TWI799160B - Continuously Electronically Controllable Linear Polarization Rotator - Google Patents

Abstract

A continuously electrically controllable linear polarization rotator, comprising a first liquid crystal cell having a first upper substrate, a first lower substrate, and a transparent liquid crystal layer between the first upper substrate and the first lower substrate; and a first The second liquid crystal cell has a second upper substrate, a second lower substrate, and a transparent liquid crystal layer between the second upper substrate and the second lower substrate; the first liquid crystal cell and the second liquid crystal cell satisfy dΔn/λ=1.2~ 1.8 constraints, λ is the wavelength of incident light passing through the first liquid crystal cell and the second liquid crystal cell, d is the thickness of the transparent liquid crystal layer, Δn is the birefringence of the transparent liquid crystal layer, and the first lower substrate and the second upper substrate are arranged oppositely , and the alignment directions of the first lower substrate and the second upper substrate are perpendicular to each other, the same voltage is applied to the two liquid crystal cells and reaches a specific voltage value, and the linear polarization angle of the outgoing light can be continuously rotated.

Description

Continuously Electronically Controllable Linear Polarization Rotator

The invention relates to the technical field of a linear polarization rotator, in particular to a continuously electrically controllable linear polarization rotator, which can continuously rotate the polarization angle of outgoing light and achieve a good degree of linear polarization.

Currently, polarization rotators made of liquid crystal materials have been widely used in the market, and related products have been released in the industry.

Further, the linear polarization direction of outgoing light is controlled by applying an electric field parallel to the substrate to make an electrically controlled linear polarization rotator, as described in the third to fifth lines on page thirteen of the specification of CN100437266 Chinese patent, "When one is greater than a predetermined When an electric field of a voltage is applied across the liquid crystal layer, the liquid crystal layer adopts a substantially 90° twist. Thus, in such an embodiment, the polarization rotator is active with the electric field applied, and without The polarization rotator does not work when an electric field is applied."

However, so far, the use of electronically controlled twisted nematic liquid crystals can only switch the polarization rotation angles of on/off (On/Off), and there is no continuity; in the current technology, polarization rotators with continuity It is necessary to fix the angle between the linear polarization direction of the incident light and the first liquid crystal layer at 0° or 90° to be effective.

The main purpose of the present invention, the present invention uses two twisted nematic liquid crystal cells to make a continuously electrically controllable linear polarization rotator, which can continuously rotate the polarization of the outgoing light after applying a voltage to the liquid crystal cell and exceeding a certain voltage value Angle, and has a good degree of linear polarization.

In order to achieve the above-mentioned purpose and effect, a first embodiment of a continuous electronically controllable linear polarization rotator of the present invention includes: a first liquid crystal cell having a first upper substrate that is horizontally aligned to a vertically orthogonal direction , a first lower substrate, and the first liquid crystal cell is filled with a transparent liquid crystal layer located between the first upper substrate and the first lower substrate; A second upper substrate and a second lower substrate in the cross direction, and the two liquid crystal cells are filled with a transparent liquid crystal layer located between the second upper substrate and the second lower substrate.

The first liquid crystal cell and the second liquid crystal cell satisfy the range restriction condition of dΔn/λ=1.2~1.8, where λ is the wavelength of incident light passing through the first liquid crystal cell and the second liquid crystal cell, and d is The thickness of the transparent liquid crystal layer of the two liquid crystal cells, Δn is the birefringence of the transparent liquid crystal layer, the first liquid crystal cell is arranged correspondingly with the first lower substrate and the second upper substrate of the second liquid crystal cell, And the alignment direction of the first lower substrate of the first liquid crystal cell and the second alignment direction of the second upper substrate of the second liquid crystal cell are perpendicular to each other, and a voltage is applied to the first liquid crystal cell and the second liquid crystal cell, To change the linear polarization direction of the outgoing light after passing through the first liquid crystal cell and the second liquid crystal cell; and when the voltage applied to the first liquid crystal cell and the second liquid crystal cell has a continuous change, the first liquid crystal cell, The linear polarization rotation angle of the outgoing light after the second liquid crystal cell has a continuous change in the linear polarization angle from 0° to 180°.

A second embodiment of a continuously electrically controllable linear polarization rotator of the present invention, comprising: A first liquid crystal cell, which has a first upper substrate and a first lower substrate that have been horizontally aligned to a vertically orthogonal direction, and the first liquid crystal cell is filled with the first upper substrate and the first lower substrate A transparent liquid crystal layer between; the first liquid crystal cell satisfies the range restriction condition of dΔn/λ=1.2~1.8, the λ is the wavelength of the incident light passing through the first liquid crystal cell, and d is the said The thickness of the transparent liquid crystal layer, Δn is the birefringence of the transparent liquid crystal layer, applying a voltage to the first liquid crystal cell to change the linear polarization direction of the outgoing light after passing through the first liquid crystal cell; Applying a voltage with a continuous change, and the applied voltage is perpendicular to the surface direction of the first upper substrate and the first lower substrate, can make the linear polarization rotation angle of the outgoing light have a continuous change of the linear polarization angle from 0° to 90° , but it is necessary to limit the polarization direction of the incident light to an angle of 0° or 90° with the alignment direction of the first upper substrate of the first liquid crystal cell.

100: The spinner

10: The first liquid crystal box

11: The first upper substrate

111: The direction of the liquid crystal guide axis close to the first upper substrate

12: The first lower substrate

13: Transparent liquid crystal layer

14: Alignment direction

15: Polarization direction of incident light

20: Second liquid crystal cell

21: The second upper substrate

22: The second lower substrate

23: Transparent liquid crystal layer

24: Second alignment direction

30: Polarizer

40: Analyzer

A: Transparent conductive film

B: incident light

C: outgoing light

E: Arrow of press voltage change

F: polarization rotation angle

λ: wavelength of incident light

d: Thickness of transparent liquid crystal layer

Δn: Birefringence of transparent liquid crystal layer

β: Angle

The first figure is a three-dimensional schematic diagram of the first liquid crystal cell and the second liquid crystal cell of the present invention.

The second figure is a schematic cross-sectional view of the line segment II-II in the first figure.

The third figure is a three-dimensional exploded schematic view of the present invention provided with a polarizer located in front of the first liquid crystal cell and an analyzer disposed behind the second liquid crystal cell.

The fourth figure is the experiment result diagram of the present invention in which the applied voltage experiment with the angle β=0° is continuously changed, and the output light is changed from 180° to 0°. The polarization angle is continuously changed.

The fifth figure is the experimental result diagram of the present invention with the applied voltage experiment with the angle β=22.5° continuously changing, so that the outgoing light changes continuously from 180° to 0° polarization angle.

The sixth figure is the experimental result of the present invention with the applied voltage experiment of continuously changing the magnitude of the included angle β=45°, so that the outgoing light is changed from 180° to 0° and the polarization angle is continuously changed.

The seventh figure is the experiment result of the present invention with the applied voltage experiment of continuously changing the magnitude of the included angle β=67.5°, so that the outgoing light changes continuously from 180° to 0°.

Figure 8 is a schematic diagram of the operation changes of the continuously electrically controllable linear polarization rotator of the present invention.

Figure 9 is a perspective view of the second embodiment of the present invention.

Figure 10 is a schematic cross-sectional view of line X-X in Figure 9.

Fig. 11 is a schematic diagram of the operation changes of the continuously electrically controllable linear polarization rotator according to the second embodiment of the present invention.

Please refer to Figures 1 to 8, a continuously electrically controllable linear polarization rotator of the present invention, the first embodiment of the rotator 100 includes: a first liquid crystal cell 10, which has a horizontal alignment process to be vertically positive A first upper substrate 11 and a first lower substrate 12 in the cross direction, that is to say, the first upper substrate 11 and the first lower substrate 12 have alignment directions 14 perpendicular to each other, and the first liquid crystal cell 10 is filled with There is a transparent liquid crystal layer 13 between the first upper substrate 11 and the first lower substrate 12; and a second liquid crystal cell 20, which has a second upper substrate 21, A second lower substrate 22, that is, the second upper substrate 21 and the second lower substrate 22 have a second alignment direction 24 perpendicular to each other, and the two liquid crystal cells 20 are filled with A transparent liquid crystal layer 23 between the two lower substrates 22 .

The first liquid crystal cell 10 and the second liquid crystal cell 20 meet the range restriction condition of dΔn/λ=1.2~1.8, and the λ is the incident light B passing through the first liquid crystal cell 10 and the second liquid crystal cell 20 wavelength, d is the thickness of the transparent liquid crystal layer 13, 23, Δn is the birefringence of the transparent liquid crystal layer 13, 23, the The first liquid crystal cell 10 is arranged correspondingly with the second upper substrate 21 of the first lower substrate 12 and the second liquid crystal cell 20, and the alignment direction 14 of the first lower substrate 12 of the first liquid crystal cell 10 is the same as that of the second liquid crystal cell 10. The second alignment direction 24 of the second upper substrate 21 of the liquid crystal cell 20 is perpendicular to each other, and a voltage is applied to the first liquid crystal cell 10 and the second liquid crystal cell 20 to change the current flow through the first liquid crystal cell 10 and the second liquid crystal cell. The direction of linear polarization of the outgoing light C behind the cell 20.

The foregoing is the main technical feature of the main embodiment of the present invention, which corresponds to the content of the first item of the scope of the patent application of this case, so that the purpose and implementation type of the present invention can be known in detail, and the technical features described in the scope of the remaining subsidiary applications are for the purpose of The detailed description or additional technical features of the first item of the patent application scope are not used to limit the scope of the first item of the patent application scope. It should be known that the first item of the patent application scope in this case does not necessarily include the description of the other subsidiary application patent scopes technical characteristics.

Continuing from the above content, the embodiment of the present invention and its application effects are further described in detail. Since the first liquid crystal cell 10 of the present invention is arranged correspondingly with the first lower substrate 12 and the second upper substrate 21 of the second liquid crystal cell 20, And the first liquid crystal cell 10 and the second liquid crystal cell 20 meet the range restriction condition of dΔn/λ=1.2~1.8, when the same voltage is applied to the first liquid crystal cell 10 and the second liquid crystal cell 20 respectively, And the birefringence characteristics of the transparent liquid crystal layers 13 and 23 can be changed through electronic control, so that after the incident light B passes through the first liquid crystal cell 10 and the second liquid crystal cell 20, the outgoing light C can have a linear polarization Rotation changes.

As shown in the third figure, in the present invention, the first liquid crystal cell 10 and the second liquid crystal cell 20 are arranged back and forth, and the polarizer 30 arranged in front of the first liquid crystal cell 10 and the polarizer 30 arranged in the rear of the second liquid crystal cell 20 are further coordinated. The analyzer 40, according to the different angles β between the liquid crystal guide axis direction 111 close to the first upper substrate 11 and the polarization direction 15 of the incident light B, β=0°, β=22.5°, β=45°, β= Four sets of experiments were carried out at 67.5°, and the analyzer 40 received the outgoing light C passing through the first liquid crystal cell 10 and the second liquid crystal cell 20. The graphs of the experimental results of four different included angles β are shown in Figures 4 to 7.

Among them, the graph of the experimental results of β=0° is shown in the fourth figure. The abscissa of the graph is the change of the applied voltage, and the unit is volts, while the left side of the ordinate is the polarization rotation angle, and the right side is the degree of linear polarization, determined by the analyzer The change of the linear polarization degree of the received outgoing light C is marked with a dark dotted line; while the change of the linear polarization rotation angle of the received outgoing light C is marked with a light colored dotted line, when the voltage of the applied voltage is increased from 1 volt to 4 volts , the linear polarization rotation angle of the outgoing light C is 180° when the applied voltage is between 1 and 1.5 volts (as shown by the double-headed arrow in the figure); when the applied voltage is further increased from 1.5 volts to In the process of 2 volts, the linear polarization rotation angle of the outgoing light C decreases rapidly, as shown by the double-headed arrow in the figure, the linear polarization rotation angle decreases from 150°, 120° to 90° all the way; when the applied voltage is changed from When 2 volts are further gradually increased to 3 volts, the linear polarization rotation angle of the outgoing light C will have a gradual decrease. The linear polarization rotation angle shown by the double-headed arrow in the figure first decreases to 60° and then decreases to 30° °; when the applied voltage is gradually increased from 3 volts to 4 volts, the rotation angle of the linear polarization of the outgoing light C is gradually reduced to 0°.

The graphs of experimental results for β=22.5°, β=45°, and β=67.5° are shown in Figures 5, 6, and 7 respectively. From the light-colored dotted line in the figure, the change trend of the linear polarization rotation angle of the incident light C is indicated. , showing that when the applied voltage is gradually increased from 1 volt to 4 volts, the linear polarization rotation angle of the outgoing light C can be changed from 180° to 0°.

Therefore, it can be seen from the above experimental results that the present invention can indeed change the electronic control mode of the birefringence of the transparent liquid crystal layers 13 and 23 through the continuous change of the magnitude of the same voltage applied to the first liquid crystal cell 10 and the second liquid crystal cell 20, The linear polarization angle of the outgoing light C after passing through the first liquid crystal cell 10 and the second liquid crystal cell 20 can change continuously from 180° to 0°. Therefore, as the eighth figure is a schematic diagram of the operation change of the continuous electronically controllable linear polarization rotator of the present invention, the incident light B in the figure passes through the first liquid crystal cell 10 and the outgoing light C after the second liquid crystal cell 20, will follow The applied voltage change arrows of the first liquid crystal cell 10 and the second liquid crystal cell 20 E increases the magnification along the direction of the arrow in the figure, so that the linear polarization rotation angle F of the outgoing light C will change continuously from 0° to 180°.

Therefore, compared with the electronically controlled twisted nematic liquid crystal of the prior art, only the switching of the linear polarization rotation angle of the two kinds of on/off (On/Off) without continuity can be obtained; the first liquid crystal cell 10 of the present invention , The second liquid crystal cell 20 satisfies the range limit between dΔn/λ=1.2~1.8, and the alignment direction 14 of the first lower substrate 12 of the first liquid crystal cell 10 is the same as the second alignment direction 14 of the second liquid crystal cell 20 The second alignment direction 24 of the upper substrate 21 is perpendicular to each other, so that the alignment direction arrangement can make the outgoing light C after passing through the first liquid crystal cell 10 and the second liquid crystal cell 20 have a transition from 180° to 0° The linear polarization angle changes continuously, which is indeed progressive.

Moreover, if the present invention is pixelated, the linear polarization direction at different positions can be arbitrarily controlled in space, that is, the application of a polarization-only spatial light modulator (Polarization-Only Spatial Light Modulator); The light modulator (Spatial light modulator, SLM) is mainly to adjust the phase of the light field at different positions in space (Phase--Only), and the present invention can extend the spatial light modulator to the function of modulating the linear polarization angle in space.

In addition, the low operating voltage of the present invention can be integrated into a TFT (Thin film transistor liquid crystal display, TFT-LCD for short), and there is no need to consider the linear polarization direction of the incident light B in operation.

The characteristics of each element of the present invention are further described in detail below. In the above-mentioned first to eighth figures, the first upper substrate 11, the first lower substrate 12, the second upper substrate 21, and the second lower substrate 22 are plated with The transparent film-like structure of the transparent conductive film A is as shown in the second figure; therefore, the first liquid crystal cell 10 and the second liquid crystal cell 20 can apply the same voltage to the transparent liquid crystal layers 13, 23, and change their birefringence characteristics that make After the incident light B passes through the first liquid crystal cell 10 and the second liquid crystal cell 20 , the outgoing light C can have a change in the direction of the linear polarization state.

Secondly, the transparent liquid crystal layers 13 and 23 are positive nematic liquid crystals.

Furthermore, the same voltage is applied to the first liquid crystal cell 10 and the second liquid crystal cell 20, and the applied voltage is perpendicular to the surfaces of the first upper substrate 11, the first lower substrate 12, the second upper substrate 21, and the second lower substrate 22. direction; thereby, by controlling the continuous change of the magnitude of the applied voltage, the outgoing light C passing through the first liquid crystal cell 10 and the second liquid crystal cell 20 can have a continuous change of the linear polarization angle from 180° to 0°.

In addition, as shown in Figures 9 to 11, the present invention is a continuously electrically controllable linear polarization rotator. The second embodiment of the rotator 100 includes: a first liquid crystal cell 10, which has a horizontal alignment process that is vertical A first upper substrate 11 and a first lower substrate 12 in the orthogonal direction, that is to say, the first upper substrate 11 and the first lower substrate 12 have alignment directions 14 perpendicular to each other, and the first liquid crystal cell 10 It is filled with a transparent liquid crystal layer 13 located between the first upper substrate 11 and the first lower substrate 12 .

Wherein, the first liquid crystal cell 10 satisfies the range restriction condition of dΔn/λ=1.2~1.8, where λ is the wavelength of the incident light B passing through the first liquid crystal cell 10, and d is the transparent liquid crystal The thickness of the layer 13, Δn is the birefringence of the transparent liquid crystal layer 13, and a voltage is applied to the first liquid crystal cell 10 to change the linear polarization direction of the outgoing light C after passing through the first liquid crystal cell 10.

Figure 11 is a schematic diagram of the operation change of the continuously electrically controllable linear polarization rotator according to the second embodiment of the present invention. The incident light B shown in the figure, when the polarization of the incident light B is set to be the same as that of the first liquid crystal cell 10 When the angle between the alignment directions of the upper substrate 11 is 0° or 90°, the outgoing light C after passing through the first liquid crystal cell 10 in the forward direction will change with the applied voltage of the first liquid crystal cell 10. Arrow E (a certain voltage When the magnification is increased along the direction of the arrow in the figure, the linear polarization rotation angle F of the outgoing light C will have a transition from 0° The linear polarization angle varies continuously between 90° and 90°. Therefore, although the second embodiment of the present invention must limit the polarization direction of the incident light B to an angle of 0° or 90° with the alignment direction of the first upper substrate 11 of the first liquid crystal cell 10, it can make the outgoing light C reach from 0° The linear polarization angle between transitions to 90° changes continuously; compared with the electronically controlled twisted nematic liquid crystal in the prior art, only two linear polarization rotation angles of on/off (On/Off) without continuity can be obtained The switch is indeed progressive.

Therefore, the aforementioned first embodiment of the present invention constitutes the rotator 100 through the first liquid crystal cell 10 and the second liquid crystal cell 20, and the first lower substrate 12 is in contact with the second upper substrate 21 of the second liquid crystal cell 20. corresponding arrangement, and make the alignment direction 14 of the first lower substrate 12 of the first liquid crystal cell 10, and the second alignment direction 24 of the second upper substrate 21 of the second liquid crystal cell 20 mutually perpendicular and orthogonal; When voltage is applied to the first liquid crystal cell and the second liquid crystal cell, the incident light C after passing through the first liquid crystal cell 10 and the second liquid crystal cell 20 can further achieve a continuous change in linear polarization angle between 0° and 180° . Moreover, the linear polarization direction of the incident light B can be in any direction, that is to say, the linear polarization direction of the incident light B is not limited; therefore, the linear polarization direction of the incident light B does not need to be considered in use.

The characteristics of each component of the second embodiment of the converter 100 of the present invention will be further described below. In the ninth to eleventh figures above, the first upper substrate 11 and the first lower substrate 12 are coated with a transparent conductive film A on the inside. transparent membranous structure.

Moreover, the transparent liquid crystal layer 13 is a positive nematic liquid crystal.

Finally, a voltage is applied to the first liquid crystal cell 10, and the applied voltage is perpendicular to the surface direction of the first upper substrate 11 and the first lower substrate 12, so that the linear polarization rotation angle of the outgoing light C can be changed from 0° to 90° The linear polarization angle between them changes continuously, but it is necessary to limit the polarization direction of the incident light B to an angle of 0° or 90° with the alignment direction of the first upper substrate of the first liquid crystal cell.

As mentioned above, in the present invention, the alignment direction of the first lower substrate 12 and the second upper substrate 21 of the second liquid crystal cell 20 is perpendicular to each other by the first liquid crystal cell 10, and the first liquid crystal cell 10, The second liquid crystal cell 20 satisfies the restriction condition of the range of dΔn/λ=1.2~1.8, and can truly break through the existing electronically controlled twisted nematic liquid crystals, which can only obtain on/off (On/Off) output. The switching of the polarization rotation angle of the incident light cannot achieve the dilemma of continuous change, but achieves the following advantages:

1. The magnitude of the same voltage applied to the first liquid crystal cell 10 and the second liquid crystal cell 20 changes continuously, so that the outgoing light C after passing through the first liquid crystal cell 10 and the second liquid crystal cell 20 can change from 0° The linear polarization angle varies continuously up to 180°.

2. The low operating voltage of the present invention can be integrated into the TFT, and the linear polarization direction of the incident light B need not be considered in operation.

100: The spinner

10: The first liquid crystal cell

11: The first upper substrate

12: The first lower substrate

14: Alignment direction

20: Second liquid crystal cell

21: The second upper substrate

22: The second lower substrate

24: Second alignment direction

Claims (7)

A continuously electrically controllable linear polarization rotator, comprising: a first liquid crystal cell, which has a first upper substrate and a first lower substrate that are horizontally aligned to a vertically orthogonal direction, and the first liquid crystal cell is filled with A transparent liquid crystal layer located between the first upper substrate and the first lower substrate; and a second liquid crystal cell, which has a second upper substrate and a second lower substrate that are horizontally aligned to a vertically orthogonal direction, And the two liquid crystal cells are filled with a transparent liquid crystal layer located between the second upper substrate and the second lower substrate; the first liquid crystal cell and the second liquid crystal cell meet the requirements of dΔn/λ=1.2~1.8 Scope limitation condition, the λ is the wavelength of the incident light passing through the first liquid crystal cell and the second liquid crystal cell, d is the thickness of the transparent liquid crystal layer, Δn is the birefringence of the transparent liquid crystal layer, the first The liquid crystal cell is arranged correspondingly with the second upper substrate of the first lower substrate and the second liquid crystal cell, and the alignment direction of the first lower substrate of the first liquid crystal cell is the same as that of the second upper substrate of the second liquid crystal cell. The two alignment directions are perpendicular to each other, and a voltage is applied to the first liquid crystal cell and the second liquid crystal cell to change the linear polarization direction of the outgoing light after passing through the first liquid crystal cell and the second liquid crystal cell; and applied to the first liquid crystal cell and the second liquid crystal cell. When the voltage of the first liquid crystal cell and the second liquid crystal cell changes continuously, the linear polarization rotation angle of the outgoing light passing through the first liquid crystal cell and the second liquid crystal cell has a linear polarization angle between 0° and 180° continuous change. The continuously electronically controllable linear polarization rotator as described in Claim 1, wherein the first upper substrate, the first lower substrate, the second upper substrate, and the second lower substrate are transparent film structures coated with a transparent conductive film inside. The continuously electrically controllable linear polarization rotator as claimed in claim 1, wherein the transparent liquid crystal layer is a positive nematic liquid crystal. The continuously electrically controllable linear polarization rotator as described in Claim 2, wherein the same voltage is applied to the first liquid crystal cell and the second liquid crystal cell, and the applied voltage is perpendicular to the first upper substrate, the first lower substrate, the second The direction of the surface of the upper substrate and the second lower substrate can make the linear polarization rotation angle of the outgoing light continuously change from 0° to 180°. A continuously electrically controllable linear polarization rotator, comprising: a first liquid crystal cell, which has a first upper substrate and a first lower substrate that are horizontally aligned to a vertically orthogonal direction, and the first liquid crystal cell is filled with A transparent liquid crystal layer located between the first upper substrate and the first lower substrate; the first liquid crystal cell satisfies the range restriction condition of dΔn/λ=1.2~1.8, and the λ is passed through the first liquid crystal The wavelength of the incident light in the cell, d is the thickness of the transparent liquid crystal layer, Δn is the birefringence of the transparent liquid crystal layer, and a voltage is applied to the first liquid crystal cell to change the output after passing through the first liquid crystal cell. The linear polarization direction of the emitted light; a voltage with a continuous change is applied to the first liquid crystal cell, and the applied voltage is perpendicular to the direction of the first upper substrate and the first lower substrate surface, so that the linear polarization rotation angle of the emitted light can have a rotation angle from 0° The linear polarization angle between 90° and 90° changes continuously, but the polarization direction of the incident light needs to be limited to an angle of 0° or 90° with the alignment direction of the first upper substrate of the first liquid crystal cell. The continuously electronically controllable linear polarization rotator as described in Claim 5, wherein the first upper substrate and the first lower substrate are transparent film structures coated with a transparent conductive film inside. The continuously electrically controllable linear polarization rotator as claimed in claim 5, wherein the transparent liquid crystal layer is a positive nematic liquid crystal.

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