CN211148904U

CN211148904U - Liquid crystal device applied to laser radar

Info

Publication number: CN211148904U
Application number: CN201922139621.9U
Authority: CN
Inventors: 吴梓荣; 熊培成; 陈嵘
Original assignee: Shenzhen AV Display Co Ltd
Current assignee: Shenzhen AV Display Co Ltd
Priority date: 2019-12-02
Filing date: 2019-12-02
Publication date: 2020-07-31
Anticipated expiration: 2029-12-02

Abstract

The utility model belongs to the technical field of laser radar, and provides a liquid crystal device applied to the laser radar, which comprises a first substrate and a second substrate; the alignment layer comprises a first alignment layer and a second alignment layer; first base plate, first alignment layer, liquid crystal layer, second alignment layer, second base plate arrange the setting in proper order, and beneficial effect lies in: the device has a simple structure, and the liquid crystal device can change the circularly polarized direction of a beam of circularly polarized light, for example, the left circularly polarized light is changed into the right circularly polarized light after passing through the liquid crystal device; the liquid crystal polarization grating film is matched to change the light propagation direction, and the requirement of laser radar optical deflection scanning is met.

Description

Liquid crystal device applied to laser radar

Technical Field

The utility model belongs to the technical field of laser radar, especially, relate to an apply to laser radar's liquid crystal device.

Background

The laser radar is a system for detecting characteristic quantities such as position, speed and the like of a target by emitting laser beams, and is widely applied to the field of laser detection. In order to adapt to two-dimensional or three-dimensional detection, the laser beam emitted by the laser radar needs to be rotated. Optical phased array elements are commonly used to control the wavefront phase of a laser beam to achieve control of the direction of the emitted beam. With the progress of liquid crystal display technology, a liquid crystal device is used as an optical phase control element, but the traditional liquid crystal device has the defects of high etching precision of liquid crystal substrate electrodes, low diffraction efficiency and the like.

SUMMERY OF THE UTILITY MODEL

The utility model discloses the technical problem that will solve is: the traditional liquid crystal device has the defects of high etching precision of the substrate electrode, low diffraction efficiency and the like.

In order to solve the technical problem, the utility model discloses a technical scheme be: the liquid crystal device comprises a liquid crystal device substrate, an orientation layer and a liquid crystal layer; the substrate comprises a first substrate and a second substrate; the alignment layer comprises a first alignment layer and a second alignment layer; the first substrate, the first orientation layer, the liquid crystal layer, the second orientation layer and the second substrate are sequentially arranged.

Furthermore, the first substrate and the second substrate are made of the same material, and the transmittance of the first substrate and the transmittance of the second substrate are more than or equal to 89%.

Furthermore, the substrate is a glass substrate attached with an indium tin oxide semiconductor transparent conductive film, and the sheet resistance is 80-400 omega/cm ²。

Further, the first orientation layer and the second orientation layer are respectively coated on the surfaces of the first substrate and the second substrate, and the orientation layers are made of polyimide materials.

Further, the liquid crystal layer comprises frame glue, space powder and liquid crystal, the liquid crystal layer is arranged between the first substrate and the second substrate, and the diameter d of the space powder is less than 4 μm.

Further, the frame glue is coated around the liquid crystal layer, and the space powder and the liquid crystal are filled in the frame glue.

furthermore, the working wave band of the liquid crystal is 800-1550nm in infrared, the absorption of the liquid crystal to incident light is less than 2%, and the change of birefringence △ n with temperature is small.

furthermore, the product of the birefringence △ n of the liquid crystal and the thickness of the liquid crystal layer meets the condition that the wavelength is not less than one quarter of the wavelength of incident light, namely delta n x d is not more than lambda/4.

The beneficial effects of the utility model reside in that: the liquid crystal device can change the circular polarization direction of a beam of circularly polarized light, for example, the left circularly polarized light is changed into the right circularly polarized light after passing through the liquid crystal device; the liquid crystal polarized light grating film can be matched to change the light propagation direction, and the requirement of laser radar optical deflection scanning is met.

Drawings

The detailed structure of the liquid crystal device of the present invention will be described in detail with reference to the accompanying drawings

Fig. 1 is a schematic structural diagram of a liquid crystal device of the present invention;

Fig. 2 is a schematic view of the light propagation direction of the polarized light of the present invention transmitting through the liquid crystal polarizing grating film;

Wherein 1-a first substrate; 10-a glass layer; 11-a conductive film; 2-a liquid crystal layer; 20-frame glue; 21-liquid crystal; 22-space powder; 3-an orientation layer; 30-a first alignment layer; 31-a second alignment layer; 4-a second substrate.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

Referring to fig. 1 and 2, the present invention provides a liquid crystal device for a laser radar, including a substrate, an alignment layer 3 and a liquid crystal layer 2, wherein the substrate includes a first substrate 1 and a second substrate 4; the alignment layer 3 includes a first alignment layer 30 and a second alignment layer 31; the first substrate 1, the first alignment layer 30, the liquid crystal layer 2, the second alignment layer 31 and the second substrate 4 are sequentially arranged.

From the above description, the beneficial effects of the present invention are: the device has simple structure, and can change the circular polarization direction of a beam of circularly polarized light when applied to radar laser.

Example 1

Referring to fig. 1, the first substrate 1 and the second substrate 4 are made of the same material, and are glass substrates with indium tin oxide semiconductor transparent conductive films, that is, ITO glass substrates, so that the transmittance of the entire liquid crystal device is relatively high, and the substrate transmittance is not less than 89%, the surfaces of the first substrate 1 and the second substrate 4 near the liquid crystal layer 2 are respectively coated with a first alignment layer 30 and a second alignment layer 31, the alignment layers 3 are made of polyimide materials, which are abbreviated as PI materials, and the alignment layers 3 are rubbed, and the polyimide is arranged in one direction, so that liquid crystal molecules can be arranged in a specific direction.

The liquid crystal layer 2 comprises frame glue 20, space powder 22 and liquid crystal 21, wherein the space powder 22 is used for supporting the first substrate 1 and the second substrate 4; the diameter d of the space powder 22 is less than 4 μm, so that the response time of the liquid crystal device is small enough, and the corresponding time can reach a fast response time of less than 50 μ s and a slow response time of less than 750 μ s; the sealant 20 is coated around the liquid crystal layer 2, and has a thickness of less than 4 μm to match the size of the space powder 22. In addition, the liquid crystal 21 of the liquid crystal layer 2 can work in the infrared 800-1550nm wave band, the absorption of the liquid crystal 21 to the incident light is less than 2%, and the variation of the birefringence index with the temperature is small, so that the whole liquid crystal device can still work normally at a lower temperature or a higher temperature.

the product of the birefringence △ n of the liquid crystal 21 and the thickness of the liquid crystal layer 2, namely the diameter d of the space powder 22, needs to satisfy the condition that the wavelength is not less than one quarter of the wavelength of incident light, namely △ n x d is not less than lambda/4, so that the whole liquid crystal device can realize the function of changing the left/right circle of polarized light, for example, the polarization direction of incident light and the friction direction of the orientation layer 3 form an angle of 45 degrees, a beam of right circularly polarized light passes through a liquid crystal device, when the liquid crystal is electrified with high voltage, the liquid crystal is arranged vertical to the substrate, the retardation of the liquid crystal device is close to zero, the propagation direction of the light passing through the liquid crystal device is not changed, when the liquid crystal is electrified with proper voltage, a certain included angle is formed between the liquid crystal and the substrate, and the retardation of the liquid crystal device can just change a beam.

for the deflection angle and the direction of deflecting of changing incident light, the utility model discloses a collocation a liquid crystal polarisation grating membrane is related to, L CPG for short, as shown in fig. 2 we set up a levogyration L CPG at the back at the liquid crystal device, when the incident light is the right circular polarisation, through levogyration L CPG, light changes into the left circular polarisation, an angle that deflects simultaneously is theta, theta is-2 sin ^-1(lambda/lambda), when the incident light is left circular polarized light, and when the incident light is left circular polarized light, the incident light is changed into right circular polarized light through a left-handed L CPG, and meanwhile, the deflected angle is theta, theta is +2sin ^-1(λ/Λ)。

by the above characteristics, the liquid crystal device is a function of switching left/right circular light deflection to each other, and the L CPG is a function of deflecting an angle of left/right circular light while changing a polarization direction.

To sum up, the utility model provides a pair of apply to its beneficial effect of liquid crystal display device of radar laser lies in: the liquid crystal device can change the circular polarization direction of a beam of circularly polarized light, for example, the left circularly polarized light is changed into the right circularly polarized light after passing through the liquid crystal device; the liquid crystal polarization grating film is matched to achieve the purpose of changing the light propagation direction and meet the requirement of optical deflection scanning of the laser radar.

The above only is the embodiment of the present invention, not limiting the patent scope of the present invention, all the equivalent structures or equivalent processes that are used in the specification and the attached drawings or directly or indirectly applied to other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A liquid crystal device applied to laser radar is characterized in that: the liquid crystal device comprises a substrate, an orientation layer and a liquid crystal layer; the substrate comprises a first substrate and a second substrate; the alignment layer comprises a first alignment layer and a second alignment layer; the first substrate, the first orientation layer, the liquid crystal layer, the second orientation layer and the second substrate are sequentially arranged.

2. A liquid crystal device as claimed in claim 1, characterized in that: the first substrate and the second substrate are made of the same material, and the transmittance of the first substrate and the transmittance of the second substrate are greater than 90%.

3. A liquid crystal device as claimed in claim 2, characterized in that: the substrate is a glass substrate with indium tin oxide semiconductor transparent conductive film, and the sheet resistance is 80-400 omega/cm ²。

4. A liquid crystal device as claimed in claim 3, characterized in that: the first orientation layer and the second orientation layer are respectively coated on the surfaces of the first substrate and the second substrate, and the orientation layers are made of polyimide materials.

5. A liquid crystal device as claimed in claim 1, characterized in that: the liquid crystal layer comprises frame glue, space powder and liquid crystal, the liquid crystal layer is arranged between the first substrate and the second substrate, and the diameter d of the space powder is less than 4 mu m.

6. The liquid crystal device of claim 5, wherein: the frame glue is coated on the periphery of the liquid crystal layer, and the space powder and the liquid crystal are filled in the frame glue.

7. The liquid crystal device of claim 6, wherein: the working wave band of the liquid crystal is 800-1550nm, the absorption of the liquid crystal to incident light is less than 2%, and the change of birefringence with temperature is small.

8. the liquid crystal device according to claim 7, wherein a product of a birefringence △ n of the liquid crystal and a thickness of the liquid crystal layer satisfies a condition that △ n × d is ≧ λ/4, which is not less than a quarter wavelength of incident light.