Spatial light modulator and electronic apparatus including the same
A spatial light modulator and an electronic apparatus including the spatial light modulator are provided. The spatial light modulator may include: a plurality of pixels configured to steer incident light; and a plurality of thermoelectric layers in which heat transfer with the plurality of pixels occurs. The plurality of pixels may include a plurality of grating structures.
1. A spatial light modulator comprising:
a first reflective layer and a second reflective layer, the second reflective layer comprising grating structures of a first group and grating structures of a second group which are independently driven, and are immediately adjacent to each other;
a cavity layer provided between the first reflective layer and the second reflective layer; and
a thermoelectric layer configured to cause heat transfer to occur between the thermoelectric layer and the second reflective layer,
wherein the thermoelectric layer comprises a first thermoelectric layer and a second thermoelectric layer to which different electrical signals are applied, wherein the first thermoelectric layer corresponds to the grating structures of the first group, and the second thermoelectric layer corresponds to the grating structures of the second group.
2. The spatial light modulator of claim 1 , wherein the first reflective layer and the cavity layer are provided between the second reflective layer and the thermoelectric layer.
3. The spatial light modulator of claim 1 , wherein the grating structures of the first group are disposed directly above the first thermoelectric layer in a thickness direction of the spatial light modulator, and the grating structures of the second group are disposed directly above the second thermoelectric layer in the thickness direction of the spatial light modulator.
4. The spatial light modulator of claim 1 , wherein, when an off signal is applied to the grating structures of the first group, a first electrical signal that causes heat transfer from the grating structures of the first group to the first thermoelectric layer, is applied to the first thermoelectric layer.
5. The spatial light modulator of claim 4 , wherein, when an on signal is applied to the grating structures of the first group, a second electrical signal that causes heat transfer from the first thermoelectric layer to the grating structures of the first group, is applied to the first thermoelectric layer.
6. The spatial light modulator of claim 5 , wherein polarities of the first electrical signal and the second electrical signal are different from each other.
7. The spatial light modulator of claim 1 , wherein, when an on signal is applied to the grating structures of the first group, an electrical signal is not applied to the first thermoelectric layer.
8. The spatial light modulator of claim 1 , wherein, when an on signal is applied to the grating structures of the first group and an off signal is applied to the grating structures of the second group, a third electrical signal that causes heat transfer from the grating structures of the second group to the second thermoelectric layer, is applied to the second thermoelectric layer.
9. The spatial light modulator of claim 8 , wherein no electrical signal is applied to the first thermoelectric layer.
10. The spatial light modulator of claim 8 , wherein a fourth electrical signal having a polarity different from that of the third electrical signal is applied to the first thermoelectric layer.
11. The spatial light modulator of claim 8 , wherein the second reflective layer further comprises grating structures of a third group, that is immediately adjacent to the grating structures of the second group and spaced apart from the grating structures of the first group,
wherein the thermoelectric layer further comprises a third thermoelectric layer corresponding to the grating structures of the second group, and
when the off signal is applied to the grating structures of the third group, a fourth electrical signal having the same polarity as that of the third electrical signal is applied to the third thermoelectric layer, or an electrical signal is not applied to the third thermoelectric layer.
12. The spatial light modulator of claim 1 , wherein before a driving signal is applied to the spatial light modulator, a signal that causes heat transfer from the second reflective layer to the thermoelectric layer is applied to the entire thermoelectric layer.
13. The spatial light modulator of claim 1 , wherein the thermoelectric layer causes heat transfer to occur by a Peltier effect.
14. The spatial light modulator of claim 1 , wherein the thermoelectric layer further comprises:
a plurality of n-type semiconductor layers and a plurality of p-type semiconductor layers alternately arranged; and
an electrode configured to electrically connect the plurality of n-type semiconductor layers and the plurality of p-type semiconductor layers, in series.
15. The spatial light modulator of claim 1 , further comprising an insulating layer provided between the first reflective layer and the thermoelectric layer.
16. The spatial light modulator of claim 1 , wherein at least one of the grating structures comprises any one of a PIN structure, a NIN structure, and a PIP structure.
17. The spatial light modulator of claim 1 , wherein pitches of the grating structures are less than a wavelength of light modulated by the spatial light modulator.
18. The spatial light modulator of claim 1 , wherein the first reflective layer is a distributed Bragg reflective layer.
19. An electronic apparatus comprising:
a spatial light modulator comprising a plurality of pixels configured to steer incident light, and a plurality of thermoelectric layers configure to control heat transfer between the plurality of pixels according to a control signal; and
a processor configured to provide the control signal that controls transfer of heat generated in the plurality of pixels to the plurality of thermoelectric layers while providing a driving signal that steers the incident light to the plurality of pixels,
wherein the plurality of pixels comprises:
a first reflective layer and a second reflective layer; and
a cavity layer provided between the first reflective layer and the second reflective layer, wherein the second reflective layer comprises grating structures of a first group and grating structures of a second group, which are independently driven and are immediately adjacent to each other, and
wherein the plurality of thermoelectric layers comprise a first thermoelectric layer and a second thermoelectric layer, to which different electrical signals are applied, the first thermoelectric layer corresponding to the grating structures of the first group and the second thermoelectric layer corresponding to the grating structures of the second group.
20. The electronic apparatus of claim 19 , wherein the processor is further configured to, when applying an on signal to the grating structures of the first group and an off signal to the grating structures of the second group, apply, to the second thermoelectric layer, a third electrical signal that causes heat transfer from the grating structures of the second group to the second thermoelectric layer.
21. The electronic apparatus of claim 20 , wherein the processor is further configured to apply no electrical signal to the first thermoelectric layer.
22. The electronic apparatus of claim 20 , wherein the processor is further configured to apply, to the first thermoelectric layer, an electrical signal for heat transfer from the first thermoelectric layer in a direction of the grating structures of the first group.
23. An electronic device for detecting an object, the electronic device comprising:
a spatial light modulator comprising a plurality of pixels; and
a processor configured to:
generate a control signal based on a pre-stored phase profile, to cause the spatial light modulator to release heat according to the control signal; and
detect the object based on an optical signal that is modulated by the spatial light modulator,
wherein the plurality of pixels comprises a plurality of groups of grating structures and a plurality of thermoelectric layers, respectively, and
wherein the plurality of thermoelectric layers are spaced apart from each other and are aligned with the plurality of groups of grating structures in a light incident direction of the spatial light modulator, respectively, and comprise n-type semiconductor layers and p-type semiconductor layers that are alternately arranged, in a direction perpendicular to the light incident direction of the spatial light modulator,
wherein the plurality of groups of grating structures comprises a first group of grating structures and a second group of grating structures, which are independently driven and are immediately adjacent to each other, and
wherein the plurality of thermoelectric layers comprise a first thermoelectric layer and a second thermoelectric layer to which different electrical signals are applied, wherein the first thermoelectric layer corresponds to the first group of grating structures, and the second thermoelectric layer corresponds to the second group of grating structures.