Optical switch

Abstract

To provide an optical switch that can switch on and off rapidly.SOLUTION: A first wire grid polarizer 11 and a second wire grid polarizer 12 have a plurality of metal wires 11b and 12b extending in a first direction and lined in a second direction at intervals of a predetermined space. A third wire grid polarizer 13 and a fourth wire grid polarizer 14 have a plurality of metal wires 13b and 14b extending in the second direction and lined in the first direction at intervals of a predetermined space. Slide driving units 16 and 17 slide the second wire grid polarizer 12 in the second direction and slide the fourth wire grid polarizer 14 in the first direction on the basis of control by the slide control unit 15.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an optical switch.

Background Art

[0002] In various technical fields, optical switches that switch between on and off by light are used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a demand for an optical switch that can switch between on and off at high speed.

Means for Solving the Problems

[0005] The present invention provides a first wire grid polarizer provided on a first transparent substrate, the first wire grid polarizer including a plurality of first metal wires extending in a first direction along the surface of the first transparent substrate, the first direction being orthogonal to a second direction, and the plurality of first metal wires being arranged at a predetermined interval in the second direction along the surface of the first transparent substrate; a second wire grid polarizer arranged to face the first wire grid polarizer, the second wire grid polarizer provided on a second transparent substrate, the second wire grid polarizer including a plurality of second metal wires extending in the first direction along the surface of the second transparent substrate, the first direction being orthogonal to a second direction, and the plurality of second metal wires being arranged at a predetermined interval in the second direction along the surface of the second transparent substrate; No. On a third transparent substrate, there is provided a third wire grid polarizer having a plurality of third metal wires extending in the second direction along the surface of the third transparent substrate, provided with a predetermined interval in the first direction along the surface of the third transparent substrate and orthogonal to the second direction; a fourth wire grid polarizer disposed to face the third wire grid polarizer, on a fourth transparent substrate, having a plurality of fourth metal wires extending in the second direction along the surface of the fourth transparent substrate, provided with a predetermined interval in the first direction along the surface of the fourth transparent substrate and orthogonal to the second direction; and a slide driving unit configured to slide the first or second wire grid polarizer in the second direction and slide the third or fourth wire grid polarizer in the first direction Optical device comprising provides a switch. In the above optical switch, when the slide driving unit positions each of the plurality of second metal wires at the center of the interval between two adjacent first metal wires among the plurality of first metal wires in a first state, the first wire grid polarizer and the second wire grid polarizer block the second polarization in incident light having a predetermined wavelength band including a first polarization and a second polarization, which is incident on the first transparent substrate, and emit the first polarization from the second transparent substrate. In the above optical switch, when the slide driving unit positions each of the second metal wires at the same position in the second direction of each of the first metal wires among the plurality of first metal wires, and sets a second state in which each of the first metal wires faces each of the second metal wires, the first wire grid polarizer and the second wire grid polarizer emit the first polarization and the second polarization in the incident light from the second transparent substrate. In the above optical switch, when the slide driving unit positions each of the plurality of fourth metal wires at the center of the interval between two adjacent third metal wires among the plurality of third metal wires in a third state, and the first polarization is incident on the third transparent substrate as incident light, the third wire grid polarizer and the fourth wire grid polarizer block the first polarization so as not to emit the first polarization from the fourth transparent substrate. In the above optical switch, when the slide driving unit positions each of the fourth metal wires at the same position in the first direction of each of the third metal wires among the plurality of third metal wires, and sets a fourth state in which each of the third metal wires faces each of the fourth metal wires, and the first polarization and the second polarization are incident on the third transparent substrate as incident light, the third wire grid polarizer and the fourth wire grid polarizer emit the first polarization and the second polarization from the fourth transparent substrate. The above optical switch further includes a slide control unit that switches between an off state in which light in the predetermined wavelength band in the incident light incident on the first transparent substrate is not emitted from the fourth transparent substrate by controlling the slide driving unit so that the first wire grid polarizer and the second wire grid polarizer are in the first state and the third wire grid polarizer and the fourth wire grid polarizer are in the third state, and an on state in which light in the predetermined wavelength band in the incident light incident on the first transparent substrate is emitted from the fourth transparent substrate by controlling the slide driving unit so that the first wire grid polarizer and the second wire grid polarizer are in the second state and the third wire grid polarizer and the fourth wire grid polarizer are in the fourth state.

Advantages of the Invention

[0006] According to the optical switch of the present invention, it is possible to switch between on and off at high speed.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6

Figure 7A

Figure 7B

Figure 8

Figure 9

Figure 10A

Figure 10B

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Embodiments for Carrying Out the Invention

[0008] Hereinafter, the optical switch, polarizer, optical filter, window, and head-mounted display of each embodiment will be described with reference to the accompanying drawings.

[0009] <Optical Switch> Figures 1 to 11 disclose an optical switch that can rapidly switch between on and off. Figure 1 shows an optical switch 101 according to an embodiment. The optical switch 101 includes first to fourth wire grid polarizers 11 to 14. The first wire grid polarizer 11 and the second wire grid polarizer 12 are arranged close to each other without contacting each other, constituting a first pair of wire grid polarizers. The third wire grid polarizer 13 and the fourth wire grid polarizer 14 are arranged close to each other without contacting each other, constituting a second pair of wire grid polarizers.

[0010] The first wire grid polarizer 11 and the second wire grid polarizer 12 are each formed by depositing a plurality of metal wires 11b and 12b such as aluminum on transparent substrates 11a and 12a such as glass substrates with a predetermined interval. If the transparent substrate 11a is the first transparent substrate, the transparent substrate 12a is the second transparent substrate, and if the metal wire 11b is the first metal wire, the metal wire 12b is the second metal wire. In order to bring the metal wire 11b of the first wire grid polarizer 11 and the metal wire 12b of the second wire grid polarizer 12 close to each other, the first wire grid polarizer 11 and the second wire grid polarizer 12 are arranged with the surfaces on which the metal wires 11b and 12b are provided facing each other.

[0011] As shown in the perspective view of Figure 2, the metal wires 11b and 12b extend in the Y direction (first direction) along the surfaces of the transparent substrates 11a and 12a, and are arranged with a predetermined interval in the X direction (second direction) along the surfaces of the transparent substrates 11a and 12a. The X direction is the horizontal direction, and the Y direction is the vertical direction perpendicular to the X direction.

[0012] The third wire grid polarizer 13 and the fourth wire grid polarizer 14 are each formed by depositing a plurality of metal wires 13b and 14b, such as aluminum, on transparent substrates 13a and 14a, such as glass substrates, with a predetermined interval therebetween by vapor deposition or the like. If the transparent substrate 13a is the third transparent substrate, the transparent substrate 14a is the fourth transparent substrate, and if the metal wire 13b is the third metal wire, the metal wire 14b is the fourth metal wire. In order to bring the metal wire 13b of the third wire grid polarizer 13 and the metal wire 14b of the fourth wire grid polarizer 14 close to each other, the third wire grid polarizer 13 and the fourth wire grid polarizer 14 are arranged with the surfaces on which the metal wires 13b and 14b are provided facing each other.

[0013] As shown in the perspective view of FIG. 3, the metal wires 13b and 14b extend in the X direction along the surfaces of the transparent substrates 13a and 14a, respectively, and are arranged with a predetermined interval in the Y direction along the surfaces of the transparent substrates 13a and 14a. That is, the first wire grid polarizer 11 and the second wire grid polarizer 12, and the third wire grid polarizer 13 and the fourth wire grid polarizer 14 are in a relationship rotated 90 degrees with respect to each other.

[0014] The positional relationship between the first pair of wire grid polarizers composed of the first wire grid polarizer 11 and the second wire grid polarizer 12 and the second pair of wire grid polarizers composed of the third wire grid polarizer 13 and the fourth wire grid polarizer 14 may be reversed. When the positional relationship is reversed, the X direction is the first direction and the Y direction is the second direction.

[0015] The optical switch 101 further includes a slide control unit 15, and slide driving units 16 and 17 controlled by the slide control unit 15. The slide driving unit 16 drives the second wire grid polarizer 12 to slide in the X direction. The slide driving unit 17 drives the fourth wire grid polarizer 14 to slide in the Y direction. The slide driving units 16 and 17 slide the second wire grid polarizer 12 and the fourth wire grid polarizer 14 by a slide mechanism using an electric field or a magnetic field, respectively.

[0016] The slide control unit 15 controls the slide driving units 16 and 17 according to the input slide instruction signal.

[0017] The optical switch 101 may be configured such that the slide driving unit 16 drives the first wire grid polarizer 11 to slide in the X direction, and the slide driving unit 17 drives the third wire grid polarizer 13 to slide in the Y direction.

[0018] FIG. 4 shows how the first wire grid polarizer 11 and the second wire grid polarizer 12 act on the incident light Lin of visible light. Visible light has a wavelength range of 380 nm to 760 nm. Visible light with a wavelength of 380 nm to 760 nm is an example of light in a predetermined wavelength band.

[0019] The interval between two adjacent metal wires 11b is about 380 nm, and the interval between two adjacent metal wires 12b is also about 380 nm. Each metal wire 12b is located at the center in the X direction between the two metal wires 11b. The interval d between the metal wire 11b and the metal wire 12b is sufficiently smaller than 190 nm, which is the distance in the X direction between the metal wire 11b and the metal wire 12b. The metal wire 11b and the metal wire 12b have a predetermined interval so as not to contact even when the metal wire 11b and the metal wire 12b are opposed to each other.

[0020] The incident light Lin includes horizontally polarized light HPL indicated by a solid line and vertically polarized light VPL indicated by a broken line. When the first wire grid polarizer 11 and the second wire grid polarizer 12 are arranged such that each metal wire 12b extending in the Y direction is located at the center between two adjacent metal wires 11b, the vertically polarized light VPL is largely blocked by the first wire grid polarizer 11 and the second wire grid polarizer 12. Therefore, the emitted light L12, which is largely horizontally polarized light HPL, is emitted behind the first wire grid polarizer 11 and the second wire grid polarizer 12.

[0021] As shown in FIG. 5A, assuming that each metal wire 12b is located at the center in the Y direction between two adjacent metal wires 11b with the second wire grid polarizer 12 not being slid by the slide driving unit 16. The state shown in FIG. 5A is defined as state 1. (The first state) When the first wire grid polarizer 11 and the second wire grid polarizer 12 are in state 1, as described with reference to FIG. 4, when incident light Lin including horizontally polarized light HPL and vertically polarized light VPL is incident on the first wire grid polarizer 11 and the second wire grid polarizer 12, the emitted light L12, which is largely horizontally polarized light HPL, is emitted. In state 1, the light quantity becomes 1 / 2 or less.

[0022] As shown in FIG. 5B, assuming that the second wire grid polarizer 12 is slid by the slide driving unit 16 so that each metal wire 12b is positioned at the same position as the X direction of each metal wire 11b, and each metal wire 11b and each metal wire 12b are opposed to each other. The state shown in FIG. 5B is defined as state 2. (The second state) When the first wire grid polarizer 11 and the second wire grid polarizer 12 are in state 2, when incident light Lin including horizontally polarized light HPL and vertically polarized light VPL is incident on the first wire grid polarizer 11 and the second wire grid polarizer 12, the vertically polarized light VPL is not blocked by the first wire grid polarizer 11 and the second wire grid polarizer 12.

[0023] Therefore, when in state 2, emitted light L12’ including horizontal polarized light HPL and vertical polarized light VPL is emitted from the second wire grid polarizer 12. However, the amount of light is reduced by the amount blocked by the metal wires 11b and 12b, and becomes, for example, 89%.

[0024] FIG. 6 shows the relationship between the wavelength and the ratio of the horizontal polarized light HPL in states 1 and 2. In state 1, since the distance in the X direction between the metal wire 11b and the metal wire 12b is 190 nm, for wavelengths less than 380 nm, the horizontal polarized light HPL and the vertical polarized light VPL mostly pass through the first wire grid polarizer 11 and the second wire grid polarizer 12. When the wavelength is 380 nm or more, the vertical polarized light VPL cannot pass through the gap between the metal wires 11b and 12b, and the ratio of the horizontal polarized light HPL increases rapidly as the wavelength increases.

[0025] In state 2, for wavelengths less than 760 nm, the horizontal polarized light HPL and the vertical polarized light VPL mostly pass through the first wire grid polarizer 11 and the second wire grid polarizer 12. When the wavelength is 760 nm or more, the vertical polarized light VPL cannot pass through the gap between the metal wires 11b and 12b, and the ratio of the horizontal polarized light HPL increases rapidly as the wavelength increases.

[0026] In FIG. 7A, assume that in a state where the fourth wire grid polarizer 14 is not slid by the slide driving unit 17, each metal wire 14b is located at the center in the Y direction between two adjacent metal wires 13b. The first wire grid polarizer 11 and the second wire grid polarizer 12 are in state 1. The third wire grid polarizer 13 and the fourth wire grid polarizer 14 is , and a state where each metal wire 13b is located at the center in the Y direction between two adjacent metal wires 14b 3 (The third state) is the case.

[0027] The third wire grid polarizer 13 and the fourth wire grid polarizer 14 are in a state rotated 90 degrees with respect to the first wire grid polarizer 11 and the second wire grid polarizer 12. Therefore, the horizontally polarized light HPL of the emitted light L12 emitted from the first wire grid polarizer 11 and the second wire grid polarizer 12 becomes vertically polarized light VPL for the third wire grid polarizer 13 and the fourth wire grid polarizer 14.

[0028] Accordingly, in FIG. 7A, the emitted light Lout emitted from the third wire grid polarizer 13 and the fourth wire grid polarizer 14 rapidly decreases at a wavelength of 380 nm or more. That is, the first wire grid polarizer 11 and the second wire grid polarizer 12 is in state 1 the third wire grid polarizer 13 and the fourth wire grid polarizer 14 is in state 3 FIG. 7A, which is this, becomes an off state that hardly transmits visible light.

[0029] In FIG. 7B, assume that the fourth wire grid polarizer 14 is slid by the slide drive unit 17 so that each metal wire 14b is positioned at the same position in the Y direction as each metal wire 13b, and each metal wire 13b and each metal wire 14b are opposed to each other. The first wire grid polarizer 11 and the second wire grid polarizer 12 are in state 2. The third wire grid polarizer 13 and the fourth wire grid polarizer 14 is a state in which each metal wire 13b and each metal wire 14b are positioned at the same position in the Y direction 4 (The fourth state) is.

[0030] When the emitted light L12' including horizontally polarized light HPL and vertically polarized light VPL is incident on the third wire grid polarizer 13 and the fourth wire grid polarizer 14, the horizontally polarized light HPL and the vertically polarized light VPL are not blocked by the third wire grid polarizer 13 and the fourth wire grid polarizer 14. Therefore, emitted light Lout including horizontally polarized light HPL and vertically polarized light VPL is emitted from the fourth wire grid polarizer 14. However, the amount of light is further reduced by the amount blocked by the metal wires 13b and 14b.

[0031] With the first wire grid polarizer 11 and the second wire grid polarizer 12, the amount of light becomes, for example, 89%. With the third wire grid polarizer 13 and the fourth wire grid polarizer 14, it further becomes, for example, 89%. Therefore, the amount of the emitted light Lout of the entire optical switch 101 is about 80% with respect to the incident light Lin.

[0032] Therefore, in FIG. 7B, at wavelengths less than 760 nm, the horizontally polarized light HPL and the vertically polarized light VPL are transmitted with an amount of light of about 80% and rapidly decrease at wavelengths of 760 nm or more. That is, the first wire grid polarizer 11 and the second wire grid polarizer 12 is in state 2 , the third wire grid polarizer 13 and the fourth wire grid polarizer 14 is in state 4 FIG. 7B, which is this, is in an on state that transmits most of the visible light.

[0033] The optical switch 101 can select an initial state in which the second wire grid polarizer 12 and the fourth wire grid polarizer 14 are not slid, and a state in which the second wire grid polarizer 12 and the fourth wire grid polarizer 14 are slid by the slide drive units 16 and 17.

[0034] Thereby, as shown in FIG. 8, the optical switch 101 can switch between an off state in which it hardly transmits visible light with wavelengths of 380 nm to 760 nm and an on state in which it almost completely transmits visible light. Since the off state and the on state can be switched only by sliding the second wire grid polarizer 12 and the fourth wire grid polarizer 14 by the slide drive units 16 and 17, the optical switch 101 can switch between the off state and the on state at high speed.

[0035] For the initial states of the first wire grid polarizer 11 and the second wire grid polarizer 12, the X-direction positions of the respective metal wires 11b and the respective metal wires 12b may be the same. For the initial states of the third wire grid polarizer 13 and the fourth wire grid polarizer 14, the Y-direction positions of the respective metal wires 13b and the respective metal wires 14b may be the same.

[0036] By developing the optical switch 101 shown in FIG. 1, the optical switch 102 shown in FIG. 9 can be configured. The optical switch 102 has a configuration in which a rotation control unit 18 and a rotation drive unit 19 are added to the optical switch 101 shown in FIG. 1. The rotation drive unit 19 can rotate the third wire grid polarizer 13 and the fourth wire grid polarizer 14 under the control of the rotation control unit 18. The rotation control unit 18 controls the rotation drive unit 19 according to the input rotation instruction signal.

[0037] The first to fourth wire grid polarizers 11 to 14 are turned on as described above, and the rotation control unit 18 controls the rotation drive unit 19 to rotate the third wire grid polarizer 13 and the fourth wire grid polarizer 14 to any angle from 0 degrees to 90 degrees.

[0038] FIG. 10A shows the same state as FIG. 7A. The first wire grid polarizer 11 and the second wire grid polarizer 12 is in state 1 and the third wire grid polarizer 13 and the fourth wire grid polarizer 14 is in state 3 are shown. The third wire grid polarizer 13 and the fourth wire grid polarizer 14 are in the same state as FIG. 1, rotated 90 degrees with respect to the first wire grid polarizer 11 and the second wire grid polarizer 12. At this time, the optical switch 102 is in an off state that hardly transmits visible light.

[0039] FIG. 10B shows a state in which the third wire grid polarizer 13 and the fourth wire grid polarizer 14 are rotated to 0 degrees by the rotation drive unit 19 from the state of FIG. 10A. The state of being rotated to 0 degrees means that the third wire grid polarizer 13 and the fourth wire grid polarizer 14 in the state rotated 90 degrees are rotated 90 degrees so that the third wire grid polarizer 13 and the fourth wire grid polarizer 14 are in the same direction as the first wire grid polarizer 11 and the second wire grid polarizer 12.

[0040] In this state, the emitted light L12, which is mostly horizontally polarized light HPL emitted from the first wire grid polarizer 11 and the second wire grid polarizer 12, passes through the third wire grid polarizer 13 and the fourth wire grid polarizer 14, except for the portion blocked by the metal wires 13b and 14b. From the third wire grid polarizer 13 and the fourth wire grid polarizer 14, the emitted light Lout, which is mostly horizontally polarized light HPL, is emitted.

[0041] FIG. 11 shows the relationship between the rotation angles of the third wire grid polarizer 13 and the fourth wire grid polarizer 14 and the ratio of the transmitted light emitted as the emitted light Lout. When the rotation angles of the third wire grid polarizer 13 and the fourth wire grid polarizer 14 are 0 degrees, the ratio of the transmitted light is about 40% at maximum. As described above, since the transmittance of the incident light Lin including the horizontally polarized light HPL and the vertically polarized light VPL through the entire first wire grid polarizer 11 to the fourth wire grid polarizer 14 is about 80%, the ratio of the transmitted light is about 40% for only the horizontally polarized light HPL.

[0042] As shown in FIG. 11, as the rotation angles of the third wire grid polarizer 13 and the fourth wire grid polarizer 14 approach from 0 degrees to nearly 90 degrees, the ratio of the transmitted light gradually decreases from about 40% to 0%.

[0043] According to the optical switch 102 shown in FIG. 9, in addition to the effect of being able to rapidly switch between an off state in which visible light is hardly transmitted and an on state in which visible light is mostly transmitted, there is an effect that the amount of transmitted light in the on state can be adjusted.

[0044] <Polarizer> FIG. 12 discloses a polarizer capable of rapidly switching between horizontally polarized light and vertically polarized light. FIG. 12 shows a polarizer 200 of an embodiment. In the polarizer 200 shown in FIG. 12, the same parts as those of the optical switch 101 shown in FIG. 1 may be denoted by the same reference numerals, and the description thereof may be omitted.

[0045] In FIG. 12, a selection instruction signal for selecting whether to make the emitted light Lout horizontally polarized light HPL or vertically polarized light VPL is input to the selection control unit 21. When a selection instruction signal for making the emitted light Lout horizontally polarized light HPL is input to the selection control unit 21, the selection control unit 21 instructs the slide control unit 15 to make the emitted light Lout horizontally polarized light HPL.

[0046] When instructed to make the emitted light Lout horizontally polarized light HPL, the slide control unit 15 sets the first wire grid polarizer 11 and the second wire grid polarizer 12 to state 1, and sets the third wire grid polarizer 13 and the fourth wire grid polarizer 14 to state 4 and drives the second wire grid polarizer 12 and the fourth wire grid polarizer 14 accordingly. The slide control unit 15 keeps the second wire grid polarizer 12 in the initial state and slides the fourth wire grid polarizer 14 to state 4 . In this way, the polarizer 200 enters a horizontal polarization emission state (first polarization emission state) in which it emits horizontally polarized light HPL (first polarization).

[0047] When instructed to make the emitted light Lout vertically polarized light VPL, the slide control unit 15 sets the first wire grid polarizer 11 and the second wire grid polarizer 12 to state 2, and sets the third wire grid polarizer 13 and the fourth wire grid polarizer 14 to state 3 and drives the second wire grid polarizer 12 and the fourth wire grid polarizer 14 accordingly. The slide control unit 15 slides the second wire grid polarizer 12 to state 2 and keeps the fourth wire grid polarizer 14 in the initial state. In this way, the polarizer 200 enters a vertical polarization emission state (second polarization emission state) in which it emits vertically polarized light VPL (second polarization).

[0048] According to the polarizer 200 shown in FIG. 12, it is possible to switch whether the emitted light Lout is horizontally polarized light HPL or vertically polarized light VPL. According to the polarizer 200, by simply sliding the second wire grid polarizer 12 and the fourth wire grid polarizer 14 by the slide drive units 16 and 17, the horizontal polarization emission state and the vertical polarization emission state can be switched. Therefore, the polarizer 200 can switch between the horizontal polarization emission state and the vertical polarization emission state at high speed.

[0049] Note that depending on the configuration of the polarizer 200, the vertically polarized light VPL may be the first polarization, the vertically polarized light emission state may be the first polarization emission state, the horizontally polarized light HPL may be the second polarization, and the horizontally polarized light emission state may be the second polarization emission state.

[0050] <Optical Filter> FIG. 13 discloses an optical filter capable of changing the transmission wavelength band. FIG. 13 shows an optical filter 300 according to an embodiment. In the optical filter 300 shown in FIG. 13, the same parts as those of the optical switch 101 shown in FIG. 1 are denoted by the same reference numerals, and the description thereof may be omitted.

[0051] In FIG. 13, a transmission wavelength instruction signal is input to the slide control unit 15. The transmission wavelength instruction signal does not necessarily have to be an instruction signal that directly instructs the wavelength to be transmitted by the optical filter 300, and may be an instruction signal that expands the band of the wavelength to be transmitted by a predetermined band toward the 760 nm side or narrows the band by a predetermined band toward the 380 nm side.

[0052] The first wire grid polarizer 11 and the second wire grid polarizer 12 is in state 1 , the third wire grid polarizer 13 and the fourth wire grid polarizer 14 is in state 3 When this is the case, the optical filter 300 is in an off state. Assume that a transmission wavelength instruction signal for instructing to expand the band of the wavelength to be transmitted by a predetermined band toward the 760 nm side is input to the slide control unit 15.

[0053] As shown in FIG. 14, the slide control unit 15 slides the second wire grid polarizer 12 by a predetermined distance in the X direction so as to bring the first wire grid polarizer 11 and the second wire grid polarizer 12 closer to state 2. Although not shown, the slide control unit 15 slides the fourth wire grid polarizer 14 by a predetermined distance in the Y direction so as to bring the third wire grid polarizer 13 and the fourth wire grid polarizer 14 closer to state 4 . The distances by which the second wire grid polarizer 12 and the fourth wire grid polarizer 14 are slid are distances corresponding to the band for broadening the wavelength to be transmitted.

[0054] As described with reference to FIG. 8, the optical switch 101 selects an off state in which visible light with wavelengths from 380 nm to 760 nm is hardly transmitted and an on state in which visible light is hardly transmitted. On the other hand, the optical filter 300 can widen the wavelength band through which the optical filter 300 transmits visible light toward 760 nm or narrow it toward 380 nm as shown in FIG. 15 by varying the distances by which the second wire grid polarizer 12 and the fourth wire grid polarizer 14 are slid.

[0055] When the wavelength band through which visible light is transmitted is narrowed toward 380 nm, the optical filter 300 emits the emitted light Lout having a blue tint. When the wavelength band through which visible light is transmitted is widened toward 760 nm, the optical filter 300 emits white emitted light Lout.

[0056] According to the optical filter 300 shown in FIG. 13, the color tone can be continuously changed by changing the transmission wavelength band of the emitted light Lout emitted from the optical filter 300.

[0057] <Window> Figures 16 and 17 disclose a window capable of changing the state of transmitting light. As shown in FIG. 16, a window 400 of an embodiment is attached to a house 410. The house 410 is located near a water surface 420 such as a sea, a lake, or a river. In FIG. 16, the sunlight SL includes horizontal polarized light HPL and vertical polarized light VPL. When the sunlight SL is reflected by the water surface 420, the reflected light RSL becomes mostly horizontal polarized light HPL. Even when there is snow instead of the water surface 420, when the sunlight SL is reflected by the snow, the reflected light RSL becomes mostly horizontal polarized light HPL.

[0058] FIG. 17 shows a window 400 of an embodiment. In the window 400 shown in FIG. 17, the same parts as the optical switch 101 shown in FIG. 1, the polarizer 200 shown in FIG. 12, or the optical filter 300 shown in FIG. 13 may be denoted by the same reference numerals, and their descriptions may be omitted.

[0059] In FIG. 17, the window glass 401 is composed of the first wire grid polarizer 11 to the fourth wire grid polarizer 14 similar to those in the optical switch 101 or the polarizer 200. The first wire grid polarizer 11 to the fourth wire grid polarizer 14, the slide control unit 15, and the slide drive units 16 and 17 constitute an optical switch similar to the optical switch 101 shown in FIG. 1.

[0060] Therefore, the window glass 401 of the window 400 can select an off state in which it hardly transmits visible light with wavelengths of 380 nm to 760 nm and an on state in which it mostly transmits visible light. That is, the window 400 can switch between a state in which it is impossible to see from the outside of the window glass 401 into the interior of the house 410 and from the interior of the house 410 to the outside of the window glass 401, and a state in which it is possible to see.

[0061] As shown by the dashed line in Fig. 17, a selection instruction signal for selecting whether to make the emitted light Lout horizontally polarized light HPL or vertically polarized light VPL is input, and a selection control unit 21 may be provided to instruct the slide control unit 15 to make the emitted light Lout horizontally polarized light HPL or vertically polarized light VPL. When the selection control unit 21 is provided, the first wire grid polarizer 11 to the fourth wire grid polarizer 14, the slide control unit 15, the slide drive units 16 and 17, and the selection control unit 21 constitute a polarizer similar to the polarizer 200 shown in Fig. 12.

[0062] When the window 400 makes the emitted light Lout emitted from the window glass 401 into the interior of the house 410 horizontally polarized light HPL according to the selection instruction signal, the water surface 420 that shines brightly due to the reflection of the horizontally polarized light HPL can be seen from the interior of the house 410 through the window glass 401. When the window 400 makes the emitted light Lout emitted from the window glass 401 into the interior of the house 410 vertically polarized light VPL according to the selection instruction signal, almost no horizontally polarized light HPL reflected by the water surface 420 can be seen, so the underwater below the water surface 420 can be seen.

[0063] Furthermore, a transmission wavelength instruction signal similar to the optical filter 300 shown in Fig. 13 may be input to the slide control unit 15 to vary the distance by which the second wire grid polarizer 12 and the fourth wire grid polarizer 14 are slid. In this way, the first wire grid polarizer 11 to the fourth wire grid polarizer 14, the slide control unit 15, and the slide drive units 16 and 17 constitute an optical filter similar to the optical filter 300 shown in Fig. 13.

[0064] Then, since the color of the emitted light Lout emitted from the window glass 401 into the interior of the house 410 can be continuously changed, it becomes possible to select the color of the light taken into the interior of the house 410 between a bluish color and white.

[0065] In this way, according to the window 400 shown in Fig. 17, the state of transmitting light can be changed.

[0066] <Head-Mounted Display> FIG. 18 discloses a head-mounted display capable of switching the video seen by the user. FIG. 18 shows a head-mounted display 500 according to an embodiment. The head-mounted display 500 is a head-mounted display for augmented reality (AR). In the head-mounted display 500 shown in FIG. 18, the same parts as the optical switch 101 shown in FIG. 1 or the polarizer 200 shown in FIG. 12 may be denoted by the same reference numerals, and the description thereof may be omitted.

[0067] The head-mounted display 500 includes left and right vertical polarization filters 51L and 51R (first polarization filters) through which external light is incident, left and right video display units 52L and 52R, left and right horizontal polarization filters 53L and 53R (second polarization filters), and left and right half mirrors 54L and 54R. Further, the head-mounted display 500 includes left and right wire grid structures 55L and 55R disposed in front of the user's left eye EL and right eye ER, a slide control unit 15, slide drive units 16 and 17, and a selection control unit 21.

[0068] The wire grid structures 55L and 55R have first to fourth wire grid polarizers 11 to 14 similar to those in the optical switch 101 or the polarizer 200.

[0069] The wire grid structure 55L or 55R, the slide control unit 15, and the slide drive units 16 and 17 constitute an optical switch similar to the optical switch 101 shown in FIG. 1. The wire grid structure 55L or 55R, the slide control unit 15, the slide drive units 16 and 17, and the selection control unit 21 constitute a polarizer similar to the polarizer 200 shown in FIG. 12.

[0070] Assume that the optical switch in the head-mounted display 500 selects an on state in which the wire grid structures 55L and 55R allow most visible light to pass through. At this time, the vertical polarization filters 51L and 51R emit the vertical polarization VPL of the light incident from the outside, and the vertical polarization VPL passes through the half mirrors 54L and 54R and the wire grid structures 55L and 55R and is incident on the left eye EL and the right eye ER.

[0071] The video display units 52L and 52R display virtual videos for AR. The virtual videos displayed on the video display units 52L and 52R are viewed by the left eye EL and the right eye ER. The video light emitted from the video display units 52L and 52R is incident on the horizontal polarization filters 53L and 53R, and the horizontal polarization filters 53L and 53R emit the horizontal polarization HPL of the incident video light. The video light that has become the horizontal polarization HPL is reflected by the half mirrors 54L and 54R and passes through the wire grid structures 55L and 55R and is incident on the left eye EL and the right eye ER.

[0072] Therefore, when the optical switch is in the on state, the user of the head-mounted display 500 can view a composite video in which a virtual video is superimposed on the real scenery.

[0073] If the polarizer in the head-mounted display 500 sets the light emitted from the wire grid structures 55L and 55R to the horizontal polarization HPL, the user can view only the virtual video. Also, if the polarizer sets the light emitted from the wire grid structures 55L and 55R to the vertical polarization VPL, the user can view only the real scenery.

[0074] Thus, according to the head-mounted display 500 shown in FIG. 18, the user can switch between a composite video in which a virtual video is superimposed on the real scenery, only the virtual video, and only the real scenery video, and view the selected video. Note that if the optical switch is turned off, it is also possible to block the user's field of view.

[0075] In Fig. 18, instead of the vertical polarization filters 51L and 51R, horizontal polarization filters 53L and 53R may be arranged at the positions of the vertical polarization filters 51L and 51R, and instead of the horizontal polarization filters 53L and 53R, vertical polarization filters 51L and 51R may be arranged at the positions of the horizontal polarization filters 53L and 53R. In this case, the horizontal polarization filters 53L and 53R are the first polarization filters, and the vertical polarization filters 51L and 51R are the second polarization filters. Also in this case, if the polarizer sets the light emitted from the wire grid assemblies 55L and 55R to horizontal polarization HPL, the user can only see the real scenery. If the polarizer sets the light emitted from the wire grid assemblies 55L and 55R to vertical polarization VPL, the user can only see the virtual image.

[0076] <Sunglasses> Applying the configuration of the window 400 shown in Fig. 17, the lenses of the sunglasses may have the same configuration as the window glass 401. By configuring the lenses of the sunglasses with the first wire grid polarizer 11 to the fourth wire grid polarizer 14, it is also possible to configure sunglasses that can select between a state where the front cannot be seen and a state where it can be seen. It is also possible to select whether to view horizontal polarization HPL or vertical polarization VPL with the sunglasses, and it is also possible to change the color tone of the scenery viewed through the sunglasses.

[0077] The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0078] 11 First wire grid polarizer 11a, 12a, 13a, 14a Transparent substrate 11b, 12b, 13b, 14b Metal wire 12 Second wire grid polarizer 13 Third wire grid polarizer 14 Fourth wire grid polarizer 15 Slide control unit 16, 17 Slide drive unit 18 Rotation control unit 19 Rotation drive unit 21 Selection control unit 51L, 51R Vertical polarization filters 52L, 52R Image display units 53L, 53R Horizontal polarization filters 54L, 54R Half mirrors 55L, 55R Wire grid structures 101, 102 Optical switches 200 Polarizer 300 Optical filter 400 Window 500 Head-mounted display EL, ER Eyes

Claims

1. On a first transparent substrate, there is provided a first wire grid polarizer having a plurality of first metal wires extending in a first direction along the surface of the first transparent substrate, provided with a predetermined interval in a second direction orthogonal to the first direction and along the surface of the first transparent substrate, and a second wire grid polarizer disposed to face the first wire grid polarizer, having a plurality of second metal wires extending in the first direction along the surface of the second transparent substrate, provided with a predetermined interval in a second direction orthogonal to the first direction and along the surface of the second transparent substrate, and a third wire grid polarizer provided on a third transparent substrate, having a plurality of third metal wires extending in the second direction along the surface of the third transparent substrate, provided with a predetermined interval in a first direction orthogonal to the second direction and along the surface of the third transparent substrate, and a fourth wire grid polarizer disposed to face the third wire grid polarizer, having a plurality of fourth metal wires extending in the second direction along the surface of the fourth transparent substrate, provided with a predetermined interval in a first direction orthogonal to the second direction and along the surface of the fourth transparent substrate, and a slide driving unit that slides the first or second wire grid polarizer in the second direction and slides the third or fourth wire grid polarizer in the first direction, and is provided with When the slide driving unit positions each of the plurality of second metal wires in the central position of the interval between two adjacent first metal wires in the plurality of first metal wires as a first state, the first wire grid polarizer and the second wire grid polarizer block the second polarized light in incident light having a predetermined wavelength band including a first polarized light and a second polarized light incident on the first transparent substrate, and emit the first polarized light from the second transparent substrate. When the slide driving unit positions each of the second metal wires at the same position in the second direction of each of the first metal wires among the plurality of first metal wires, and sets a second state in which each of the first metal wires faces each of the second metal wires, the first wire grid polarizer and the second wire grid polarizer emit the first polarization and the second polarization in the incident light from the second transparent substrate, When the slide driving unit sets a third state in which each of the fourth metal wires among the plurality of fourth metal wires is positioned at the center of the interval between two adjacent third metal wires among the plurality of third metal wires, and the first polarization is incident as incident light on the third transparent substrate, the third wire grid polarizer and the fourth wire grid polarizer block the first polarization so as not to emit the first polarization from the fourth transparent substrate, When the slide driving unit positions each of the fourth metal wires at the same position in the first direction of each of the third metal wires among the plurality of third metal wires, and sets a fourth state in which each of the third metal wires faces each of the fourth metal wires, and the first polarization and the second polarization are incident as incident light on the third transparent substrate, the third wire grid polarizer and the fourth wire grid polarizer emit the first polarization and the second polarization from the fourth transparent substrate, By controlling the slide driving unit so that the first wire grid polarizer and the second wire grid polarizer are in the first state, and the third wire grid polarizer and the fourth wire grid polarizer are in the third state, an off state in which light in the predetermined wavelength band in the incident light incident on the first transparent substrate is not emitted from the fourth transparent substrate, and by controlling the slide driving unit so that the first wire grid polarizer and the second wire grid polarizer are in the second state, and the third wire grid polarizer and the fourth wire grid polarizer are in the fourth state, an on state in which light in the predetermined wavelength band in the incident light incident on the first transparent substrate is emitted from the fourth transparent substrate, and further comprising a slide control unit for switching between the two states Optical switch.

2. a rotation driving unit that rotates the third and fourth wire grid polarizers; a rotation control unit that controls the rotation driving unit to rotate the third and fourth wire grid polarizers; The optical switch according to claim 1, further comprising.

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