embodiments, multiple laser damage detection mechanisms210can be coupled together, such as in series, and the laser controller208can receive control feedback associated with the group of laser damage detection mechanisms210. Again, in particular embodiments, each laser damage detection mechanism210can include a bypass mechanism that allows current to flow through a laser damage detection mechanism210even when at least one conductive trace of the laser damage detection mechanism210has been interrupted. This allows the LED or other feedback device of the damaged detection mechanism210to stop working while allowing the current to flow through the other laser damage detection mechanisms210. In some embodiments, this also allows the current flowing through the entire collection of laser damage detection mechanisms210to be sensed or measured, which allows the laser controller208to detect damage to one or more of the laser damage detection mechanisms210based on changes in the current.

AlthoughFIGS. 1 and 2illustrate two examples of systems100and200having laser damage detection mechanisms for safety interlock and fault detection, various changes may be made toFIGS. 1 and 2. For example, the lasers102and202and their associated components (such as the housings106and206and laser controllers108and208) have been described here at a high level. Numerous additional features now known or later developed can be incorporated into a system that includes a laser and that uses at least one laser damage detection mechanism to detect stray beam energy.

FIG. 3illustrates an example laser damage detection mechanism300for safety interlock and fault detection in accordance with this disclosure. The laser damage detection mechanism300can, for example, be used in the systems100and200ofFIGS. 1 and 2. However, the laser damage detection mechanism300can be used in any other suitable system to detect stray beam energy.

As shown inFIG. 3, the laser damage detection mechanism300includes a substrate302and at least one first conductive trace304. The substrate302generally represents any suitable structure that carries at least the first conductive trace304. In some embodiments, the first conductive trace304can be formed on or over an outer surface of the substrate302, such as by using 3D printing or patterning/etching. In other embodiments, the first conductive trace304can be formed within the substrate302. The substrate302includes any suitable structure that includes or carries at least one conductive trace, such as a polyimide film (like KAPTON), a fabric, a wall panel, or at least a portion of a graphite, aluminum, plastic, or steel laser housing.

The first conductive trace304in this example travels back and forth repeatedly across the substrate302. In some embodiments, the open or non-conductive spaces between different portions of the first conductive trace304are smaller than the expected beam size of a high-energy laser beam. In this particular example, the first conductive trace304includes vertical linear portions that are connected by semi-circular or other connecting portions on top and bottom. However, note that the specific pattern of the first conductive trace304shown inFIG. 3is for illustration only, and any other suitable pattern can be used for the first conductive trace304. For instance, the first conductive trace304can have horizontal linear portions that are connected by semi-circular or other connecting portions on the right and left, or the first conductive trace304can have horizontal, vertical, or other wavy portions that are connected by semi-circular or other connecting portions. In general, the first conductive trace304can have any suitable pattern that allows the first conductive trace304to be damaged by stray laser energy.

A feedback device (in this example at least one LED306) is electrically coupled to the first conductive trace304. When an electrical current flows through the first conductive trace304, the LED306generates illumination. When the first conductive trace304is damaged and the flow of the electrical current is interrupted, the LED306stops generating illumination. In this way, the LED306provides feedback to identify whether damage has occurred to the first conductive trace304. Each LED306includes any suitable structure configured to generate illumination for a laser damage detection mechanism. Note, however, that the use of a feedback device is not necessarily required.

First and second electrical connectors308and310provide for electrical connection of the laser damage detection mechanism300to one or more other components, and the first conductive trace304forms an electrical connection between the connectors308and310. For example, in some embodiments, the connectors308and310can be used to couple adjacent laser damage detection mechanisms300in a series manner. As another example, one or both connectors308and310can be used to couple the laser damage detection mechanism300to a power supply or a current sensor as described in more detail below. Each connector308and310includes any suitable structure providing an electrical connection between at least one conductive trace of a laser damage detection mechanism and an external component.

Optionally, the laser damage detection mechanism300can include a second conductive trace312, which may be referred to as a “bypass” trace or path. The second conductive trace312forms another electrical connection between the connectors308and310. If and when the first conductive trace304is damaged by stray laser energy (or in any other manner), electrical current can be redirected from the first conductive trace304to the second conductive trace312. As a result, damage to the first conductive trace304causes the LED306to stop illuminating, but current can flow through the laser damage detection mechanism300via the second conductive trace312. This may allow, for example, multiple laser damage detection mechanisms300to be used in series, where a failure of the first conductive trace304in one laser damage detection mechanism300is bypassed so that the LEDs306in the other laser damage detection mechanisms300can generate illumination.

The second conductive trace312can be formed from any suitable conductive material(s), such as copper or aluminum. The second conductive trace312can also be formed in any suitable manner, such as by 3D printing onto a substrate or by depositing conductive material and patterning/etching the conductive material.

In order to support the ability of the second conductive trace312to bypass a failed first conductive trace304, one or both connectors308and310can support a mechanism that redirects electrical current onto the second conductive trace312. For example, in some embodiments, one or both connectors308and310can include a shunt wire that is coated with an insulator (such as an oxide). Upon a failure of the first conductive trace304, a voltage buildup can burn through or melt the insulation of the shunt wire, causing the shunt wire to become much more conductive. This allows the electrical current to flow over the shunt wire to the second conductive trace312, bypassing the failed first conductive trace304.

Note, however, that any other suitable mechanisms can be used here to allow current to flow through the second conductive trace312. As long as the second conductive trace312is able to pass current when the first conductive trace304fails, multiple laser damage detection mechanisms300can be coupled in series such that one or more detection mechanisms300can generate illumination or other feedback even when one or more other detection mechanisms300fail.

Also note that there are various ways in which damage to a laser damage detection mechanism300can be detected. For example, the failure of a first conductive trace304in a laser damage detection mechanism300can interrupt the current flowing through an electrical circuit. Even if the current is quickly redirected onto the second conductive trace312, the interruption of the current can be detected. As another example, an apparent change in the electrical circuit formed through a laser damage detection mechanism300can be detected. For instance, the second conductive trace312may be shorter than the first conductive trace304and may lack an LED or other feedback device, so the second conductive trace312can have a smaller resistance than the first conductive trace304and the LED306. When current is redirected onto the second conductive trace312after the first conductive trace304is damaged, this can allow the current flowing through the electrical circuit to increase. This increase can be detected and used as an indication that damage has occurred to a laser damage detection mechanism300.

AlthoughFIG. 3illustrates one example of a laser damage detection mechanism300for safety interlock and fault detection, various changes may be made toFIG. 3. For example, the laser damage detection mechanism300can have any suitable size, shape, and dimensions. Also, each of the conductive traces304and312can have any suitable pattern. Further, the laser damage detection mechanism300can include any suitable number of each component.

In addition, while the laser damage detection mechanism300has been described as having a single substrate302and a single first conductive trace304, other embodiments of the laser damage detection mechanism300can also be used. For instance, in other embodiments, a laser damage detection mechanism300can include multiple substrates302that are stacked on top of each other, or separate laser damage detection mechanisms300can be stacked on top of each other. At least two of the substrates302can include different first conductive traces304having different patterns, such as when one substrate has the same pattern as another substrate but the pattern is rotated by some angle (such as 90°). This stacking may allow each individual substrate302to have open or non-conductive spaces (spaces without a first conductive trace) larger than the expected size of the beam energy, while the collection of substrates302has open or non-conductive spaces smaller than the expected size of the beam energy. Separate LEDs306and conductive traces312can also be provided for each substrate302.

FIGS. 4 and 5illustrate an example use of laser damage detection mechanisms for safety interlock and fault detection in accordance with this disclosure. For ease of explanation, the laser damage detection mechanism300ofFIG. 3is used inFIGS. 4 and 5. However, the use of the laser damage detection mechanism300shown inFIGS. 4 and 5is for illustration only. The laser damage detection mechanism300can be used in any other suitable manner.

As shown inFIG. 4, multiple instances of the laser damage detection mechanism300(referred to respectively as first and second laser damage detection mechanisms300aand300b) are coupled in series. The first laser damage detection mechanism300aincludes a first substrate302a, a first conductive trace304a, a first LED306a, first and second connectors308aand310a, and a second conductive trace312a. The second laser damage detection mechanism300bincludes a second substrate302b, a third conductive trace304b, a second LED306b, third and fourth connectors308band310b, and a fourth conductive trace312b.

The second connector310aof the first laser damage detection mechanism300aconnects to the third connector308bof the second laser damage detection mechanism300b. Thus, the first conductive trace304aor the second conductive trace312acan be electrically connected to the third conductive trace304bor the fourth conductive trace312bthrough the second connector310aand the third connector308b. InFIG. 4, when both laser damage detection mechanisms300a-300bare undamaged, an electrical current can flow through both the first conductive trace304aand the third conductive trace304b. As a result, both LEDs306aand306bgenerate illumination as shown inFIG. 4.

InFIG. 5, a laser beam502(which might represent either of the high-energy beams104and204) has been directed towards a mirror or other optical element504in a laser system. However, the beam502has moved somewhat off the optical element504, which is typically referred to as “beam walking.” A portion of the beam502therefore strays and strikes the first laser damage detection mechanism300ain this example, forming a cut506partially or completely through the first laser damage detection mechanism300a. This cut506damages the first conductive trace304aand interrupts the electrical circuit formed using the first conductive trace304a. As a result, the LED306aof the first laser damage detection mechanism300astops generating illumination, thereby providing visual feedback identifying the first laser damage detection mechanism300aas being damaged.

As described above, in some embodiments, the connector308aof the first laser damage detection mechanism300acan include a shunt wire wrapped in insulation. Similar structures can be used in any or all of the connectors308b,310a,310b. When the first conductive trace304ais cut, the voltage on the connector308acauses the insulation to burn away or melt, forming an effective electrical connection to the second conductive trace312a. Thus, electrical current can flow from the connector308ato the connector310athrough the second conductive trace312a. In the absence of damage to the second laser damage detection mechanism300b, the electrical current then flows through the third conductive trace304b, causing the LED306bto generate illumination. This approach allows the LED306aof the damaged laser damage detection mechanism300ato stop generating illumination, while the LED306bof the undamaged laser damage detection mechanism300bcan continue generating illumination. This provides an easy mechanism for identifying damaged detection mechanisms.

AlthoughFIGS. 4 and 5illustrate one example use of laser damage detection mechanisms for safety interlock and fault detection, various changes may be made toFIGS. 4 and 5. For example, a single laser damage detection mechanism300can be used here, or multiple laser damage detection mechanisms300in any suitable arrangement can be used here. Also, the laser damage detection mechanisms300can be used with any suitable laser that produces any suitable beam. In addition, the laser damage detection mechanisms300can be damaged in other ways besides a beam walking off a mirror.

FIG. 6illustrates another example laser damage detection mechanism600for safety interlock and fault detection in accordance with this disclosure. The laser damage detection mechanism600here includes a substrate602, a first conductive trace604, an LED606, first and second electrical connectors608and610, and a second conductive trace612. These components602-612can be the same as or similar to the corresponding components302-312described above, except the first conductive trace604here has a different pattern. Namely, in this example, the first conductive trace604has a smaller trace pattern, so the open or non-conductive spaces between portions of the first conductive trace604are smaller than the open or non-conductive spaces between portions of the first conductive trace304. The pattern inFIG. 6may be needed or desired when the size of the stray beam energy striking the laser damage detection mechanism600is expected to be smaller compared to the laser damage detection mechanism300.

Note that multiple instances of the laser damage detection mechanism600can be used independently or can be coupled together in the manner shown inFIGS. 4 and 5. Also note that different laser damage detection mechanisms having different designs can be used independently or together in the same system. For example, laser damage detection mechanisms having larger spaces can be coupled to laser damage detection mechanisms having smaller spaces as needed or desired. In general, any number of laser damage detection mechanisms can be used independently or together, and each laser damage detection mechanism can have any suitable pattern for its first conductive trace. Different laser damage detection mechanisms may or may not have different patterns for their conductive traces.

AlthoughFIG. 6illustrates another example of a laser damage detection mechanism600for safety interlock and fault detection, various changes may be made toFIG. 6. For example, the laser damage detection mechanism600can have any suitable size, shape, and dimensions. Also, each of the conductive traces604and612can have any suitable pattern. Further, the laser damage detection mechanism600can include any suitable number of each component, and the feedback device may or may not be included.

In addition, while the laser damage detection mechanism600has been described as having a single substrate602and a single first conductive trace604, other embodiments of the laser damage detection mechanism600can also be used. For instance, in other embodiments, a laser damage detection mechanism600can include multiple substrates602that are stacked on top of each other, or separate laser damage detection mechanisms600can be stacked on top of each other. At least two of the substrates602can include different first conductive traces604having different patterns, such as when one substrate has the same pattern as another substrate but the pattern is rotated by some angle (such as 90°). This stacking may allow each individual substrate602to have open or non-conductive spaces larger than the expected size of the beam energy, while the collection of substrates602has open or non-conductive spaces smaller than the expected size of the beam energy. Separate LEDs606and conductive traces612can also be provided for each substrate602.

FIGS. 7A through 7Cillustrate example electrical circuits formed using laser damage detection mechanisms in accordance with this disclosure. In particular, the electrical circuits shown inFIGS. 7A through 7Ccan be formed by the conductive traces of multiple laser damage detection mechanisms (such as one or both of the laser damage detection mechanisms300or600).

As shown inFIG. 7A, multiple laser damage detection mechanisms300or600are coupled in series. This can be accomplished by attaching the connector310or610(shown inFIGS. 3 and 6, respectively) of one laser damage detection mechanism300or600to the connector308or608(shown inFIGS. 3 and 6, respectively) of a subsequent laser damage detection mechanism300or600. The first laser damage detection mechanism300or600is coupled to a power supply702, such as by coupling the connector308or608of the first laser damage detection mechanism300or600to the power supply702. The last laser damage detection mechanism300or600is coupled to a current sensor704, such as by coupling the connector310or610of the last laser damage detection mechanism300or600to the current sensor704.

The power supply702represents any suitable source of electrical current that can flow through an electrical circuit700, such as a direct current (DC) or alternating current (AC) power supply. The current sensor704represents any suitable structure configured to detect the presence (and optionally measure the amount) of current flowing through the electrical circuit700. Outputs of the current sensor704can be provided to a laser controller108or208(shown inFIGS. 1 and 2, respectively) so that the laser controller108or208can determine if and when the flow of current detected by the current sensor704is interrupted or changes (possibly indicating that a fault has occurred).

InFIG. 7A, all of the laser damage detection mechanisms300or600are undamaged, so the electrical circuit700is intact. Current flows from the power supply702through the first conductive trace304or604(shown inFIGS. 3 and 6, respectively) of each laser damage detection mechanism300or600. As a result, all LEDs306or606of the laser damage detection mechanisms300or600generate illumination. Also, the current sensor704can detect the current flowing through the electrical circuit700and optionally measure a generally-steady amount of current flowing through the electrical circuit700.

InFIG. 7B, one of the laser damage detection mechanisms300or600has been damaged, creating an open circuit706. This condition occurs after the first conductive trace304or604of the damaged detection mechanism300or600has been cut but before the current is rerouted over the second conductive trace312or612(shown inFIGS. 3 and 6, respectively) of the damaged detection mechanism300or600. The current sensor704can detect the interruption of the current and generate one or more outputs for the laser controller108or208. The laser controller108or208can use the output(s) to detect a fault and shut down the laser102or202(shown inFIGS. 1 and 2, respectively). Since the open circuit706can be detected very quickly, this process helps achieve ultra-fast shutdown of the laser102or202.

InFIG. 7C, the first conductive trace304or604of the damaged detection mechanisms300or600remains damaged, but the open circuit706has been replaced by a bypass connection708. The bypass connection708is formed by the second conductive trace312or612in the damaged detection mechanism300or600. The formation of the bypass connection708allows the LEDs306or606in the other laser damage detection mechanisms300or600to generate illumination, while the LED306or606in the damaged detection mechanism300or600can remain off. As a result, personnel can easily identify the damaged detection mechanism300or600.

Note that while the current sensor704inFIG. 7Ccan again detect an electrical current in this state, a shutdown of the laser102or202may have already been initiated by the laser controller108or208in response to the open circuit706. Alternatively, the condition inFIG. 7Ccan be detected by the laser controller108or208, such as when the damaged detection mechanism300or600has a shorter conductive pathway without an LED that reduces the overall resistance in the electrical circuit. This condition can be detected by the laser controller108or208, which can detect a fault and shut down the laser102or202.

AlthoughFIGS. 7A through 7Cillustrate examples of electrical circuits formed using laser damage detection mechanisms, various changes may be made toFIGS. 7A through 7C. For example, as noted above, the laser damage detection mechanisms300or600can be arranged in various ways and need not necessarily be arranged in series to form a single electrical circuit. Other arrangements of laser damage detection mechanisms300or600are also possible, including those in which single laser damage detection mechanisms300or600are used and coupled directly or indirectly to a laser controller108or208. Also, the components inFIGS. 7A through 7Ccan be rearranged, such as when the current sensor704is positioned between two laser damage detection mechanisms300or600. In addition, any other suitable mechanism(s) can be used to sense changes to one or more voltages, currents, or other electrical characteristics within the electrical circuits.

FIG. 8illustrates an example method800of using one or more laser damage detection mechanisms for safety interlock and fault detection in accordance with this disclosure. For ease of explanation, the method800is described as involving the use of one or more laser damage detection mechanisms300or600ofFIG. 3 or 6in the system100or200ofFIG. 1 or 2. However, the method800can involve the use of any suitable laser damage detection mechanism(s) in any suitable system.

As shown inFIG. 8and referring toFIGS. 7A through 7Cunless specified otherwise, one or more laser damage detection mechanisms are positioned around a laser at step802, and a laser controller is arranged to receive control feedback associated with an electrical circuit that includes the laser damage detection mechanism(s) at step804. This can include, for example, installing one or more films, fabrics, wall panels, or other substrates carrying or including conductive traces around the laser102(shown inFIG. 1). This can also include placing a housing206carrying or including conductive traces around the laser202(both shown inFIG. 2). This can optionally further include coupling multiple laser damage detection mechanisms300or600in series. In addition, this can include coupling a current sensor704or other suitable sensor (in series or otherwise) to the laser damage detection mechanism(s)300or600and to a laser controller108or208(shown inFIGS. 1 and 2, respectively).

During operation, at least one current flows through the laser damage detection mechanism(s) at step806. This can include, for example, current from the power supply702passing through the first conductive trace(s)304or604(shown inFIGS. 3 and 6, respectively) of the laser damage detection mechanism(s)300or600. Feedback is generated at the laser damage detection mechanism(s) at step808. This can include, for example, the current passing through the first conductive trace(s)304or604and causing the LED(s)306or606to generate illumination. As long as no damage occurs to the laser damage detection mechanism(s)300or600at step810, the process can continue to repeat steps806and808.

If and when damage occurs to at least one laser damage detection mechanism at step810, the damaged detection mechanism(s)300or600stop(s) generating feedback at step812, and a fault is detected and shutdown of the laser is initiated at step814. This can include, for example, the LED306or606of the damaged detection mechanism(s)300or600no longer generating illumination. This can also include the laser controller108or208detecting an interruption or alteration of the current flowing through the laser damage detection mechanism(s)300or600based on the output(s) from the current sensor704or other control feedback. This can further include the laser controller108or208causing the laser102or202to shut down, redirecting a high-energy beam104or204(shown inFIGS. 1 and 2, respectively) to a beam dump, or performing other functions.

The current can be rerouted into a bypass path of each damaged detection mechanism at step816. This can include, for example, shunting incoming current received at a connector308,310,608, or610(shown inFIGS. 3 and 6, respectively) from the first conductive trace304or604of the damaged detection mechanism(s)300or600to the second conductive trace312or612(shown inFIGS. 3 and 6, respectively) of the damaged detection mechanism(s)300or600. As a result, feedback can be generated at any non-damaged detection mechanism(s) at step818. This can include, for example, the LED306or606of each non-damaged detection mechanism300or600generating illumination. Among other things, shutdown of the laser102or202can be initiated rapidly, and the damaged detection mechanism(s)300or600can be easily identified by the lack of illumination from the associated LED(s)306or606.

AlthoughFIG. 8illustrates one example of a method800of using one or more laser damage detection mechanisms for safety interlock and fault detection, various changes may be made toFIG. 8. For example, while shown as a series of steps, various steps inFIG. 8can overlap, occur in parallel, occur in a different order, or occur any number of times. Also, various steps inFIG. 8can be omitted if desired, such as when steps816-818are omitted when bypassing is not required (like when one or more laser damage detection mechanisms are used individually and are not coupled together in series).