Filter for selective transmission of visible rays and infrared rays using an electrical signal

1. A tunable filter, comprising:

a first filter configured to control a degree of absorption of a visible ray by changing a molecular array, based on a control of an electrical signal; and

a second filter configured to control a degree of reflection of an infrared (IR) ray by changing a reflectivity, based on the control of the electrical signal,

wherein the first filter is configured by a first layer and a second layer each including an LC molecule and a dye molecule, and

the molecules included in the first layer and the molecules included in the second layer are disposed vertically to an optical axis of a visible ray.

2. The tunable filter of claim 1 , wherein the first filter is configured by at least a single layer including a liquid crystal (LC) molecule and a dye molecule.

3. The tunable filter of claim 1 , wherein the first filter is configured to dispose the LC molecule and the dye molecule for a visible ray to be absorbed in the first filter when turned OFF by the electrical signal, and

dispose the LC molecule and the dye molecule for a visible ray to be transmitted to the first filter when turned ON by the electrical signal.

4. The tunable filter of claim 1 , wherein the first filter is configured to dispose the LC molecule and the dye molecule to be vertical to an optical axis of a visible ray when turned OFF by the electrical signal, and

dispose the LC molecule and the dye molecule to be horizontal to a progression direction of a visible ray when turned ON by the electrical signal.

5. The tunable filter of claim 1 , wherein the second filter is configured by a layer including an LC molecule and a layer including a polymer molecule.

6. The tunable filter of claim 1 , wherein the second filter is configured to change a reflectivity for an IR ray to be reflected to the second filter when turned OFF by the electrical signal, and

change a reflectivity for an IR ray to be transmitted to the second filter when turned ON by the electrical signal.

7. The tunable filter of claim 1 , wherein the second filter is configured to

set a refractive index of a layer including an LC molecule to differ from a refractive index of a layer including a polymer molecule such that the IR ray is reflected to the second filter when turned OFF by the electrical signal, and

set a refractive index of a layer including an LC molecule to be identical to a refractive index of a layer including a polymer molecule such that the IR ray is transmitted to the second filter when turned ON by the electrical signal.

8. The tunable filter of claim 1 , wherein the second filter represents a Distributed Bragg Reflector (DBR) structure, using an LC molecule and a polymer molecule.

9. A camera, comprising:

a first filter configured to absorb a visible ray based on a control of an electrical signal;

a second filter configured to reflect an infrared (IR) ray based on a control of the electrical signal; and

a sensor configured to sense at least one of a color image and a depth image,

wherein when sensing the color image, the first filter and the second filter are configured to transmit the visible ray and the second filter is further configured to reflect the IR ray, and

wherein when sensing the depth image, the first filter and the second filter are configured to transmit the IR ray and the first filter is further configured to absorb the visible ray.

10. The camera of claim 9 , wherein the filter is configured to perform turning ON/OFF of the first filter and the second filter repeatedly, based on the electrical signal, and transmit a visible ray or an IR ray selectively.

11. The camera of claim 9 , wherein the filter is configured to turn ON the first filter based on the electrical signal, and turn OFF the second filter to transmit a visible ray for sensing a color image, and

turn OFF the first filter based on the electrical signal, and turn ON the second filter to transmit an IR ray for sensing a depth image.

12. The camera of claim 9 , wherein the first filter comprises an LC molecule and a dye molecule.

13. The camera of claim 9 , wherein the second filter represents a Distributed Bragg Reflector (DBR) structure.

14. The camera of claim 9 , wherein the second filter is configured to change a reflectivity of a filter, using an LC molecule and a polymer molecule.

15. The tunable filter of claim 1 , wherein the first filter has a guest-host structure which is configured to transmit the visible ray based on the electrical signal.

16. The tunable filter of claim 1 , wherein the second filter has a holographic polymer dispersed liquid crystal (HPDLC) structure, which is configured to transmit the infrared (IR) ray based the electrical signal.

17. The tunable filter of claim 15 , wherein the second filter has a holographic polymer dispersed liquid crystal (HPDLC) structure, which is configured to transmit the infrared (IR) ray based the electrical signal.

18. The tunable filter of claim 1 , wherein

the first filter is configured to transmit the visible ray based on the control of the electrical signal to sense a color image during a first time interval; and

the second filter configured to transmit the infrared (IR) ray based on the control of the electrical signal to sense a depth image during a second time interval.

19. A filter, comprising:

a first filter configured to absorb a visible ray by controlling an electrical signal; and

a second filter configured to reflect an infrared (IR) ray by controlling the electrical signal,

wherein the second filter is configured to

set a refractive index of a layer including an LC molecule to differ from a refractive index of a layer including a polymer molecule such that the IR ray is reflected to the second filter when turned OFF by the electrical signal, and

set a refractive index of a layer including an LC molecule to be identical to a refractive index of a layer including a polymer molecule such that the IR ray is transmitted to the second filter when turned ON by the electrical signal.