Systems and methods for implementing spring loaded mechanical key switches with variable displacement sensing
Systems and methods are disclosed that enable spring loaded mechanical key switch assemblies having variable displacement sensing capabilities. In one example, the disclosed key switch assemblies may be implemented in a keyboard system and used for providing variable displacement output signals that may be processed by a controller for input to a host processing device of an information handling system, such as a desktop or notebook computer. In another example, the disclosed key switch assemblies may be configured to provide both a digital “make” connection signal and separate variable displacement output signal/s that may be processed for input to a host processing device of an information handling system.
1. A keyboard system, comprising:
one or more spring loaded mechanical key switch assemblies, each of the key switch assemblies comprising:
a key switch housing having a first end and a second end,
a downwardly depressable key component movably received within the key switch housing and having a first end and a second end, the first end of the depressable key component being linearly movable downward between an extended position and a depressed position relative to the first end of the key switch housing with the first end of the depressable key component being closer to the first end of the key switch housing in the depressed position than in the extended position,
a spring element configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position, and
variable displacement-sensing circuitry configured to detect downward linear displacement of the depressable key component relative to the key switch housing and to provide one or more variable displacement signals that vary in character based on the amount of linear displacement of the depressable key component between the extended position and the depressed position; and
displacement measurement circuitry coupled to receive the variable displacement signals and to determine in real time the relative linear displacement of the depressable key component between the extended position and the depressed position based on the character of the provided variable displacement signals.
2. The system of claim 1 , where the one or more variable displacement signals provided by the variable displacement-sensing circuitry are analog signals that comprises at least one of capacitive sensing circuitry, resistive sensing circuitry, optical sensing circuitry, electrical field (E-field) change detection circuitry, magnetic field (H-field) change detection circuitry, or a combination thereof.
3. The system of claim 1 , where the displacement measurement circuitry is configured to determine and output a respective displacement-based scan code to one or more external devices corresponding to the particular determined real-time downward linear key displacement level for each of the key switch assemblies.
4. The system of claim 1 , further comprising digital signal circuitry configured to provide an on/off digital output signal when the depressable key component is depressed downward by a predetermined extent.
5. The system of claim 1 , where the drepressable key component is linearly movable downward and upward along a single axis.
6. The system of claim 1 , where the second end of the depressable key component is closer to the second end of the key switch housing when the depressable key component is in the extended position than when the depressable key component is in the second position.
7. A keyboard system, comprising:
one or more spring loaded mechanical key switch assemblies, each of the key switch assemblies comprising:
a key switch housing having a first end and a second end,
a depressable key component movably received within the key switch housing and having a first end and a second end, the first end of the depressable key component being movable between an extended position and a depressed position relative to the first end of the key switch housing with the first end of the depressable key component being closer to the first end of the key switch housing in the depressed position than in the extended position,
a spring element configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position, and
variable displacement-sensing circuitry configured to detect displacement of the depressable key component relative to the key switch housing and to provide one or more variable displacement signals that vary in character based on the amount of displacement of the depressable key component between the extended position and the depressed position; and
displacement measurement circuitry coupled to receive the variable displacement signals and to determine in real time the relative displacement of the depressable key component between the extended position and the depressed position based on the character of the provided variable displacement signals;
where the depressable key component further comprises a plunger axle provided on the second end of the depressable key component, the plunger axle being closer to the second end of the key switch housing when the depressable key component is in the extended position than when the depressable key component is in the second position; where the key switch housing further comprises a key well provided on the second end of the key switch housing, a plunger cavity being defined in the key well, the plunger cavity being configured to receive the plunger axle therein when the depressable key component is depressed; and where the variable displacement-sensing circuitry is provided adjacent the second end of the key switch housing, the variable displacement-sensing circuitry being configured to detect displacement of the depressable key component relative to the key switch housing by sensing a position of the plunger axle within the key well.
8. The system of claim 7 , where the variable displacement-sensing circuitry comprises multiple stationary electrically conductive elements disposed within the key well so as to be adjacent or within the plunger cavity, each of the stationary electrically conductive elements being coupled to provide a respective variable displacement signal as an induced voltage signal to the displacement measurement circuitry; and a movable electrically conductive element configured to travel with the plunger axle relative to the stationary electrically conductive elements as the depressable key component moves between the extended position and the depressed position; where the displacement measurement circuitry is configured to monitor the induced voltage between each of the stationary electrically conductive elements and the movable electrically conductive element to determine in real time the relative displacement of the depressable key component between the extended position and the depressed position.
9. The system of claim 7 , where the variable displacement-sensing circuitry comprises multiple optical sensors and one or more light sources disposed within the key well, each given one of the multiple optical sensors being configured to receive light transmitted across the plunger cavity from at least one of the light sources when the plunger axle is not positioned in the plunger cavity between the given optical sensor and at least one of the light sources; and where the plunger axle is configured to block light transmitted across the plunger cavity from the at least one light source when the plunger axle is positioned between the given optical sensor and the at least one light source; where each of the optical sensors is coupled to provide a respective variable displacement signal as a light detection signal to the displacement measurement circuitry that indicates in real time whether or not light is currently being received across the plunger cavity from one of the light sources.
10. A keyboard system, comprising:
one or more spring loaded mechanical key switch assemblies, each of the key switch assemblies comprising:
a key switch housing having a first end and a second end,
a depressable key component movably received within the key switch housing and having a first end and a second end, the first end of the depressable key component being movable between an extended position and a depressed position relative to the first end of the key switch housing with the first end of the depressable key component being closer to the first end of the key switch housing in the depressed position than in the extended position,
a spring element configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position, and
variable displacement-sensing circuitry configured to detect displacement of the depressable key component relative to the key switch housing and to provide one or more variable displacement signals that vary in character based on the amount of displacement of the depressable key component between the extended position and the depressed position; and
displacement measurement circuitry coupled to receive the variable displacement signals and to determine in real time the relative displacement of the depressable key component between the extended position and the depressed position based on the character of the provided variable displacement signals;
digital signal circuitry configured to provide an on/off digital output signal when the depressable key component is depressed downward by a predetermined extent; and
a keyboard controller coupled to receive the on/off digital output signal from the digital signal circuitry, the keyboard controller being configured to process the on/off digital output signal and to provide processed digital key information based on the on/off digital output signal to an external device.
11. The system of claim 10 , where the displacement measurement circuitry is coupled to provide a variable displacement mode signal to the keyboard controller that instructs the keyboard controller whether or not to provide the processed digital key information based on the on/off digital output signal to an external device; and where the keyboard controller is configured to respond to the variable displacement mode signal by providing the processed digital key information based on the on/off digital output signal to an external device when instructed to do so by the variable displacement mode signal, and by not providing the processed digital key information based on the on/off digital output signal to an external device when instructed not to do so by the variable displacement mode signal.
12. An information handling system including the keyboard system of claim 10 , comprising:
at least one host processing device configured to execute a user application thereon; and
a keyboard system according to claim 10 ;
where the keyboard controller is configured to process the on/off digital output signal and to provide the processed digital key information based on the on/off digital output signal to the at least one user application executing on the host processing device; and
where the displacement measurement circuitry is configured to determine and output a respective processed displacement-based output signal to the host processing device.
13. A spring loaded mechanical key switch assembly, comprising:
a key switch housing having a first end and a second end;
a downwardly depressable key component movably received within the key switch housing and having a first end and a second end, the first end of the depressable key component being linearly movable downward between an extended position and a depressed position relative to the first end of the key switch housing with the first end of the depressable key component being closer to the first end of the key switch housing in the depressed position than in the extended position;
a spring element configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position; and
variable displacement-sensing circuitry configured to detect downward linear displacement of the depressable key component relative to the key switch housing and to provide one or more variable displacement signals that vary in character based on the amount of linear displacement of the depressable key component between the extended position and the depressed position.
14. The key switch assembly of claim 13 , where the one or more variable displacement signals provided by the variable displacement-sensing circuitry are analog signals that comprise at least one of capacitive sensing circuitry, resistive sensing circuitry, optical sensing circuitry, electrical field (E-field) change detection circuitry, magnetic field (H-field) change detection circuitry, or a combination thereof.
15. The key switch assembly of claim 13 , where the variable displacement-sensing circuitry comprises optical sensing circuitry.
16. The key switch assembly of claim 13 , further comprising digital signal circuitry configured to provide an on/off digital output signal when the depressable key component is depressed downward by a predetermined extent.
17. The key switch assembly of claim 13 , where the drepressable key component is linearly movable downward and upward along a single axis.
18. The key switch assembly of claim 13 , where the second end of the depressable key component is closer to the second end of the key switch housing when the depressable key component is in the extended position than when the depressable key component is in the second position.
19. The method of claim 13 , where the drepressable key component is linearly movable downward and upward along a single axis; and where the method further comprises responding to downward linear displacement of the depressable key component along a single axis between the extended position and the depressed position by using the variable displacement-sensing circuitry to detect downward linear displacement of the depressable key component along the single axis relative to the key switch housing, and to provide one or more variable displacement signals that vary in character based on the amount of downward linear displacement of the depressable key component along the single axis between the extended position and the depressed position.
20. The key switch assembly of claim 13 , where the second end of the depressable key component is closer to the second end of the key switch housing when the depressable key component is in the extended position than when the depressable key component is in the second position.
21. A spring loaded mechanical key switch assembly, comprising:
a key switch housing having a first end and a second end;
a depressable key component movably received within the key switch housing and having a first end and a second end, the first end of the depressable key component being movable between an extended position and a depressed position relative to the first end of the key switch housing with the first end of the depressable key component being closer to the first end of the key switch housing in the depressed position than in the extended position;
a spring element configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position; and
variable displacement-sensing circuitry configured to detect displacement of the depressable key component relative to the key switch housing and to provide one or more variable displacement signals that vary in character based on the amount of displacement of the depressable key component between the extended position and the depressed position;
where the depressable key component further comprises a plunger axle provided on the second end of the depressable key component, the plunger axle being closer to the second end of the key switch housing when the depressable key component is in the extended position than when the depressable key component is in the second position; where the key switch housing further comprises a key well provided on the second end of the key switch housing, a plunger cavity being defined in the key well, the plunger cavity being configured to receive the plunger axle therein when the depressable key component is depressed; and where the variable displacement-sensing circuitry is provided adjacent the second end of the key switch housing, the variable displacement-sensing circuitry being configured to detect displacement of the depressable key component relative to the key switch housing by sensing a position of the plunger axle within the key well.
22. The key switch assembly of claim 21 , where the variable displacement-sensing circuitry comprises multiple stationary electrically conductive elements disposed within the key well so as to be adjacent or within the plunger cavity, each of the stationary electrically conductive elements being configured to provide a respective variable displacement signal as an induced voltage signal; and a movable electrically conductive element configured to travel with the plunger axle relative to the stationary electrically conductive elements as the depressable key component moves between the extended position and the depressed position; where the respective variable displacement signal provided by each given stationary electrically conductive element at any given time is indicative of the position of the movable electrically conductive element relative to the given stationary electrically conductive element at that given time.
23. The key switch assembly of claim 21 , where the variable displacement-sensing circuitry comprises multiple optical sensors and one or more light sources disposed within the key well, each given one of the multiple optical sensors being configured to receive light transmitted across the plunger cavity from at least one of the light sources when the plunger axle is not positioned in the plunger cavity between the given optical sensor and at least one of the light sources; where the plunger axle is configured to block light transmitted across the plunger cavity from the at least one light source when the plunger axle is positioned between the given optical sensor and the at least one light source; where each given one of the optical sensors is coupled to provide a respective variable displacement signal as a respective light detection signal that indicates in real time whether or not light is currently being received across the plunger cavity from one of the light sources.
24. The key switch assembly of claim 21 , where the spring element of the key switch assembly comprises a coil spring having a central opening that is disposed around the plunger axle, the coil spring being configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position and to return the depressable key component to its non-depressed extended position in the absence of a downward force applied to the depressable key component.
25. A method of operating one or more key switch assemblies, comprising:
providing one or more spring loaded mechanical key switch assemblies, each of the key switch assemblies comprising:
a key switch housing having a first end and a second end,
a downwardly depressable key component movably received within the key switch housing and having a first end and a second end, the first end of the depressable key component being linearly movable downward between an extended position and a depressed position relative to the first end of the key switch housing with the first end of the depressable key component being closer to the first end of the key switch housing in the depressed position than in the extended position,
a spring element configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position, and
variable displacement-sensing circuitry; and
responding to downward linear displacement of the depressable key component between the extended position and the depressed position by using the variable displacement-sensing circuitry to detect downward linear displacement of the depressable key component relative to the key switch housing, and to provide one or more variable displacement signals that vary in character based on the amount of downward linear displacement of the depressable key component between the extended position and the depressed position.
26. The method of claim 25 , where each of the key switch assemblies further comprises digital signal circuitry, and where the method further comprises using the digital signal circuitry to configured to provide an on/off digital output signal when the depressable key component is depressed downward by a predetermined extent.
27. A method of operating one or more key switch assemblies, comprising:
providing one or more spring loaded mechanical key switch assemblies, each of the key switch assemblies comprising:
a key switch housing having a first end and a second end,
a depressable key component movably received within the key switch housing and having a first end and a second end, the first end of the depressable key component being movable between an extended position and a depressed position relative to the first end of the key switch housing with the first end of the depressable key component being closer to the first end of the key switch housing in the depressed position than in the extended position,
a spring element configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position, and
variable displacement-sensing circuitry; and
responding to displacement of the depressable key component between the extended position and the depressed position by using the variable displacement-sensing circuitry to detect displacement of the depressable key component relative to the key switch housing, and to provide one or more variable displacement signals that vary in character based on the amount of displacement of the depressable key component between the extended position and the depressed position;
where the depressable key component further comprises a plunger axle provided on the second end of the depressable key component, the plunger axle being closer to the second end of the key switch housing when the depressable key component is in the extended position than when the depressable key component is in the second position; where the key switch housing further comprises a key well provided on the second end of the key switch housing, a plunger cavity being defined in the key well, the plunger cavity being configured to receive the plunger axle therein when the depressable key component is depressed; where the variable displacement-sensing circuitry is provided adjacent the second end of the key switch housing; and where the method further comprises using the variable displacement-sensing circuitry to detect displacement of the depressable key component relative to the key switch housing by sensing a position of the plunger axle within the key well.
28. A method of operating one or more key switch assemblies, comprising:
providing one or more spring loaded mechanical key switch assemblies, each of the key switch assemblies comprising:
a key switch housing having a first end and a second end,
a depressable key component movably received within the key switch housing and having a first end and a second end, the first end of the depressable key component being movable between an extended position and a depressed position relative to the first end of the key switch housing with the first end of the depressable key component being closer to the first end of the key switch housing in the depressed position than in the extended position,
a spring element configured to provide a resilient force to resist downward movement of the depressable key component from the extended position to the depressed position, and
variable displacement-sensing circuitry; and
responding to displacement of the depressable key component between the extended position and the depressed position by using the variable displacement-sensing circuitry to detect displacement of the depressable key component relative to the key switch housing, and to provide one or more variable displacement signals that vary in character based on the amount of displacement of the depressable key component between the extended position and the depressed position;
where each of the key switch assemblies further comprises digital signal circuitry, and where the method further comprises using the digital signal circuitry to configured to provide an on/off digital output signal when the depressable key component is depressed downward by a predetermined extent; and
where the method further comprises:
receiving the on/off digital output signal from the digital signal circuitry in a keyboard controller, and using the keyboard controller to process the on/off digital output signal and to provide processed digital key information based on the on/off digital output signal to an external device, and
receiving the variable displacement signals in displacement measurement circuitry, and using the variable displacement signals to determine in real time the relative displacement of the depressable key component between the extended position and the depressed position based on the current character of the provided variable displacement signals.
29. The method of claim 28 , further comprising:
executing at least one user application on a host processing device;
using the keyboard controller to process the on/off digital output signal and to provide the processed digital key information based on the on/off digital output signal to the at least one user application executing on the host processing device; and
using the displacement measurement circuitry to determine and output a respective processed displacement-based output signal to the host processing device.