CN114002855B - Axicon lens, minimum base angle adjustment device and adjustment method of axicon lens - Google Patents

Abstract

The present invention relates to the technical field of lenses, in particular to an axicon lens, a device for adjusting the minimum base angle of the axicon lens, and an adjustment method. The axicon lens of the present invention includes an electrode and a liquid crystal layer; the electrode includes a first electrode and a second electrode, and the liquid crystal layer is located on the first between an electrode and a second electrode; the distance between the first electrode and the second electrode is 0.1mm to 0.7mm; the electrode is used to receive the first driving voltage v1, and the first driving voltage v1 is the distance between the first electrode and the second electrode voltage between the two electrodes. The device for adjusting the minimum base angle of an axicon lens of the present invention includes a driving power source and an axicon lens. The adjusting method of the present invention enables the electrode of the lens to receive the first driving voltage v1 and adjust the value of the first driving voltage v1. The present invention adjusts the minimum base angle of the axicon lens quickly and in real time by adjusting the value of the first driving voltage v1 of the axicon lens, and obtains a smaller minimum base angle than the prior art.

Description

Axicon, minimum base angle adjustment device and adjustment method of axicon

technical field

The invention relates to the technical field of lenses, in particular to an axicon lens, a device for adjusting the minimum base angle of the axicon lens, and an adjustment method.

Background technique

Axicon is an important optical component, which can refract incident light according to a certain angle. Through the interference and diffraction between these refracted light beams, the focal line of the axicon can become very long, and a long focal length line can be generated along the optical axis. When a Gaussian beam passes through an axicon, it becomes a Bessel beam, which can greatly reduce the effect of diffraction and have a uniform intensity distribution in the light field on the focal line. These characteristics of the axicon make it It has been widely used, such as for generating non-collinear harmonics, for highly sensitive fluorescence measurement, for nanoparticle screening, and replacing ball lenses with axicons to solve the problem of defocusing. Another significant advantage of the axicon is that it can obtain depth information of an imaged object.

There are also many methods in the technology that can generate Bessel beams, such as:

1. A Bessel beam is generated by adding a diaphragm with an annular clear aperture to the back focal plane of a traditional converging lens;

2. Using a spatial light modulator to generate a Bessel beam;

3. Use TAG lens to generate Bessel beam;

4. Use an axicon to generate a Bessel beam.

However, the focal depth of the Bessel beam generated by adding a diaphragm with an annular clear aperture to the back focal plane of the traditional converging lens is not as large as that of the traditional axicon; the Bessel beam generated by using a spatial light modulator The cost of the method is high, and the modulation function is complex; the minimum base angle of the cone lens formed by the method of using the TAG lens to generate the Bessel beam is affected by the conical cavity and the liquid medium, and the minimum base angle cannot be easily and quickly performed. , adjust in real time.

In practical applications, there are many cases where an axicon lens is used to generate a Bessel beam. However, when an axicon is used to generate a Bessel beam, since the maximum non-diffracted distance of the Bessel-Gaussian beam is inversely proportional to the minimum base angle of the axicon, it is necessary to obtain a larger Bessel-Gaussian beam. Without the diffraction distance, an axicon lens with a smaller minimum base angle value is required. However, due to the limitation of the traditional axicon lens, the minimum base angle of the axicon lens is limited to about 0.5 degrees to 1 degree, which seriously limits the generated The maximum non-diffraction distance of the Bessel-Gaussian beam, so the use of the existing axicon can not obtain a larger depth of field and higher definition images. Moreover, since the minimum base angle of the axicon lens has been fixed after the traditional axicon lens is manufactured, if the minimum base angle of the axicon lens is to be changed, only the axicon lens can be replaced, so it is impossible to adjust the minimum base angle quickly and in real time in practical applications. Therefore, the traditional axicon cannot be used in applications that need to change the minimum base angle quickly and in real time.

SUMMARY OF THE INVENTION

In view of this, the present invention provides an axicon lens, an axicon lens minimum base angle adjustment device and an adjustment method to solve the problem that the minimum base angle value of the axicon lens in the prior art is too large, resulting in the largest Bessel-Gaussian beam generated by the axicon lens. There is no problem that the diffraction distance is short, and the minimum base angle of the axicon cannot be quickly adjusted in real time.

In order to solve the above-mentioned technical problems, the present invention is realized through the following technical solutions:

In a first aspect, the present invention provides an axicon lens, the axicon lens includes a liquid crystal lens element, and the liquid crystal lens element includes an electrode and a liquid crystal layer;

The electrode includes a first electrode and a second electrode, and the second electrode is a circular hole-shaped electrode;

the liquid crystal layer is located between the first electrode and the second electrode;

In the normal direction along the plane of the first electrode, the distance between the first electrode and the second electrode is 0.1 mm to 0.7 mm;

The electrodes are used to receive a first driving voltage V1, and the first driving voltage is a voltage between the first electrode and the second electrode.

Preferably, in the normal direction along the plane of the first electrode, the distance between the first electrode and the second electrode is 0.2 mm to 0.5 mm;

The range of the first driving voltage V1 is 0V to 35V.

In a second aspect, the present invention provides an axicon lens, the axicon lens includes a liquid crystal lens element, and the liquid crystal lens element includes an electrode and a liquid crystal layer;

The electrode includes a first electrode and a second electrode, and the second electrode is a circular hole-shaped electrode;

the liquid crystal layer is located between the first electrode and the second electrode;

The electrode further includes a third electrode, the second electrode is located between the first electrode and the third electrode, and the liquid crystal layer is located between the first electrode and the second electrode, in a normal direction along the plane of the first electrode In the direction, the distance between the first electrode and the second electrode is d1, and the distance between the second electrode and the third electrode is d2, where 0≤d2≤0.4, d2/2+0.3≤d1 ≤-d2/2+0.7, where d1 and d2 are in mm;

The electrodes are used to receive a first driving voltage V1 and a second driving voltage V2, the first driving voltage V1 is the voltage between the first electrode and the second electrode, and the second driving voltage V2 is the first electrode and the second driving voltage V2. voltage between the third electrodes.

Preferably, wherein V1 and V2 satisfy: 0≤V2≤40, 0≤V1≤3×V2/4+30, wherein the unit of V1 and V2 is V.

In a third aspect, the present invention provides a device for adjusting the minimum base angle of an axicon lens, comprising a drive power source and the axicon lens described in the first aspect, the drive power source is used to provide the first drive voltage V1, and the drive power source is used to provide the first drive voltage V1. is an adjustable power supply.

Preferably, a driving voltage adjustment module is also included, the driving voltage adjustment module is used to adjust the value of the first driving voltage V1 provided by the driving power supply, wherein the value range of the adjustment amount ΔV of V1 is ΔV1/V1≤0.07.

In a fourth aspect, the present invention provides a device for adjusting the minimum base angle of an axicon lens, comprising a driving power source and the axicon lens described in the first aspect, wherein the driving power source is used to provide a first driving voltage V1 and a second driving voltage V2, The first driving voltage V1 or/and the second driving voltage V2 provided by the driving power supply are adjustable voltages.

Preferably, a driving voltage adjustment module is further included, and the driving voltage adjustment module is used to adjust the first driving voltage V1 or/and the second driving voltage V2;

The value range of the adjustment amount ΔV1 of V1 is ΔV1/V1≤0.07, and the value range of the adjustment amount ΔV2 of V2 is ΔV2/V2≤0.07.

In a fifth aspect, the present invention provides a method for adjusting the minimum base angle of an axicon lens, including the electrodes of the axicon lens in the first aspect receiving a first driving voltage V1;

Adjust the value of the first driving voltage V1.

Preferably, the value range of the adjustment amount ΔV1 of V1 is ΔV1/V1≤0.07.

In a sixth aspect, the present invention provides a method for adjusting the minimum base angle of an axicon lens, including:

The electrodes of the axicon lens in the first aspect receive the first driving voltage V1 and the second driving voltage V2;

Adjust the value of the first driving voltage V1 or/and the second driving voltage V2.

Preferably, the value range of the adjustment amount ΔV1 of V1 is ΔV1/V1≤0.07, and the value range of the adjustment amount ΔV2 of V2 is ΔV2/V2≤0.07.

Beneficial effects of the present invention: Compared with the prior art, the axicon lens, the minimum base angle adjustment device and the adjustment method of the axicon lens provided by the present invention, by setting the distance between the first electrode and the second electrode at 0.1mm to 0.7mm mm, and add a first driving voltage between the first electrode and the second electrode, and use the electric field formed by the electric field to drive the liquid crystal molecules to be arranged in an approximate conical shape, so that all the incident light passing through the liquid crystal layer is a The same angle is refracted to form a liquid crystal axicon that can be driven by a voltage. And by adjusting the value of the first driving voltage to control the distribution of the electric field in the space, so as to adjust the minimum base angle of the liquid crystal cone lens, the adjustment process does not need to change the shape of the cone lens, and does not need to reprocess the cone lens, so Without being limited by the processing technology, a smaller minimum base angle can be obtained than that of the prior art axicon. Since the minimum base angle of the axicon lens changes rapidly and continuously with the continuous change of the driving voltage V1, using the device and method for adjusting the minimum base angle of the axicon lens of the present application, without changing the external structure and size of the axicon lens, it is convenient to , adjust the minimum base angle of the Axicon in real time and quickly.

Description of drawings

FIG. 1 is a schematic structural diagram of a liquid crystal lens element according to Embodiment 1 of the present invention.

FIG. 2 is a schematic structural diagram of a liquid crystal lens element according to Embodiment 2 of the present invention.

FIG. 3 is a wavefront diagram when d1=0.3mm, d2=0.02mm, v1=40V, and v2=20V in the present invention.

FIG. 4 is a wavefront diagram when d1=0.7mm, d2=0.02mm, v1=40V, and v2=20V in the present invention.

FIG. 5 is a wavefront diagram when d1=0.5mm, d2=0.4mm, v1=40V, and v2=20V in the present invention.

FIG. 6 is a wavefront diagram of the present invention when d1=0.35mm, d2=0.1mm, v1=40V, and v2=20V.

FIG. 7 is a wavefront diagram when d1=0.65mm, d2=0.1mm, v1=40V, v2=20V in the present invention.

FIG. 8 is a wavefront diagram when d1=0.4mm, d2=0.2mm, v1=40V, and v2=20V in the present invention.

FIG. 9 is a wavefront diagram when d1=0.6mm, d2=0.2mm, v1=40V, and v2=20V in the present invention.

FIG. 10 is a wavefront diagram when d1=0.3mm, d2=0.1mm, v1=0V, and v2=30V in the present invention.

FIG. 11 is a wavefront diagram when d1=0.3mm, d2=0.1mm, v1=20V, and v2=0V in the present invention.

FIG. 12 is a wavefront diagram when d1=0.3mm, d2=0.1mm, v1=20V, and v2=40V in the present invention.

FIG. 13 is a wavefront diagram when d1=0.3mm, d2=0.1mm, v1=30V, and v2=0V in the present invention.

Fig. 14 is a wavefront diagram when d1=0.3mm, d2=0.1mm, v1=40V, v2=40V in the present invention.

FIG. 15 is a wavefront diagram when d1=0.3mm, d2=0.1mm, v1=50V, and v2=40V in the present invention.

FIG. 16 is a wavefront diagram when d1=0.3mm, d2=0.1mm, v1=60V, and v2=40V in the present invention.

FIG. 17 is a wavefront diagram when d1=0.3mm, d2=0.1mm, v1=37.5V, and v2=10V in the present invention.

FIG. 18 is a schematic structural diagram of Embodiment 13 of the present invention.

Description of main component symbols: first transparent substrate 11, second transparent substrate 12, third transparent substrate 13, first electrode 21, second electrode 22, third electrode 23, liquid crystal layer 3, insulating layer 4, spacer 5, Laser 6 , polarizer 7 , high reflection mirror 8 , cone lens 9 , photodetector 10 and oscilloscope 12 .

The following specific embodiments will further illustrate the present invention in conjunction with the above drawings.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the descriptions involving "first", "second", etc. in the present invention are only for the purpose of description, and should not be construed as indicating or implying their relative importance or implying the number of indicated technical features . Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In addition, the technical solutions between the various embodiments can be combined with each other, but must be based on the realization by those of ordinary skill in the art. When the combination of technical solutions is contradictory or cannot be realized, it should be considered that the combination of such technical solutions does not exist. , is not within the scope of protection required by the present invention.

Example 1

This embodiment provides an axicon lens. As shown in FIG. 1 , the cone lens in this embodiment includes a liquid crystal lens element, and the liquid crystal lens element includes electrodes and a liquid crystal layer 3 ;

The electrodes include a first electrode 21 and a second electrode 22, and the second electrode 22 is a hole-shaped electrode;

The liquid crystal layer 3 is located between the first electrode 21 and the second electrode 22;

In the normal direction along the plane of the first electrode 21, the distance between the first electrode 21 and the second electrode 22 is 0.1 mm to 0.7 m;

The electrodes are used to receive the first driving voltage V1 , and the first driving voltage is the voltage between the first electrode 21 and the second electrode 22 .

The first electrode 21 can be a transparent electrode, such as an ITO electrode or an AZO electrode, and the second electrode 22 can be a transparent electrode or a non-transparent electrode such as a metal electrode, wherein the metal electrode material includes but is not limited to Al, Pt, and Cr.

When the distance between the first electrode 21 and the second electrode 22 is 0.1 mm to 0.7 m, a voltage is applied between the first electrode 21 and the second electrode 22, and a voltage is applied between the first electrode 21 and the second electrode 22. An electric field is formed between the liquid crystal molecules, which can make the liquid crystal molecules arranged in a conical shape or an approximate conical shape, so that all incident light rays passing through the liquid crystal layer 3 are refracted at the same angle, thereby forming a liquid crystal cone lens that can be driven by voltage. . And by adjusting the value of the first driving voltage to control the distribution of the electric field in the space, so as to adjust the minimum base angle of the liquid crystal cone lens, the adjustment process does not need to change the shape of the cone lens, and does not need to reprocess the cone lens, so Not limited by the processing technology, a smaller minimum base angle than that of the prior art axicon can be obtained. Since the minimum base angle of the axicon changes rapidly and continuously with the continuous change of the driving voltage V1, the axicon of this embodiment is used. The minimum base angle of the axicon lens can be adjusted conveniently, quickly and in real time without changing the shape, structure and size of the axicon lens.

Example 2

In this embodiment, on the basis of Embodiment 1, the distance between the first electrode 21 and the second electrode 22 is limited within the range of 0.2 mm to 0.5 mm, and the first driving voltage V1 is limited within the range of 0V to 35V. Within the range of the aforementioned distance and voltage, the arrangement of the liquid crystal molecules is the closest to the cone shape, and the imaging effect using the axicon lens is also the best.

Example 3

As shown in FIG. 2 , this embodiment provides a liquid crystal cone lens with another structure. The liquid crystal cone lens in this embodiment includes a liquid crystal lens element, and the liquid crystal lens element includes an electrode and a liquid crystal layer;

The electrodes include a first electrode 21 and a second electrode 22, and the second electrode 22 is a hole-shaped electrode;

the liquid crystal layer is located between the first electrode 21 and the second electrode 22;

The electrodes further include a third electrode 23, the second electrode 22 is located between the first electrode 21 and the third electrode 23, and the liquid crystal layer is located between the first electrode 21 and the second electrode 22, along the first electrode 21 and the second electrode 22. In the normal direction of the plane of the electrode 21, the distance between the first electrode 21 and the second electrode 22 is d1, and the distance between the second electrode 22 and the third electrode 23 is d2, where 0< d2<0.4, d2/2+0.3<d1<-d2/2+0.7, where the unit of d1 and d2 is mm;

The electrodes are used to receive a first driving voltage V1 and a second driving voltage V2, the first driving voltage V1 is the voltage between the first electrode 21 and the second electrode 22, and the second driving voltage V2 is the first driving voltage V2. The voltage between the electrodes and the third electrode 23 .

In this embodiment, a third electrode 23 is added, and the distance between the first electrode 21 , the second electrode 22 and the third electrode 23 satisfies 0≤d2≤0.4, d2/2+0.3≤d1≤-d2/2+0.7 . This embodiment can simultaneously provide the first driving voltage and the second driving voltage for the liquid crystal cone lens. After adopting the aforementioned structure, under the combined action of the first driving voltage and the second driving voltage, the liquid crystal molecules are arranged in a cone shape, so that all the The incident light rays passing through the liquid crystal layer 3 are all refracted at the same angle. Wavefront diagrams using the aforementioned structure are shown in FIGS. 3 to 9 . FIGS. 3 to 9 are wavefront diagrams obtained by using different electrode spacing distances while keeping the first driving voltage and the second driving voltage unchanged. It can be seen from the figure that the wavefront diagram of the liquid crystal cone lens satisfying the aforementioned distance relationship is close to a cone.

In this embodiment, the flexibility of adjusting the minimum base angle of the axicon lens can be increased by matching the first driving voltage or the second driving voltage, and the relative size between the first driving voltage or the second driving voltage can be set to make the Axicons switch conveniently and quickly between positive and negative axicon states. For example, when the first and second driving voltages are set to V1 greater than V2, the liquid crystal lens is a positive conical lens, and when the first and second driving voltages are set to V1 less than V2, the liquid crystal lens is a negative conical lens. Since the minimum base angle of the axicon lens can change rapidly with the change of the driving voltage V1 or V2, this embodiment can adjust the driving voltage V1 or/ and the second driving voltage V2 to adjust the minimum base angle of the axicon lens conveniently, quickly and in real time.

Example 4

In this embodiment, on the basis of Embodiment 3, the value ranges of V1 and V2 are further limited to 0≤V2≤40, 0≤V1≤3×V2/4+30, where the unit of v1 and v2 is V. In this embodiment, on the basis of Embodiment 3, when the difference between the first driving voltage and the second driving voltage is limited within the aforementioned range, the arrangement of the liquid crystal molecules is the closest to a cone, and the imaging effect of using the cone lens is also most.

Example 5

This embodiment provides a device for adjusting the minimum base angle of an axicon lens, including a driving power source and the axicon lens in Embodiment 1 or Example 2, where the driving power source is used to provide the first driving voltage V1, and the driving power source can be Adjust the power supply. In this example, an adjustable power supply is used to provide the first driving voltage for Embodiment 1 or Embodiment 2, so that the arrangement of liquid crystal molecules in the liquid crystal layer 3 can be changed by adjusting the voltage value output by the adjustable power supply, thereby changing the minimum base angle of the cone lens . The device adjusts the minimum base angle of the axicon lens by changing the voltage, without changing the shape and structure of the axicon lens, and can realize the adjustment of the minimum base angle of the axicon lens quickly and in real time.

Example 6

This example adds a driving voltage adjustment module on the basis of Example 5, including a driving voltage adjustment module, the driving voltage adjustment module is used to adjust the value of the first driving voltage V1 provided by the driving power supply, wherein the value of the adjustment amount ΔV of V1 is the value of The range is ΔV1/V1≤0.07. The device can use the driving voltage adjustment module to continuously change the first driving voltage in real time to continuously adjust the minimum base angle of the axicon, and when the value of V1 is adjusted within the range of ΔV1/V1≤0.07, the minimum base angle of the axicon is relative to V1 The rate of change is small, so that the device can adjust the minimum base angle of the cone lens more accurately.

Example 7

The device for adjusting the minimum base angle of an axicon lens provided in this embodiment includes a drive power source and the axicon lens in Embodiment 3 or 4. The drive power source is used to provide a first drive voltage V1 and a second drive voltage V2. The provided first driving voltage V1 or/and the second driving voltage V2 are adjustable voltages. In this embodiment, a driving power supply is used to provide an adjustable first driving voltage V1 or/and a second driving voltage V2 for the axicon lens. In this way, on the one hand, the value of the first driving voltage V1 or/and the second driving voltage V2 can be changed. Fast and real-time adjustment of the minimum base angle of the axicon, and on the other hand, by changing the magnitude relationship between the first driving voltage V1 or/and the second driving voltage V2 to switch between the positive and negative axicon states .

Example 8

In this embodiment, on the basis of Embodiment 7, the first drive voltage V1 or/and the second drive voltage V2 are adjusted by the drive voltage adjustment module, and the adjustment range is ΔV1/V1≤0.07, wherein the adjustment amount of V2 The value range of ΔV2 is ΔV2/V2≤0.07. The device can use the driving voltage adjustment module to continuously change the first driving voltage and the second driving voltage in real time to continuously adjust the minimum base angle of the cone lens in real time. The rate of change of the minimum base angle of the lens relative to V1 or V2 is small, which makes the adjustment of the minimum base angle of the axicon lens more precise.

Example 9

This embodiment provides a method for adjusting the minimum base angle of an axicon lens. The method of this embodiment applies a first driving voltage V1 to the electrodes of the axicon lens in Embodiment 1 or 2, and applies a first driving voltage V1 between the first electrode 21 and the second electrode 22 . An electric field is formed between the two, and the liquid crystal molecules are arranged in an approximate conical shape by using the formed electric field, and the distribution of the electric field in space is controlled by adjusting the value of the first driving voltage V1, thereby adjusting the minimum base angle of the liquid crystal cone lens. The aforementioned The adjustment process does not need to change the shape of the axicon lens, and does not need to reprocess the axicon lens, so it is not limited by the processing technology, and a smaller minimum base angle than the prior art axicon lens can be obtained. Since the minimum base angle of the axicon lens can be changed rapidly with the change of the driving voltage V1, this embodiment can conveniently, quickly and real-time determine the minimum base angle of the axicon lens without changing the shape, structure and size of the axicon lens. make adjustments.

Example 10

In this embodiment, on the basis of Embodiment 8, V1 is adjusted within the range of ΔV1/V1≤0.07. Within the aforementioned range, the change rate of the minimum base angle of the axicon lens relative to ΔV1 is small, so that the adjustment of the minimum base angle of the axicon lens is less effective. More precision.

Example 11

This embodiment provides a method for adjusting the minimum base angle of an axicon lens, including: adding a first driving voltage V1 and a second driving voltage V2 to the electrodes of the axicon lens in Embodiment 3 or 4, and applying the first driving voltage V1 and the second driving voltage V1 to the second driving voltage V2 The electric field is formed under the comprehensive action of the driving voltage V2, and the liquid crystal molecules are arranged in an approximate conical shape by using the formed electric field, and the distribution of the electric field in space is controlled by adjusting the value of the first driving voltage V1 and the V2 value of the second driving voltage. , so as to adjust the minimum base angle of the liquid crystal axicon. The aforementioned adjustment process does not require changing the shape of the axicon, and does not need to reprocess the axicon, so it will not be limited by the processing technology, and can obtain more Small minimum bottom corner. Since the minimum base angle of the axicon lens can change rapidly with the change of the driving voltage V1 or V2, this embodiment can adjust the driving voltage V1 or/ and the second driving voltage V2 to adjust the minimum base angle of the axicon lens conveniently, quickly and in real time. In addition, by changing the magnitude relationship between V1 or V2, the axicon can be switched between the positive axicon and the negative axicon.

For example, the electrodes can be set to receive the first set of voltages. In this set of voltages, the first driving voltage V1 is set to 0V, and the second driving voltage V2 is set to 30V. At this time, the wavefront obtained by simulation is shown in Figure 10. At this time, Axicons are negative axicons.

For example, the electrodes can be set to receive a second set of voltages. In this set of voltages, the first driving voltage V1 is set to 20V, and the second driving voltage V2 is set to 0V. At this time, the wavefront obtained by simulation is shown in Figure 11. At this time, Axicons are positive axicons. At this time, the first drive voltage V1 remains unchanged at 20V, and the second drive voltage V2 is adjusted to 40V as the third set of voltages. According to the aforementioned settings, the electrodes receive the third set of voltages. At this time, the wavefront diagram obtained by the simulation is as follows Figure 12. In the foregoing process, the second driving voltage V1 is lower than the first driving voltage V2, and the liquid crystal lens forms a negative conical lens at this time.

The electrodes can also be set to receive a fourth group of voltages. In this group of voltages, the second driving voltage V2 is set to 0V and the first driving voltage V1 is set to 30V. The wavefront diagram obtained by simulation is shown in FIG. 13 .

The electrodes can also be set to receive a fifth set of voltages. In this set of voltages, the second driving voltage V2 is set to 40V and the first driving voltage V1 is set to 40V. The wavefront diagram obtained by simulation is shown in FIG. 14 .

At this time, the second driving voltage V2 remains unchanged at 40V, and the first driving voltage V1V2 is adjusted to 50V as the sixth group of voltages. The voltage driving module outputs the sixth group of voltages according to the aforementioned settings. At this time, the wavefront diagram obtained by the simulation is shown in the figure 15 shown. In the foregoing process, the second driving voltage V2 is lower than the first driving voltage V1, and at this time, the liquid crystal lens forms a positive conical lens.

It is also possible to keep the second driving voltage V2 unchanged at 40V, and adjust the first driving voltage V1 to 60V as the seventh group of voltages. The voltage driving module outputs the seventh group of voltages according to the aforementioned settings. At this time, the wavefront diagram obtained by the simulation is as follows: Figure 16.

The electrodes can also be set to receive an eighth group of voltages. In this group of voltages, the second driving voltage V2 is set to 10V and the first driving voltage V1 is set to 37.5V. The wavefront diagram obtained by simulation is shown in FIG. 17 .

Example 12

In this embodiment, on the basis of Embodiment 11, V1 and V2 are adjusted within the range of ΔV1/V1≤0.07 or/and ΔV2/V2≤0.07, and the change of the minimum base angle of the cone lens relative to V1 and V2 within the aforementioned range The ratio is small, which makes the adjustment of the minimum base angle of the axicon lens more accurate.

Example 13

As shown in FIG. 18 , the present embodiment adds a laser 6 , a polarizer 7 , a photodetector 10 and an oscilloscope 12 on the basis of the axicon lens 9 in the third or fourth embodiment, wherein the axicon lens 9 , the photodetector 10 and the oscilloscope 12 in order. Turn on the laser 6, apply an electric field to the liquid crystal lens, adjust V1 to be equal to 50V, and V2 to be equal to 40V. At this time, the optical properties of the liquid crystal conical lens are the optical properties of a positive conical lens. The photodetector 10 is used to scan and display on the oscilloscope 12. The light intensity distribution of the outgoing light keeps V2 unchanged, adjust V1 equal to 60, use the photodetector 10 to scan, and present the light intensity distribution of the outgoing light on the oscilloscope 12 . Through the analysis of the light intensity distribution, it can be found that the light intensity distribution is different during the propagation of the outgoing beam, and the position of the peak light intensity changes with the change of the applied electric field. Therefore, the minimum base angle of the liquid crystal cone lens can be changed by changing the magnitude of the applied electric field. In this embodiment, one or more types of high-reflection mirrors 8 may also be used to adjust the collimation of the incident laser light.

In the present invention, an insulating member can also be provided between the first electrode 21 and the second electrode 22 and between the second electrode 22 and the third electrode 23, wherein the insulating member between the first electrode 21 and the second electrode 22 is insulating Layer 4, the first electrode 21 and the second electrode 22 are effectively separated by the insulating layer 4 to prevent short circuit between the two electrodes. The insulating member between the second electrode 22 and the third electrode 23 is the spacer 5 provided in the liquid crystal layer 3 . The spacers 5 are arranged at the edge of the liquid crystal layer 3 in the radial direction, on the one hand to support the liquid crystal layer 3 to a predetermined thickness, and on the other hand to insulate between the second electrode 22 and the third electrode 23 . The cone lens of this embodiment further includes a first transparent substrate 11, a second transparent substrate 12, and a third transparent substrate 13, the first electrode 21 is disposed on the first transparent substrate 11, and the second electrode 22 is disposed on the first transparent substrate 11. On the two transparent substrates 12 , the third electrode 23 is disposed on the third transparent substrate 13 . The three transparent substrates can support and protect the three electrodes well, so that the structure and performance of the liquid crystal cone lens are more stable.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced. Without departing from the spirit and scope of the technical solutions of the present invention.

Claims (10)

1. An axicon lens comprising a liquid crystal lens element comprising an electrode and a liquid crystal layer;

the electrodes comprise a first electrode and a second electrode, and the second electrode is a round hole-shaped electrode;

the liquid crystal layer is positioned between the first electrode and the second electrode;

a distance between the first electrode and the second electrode in a direction normal to a plane of the first electrode is 0.1mm to 0.7 mm;

the electrode is used for receiving a first driving voltage V1, and the first driving voltage is a voltage between the first electrode and the second electrode.

2. The axicon lens of claim 1,

a distance between the first electrode and the second electrode in a direction normal to a plane of the first electrode is 0.2mm to 0.5 mm;

the first driving voltage V1 ranges from 0V to 35V.

3. An axicon lens, wherein the axicon lens comprises a liquid crystal lens element comprising an electrode and a liquid crystal layer;

the electrodes comprise a first electrode and a second electrode, and the second electrode is a round hole-shaped electrode;

the liquid crystal layer is positioned between the first electrode and the second electrode;

the electrodes further comprise a third electrode, the second electrode being located between the first electrode and the third electrode, the liquid crystal layer being located between the first electrode and the second electrode, the distance between the first electrode and the second electrode being d1 in a direction normal to the plane of the first electrode, the distance between the second electrode and the third electrode being d2, wherein 0. ltoreq. d 2. ltoreq.0.4, d2/2+ 0.3. ltoreq. d 1. ltoreq. -d2/2+0.7, wherein the units of d1 and d2 are mm;

the electrodes are used for receiving a first driving voltage V1 and a second driving voltage V2, the first driving voltage V1 is a voltage between the first electrode and the second electrode, and the second driving voltage V2 is a voltage between the first electrode and the third electrode.

4. The axicon lens of claim 3, wherein V1 and V2 satisfy: 0 is more than or equal to V2 is more than or equal to 40, 0 is more than or equal to V1 is more than or equal to 3 xV 2/4+30, wherein the unit of V1 and V2 is V.

5. The axicon lens minimum base angle adjustment apparatus comprising a driving power supply for supplying the first driving voltage V1 and an axicon lens as claimed in claim 1 or 2, wherein the driving power supply is an adjustable power supply.

6. The apparatus of claim 5, further comprising a driving voltage adjusting module, wherein the driving voltage adjusting module is configured to adjust a value of a first driving voltage V1 provided by the driving power supply, and a value of the adjustment amount Δ V of V1 is Δ V1/V1 ≦ 0.07.

7. The axicon lens minimum base angle adjustment apparatus comprising a driving power supply and an axicon lens as claimed in claim 3 or 4, wherein the driving power supply is used for providing a first driving voltage V1 and a second driving voltage V2, and the first driving voltage V1 or/and the second driving voltage V2 provided by the driving power supply are adjustable voltages.

8. The apparatus of claim 7, further comprising a driving voltage adjusting module for adjusting a value of a first driving voltage V1 or/and a value of a second driving voltage V2 provided by the driving power supply;

wherein the adjustment amount delta V1 of V1 has a value range of delta V1/V1 which is less than or equal to 0.07, and the adjustment amount delta V2 of V2 has a value range of delta V2/V2 which is less than or equal to 0.07.

9. The method for adjusting the minimum base angle of the conical lens is characterized by comprising the following steps:

the electrode of the axicon lens of claim 1 or 2 receiving a first drive voltage V1;

and adjusting the value of the first driving voltage V1 according to the received first driving voltage V1.

10. The method of claim 9, wherein the adjustment amount Δ V1 of V1 is in a range of Δ V1/V1 ≤ 0.07.

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