Feedback device and method of providing thermal feedback using the same
Disclosed herein are a feedback device and a method of providing thermal feedback using the same. The feedback device according to an embodiment of the present disclosure includes a thermoelectric module including a substrate having flexibility, a thermoelement disposed on the substrate and configured to perform a thermoelectric operation for thermal feedback, and a contact surface disposed on the substrate, and configured to transfer heat generated through the thermoelectric operation to a user through the substrate and the contact surface to output the thermal feedback; and a feedback controller configured to control the thermoelectric module, and wherein the feedback controller controls the thermoelectric module so that, after a temperature of the contact surface reaches a maximum temperature, the temperature of the contact surface is maintained within a predetermined temperature range during an entire thermoelectric operation time interval.
1. A feedback device comprising:
a thermoelectric module including a flexible substrate, a thermoelement disposed on the substrate configured to perform a thermoelectric operation for thermal feedback, and a contact surface disposed on the substrate configured to transfer heat generated by the thermoelectric operation to a user, wherein the heat is transferred through the substrate and the contact surface to an output for the thermal feedback; and
a feedback controller configured to control the thermoelectric module,
wherein:
the thermoelectric operation includes an exothermic operation and an endothermic operation,
the feedback controller controls the thermoelectric module so a temperature of the contact surface is maintained within a predetermined temperature range during a thermoelectric operation time interval after the temperature of the contact surface reaches a target temperature; and
the feedback controller controls the thermoelectric module so a temperature rise or a temperature drop that exceeds a predetermined threshold value, periodically occurs in the contact surface after the temperature of the contact surface reaches the predetermined temperature range.
2. A feedback device for providing a thermal feedback including at least one of a hot feedback and a cold feedback, the feedback device comprising:
a thermoelectric module comprising a flexible substrate, a thermoelement disposed on the substrate configured to perform a thermoelectric operation for the thermal feedback, and a contact surface disposed on the substrate configured to transfer heat generated by the thermoelectric operation to a user; and
a feedback controller configured to control the thermoelectric module,
wherein the thermoelectric operation including at least one of an exothermic operation and an endothermic operation,
wherein the heat being transferred through the substrate and the contact surface to an output for the thermal feedback,
wherein the feedback controller controls the thermoelectric module so a temperature rise and a temperature drop occur in the contact surface periodically after a temperature of the contact surface reaches a target temperature related to the thermal feedback, and
wherein the temperature of the contact surface is maintained within a predetermined temperature range while the temperature rise and the temperature drop occur.
3. The feedback device of claim 2 , wherein:
the feedback controller applies a first electric signal having a constant voltage or a constant current to the thermoelectric module to cause that the temperature of the contact surface reaches the target temperature related to the thermal feedback for providing a cold sensation to the user, and
the feedback controller applies a second electric signal having a duty cycle to the thermoelectric module to cause that the temperature of the contact surface repeats the temperature rise and the temperature drop for enhancing the cold sensation of the user.
4. The feedback device of claim 3 , wherein the first electric signal and the second electric signal cause the thermoelectric module to perform the endothermic operation.
5. The feedback device of claim 4 , wherein:
waste heat is accumulated inside the feedback device while the thermoelectric module performs the endothermic operation by an on-period of the duty cycle; and
the temperature of the contact surface rises due to the waste heat in an off-period of the duty cycle.
6. The feedback device of claim 5 , wherein:
the feedback device further comprises a heat radiator configured to dissipate at least a portion of the waste heat to the outside of the feedback device; and
while the portion of the waste heat is dissipated to the outside of the feedback device by the heat radiator, the temperature of the contact surface is maintained within the predetermined temperature range.
7. The feedback device of claim 5 , wherein:
the feedback controller controls the thermoelectric module so a temperature variation of the contact surface between the on-period of the duty cycle and the off-period of the duty cycle is larger than or equal to a threshold temperature difference, and
the threshold temperature difference indicating a temperature difference that allows the user to perceive a temperature change.
8. The feedback device of claim 7 , wherein the temperature variation of the contact surface is adjusted according to a proportion between the on-period of the duty cycle and the off-period of the duty cycle.
9. The feedback device of claim 7 , wherein a proportion of the off-period .of the duty cycle to the on-period of the duty cycle is higher than or equal to 0.9.
10. The feedback device of claim 2 , wherein the target temperature is lower than an initial temperature.
11. The feedback device of claim 10 , wherein the predetermined temperature range is higher than the target temperature and lower than the initial temperature.
12. The feedback device of claim 2 , wherein the feedback controller applies a third electric signal having a constant voltage, a constant current or a duty cycle to the thermoelectric module to cause that the temperature of the contact surface reaches the target temperature related to the thermal feedback for providing a cold sensation to the user and repeats the temperature rise and the temperature drop for enhancing the cold sensation of the user.
13. The feedback device of claim 2 , wherein:
the feedback controller applies a fourth electric signal having a constant voltage or a constant current to the thermoelectric module to cause that the temperature of the contact surface reaches the target temperature related to the thermal feedback for providing a hot sensation to the user, and
the feedback controller applies a fifth electric signal having a duty cycle to the thermoelectric module to cause that the temperature of the contact surface repeats the temperature rise and the temperature drop for enhancing the hot sensation of the user.
14. The feedback device of claim 13 , wherein the fourth electric signal and the fifth electric signal cause the thermoelectric module to perform the exothermic operation.
15. The feedback device of claim 13 , wherein the target temperature is higher than an initial temperature.
16. The feedback device of claim 15 , wherein the predetermined temperature range is lower than the target temperature and higher than the initial temperature.
17. The feedback device of claim 2 , wherein the feedback controller applies a sixth electric signal having a constant voltage, a constant current or a duty cycle to the thermoelectric module to cause that the temperature of the contact surface reaches the target temperature related to the thermal feedback for providing a hot sensation to the user and repeats the temperature rise and the temperature drop for enhancing the hot sensation of the user.
18. A method for providing a thermal feedback including at least one of a hot feedback and a cold feedback, the feedback device comprising:
a thermoelectric module comprising a flexible substrate, a thermoelement disposed on the substrate configured to perform a thermoelectric operation for the thermal feedback, and a contact surface disposed on the substrate configured to transfer heat generated by the thermoelectric operation to a user; and
a feedback controller configured to control the thermoelectric module,
wherein:
the thermoelectric operation includes at least one of an exothermic operation and an endothermic operation, and
the heat is transferred through the substrate and the contact surface to an output for the thermal feedback, the method comprising:
controlling the thermoelectric module such that a temperature of the contact surface reaches a target temperature related to the thermal feedback, and
controlling the thermoelectric module so a temperature rise and a temperature drop occur in the contact surface periodically after the temperature of the contact surface reaches the target temperature related to the thermal feedback,
wherein the temperature of the contact surface is maintained within a predetermined temperature range while the temperature rise and the temperature drop occur.
19. A non-transitory computer readable medium storing a program to execute the method of claim 18 .