Non-mechanical RGB laser beam deflection system based on dielectric electrowetting

Abstract

The invention relates to a non-mechanical RGB laser beam deflection system based on dielectric electrowetting, and belongs to the technical field of beam deflection control and optical information processing devices. The basic structure of the device comprises an RGB laser (1), a glass prism (2), a liquid prism (5), a voltage control electrode on the inner wall, an adjustable mirror (11) and a supporting frame (12). The RGB laser comprises three wavelengths of red light, green light and blue light, the glass prism (2) is used for separating RGB light beams, the liquid prism (5) is formed by upper-layer polymethylphenylsiloxane (7) and a lower-layer potassium chloride aqueous solution (8), and the inner wall of the prism is sequentially coated with an indium tin oxide conductive layer, a dielectric coating and a hydrophobic Teflon coating; the control voltage of the left side electrode (3) and the right side electrode (4) is changed, the curvature of an interface between liquid is modulated through the electrowetting effect between the hydrophobic coating and the conductive solution so as to achieve accurate deflection control over RGB light beams, and technical support is provided for application in the fields of visible light communication, digital display and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of light beam deflection control and optical information processing devices, and in particular relates to a non-mechanical RGB laser beam deflection system based on dielectric electrowetting. Background Art

[0002] Beam deflection technology dynamically controls the deflection angle and scanning pattern of an incident light beam by modulating the physical parameters of optical elements, allowing the beam to deflect along a specified trajectory in a spatial optical path. Currently, it is widely used in optical communications, laser detection, laser manufacturing, optical imaging, and display. Traditional mechanical beam deflection systems rely on movable components to achieve beam control, but suffer from problems such as large mechanical inertia, slow response, and high power consumption, making it difficult to meet the demands of high-precision, miniaturized optical systems. In recent years, non-mechanical beam deflection technology has become a research hotspot for scholars at home and abroad. Liquid prisms based on the electrowetting-on-dielectric (EWOD) effect can achieve beam deflection without mechanical motion by modulating the shape of the liquid interface via voltage. These prisms offer advantages such as short response time, low power consumption, and long service life.

[0003] RGB lasers are light sources that can simultaneously emit three visible light sources: red, green, and blue. In laser displays, they can be used to synthesize color images with varying contrast requirements. In optical communications, they can be combined with wavelength division multiplexing technology to achieve high-speed data transmission. Existing EWOD beam deflection systems are mostly designed for single-wavelength light sources. When applied to RGB laser sources, the difference in refractive index between different wavelengths at the liquid interface can easily lead to spatial separation of the multi-wavelength beams, making synchronous alignment difficult. This severely restricts their application in wide-field-of-view, high-dynamic-range scenarios.

[0004] Currently, the main development directions for EWOD beam deflection technology are improving the control accuracy of EWOD systems, using cascaded liquid prisms to increase the angular deflection range, and collaboratively controlling multi-wavelength beams to expand application scenarios. High-precision, large-angle, synchronous deflection of RGB lasers is a major challenge facing current technological development, requiring further design and optimization of the system architecture. Summary of the Invention

[0005] The technical problem to be solved by the present invention is: by introducing a glass prism and a liquid prism based on the electrowetting effect to form a non-mechanical beam deflection system, the problems of the existing single-wavelength EWOD beam deflection system, such as multi-beam spatial separation and synchronous deflection misalignment caused by refractive index differences when driving RGB three-color lasers, are solved, thereby achieving precise, tunable and contactless beam deflection control of RGB lasers.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] The glass prism (2) is used to separate the RGB light beams and compensate the initial dispersion of the three-color light beams by pre-spectroscopy; the liquid prism (5) is a hollow rectangular glass structure, the interior of the prism is filled with an upper layer of polymethylphenylsiloxane (7) and a lower layer of potassium chloride aqueous solution (8), and the inner wall of the prism is coated with an indium tin oxide conductive layer, a dielectric coating and a hydrophobic Teflon coating in sequence; the voltage control electrode uses a contact pad made of a highly conductive material and is integrated on the inner wall of the liquid prism, the left voltage control electrode (3) and the right voltage control electrode (4) are used to apply an external voltage to change the curvature of the liquid-liquid interface, and the RGB light beam is controlled to deflect to the left or right relative to the optical axis through the electrowetting effect between the hydrophobic coating and the conductive solution, and the specific deflection angle is regulated by Young's equation and Snell's law; the ground electrode (6) is set at the bottom of the prism; the adjustable mirror (11) is used to redirect the vertical RGB light beam (9) into a horizontal RGB light beam (10) to facilitate integration into a planar optical system; the support frame (12) is used to fix and align the system.

[0008] The advantages of this invention include utilizing the voltage-driven electrowetting effect to modulate the liquid interface morphology to achieve beam deflection. Its simple structure and lack of any mechanical moving parts overcome the inherent drawbacks of traditional mechanical systems. Furthermore, the multi-beam deflection control structure, composed of a pre-splitting glass prism and a dynamically controlled liquid prism, effectively increases the deflection range for RGB lasers. Furthermore, by combining Young's equation and Snell's law to control the system's ability to coordinate the deflection of multiple wavelength beams, high-precision, wide-range synchronized beam control is achieved, resolving the technical difficulties encountered when applying existing single non-mechanical technologies to multi-wavelength light sources. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 Schematic diagram of the structure of the non-mechanical RGB laser beam deflection system based on dielectric electrowetting according to the present invention.

[0010] Figure 2 (a) shows the geometric shape of the liquid-liquid interface when a voltage is applied to the left side wall of the liquid prism by the beam deflection system of the present invention; Figure 2 (b) The geometric shape of the liquid-liquid interface when a voltage is applied to the right wall of the liquid prism.

[0011] Figure 3 (a) is a side view of the hollow rectangular liquid prism of the beam deflection system described in the present invention; (b) is a top view of the liquid prism.

[0012] Figure 4(a) is the liquid-liquid interface contact angle of the liquid prism in the beam deflection system described in the present invention when there is no external voltage; (b) is the contact angle of the liquid-liquid interface when a 90V voltage is applied to the left wall; (c) is the contact angle of the liquid-liquid interface when a 90V voltage is applied to the right wall; (d) is a schematic diagram of the direction of the liquid-liquid interface under different applied voltages; (e) is the prism vertex angle corresponding to red light under different external voltages; (f) is the prism vertex angle corresponding to green light under different external voltages; (g) is the prism vertex angle corresponding to blue light under different external voltages.

[0013] Figure 5 It is the apex angle of the liquid prism of the beam deflection system of the present invention when different external voltages are applied.

[0014] Figure 6 These are the deflection angles of three light beams under different external voltages when the light beam deflection system of the present invention is not provided with a glass prism.

[0015] Figure 7 The deflection angles of three light beams under different external voltages after the glass prism is introduced into the light beam deflection system of the present invention.

[0016] Figure 8 (a) is the beam spot distribution measured along the X-axis when the beam deflection system of the present invention has a glass prism; (b) is the beam spot distribution measured along the X-axis when the glass prism is not set. DETAILED DESCRIPTION

[0017] The present invention will be described in detail below with reference to the accompanying drawings.

[0018] Figure 1The present invention discloses a non-mechanical RGB laser beam deflection system structure based on dielectric electrowetting, which comprises: an RGB laser (1), a glass prism (2), a liquid prism (5), a left voltage control electrode (3), a right voltage control electrode (4), a ground electrode (6), an adjustable mirror (11), and a support frame (12). The glass prism (2) is used to separate the RGB light beams and compensate the initial dispersion of the three-color light beams by pre-spectroscopy; the liquid prism (5) is a hollow rectangular glass structure, the interior of the prism is filled with an upper layer of polymethylphenylsiloxane (7) and a lower layer of potassium chloride aqueous solution (8), and the inner wall of the prism is coated with an indium tin oxide conductive layer, a dielectric coating and a hydrophobic Teflon coating in sequence; the voltage control electrode uses a contact gasket made of a highly conductive material and is integrated on the inner wall of the liquid prism, the left voltage control electrode (3) and the right voltage control electrode (4) are used to apply an external voltage to change the curvature of the liquid-liquid interface, and the RGB light beams are controlled to deflect left or right relative to the optical axis through the electrowetting effect between the hydrophobic coating and the conductive solution, and the specific deflection angle is regulated by Young's equation and Snell's law; the ground electrode (6) is set at the bottom of the prism; the adjustable mirror (11) is used to redirect the vertically emitted light beam to a horizontal light path, so as to facilitate integration into a planar optical system; the support frame (12) is used to fix and align the system.

[0019] Figure 2 The diagram shows the deformation of the liquid-liquid interface and the beam deflection when external voltage is applied on the left and right sides of this embodiment. Figure 2 (a) shows that when an external voltage is applied to the left side of the liquid prism, the light beam is deflected to the right (along the +X axis); Figure 2 (b) shows that when an external voltage is applied to the right side of the liquid prism, the light beam is deflected to the left (along the -X axis).

[0020] Figure 3 The side view and top view of the hollow rectangular liquid prism of this embodiment are shown. The outer wall of the liquid prism is made of transparent glass, and forms a hollow glass cavity (13) with the upper glass plate (13) and the bottom glass plate (15). The specific dimensions are as follows: length 10 mm (2), width 10 mm (3), height 30 mm (1), thickness 2 mm (4); the inner wall of the glass prism is coated with a multi-layer structure, which is an indium tin oxide coating (9) as a transparent conductive layer for power drive, with a thickness of about 400 nanometers (12), a dielectric coating (7) to ensure electrical isolation and define the capacitor interface, with a thickness of about 3 microns (11), and a hydrophobic Teflon coating (6) for enhancing liquid fluidity to improve the interface response speed, with a thickness of about 650 nanometers (10).

[0021] Figure 4The interface changes of the glass prism under different external voltages of this embodiment are demonstrated. When the applied external voltage is 0V, the contact angle of the solid-liquid interface is initially 142° due to the hydrophobicity of the Teflon coating. Figure 4 (b) and (c) show that after applying an external voltage, the EWOD effect causes significant changes in the liquid-liquid interface. When a 90V external voltage is applied on the left and right sides, the contact angles of the interfaces are 58°±1° and 56°±1°, respectively, indicating that the liquid prism can withstand a maximum external voltage of 90V, and the maximum change in the interface contact angle is 86°±1°.

[0022] The electrowetting effect at the liquid prism interface in this embodiment is described by Young's equation:

[0023]

[0024] where c = ε0ε r / d, ε0 is the dielectric constant in vacuum, ε r is the dielectric constant of the insulating material, d is the thickness of the dielectric layer, and V is the externally applied voltage. L and the right control voltage V R , the contact angle θ of the solid-liquid interface on both sides is controlled by the electrowetting effect L and θ R Change, contact angle relative to the initial angle θ i The change in can be estimated by formula (1). The refraction process of the light beam at the liquid-liquid interface is described by Snell's law. The deflection angle of the incident light beam after leaving the liquid prism can be calculated by the following formula:

[0025]

[0026] in is the prism apex angle, n0, n1, and n2 are the refractive indices of air, polymethylphenylsiloxane, and water, respectively. Combined with the geometric relationship between the contact angles of the liquid inside the prism and each side wall, the deflection angle of the light beam passing through the liquid prism under different external applied voltages can be estimated.

[0027] Figure 5 The apex angle of the liquid prism of this embodiment under different external applied voltages is demonstrated. When the external voltage applied to the control electrode varies in the range of 0-90V, the apex angle of the liquid prism can reach a maximum of 34°, indicating that when the external voltage is 90V, the beam deflection capability of the liquid prism reaches its maximum.

[0028] Figure 6The deflection angles of the three beams of this embodiment, without a glass prism, are shown under different external applied voltages. When the external voltage is 90V, the maximum beam deflection angles of the red laser are 7.91° and 7.7° in the X-axis and -X-axis directions, respectively; the maximum beam deflection angles of the green laser are 8.32° and 8.12° in the X-axis and -X-axis directions, respectively; and the maximum beam deflection angles of the blue laser are 8.64° and 8.43° in the X-axis and -X-axis directions, respectively.

[0029] Figure 7 The deflection angles of the three beams under different external voltages after the glass prism is introduced into this embodiment are demonstrated. When the external voltage is 90V, the maximum beam deflection angles of the red laser increase to 8.43° and 8.01° in the X-axis and -X-axis directions, respectively. The maximum beam deflection angles of the green laser increase to 8.95° and 8.64° in the X-axis and -X-axis directions, respectively. The maximum beam deflection angles of the blue laser increase to 9.46° and 9.05° in the X-axis and -X-axis directions, respectively.

[0030] In this embodiment, the beam deflection performance changes slightly when the external applied voltage varies in the range of 0-60V. In the range of 60V-90V, the beam deflection angle increases rapidly as the external voltage increases. When the external applied voltage exceeds 90V, the deflection angle reaches its maximum value due to the electrowetting saturation effect, and increasing the voltage cannot cause additional deformation of the liquid interface. At this time, the operating voltage of the liquid prism reaches the upper limit, which may cause the insulating layer and dielectric layer coated on the inner wall to fail.

[0031] Figure 8 The beam spot distribution along the X-axis of this embodiment is shown, with the reference center being X0Y0. This shows that the introduction of glass prisms can achieve more effective deflection of multiple beams and further increase the deflection angle.

Claims

1. A non-mechanical RGB laser beam deflection system based on dielectric electrowetting, comprising: RGB laser (1), glass prism (2), liquid prism (5), left voltage control electrode (3), right voltage control electrode (4), ground electrode (6), adjustable mirror (11) and support frame (12); the RGB laser includes three wavelengths of red light, green light and blue light, the glass prism (2) is used to separate the RGB light beams and guide them into the liquid prism to compensate for the initial dispersion of the three-color light beams; the liquid prism (5) is a hollow rectangular glass structure, the liquid filled inside is formed by an upper layer of polymethylphenylsiloxane (7) and a lower layer of potassium chloride aqueous solution (8), and the glass substrate of the inner wall of the prism is coated with an indium tin fluoride conductive layer, a dielectric coating and a hydrophobic Teflon coating in sequence; the left voltage control electrode (3) and the right voltage control electrode (4) are used to apply an external voltage to change the curvature of the liquid-liquid interface to control the RGB light beam to deflect left or right relative to the optical axis; the adjustable mirror (11) is used to redirect the vertical RGB light beam (9) into a horizontal RGB light beam (10) to facilitate integration into a planar optical system; The support frame (12) is used for fixing and aligning the system.

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