Electrically tunable focusing liquid crystal lightsaber device and working method

Abstract

The application provides a liquid crystal sword device with electrically controllable focusing and a working method. The device comprises, from top to bottom, a first glass substrate, a first orientation layer, a liquid crystal layer, a second orientation layer, a flat plate electrode layer and a second glass substrate. The first orientation layer is provided with a pattern electrode, which comprises a first fan-shaped unit A, a second fan-shaped unit B and a concentric circular arc unit C. The device further comprises electrode pins G, D, E and F. The same frequency and different amplitude voltages are applied to the first fan-shaped unit A and the second fan-shaped unit B respectively to form an asymmetric electric field, drive the liquid crystal molecules of the liquid crystal layer to deflect and form the liquid crystal sword device. The device has continuous variation of optical power, relatively inconspicuous dispersion, simple process, low cost, small size and electrically controllable focusing. By adjusting the voltage of the pattern electrode, different optical power variation ranges, i.e. different depth of field sizes, can be obtained. By adjusting the voltage, the positive and negative lens effects of the sword device can be switched.

Description

Technical Field

[0001] This invention belongs to the field of optical imaging technology, and specifically relates to an electrically controllable focusing liquid crystal lightsaber device and its working method. Background Technology

[0002] Depth of focus (DOF) is a crucial parameter in optical systems, determining the range of variation between the focal plane and the image plane. Large depth-of-focus (LOSE) optical systems have long been a focus of attention due to their superior characteristics and significant importance in many practical applications. Researchers have proposed numerous methods to extend DDF, such as optical apodization, wavefront coding, axial pyramids, and lightsaber optics (LSOEs). Compared to other optical devices, lightsabers exhibit relatively good imaging stability because their refractive power distribution remains constant regardless of aperture size. Numerical simulations and experiments have investigated large DDF imaging using Strell ratio, modulation transfer function (MTF), and visual acuity, yielding promising results. Because lightsabers are rotationally asymmetric structures—meaning their refractive power continuously varies with the rotational azimuth angle—they can also be used to generate vortex beams and enhance image edge contrast. However, this rotational asymmetry makes their fabrication extremely difficult, and the DDF cannot be changed.

[0003] Most proposed lightsaber devices are diffractive devices, which form a discontinuous, stepped, asymmetric phase distribution by uneven exposure of photoresist. Although they can achieve large depth-of-field imaging, this method relies on precision micromachining and injection molding technology, which has the disadvantages of complex processes, high costs, severe dispersion, and inability to electronically control focusing, making it difficult to apply in fields such as eye disease correction and extended depth-of-field imaging.

[0004] Liquid crystal lenses, whose optical properties can be adjusted by regulating the driving voltage, are considered potential candidates to replace or simplify bulky traditional optical devices. Their advantages include electrically controllable focusing, small size, light weight, low cost, and low power consumption. This invention designs a novel liquid crystal lightsaber, which is simpler to manufacture than traditional lightsabers and does not rely on high-resistivity films to achieve a uniform electric field distribution, overcoming the instability of high-resistivity film characteristics. Furthermore, it features a parabolic axial electric field distribution, and its depth of focus and refractive power can be altered by changing the applied voltage. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and propose an electrically controllable focusing refractive liquid crystal lightsaber device to solve the problems of complex manufacturing process, high cost, severe dispersion and inability to be electrically controlled for focusing in existing lightsaber devices.

[0006] To achieve the above-mentioned objectives, the technical solution of this invention is as follows:

[0007] An electrically controllable focusing liquid crystal lightsaber device includes, from top to bottom, a first glass substrate 1, a first alignment layer 2, a liquid crystal layer 8, a second alignment layer 4, a flat electrode layer 5, and a second glass substrate 6. The first alignment layer 2 is provided with a patterned electrode 7, and the liquid crystal layer 8 is provided with a spacer 3.

[0008] The patterned electrode 7 includes a first sector unit A, a second sector unit B, and a concentric arc unit C, as well as electrode pins G, D, E, and F.

[0009] The first sector unit A and the second sector unit B are respectively located on the left and right sides of the center of the pattern electrode 7. Each sector unit includes an arc segment 71 and a straight segment 72. Each straight segment 72 forms the boundary line between the sector unit and the concentric arc unit C. Each arc segment 71 is concentrically arranged in each sector area. The length of each arc segment 71 in each sector area increases linearly in the radial direction with the center of the pattern electrode as the center, and adjacent arc segments 71 are connected in series with straight segments 72.

[0010] The concentric arc unit C includes multiple concentric arcs, and the two ends of each concentric arc are respectively connected to the straight section of the sector unit. Each concentric arc of the concentric arc unit C is aligned and connected to the arc segment corresponding to sector unit A and sector unit B in the circumferential direction.

[0011] The outermost electrode pin D of the first sector unit A is connected, and the center electrode pin E is connected; electrode pins D and E are used to control the voltage distribution of the first sector unit A.

[0012] The outermost connecting electrode pin G of the second sector unit B and the center connecting electrode pin F of the second sector unit B are used to control the voltage distribution of the second sector unit B.

[0013] The first alignment layer 2 and the second alignment layer 4 have opposite and parallel surface alignment directions; the patterned electrode 7 and the flat electrode layer 5 are transparent conductive films, and the flat electrode layer 5 is used as a ground electrode; the spacer 3 is used to control the thickness of the liquid crystal layer.

[0014] Voltages of the same frequency but different amplitudes are applied to the first sector unit A and the second sector unit B respectively to form an asymmetric electric field, which drives the liquid crystal molecules of the liquid crystal layer 8 to deflect, thus forming a liquid crystal light sword device.

[0015] As a preferred embodiment, the first sector unit A and the second sector unit B serve as two generators for producing a parabolic electric field distribution. Because the length of the arc segment of the first sector unit A and the second sector unit B increases linearly from the center along the radial direction, a parabolic impedance distribution is generated from the center along the radial direction, thus producing a parabolic electric field distribution after applying a voltage.

[0016] As a preferred embodiment, the diameter of spacer 3 is 30 micrometers.

[0017] As a preferred embodiment, the first glass substrate 1 and the second glass substrate 6 have the same thickness, both being 0.2 to 0.5 mm.

[0018] As a preferred embodiment, the patterned electrode 7 and the flat electrode layer 5 are transparent ITO conductive films.

[0019] As a preferred embodiment, the first alignment layer 2 and the second alignment layer 4 are thin films coated with polyimide, tilted vapor-deposited silicon monoxide thin films, or liquid crystal photoalignment thin films, with surface orientations of 0° and 180°, respectively.

[0020] As a preferred method, the patterned electrode 7 is obtained by optical etching, and the material is indium tin oxide (ITO).

[0021] As a preferred embodiment, the relative refractive index Δn of the liquid crystal layer 8 is 0.25.

[0022] The second objective of this invention is to provide a method for operating the electrically controllable focusing liquid crystal lightsaber device, wherein: when no driving voltage is applied, the electrode pins D, E, F, and G in the patterned electrode 7 have the same orientation direction as the orientation direction of the liquid crystal molecules, which are 0° and 180° respectively, and there is no lens effect; when a driving voltage is applied, the electrode pins G, F, E, and D are connected to V1, V2, V3, and V4 respectively, and the driving voltages V1, V2, V3, and V4 are used to generate a rotational asymmetric electric field distribution in the direction from the first sector unit A, the second sector unit B, and from the second sector unit B to the first sector unit A or from the first sector unit A to the second sector unit B. By taking the linear region of the liquid crystal material's response to voltage, a refractive liquid crystal lightsaber device can be obtained.

[0023] The liquid crystal lightsaber device proposed in this invention can achieve continuously varying optical power in different radial directions. When driving voltages of different amplitudes are applied to the first sector unit A and the second sector unit B, which generate a parabolic electric field distribution, the potential difference inside the liquid crystal lightsaber device will continuously change with the radial angle of the concentric arc unit C, and the electric field strength will also continuously change with the radial angle. Therefore, this invention can obtain optical power that continuously varies with the radial angle, achieving the effect of a lightsaber device.

[0024] The beneficial effects of this invention are as follows: Compared with the prior art, the refractive liquid crystal lightsaber device of this invention has continuously varying optical power, relatively insignificant chromatic aberration, simple manufacturing process, low cost, small size, and can be electrically controlled for focusing. By adjusting the voltage of the patterned electrodes, different ranges of optical power variation can be obtained, i.e., different depths of field; the positive and negative lens effects of the lightsaber device can also be switched by adjusting the voltage; furthermore, if the same voltage is applied to the two generators, the first sector unit A and the second sector unit B, a liquid crystal lens with a single optical power can be obtained, at which point the depth of field is minimized. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of an electrically controllable focusing liquid crystal lightsaber device according to the present invention.

[0026] Figure 2 This is a cross-sectional view of the patterned electrode of the present invention.

[0027] Figure 3 The potential distribution of the patterned electrode with positive optical power obtained by COMSOL simulation in this invention.

[0028] Figure 4 The potential distribution of the patterned electrode with negative optical power obtained by COMSOL simulation in this invention.

[0029] Figure 5 This is an interference diagram showing the positive optical power of the liquid crystal lightsaber device of the present invention.

[0030] Figure 6 This is an interference diagram of the negative optical power of the liquid crystal lightsaber device of the present invention.

[0031] 1 is the first glass substrate, 2 is the first alignment layer, 3 is the spacer, 4 is the second alignment layer, 5 is the flat electrode layer, 6 is the second glass substrate, 7 is the pattern electrode, 8 is the liquid crystal layer, 71 is the arc segment, 72 is the straight segment, A is the first sector unit, B is the second sector unit, and C is the concentric arc unit. Detailed Implementation

[0032] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0033] Example 1

[0034] like Figure 1As shown, this embodiment provides an electrically controllable focusing liquid crystal lightsaber device, including a first glass substrate 1, a first alignment layer 2, a liquid crystal layer 8, a second alignment layer 4, a flat electrode layer 5, and a second glass substrate 6 arranged sequentially from top to bottom. The first alignment layer 2 is provided with a patterned electrode 7, and the liquid crystal layer 8 is provided with a spacer 3.

[0035] like Figure 2 As shown, the patterned electrode 7 includes a first sector unit A, a second sector unit B, and a concentric arc unit C, and also includes electrode pins G, D, E, and F;

[0036] The first sector unit A and the second sector unit B are respectively located on the left and right sides of the center of the pattern electrode 7. Each sector unit includes an arc segment 71 and a straight segment 72. Each straight segment 72 forms the boundary line between the sector unit and the concentric arc unit C. Each arc segment 71 is concentrically arranged in each sector area. The length of each arc segment 71 in each sector area increases linearly in the radial direction with the center of the pattern electrode as the center, and adjacent arc segments 71 are connected in series with straight segments 72.

[0037] The concentric arc unit C includes multiple concentric arcs, and the two ends of each concentric arc are respectively connected to the straight section of the sector unit. Each concentric arc of the concentric arc unit C is aligned and connected to the arc segment corresponding to sector unit A and sector unit B in the circumferential direction.

[0038] The outermost electrode pin D of the first sector unit A is connected, and the center electrode pin E is connected; electrode pins D and E are used to control the voltage distribution of the first sector unit A.

[0039] The outermost connecting electrode pin G of the second sector unit B and the center connecting electrode pin F of the second sector unit B are used to control the voltage distribution of the second sector unit B.

[0040] The first alignment layer 2 and the second alignment layer 4 have opposite and parallel surface alignment directions; the patterned electrode 7 and the flat electrode layer 5 are transparent conductive films, and the flat electrode layer 5 is used as a ground electrode; the spacer 3 is used to control the thickness of the liquid crystal layer.

[0041] Voltages of the same frequency but different amplitudes are applied to the first sector unit A and the second sector unit B respectively to form an asymmetric electric field, which drives the liquid crystal molecules of the liquid crystal layer 8 to deflect, thus forming a liquid crystal light sword device.

[0042] The first sector unit A and the second sector unit B serve as two generators for producing a parabolic electric field distribution. Because the length of the arc segment of the first sector unit A and the second sector unit B increases linearly from the center along the radial direction, a parabolic impedance distribution is generated from the center along the radial direction. Therefore, a parabolic electric field distribution is generated after applying a voltage.

[0043] Preferably, the diameter of spacer 3 is 30 micrometers.

[0044] Preferably, the first glass substrate 1 and the second glass substrate 6 have the same thickness, both being 0.2 to 0.5 mm.

[0045] Preferably, the patterned electrode 7 and the planar electrode layer 5 are transparent ITO conductive films. They have high conductivity and high transmittance in the visible light range.

[0046] Preferably, the first alignment layer 2 and the second alignment layer 4 are thin films coated with polyimide, tilted vapor-deposited silicon monoxide thin films, or liquid crystal photoalignment thin films, with surface orientations of 0° and 180°, respectively.

[0047] Preferably, the patterned electrode 7 is obtained by optical etching and the material is indium tin oxide (ITO).

[0048] Preferably, the relative refractive index Δn of the liquid crystal layer 8 is 0.25.

[0049] This embodiment also provides a method for operating the electrically controllable focusing liquid crystal lightsaber device: When no driving voltage is applied, the electrode pins D, E, F, and G in the patterned electrode 7 have the same orientation direction as the orientation direction of the liquid crystal molecules, which are 0° and 180° respectively, and there is no lens effect; when a driving voltage is applied, the electrode pins G, F, E, and D are connected to V1, V2, V3, and V4 respectively. The driving voltages V1, V2, V3, and V4 are used to generate a rotational asymmetric electric field distribution in the direction from the first sector unit A, the second sector unit B, and from the second sector unit B to the first sector unit A or from the first sector unit A to the second sector unit B. By taking the linear region of the liquid crystal material's response to voltage, a refractive liquid crystal lightsaber device can be obtained.

[0050] To verify the structure of this invention, COMSOL was used to simulate it. When V1 = 1.5V, V2 = 2.5V, V3 = 2V, and V4 = 1.8V, the following results were obtained: Figure 3 The potential distribution diagram of the patterned electrodes is shown; when V1 = 2.5V, V2 = 1.5V, V3 = 1.8V, and V4 = 2V, the following is obtained: Figure 4 The potential distribution diagram of the patterned electrodes is shown. The result is the same as the potential distribution required for the liquid crystal lightsaber device. Based on the structure of this invention, a 5mm diameter liquid crystal lightsaber device was fabricated, and the measured interference pattern is shown below. Figure 5 , Figure 6 As shown, the same wavefront as the lightsaber device was obtained, and the area inside the white circle is the effective region of the liquid crystal lightsaber device.

[0051] Example 2

[0052] A polarizer is placed on the outside of the first glass substrate 1 of the liquid crystal lightsaber device provided in Embodiment 1. The polarization axis of the polarizer is parallel to the orientation direction of the liquid crystal lightsaber device. It is applied to a large depth-of-focus optical imaging system with adjustable optical power and depth of focus.

[0053] To observe the operation of the liquid crystal lightsaber device prepared in Example 1, the device was tested using a 532nm laser interference optical path. The interference pattern of the device was observed by adjusting the voltages of the four electrode pins D, E, F, and G on the patterned electrode 2. Figure 5 The interference pattern of the liquid crystal lightsaber device inside the white circle is shown when V1 = 1.5V, V2 = 2.5V, V3 = 2V, and V4 = 1.8V. Figure 6 This is the case when V1 = 2.5V, V2 = 1.5V, V3 = 1.8V, and V4 = 2V. In this case, the white circle represents the interference pattern of the liquid crystal lightsaber device. (From...) Figure 5 As can be seen from Figure 6, the number of stripes and the amount of change are different. It can be verified that by adjusting the driving voltages V1, V2, V3, and V4, the optical power and depth of field of this liquid crystal light sword device can be changed, which can be applied to a large depth of field imaging system with adjustable optical power and depth of field.

[0054] Example 3

[0055] According to Example 1, two liquid crystal lightsaber devices with the same structure and equal liquid crystal thickness are fabricated. The second glass substrate 6 of the first liquid crystal lightsaber device and the first glass substrate 1 of the second liquid crystal lightsaber device are close together, with the effective areas aligned. The orientation directions of the two liquid crystal lightsaber devices are perpendicular, which can remove the polarizer, perform unbiased imaging, improve the transmittance of the device, and be applied to a large depth-of-field optical imaging system with adjustable optical power and depth of field.

[0056] Applying the same voltage to two liquid crystal lightsaber devices creates a lightsaber lens effect. When natural light enters the first device, it splits into e-rays and o-rays; the e-rays are modulated, while the o-rays remain unmodulated. When light enters the second device, the modulated e-rays become o-rays and are no longer modulated, while the previously unmodulated o-rays become e-rays, are modulated, and then emitted, achieving polarization-free imaging and improving the device's transmittance. Using this method, polarizers can be removed while the device's optical power and depth of field can still be changed, enabling applications in large depth-of-field imaging systems where both optical power and depth of field are adjustable.

[0057] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A liquid crystal lightsaber device with electrically controllable focusing, characterized in that: The first glass substrate (1), first alignment layer (2), liquid crystal layer (8), second alignment layer (4), flat electrode layer (5), and second glass substrate (6) are arranged sequentially from top to bottom. The first alignment layer (2) is provided with patterned electrodes (7), and the liquid crystal layer (8) is provided with spacers (3). The patterned electrode (7) includes a first sector unit A, a second sector unit B, and a concentric arc unit C, and also includes electrode pins G, D, E, and F. The first sector unit A and the second sector unit B are respectively located on the left and right sides of the center of the pattern electrode (7). Each sector unit includes an arc segment (71) and a straight segment (72). Each straight segment (72) forms the boundary line between the sector unit and the concentric arc unit C. Each arc segment (71) is concentrically set in each sector area. The length of each arc segment (71) in each sector area increases linearly in the radial direction with the center of the pattern electrode as the center, and adjacent arc segments (71) are connected in series with straight segments (72). The concentric arc unit C includes multiple concentric arcs, and the two ends of each concentric arc are respectively connected to the straight section of the sector unit. Each concentric arc of the concentric arc unit C is aligned and connected to the arc segment corresponding to sector unit A and sector unit B in the circumferential direction. The outermost electrode pin D of the first sector unit A is connected, and the center electrode pin E is connected; electrode pins D and E are used to control the voltage distribution of the first sector unit A. The outermost connecting electrode pin G of the second sector unit B and the center connecting electrode pin F of the second sector unit B are used to control the voltage distribution of the second sector unit B. The first alignment layer (2) and the second alignment layer (4) have opposite and parallel surface alignment directions; the patterned electrode (7) and the flat electrode layer (5) are transparent conductive films, and the flat electrode layer (5) is used as a ground electrode; the spacer (3) is used to control the thickness of the liquid crystal layer; Voltages of the same frequency but different amplitudes are applied to the first sector unit A and the second sector unit B respectively to form an asymmetric electric field, which drives the liquid crystal molecules of the liquid crystal layer (8) to deflect, forming a liquid crystal light sword device.

2. The electrically controllable focusing liquid crystal lightsaber device according to claim 1, characterized in that: The first sector unit A and the second sector unit B serve as two generators for producing parabolic electric field distributions.

3. The electrically controllable focusing liquid crystal lightsaber device according to claim 1, characterized in that: The spacer (3) has a diameter of 30 micrometers.

4. The electrically controllable focusing liquid crystal lightsaber device according to claim 1, characterized in that: The first glass substrate (1) and the second glass substrate (6) have the same thickness, both being 0.2 to 0.5 mm.

5. The electrically controllable focusing liquid crystal lightsaber device according to claim 1, characterized in that: The patterned electrode (7) and the flat electrode layer (5) are transparent ITO conductive films.

6. The electrically controllable focusing liquid crystal lightsaber device according to claim 1, characterized in that: The first orientation layer (2) and the second orientation layer (4) are thin films coated with polyimide, tilted vapor-deposited silicon monoxide films, or liquid crystal photo-aligned films, with surface orientations of 0° and 180°, respectively.

7. The electrically controllable focusing liquid crystal lightsaber device according to claim 1, characterized in that: The patterned electrode (7) is obtained by optical etching and is made of indium tin oxide (ITO).

8. The electrically controllable focusing liquid crystal lightsaber device according to claim 1, characterized in that: The relative refractive index Δn of the liquid crystal layer (8) is 0.

25.

9. The method of operating the electrically controllable focusing liquid crystal lightsaber device according to any one of claims 1 to 8, characterized in that: When no driving voltage is applied, the electrode pins D, E, F, and G in the patterned electrode (7) have the same orientation direction as the orientation direction of the liquid crystal molecules as the orientation direction of the orientation layer they are close to, which are 0° and 180° respectively, and there is no lens effect. When a driving voltage is applied, the electrode pins G, F, E, and D are connected to V1, V2, V3, and V4 respectively. The driving voltages V1, V2, V3, and V4 are used to generate a rotational asymmetric electric field distribution in the direction from the first sector unit A, the second sector unit B, and from the second sector unit B to the first sector unit A or from the first sector unit A to the second sector unit B. By taking the linear region of the liquid crystal material's response to voltage, a refractive liquid crystal light sword device can be obtained.

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