TW202138846A - Varaiable focal length optical element - Google Patents

Abstract

A variable focal length optical element is provided. The variable focal length optical element includes a first substrate, a bearing layer, a piezoelectric film, a driving electrode and a light transmitting layer. The first substrate has a first surface and a second surface opposite to each other. The bearing layer is located on the first surface of the first substrate and has a light-passing region penetrating the bearing layer. The bearing layer has a convex protruding structure, which surrounds the light-passing region, wherein the convex protruding structure extends from the first surface of the first substrate to the center of the light-passing region in the radial direction of the light-passing region. The piezoelectric film is located on the bearing layer.

Description

Variable focus optics

The present invention relates to an optical element, and particularly relates to a variable focal length optical element.

Optical components with zoom capability have been applied to various optical systems, such as imaging optics with autofocus, adaptive optical systems, light switches, virtual reality (VR) or augmented reality (Augmented Reality, AR) Wearable display devices, etc. Common zoom optical elements can be divided into two types according to their principles. The first type of zoom optical elements use the relative distance between the optical axis directions of the lenses to achieve the zoom function, and the second type of zoom optical elements are deformable ( Deformable) optical lens.

Specifically, at least one lens of the first type of zoom optical element requires an external linear drive device to change the relative distance of the lens to achieve the objective of optical zoom. Therefore, there are disadvantages such as larger volume, higher difficulty in precision control, and driving noise. On the other hand, the second type of zoom optical element uses a deformable optical lens and does not require a linear drive unit; it has the advantages of small size, high precision, fast response, and silent operation. Among the optical zoom elements with deformable optical lenses, the zoom optical elements driven by the piezoelectric effect have a response rate of more than tens of thousands of hertz (kHz), and can be used to produce Micro Electro Mechanical System (MEMS) The manufacturing process can further miniaturize the structure of the optical zoom element and mass production, so it has a wide range of commercial applications.

The "prior art" paragraph is only used to help understand the content of the present invention, so the contents disclosed in the "prior art" paragraph may include some conventional technologies that do not constitute the common knowledge in the technical field. The content disclosed in the "prior art" paragraph does not represent the content or the problem to be solved by one or more embodiments of the present invention, and has been known or recognized by those with ordinary knowledge in the technical field before the application of the present invention.

The invention provides a variable focal length optical element, which has a simple manufacturing process and stable optical characteristics.

The other objectives and advantages of the present invention can be further understood from the technical features disclosed in the present invention.

In order to achieve one or part or all of the above objectives or other objectives, an embodiment of the present invention provides a variable focal length optical element. The variable focus optical element includes a first substrate, a carrying layer, a piezoelectric film, a driving electrode, and a light-transmitting layer. The first substrate has a first surface and a second surface opposite to each other. The first substrate has a first cavity, wherein the first cavity penetrates the first surface and the second surface. The supporting layer is located on the first surface of the first substrate and has a light passing area penetrating the supporting layer. The supporting layer has a convex structure that encloses the light passing area, wherein the convex structure is in the radial direction of the light passing area It extends from the first surface of the first substrate to the center of the light-passing area. The piezoelectric film is located on the carrier layer. The driving electrode is located on the carrier layer and is used to drive the piezoelectric film, wherein the driving electrode applies a driving voltage to the piezoelectric film to cause the piezoelectric film to stretch and deform and pull the convex structure to bend and deform. The light-transmitting layer is overlapped and arranged on the protruding structure, and the light-transmitting layer covers the light-passing area.

In an embodiment of the present invention, the aforementioned variable focus optical element further includes a second substrate and an elastic film. The second substrate is located on the second surface of the first substrate and has at least one second cavity and at least one second cavity. The cavity is in communication with the first cavity of the first substrate, and the second substrate is located between the elastic film and the first substrate, the elastic film covers the second substrate, and the elastic coefficient of the elastic film is smaller than the elastic coefficient of the light-transmitting layer.

In an embodiment of the present invention, the above-mentioned carrier layer includes a first insulating layer, a second insulating layer, and a wafer layer. The second insulating layer is overlapped with the first insulating layer. The wafer layer is located between the first insulating layer and the second insulating layer, wherein the piezoelectric film is disposed on the first insulating layer, and the light-transmitting layer is disposed on the piezoelectric film.

In an embodiment of the present invention, the material of the above-mentioned light-transmitting layer includes a polymer material or glass.

In an embodiment of the present invention, the above-mentioned light-transmitting layer is a first insulating layer, the carrier layer includes a second insulating layer and a wafer layer, the first insulating layer is stacked on the wafer layer, and the wafer layer is located on the second insulating layer. Between the insulating layer and the light-transmitting layer.

In an embodiment of the present invention, the above-mentioned carrier layer includes a first insulating layer and a wafer layer, the light-transmitting layer is a second insulating layer, the wafer layer is located between the first insulating layer and the light-transmitting layer, and the light-transmitting layer Located between the first substrate and the wafer layer, the variable focus optical element further includes an auxiliary piezoelectric film, and the auxiliary piezoelectric film is disposed on the light-transmitting layer.

In an embodiment of the present invention, the above-mentioned carrier layer includes a second insulating layer and a wafer layer, the second insulating layer is located between the first substrate and the wafer layer, and the light-transmitting layer is located between the wafer layer and the piezoelectric film. The piezoelectric film covers the light-transmitting area, and the material of the light-transmitting layer includes polymer material or glass.

In an embodiment of the present invention, the shape of the aforementioned driving electrode is ring-shaped, and the driving electrode surrounds the light-passing area.

In an embodiment of the present invention, the above-mentioned driving electrode includes a plurality of arc-shaped electrodes, these arc-shaped electrodes are arranged on the ring area, the ring area surrounds the light transmission area, and any arc-shaped electrode drives The polarity direction of the voltage is opposite to the polarity direction of the driving voltage applied by these adjacent arc-shaped electrodes.

In an embodiment of the present invention, the above-mentioned driving voltage ranges from 0 to 50 volts.

In an embodiment of the present invention, the above-mentioned piezoelectric film has an open area, and the boundary of the open area is the same as the boundary of the light transmission area.

In an embodiment of the present invention, the aforementioned variable focal length optical element further includes an optical liquid suitable for filling the first cavity, wherein the light-transmitting layer directly contacts the optical liquid.

Based on the above, the embodiments of the present invention have at least one of the following advantages or effects. In the embodiment of the present invention, the variable focus optical element can be applied to the piezoelectric film with a predetermined driving voltage to cause the piezoelectric film to produce stress and deformation, which in turn drives the convex structure of the carrier layer and the light-transmitting layer to deform. In addition, the carrier layer can be fabricated by using the process technology of covering silicon on the insulating layer, and can be integrated with the existing process technology for easy fabrication. In addition, the variable focus optical element is provided with an elastic film with a relatively small elastic coefficient, so that the piezoelectric film located in the luminous flux region can still maintain an approximate spherical shape when the driving voltage is applied under different environmental conditions. And effectively maintain the optical quality of the variable focal length optical element.

In order to make the above-mentioned features and advantages of the present invention more comprehensible, the following specific embodiments are described in detail in conjunction with the accompanying drawings.

The foregoing and other technical content, features, and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the drawings. The directional terms mentioned in the following embodiments, for example: up, down, left, right, front or back, etc., are only directions for referring to the attached drawings. Therefore, the directional terms used are used to illustrate but not to limit the present invention.

FIG. 1A is a schematic cross-sectional view of a variable focal length optical element according to an embodiment of the present invention. FIG. 1B is a schematic top view of the variable focal length optical element of FIG. 1A. 1A, the variable focus optical element 100 of this embodiment includes a first substrate 110, a piezoelectric film 120, an optical liquid 130, a carrier layer 140, a driving electrode 150, a light-transmitting layer 160, a second substrate 170, and an elastic film 180. It should be noted that, in order to highlight the important technical features of the present invention, the drawings only represent schematic diagrams, and are not drawn to scale. In this embodiment, the material of the first substrate 110 is, for example, silicon, but the invention is not limited to this. In this embodiment, the piezoelectric film 120 is made of a light-transmitting material, such as a single crystal (single crystal) piezoelectric film, but the present invention is not limited to this. In other embodiments, the piezoelectric film 120 It can be a non-light-transmitting material. In this embodiment, the material of the optical liquid 130 is a light-transmitting material known to those skilled in the art, and will not be repeated here. The material of the light-transmitting layer 160 includes, for example, organic molecular materials, polymer materials, or transparent materials such as glass (silica), the material of the second substrate 170 is, for example, glass, and the material of the elastic film 180 is, for example, Parylene or Polydimethylsiloxane (PDMS), but the present invention is not limited to this.

Specifically, as shown in FIG. 1A, in this embodiment, the first substrate 110 has a first surface 111 and a second surface 112 opposite to each other, and the first substrate 110 has a first cavity 113, such as a first cavity. 113 is located at the center of the first substrate 110, wherein the first cavity 113 penetrates the first surface 111 and the second surface 112. In addition, in this embodiment, the second substrate 170 is located on the second surface 112 of the first substrate 110, wherein the second substrate 170 has at least one second cavity 171. For example, as shown in FIG. 1A and FIG. 1B, in this embodiment, at least one second cavity 171 includes a plurality of cylindrical cavities CH, of which at least one second cavity 171 and the first substrate 110 A cavity 113 is connected, but the invention is not limited to this. In other embodiments, the second cavity 171 may be a triangular column, a quadrangular column, or a cavity with other shapes, and the present invention is not particularly limited.

Furthermore, as shown in FIG. 1A, in this embodiment, the optical liquid 130 is suitable to fill the first cavity 113, and the optical liquid 130 also fills at least one second cavity 171. In this embodiment, the second substrate 170 is located between the elastic film 180 and the second surface 112 of the first substrate 110, and the elastic film 180 covers the second substrate 170 and at least one second cavity 171 to seal the optical liquid 130. On the other hand, the light-transmitting layer 160 is located on the first surface 111 of the first substrate 110, and the optical liquid 130 filling the first cavity 113 and the second cavity 171 directly contacts the light-transmitting layer 160 and the elastic film 180.

On the other hand, as shown in FIG. 1A, in this embodiment, the carrier layer 140 is located on the first surface 111 of the first substrate 110. More specifically, as shown in FIG. 1A, in this embodiment, the carrier layer 140 includes a first insulating layer IL1, a second insulating layer IL2, and a wafer layer WF. The second insulating layer IL2 is overlapped with the first insulating layer IL1. The wafer layer WF is located between the first insulating layer IL1 and the second insulating layer IL2. For example, in this embodiment, the material of the wafer layer WF is, for example, silicon, and the material of the first insulating layer IL1 and the second insulating layer IL2 is, for example, silicon oxide. In this way, the carrier layer 140 can be fabricated using a silicon-on-insulator (SOI) process technology, and can be integrated with the existing process technology, making it easy to manufacture.

As shown in FIG. 1A, in this embodiment, the carrier layer 140 has a light pass area CA penetrating the carrier layer 140. Furthermore, the carrier layer 140 has a protruding structure PS, the protruding structure PS encloses the light passing area CA, wherein the protruding structure PS extends from the first surface 111 of the first substrate 110 in the radial direction R of the light passing area CA. Extending to the center of the light-passing area CA means that the carrier layer 140 completely covers the first surface 111 of the first substrate 110 and extends to the center of the light-passing area CA, and the extended part is the protruding structure PS. In other words, the projected area of the light-passing area CA on the first substrate 110 is smaller than the projected area of the first cavity 113 on the first substrate 110. Specifically, in this embodiment, the protruding structure PS of the carrier layer 140 is composed of the wafer layer WF and the first insulating layer IL1 (that is, the boundary of the second insulating layer IL2 and the boundary of the first substrate 110 Same), but the present invention is not limited to this. In other embodiments, the carrier layer 140 may be a single-layer structure, and the carrier layer 140 extends toward the center of the light-passing area CA to form the protruding structure PS. The carrier layer 140 may be, for example, an insulating layer or a semiconductor layer.

As shown in FIG. 1A, the piezoelectric film 120 is located on the carrier layer 140, wherein the piezoelectric film 120 is disposed on the first insulating layer IL1, and the light-transmitting layer 160 is located on the piezoelectric film 120. However, the present invention is not limited to this. In other embodiments, the light-transmitting layer 160 may be disposed between the piezoelectric film 120 and the carrier layer 140, or the piezoelectric film 120 may be formed by other stacking methods. With light-transmitting layer 160. The piezoelectric film 120 has an open area, and the boundary of the open area is the same as the boundary of the light passing area CA, but the present invention is not limited to this. In other embodiments, the projected area of the opening area of the piezoelectric film 120 on the first substrate 110 may be greater than or equal to the projected area of the light-passing area CA on the first substrate 110. As shown in FIG. 1A, in this embodiment, the light-transmitting layer 160 is overlapped and disposed on the protrusion structure PS of the piezoelectric film 120 and the carrier layer 140, and the light-transmitting layer 160 covers the light-passing area CA.

More specifically, as shown in FIG. 1B, in this embodiment, the projection range of the light-transmitting layer 160 on the first substrate 110 completely covers the light-passing area CA, and the projection of the light-passing area CA on the first substrate 110 The area overlaps with the first cavity 113. In addition, as shown in FIG. 1B, in this embodiment, the projection range of the first cavity 113 on the first substrate 110 and the projection range of the at least one second cavity 171 on the first substrate 110 at least partially overlap. In particular, the projection range of the second cavity 117 on the first substrate 110 and the projection range of the light-passing area CA on the first substrate 110 will not overlap, which ensures that the setting of the second cavity 117 will not affect Optical performance of light passing through the luminous area CA.

Next, please continue to refer to FIG. 1A and FIG. 1B. In this embodiment, the driving electrode 150 is located on the carrier layer 140 and is used to drive the piezoelectric film 120. For example, as shown in FIG. 1A, in this embodiment, the piezoelectric films 120 are respectively clamped by the corresponding driving electrodes 150. The driving electrodes 150 include a first driving electrode 151 and a second driving electrode 152. The first driving electrode 151, the piezoelectric film 120, and the second driving electrode 152 are sequentially stacked on the carrier layer 140 from bottom to top. In more detail, as shown in FIG. 1A, in this embodiment, the piezoelectric film 120 has an outer surface 120 a and an inner surface 120 b opposite to each other. The outer surface 120 a faces the light-transmitting layer 160, and the inner surface 120 b faces the carrier layer 140. The first driving electrode 151 is located between the carrier layer 140 and the inner surface 120 b of the piezoelectric film 120. The second driving electrode 152 is located between the outer surface 120 a of the piezoelectric film 120 and the light-transmitting layer 160. For example, the materials of the first driving electrode 151 and the second driving electrode 152 may be platinum and gold, respectively. Moreover, as shown in FIG. 1B, the shape of the driving electrode 150 is a ring shape, and the driving electrode 150 surrounds the light passing area CA.

In this way, when the driving electrode 150 applies a driving voltage to the piezoelectric film 120, the piezoelectric film 120 is compressed or stretched by the electric field (for example, the piezoelectric film 120 is compressed or stretched in a direction parallel to the first substrate 110) , Pulling the convex structure PS to bend and deform (for example, the convex structure PS bends in a direction parallel to the normal line of the first substrate 110), and drives the light-transmitting layer 160 to deform, so as to achieve the purpose of optical zooming. In this embodiment, the piezoelectric film 120 is deformed under the influence of the electric field, so that the protruding structure PS of the carrier layer 140 and the light-transmitting layer 160 are both deformed due to the elastic coefficient of the protruding structure PS of the carrier layer 140 A larger value can enhance the structural strength of the light-transmitting layer 160 with a smaller elastic coefficient. Therefore, as the electric field changes, the light-transmitting layer 160 can move away from the first cavity 113 or bend toward the first cavity 113 to form a convex spherical surface or a concave spherical surface to achieve the purpose of zooming.

On the other hand, in this embodiment, the elastic coefficient of the elastic film 180 is smaller than the elastic coefficient of the light-transmitting layer 160. In this way, the arrangement of the elastic film 180 with a relatively small coefficient of elasticity can absorb the volume change of the light-transmitting layer 160 when deformed, so that the light-transmitting layer 160 located in the light-passing area CA is covered by the piezoelectric film 120. When the driving voltage is applied, the shape close to the spherical surface can still be maintained, and the optical quality of the variable focus optical element 100 can be effectively maintained.

For example, in this embodiment, the length and width of the first substrate 110, the transparent layer 160, the second substrate 170, and the elastic film 180 are all about 3-13 millimeters (mm), and the first substrate 110, the transparent The thicknesses of the optical layer 160, the second substrate 170, and the elastic film 180 are about 10 micrometers, 25 micrometers, 300 micrometers, and 10 micrometers, respectively. The diameter of the first cavity 113 is about 4 mm, and the diameter of the second cavity 171 is about 1.8 mm. It should be noted that the numerical ranges here are for illustrative purposes only, and are not intended to limit the present invention.

On the other hand, in this embodiment, the outer diameter of the driving electrode 150 is about 2-10 mm, the inner diameter is about 0.5-6 mm, the diameter of the light-passing area CA is about 0.5-6 mm, and the diameter of the carrier layer 140 is about 0.5-6 mm. The size of the projecting structure PS is about 0.5-4 mm. In particular, according to the change of the size of the protruding structure PS, the elastic coefficient is also different, and the protrusion width of the light-transmitting layer 160 also varies. In this way, when the driving electrode 150 applies an appropriate driving voltage to the piezoelectric film 120, the tensile force generated by the piezoelectric film 120 will maintain the deformation generated by the protruding structure PS and the light-transmitting layer 160 within the required range. Inside. In this way, under the above configuration, through the strain action of the optical liquid 130, the piezoelectric film 120, the protruding structure PS of the carrier layer 140, and the light-transmitting layer 160, the variable focus optical element 100 can affect the light-transmitting area CA The radius of curvature of the transparent layer 160 is adjusted to achieve the effect of changing the focal length. Hereinafter, this will be further explained in conjunction with FIGS. 2A to 2F.

FIG. 2A is a schematic cross-sectional view of the variable focus optical element 100 of FIG. 1A when a driving voltage is applied. Specifically, as shown in FIG. 2A, the piezoelectric film 120 is applied with a driving voltage, which in turn drives the light-transmitting layer 160 to deform, and the carrier layer 140, the piezoelectric film 120, the driving electrode 150, and the light-transmitting layer 160 can collectively form The zoomable cavity is in communication with the first cavity 113. In particular, since the thickness of the piezoelectric film 120 and the driving electrode 150 can be much smaller than the thickness of the carrier layer 140, the area enclosed by the light-passing area CA and the light-transmitting layer 160 can also be directly regarded as a variable-focus cavity. The range of the first cavity 113 will be changed due to the deformation of the carrier layer 140, but the zoomable cavity still maintains communication with the first cavity 113. In this embodiment, when the light-transmitting layer 160 is deformed, since the first cavity 113, the second cavity 171 and the variable-focus cavity form a sealed space, the volume of the optical liquid 130 in the cavity is filled. Will remain constant, so the optical liquid 130 will flow in the first cavity 113, the second cavity 171 and the variable-focus cavity. Since the elastic coefficient of the elastic film 180 is much smaller than that of the light-transmitting layer 160, the light-transmitting layer 160 can be configured to deform At this time, the volume changes, and the elastic film 180 covering the second cavity 171 of the second substrate 170 will also deform accordingly, so that the optical liquid 130 can flow smoothly without causing unnecessary deformation. In other words, if the elastic film 180 is not provided, the deformation of the light-transmitting layer 160 will be affected. With the provision of the elastic film 180, the shape deformation of the surface of the light-transmitting layer 160 can conform to the expected deformation and remain variable. The optical quality of the focal length optical element 100. In this way, with the arrangement of the elastic film 180 with a relatively small elasticity coefficient, the light-transmitting layer 160 located in the light-passing area CA can still maintain an approximate spherical shape when a driving voltage is applied, thereby effectively maintaining the variable focal length. The optical quality of the optical element 100.

2B to 2E are data comparison diagrams of the radius of curvature and the ideal radius of curvature of the variable focus optical element 100 of FIG. 1A when different driving voltages are applied. FIG. 2F is a graph showing the relationship between the amount of deformation of the piezoelectric film 120 in FIG. 2A and the simulation data of the driving voltage. Specifically, in this embodiment, when a certain driving voltage is applied to the driving electrode 150, the deformation data generated by the light-transmitting layer 160 is simulated and analyzed, and the results are shown in FIGS. 2B to 2E.

In detail, as shown in FIGS. 2B to 2E, in this embodiment, the direction of deformation of the piezoelectric film 120 and the light-transmitting layer 160 of the variable focus optical element 100 can be changed by changing the positive and negative voltages. Specifically, the direction in which the light-transmitting layer 160 of the variable focal length optical element 100 is deformed can be away from the first cavity 113 or bend toward the first cavity 113. Moreover, by changing the magnitude of the voltage, the deformation of the transparent layer 160 driven by the piezoelectric film 120 of the variable focus optical element 100 can be changed. As shown in FIG. 2B, when the driving voltage is +10V, the maximum amount of deformation of the center sagittal of the variable focus optical element 100 (that is, the maximum amount of deformation of the light-transmitting layer 160) is +5.2 microns, as shown in FIG. 2C When the driving voltage is +5V, the maximum amount of deformation of the center sagittal of the variable focus optical element 100 is +3.0 microns, and as shown in FIGS. 2B to 2C, the direction of deformation of the variable focus optical element 100 is far away from the first A cavity 113 is curved. On the other hand, as shown in FIG. 2D, when the driving voltage is -5V, the maximum amount of deformation of the center sagittal of the variable focus optical element 100 is -4.5 micrometers, as shown in FIG. 2E, when the driving voltage is -10V The maximum amount of deformation of the center sagittal of the variable focus optical element 100 is -12 micrometers, and as shown in FIGS. 2D to 2E, the deformation direction of the variable focus optical element 100 is curved toward the first cavity 113.

Moreover, as shown in FIGS. 2B to 2E, the light-transmitting layer 160 of the variable focal length optical element 100 is very close to the ideal spherical contour. In other words, through the strain action of the optical liquid 130, the piezoelectric film 120, the protruding structure PS of the carrier layer 140, and the light-transmitting layer 160, the radius of curvature of the light-transmitting layer 160 of the variable focus optical element 100 is close to the ideal value, which can effectively reduce The spherical aberration effectively maintains the optical quality of the variable focal length optical element 100.

Furthermore, as shown in FIG. 2F, in this embodiment, applying a predetermined driving voltage to the piezoelectric film 120 can effectively cause the piezoelectric film 120 to generate different stretching stresses and deformations. For example, in this embodiment, the driving voltage can range from 0 to 50 volts, and the piezoelectric film 120 can be effectively deformed by modulating the voltage. It should be noted that the numerical ranges here are for illustrative purposes only, and are not intended to limit the present invention. For example, depending on the design of different piezoelectric materials and structural dimensions, in other embodiments, the range of the driving voltage may preferably be greater than 30 volts, -25 to 25 volts, or -50 to 50 volts. The variable focal length optical element 100 can reach the desired focal length value, and the present invention is not limited thereto.

In this way, the variable focal length optical element 100 of this embodiment is applied to the piezoelectric film 120 with a predetermined driving voltage, so that the piezoelectric film 120 is deformed by stretching stress, and then drives the convex structure PS of the carrier layer 140 to bend and deform. The transparent layer 160 is deformed. In addition, the carrier layer 140 can be fabricated by a silicon-on-insulator (SOI) process technology, and can be integrated with the existing process technology for easy fabrication.

On the other hand, with the arrangement of the elastic film 180, the optical liquid 130 can be filled with a larger volume tolerance value. In other words, when the arrangement of the elastic film 180 is used, the volume caused by the filling of the optical liquid can be completely absorbed. Error to eliminate the error of diopter. In this way, with the arrangement of the elastic film 180, the light-transmitting layer 160 will not be deformed when the driving voltage is not applied.

Fig. 3 is a schematic top view of another embodiment of a variable focal length optical element according to the present invention. Referring to FIG. 3, the variable focus optical element 300 of this embodiment is similar to the variable focus optical element 100 of FIG. 1A, and the difference between the two is as follows. As shown in FIG. 3, the driving electrode 350 of the variable focal length optical element 300 includes a plurality of arc-shaped electrodes CE1 and CE2. These arc-shaped electrodes CE1 and CE2 are arranged on the ring area CR, which surrounds the light flux. In the area CA, the polarity direction of the driving voltage of any arc-shaped electrode CE1 and CE2 is opposite to the polarity direction of the driving voltage applied to the adjacent arc-shaped electrodes CE1 and CE2. For example, these arc-shaped electrodes CE1 and CE2 are alternately arranged on the circular area CR, and the polarity direction of the driving voltage of any arc-shaped electrode CE1 is equal to that of the driving voltage applied by the adjacent arc-shaped electrode CE2. The polarity direction is opposite, that is, the polarity direction of the driving voltage of any arc-shaped electrode CE2 is opposite to the polarity direction of the driving voltage applied by the adjacent arc-shaped electrode CE1. In this way, the driving electrode 350 of the variable focus optical element 300 can be adapted to drive the piezoelectric film 320 that does not have a spontaneous polarity, and the polarity of the piezoelectric film 320 can be matched with a circle with a specific driving voltage direction after being initialized. The arc-shaped electrodes CE1 and CE2 are further deformed. In this way, in this embodiment, the variable focus optical element 300 can also cause the piezoelectric film 320 to stretch and deform by changing the positive and negative voltages, which affects the direction of the deformation of the carrier layer 140. Specifically, the direction in which the carrier layer 140 is deformed can be away from the first cavity 113 or bend toward the first cavity 113, thereby driving the light-transmitting layer 160 to form a convex spherical surface or a concave spherical surface.

In this way, the variable focal length optical element 300 of this embodiment can also be applied to the piezoelectric film 320 by using a predetermined driving voltage to cause the piezoelectric film 320 to generate stretching stress and deformation, thereby driving the protruding structure PS of the carrier layer 140 and The transparent layer 160 is deformed.

4 is a schematic cross-sectional view of another embodiment of a variable focal length optical element according to the present invention. Please refer to FIG. 4, the variable focus optical element 400 of this embodiment is similar to the variable focus optical element 100 of FIG. 1A, and the difference between the two is as follows. As shown in FIG. 4, in this embodiment, the light-transmitting layer 460 is disposed between the piezoelectric film 420 and the carrier layer 440. For example, the light-transmitting layer 460 may be formed of the first insulating layer IL1 of FIG. 1A, which is made of silicon oxide and has light-transmitting properties, and the carrier layer 440 only includes the second insulating layer IL2 and the wafer layer WF. Specifically, as shown in FIG. 4, in this embodiment, the light-transmitting layer 460 (the first insulating layer IL1) is stacked on the wafer layer WF, and the wafer layer WF is located on the second insulating layer IL2 and the light-transmitting layer WF. Between layers 460. In this way, the production of the carrier layer 440 and the light-transmitting layer 460 can be fabricated using the silicon-on-insulator (SOI) process technology, and can be integrated with the existing process technology, and the fabrication is simple, but the present invention does not This is limited. In other embodiments, the carrier layer 440 also includes only the second insulating layer IL2 and the wafer layer WF. The second insulating layer IL2 is located between the first substrate 110 and the wafer layer WF, and the light-transmitting layer 460 is located on the wafer layer. Between the WF and the piezoelectric film 420, and the piezoelectric film 420 covers the light transmission area CA, the material of the piezoelectric film 420 may optionally include polymer materials or glass. In addition, as shown in FIG. 4, in this embodiment, the piezoelectric film 420 can selectively cover the light-passing area CA.

In this way, the variable focal length optical element 400 of this embodiment can also be applied to the piezoelectric film 420 by using a predetermined driving voltage, so that the piezoelectric film 420 generates stretching stress and deformation, thereby driving the protruding structure PS of the carrying layer 440 and the light transmission. The layer 460 is deformed. In this embodiment, since the variable focal length optical element 400 and the variable focal length optical element 100 have a similar structure, the variable focal length optical element 400 has the advantages mentioned in the variable focal length optical element 100, and will not be omitted here. Go into details.

5 is a schematic cross-sectional view of another embodiment of a variable focal length optical element according to the present invention. Please refer to FIG. 5, the variable focus optical element 500 of this embodiment is similar to the variable focus optical element 100 of FIG. 1A, and the difference between the two is as follows. As shown in FIG. 5, in this embodiment, the carrier layer 540 only includes the first insulating layer IL1 and the wafer layer WF. The light-transmitting layer 560 may be formed of the second insulating layer IL2 of FIG. 1A and has light-transmitting properties. The material is silicon oxide. Specifically, as shown in FIG. 5, the wafer layer WF is located between the first insulating layer IL1 and the light-transmitting layer 560, and the light-transmitting layer 560 is located between the first substrate 110 and the wafer layer WF. In this embodiment, the variable focus optical element 100 may optionally further include an auxiliary piezoelectric film AP. The auxiliary piezoelectric film AP is disposed on the light-transmitting layer 560 and may selectively cover only the light-transmitting area to improve The light-transmitting layer 560 is stable, and the auxiliary piezoelectric film AP will not be deformed due to stretching stress due to the driving voltage.

In this embodiment, since the variable focal length optical element 500 and the variable focal length optical element 100 have a similar structure, the variable focal length optical element 500 has the advantages mentioned in the variable focal length optical element 100, and will not be omitted here. Go into details.

6 is a schematic cross-sectional view of another embodiment of a variable focal length optical element according to the present invention. Please refer to FIG. 6, the variable focus optical element 700 of this embodiment is similar to the variable focus optical element 100 of FIG. 1A, and the difference between the two is as follows. As shown in FIG. 6, in this embodiment, the carrier layer of FIG. 1A is the light-transmitting layer 760 and is formed of an insulating layer. The material is silicon oxide or glass. The first substrate 110 and the light-transmitting layer 760 can be a silicon glass bonded wafer (SOG wafer). In this embodiment, in the light-transmitting layer 760 of the variable focal length optical element 700, the convex structure (supporting layer) of the supporting layer that is the same as that of FIG. Layer of through holes. Specifically, as shown in FIG. 6, the light-transmitting layer 760 is located between the first substrate 110 and the piezoelectric film 120.

In this way, the variable focus optical element 700 of this embodiment can also be applied to the piezoelectric film 120 with a predetermined driving voltage, so that the piezoelectric film 120 is deformed by stretching stress, thereby driving the light-transmitting layer 760 to deform. In this embodiment, the variable focal length optical element 700 and the variable focal length optical element 100 have similar piezoelectric film stretching stress and deformation, so the variable focal length optical element 700 has the advantages mentioned in the variable focal length optical element 100. This will not be repeated here.

In summary, the embodiments of the present invention have at least one of the following advantages or effects. In the embodiment of the present invention, the variable focal length optical element can be applied to the piezoelectric film with a predetermined driving voltage, so that the piezoelectric film generates stretching stress and deformation, which in turn drives the convex structure of the carrier layer and the light-transmitting layer to bend and deform . In addition, the carrier layer can be fabricated by using the process technology of covering silicon on the insulating layer, and can be integrated with the existing process technology for easy fabrication. In addition, the variable focus optical element is provided with an elastic film with a relatively small elastic coefficient, so that the piezoelectric film located in the luminous flux region can still maintain an approximate spherical shape when the driving voltage is applied under different environmental conditions. And effectively maintain the optical quality of the variable focal length optical element.

However, the above are only preferred embodiments of the present invention, and should not be used to limit the scope of implementation of the present invention, that is, simple equivalent changes and modifications made in accordance with the scope of the patent application of the present invention and the description of the invention, All are still within the scope of the invention patent. In addition, any embodiment of the present invention or the scope of the patent application does not have to achieve all the objectives or advantages or features disclosed in the present invention. In addition, the abstract part and title are only used to assist in searching for patent documents, and are not used to limit the scope of rights of the present invention. In addition, the terms "first" and "second" mentioned in this specification or the scope of the patent application are only used to name the element (element) or to distinguish different embodiments or ranges, and are not used to limit the number of elements. Upper or lower limit.

100, 300, 400, 500, 700: Variable focal length optics 110: First substrate 111: first surface 112: second surface 113: first cavity 120, 320, 420: piezoelectric film 120a: outer surface 120b: inner surface 130: optical liquid 140, 440, 540: carrier layer 150, 350: drive electrodes 151: first drive electrode 152: second drive electrode 160, 460, 560, 760: light-transmitting layer 170: second substrate 171: The second cavity 180: elastic membrane AP: auxiliary piezoelectric film CH: Cylindrical cavity CA: Luminous area CE1, CE2: arc-shaped electrodes CR: ring area PS: protruding structure R: radial direction IL1: first insulating layer IL2: second insulating layer WF: Wafer layer

FIG. 1A is a schematic cross-sectional view of a variable focal length optical element according to an embodiment of the present invention. FIG. 1B is a schematic top view of the variable focal length optical element of FIG. 1A. 2A is a schematic cross-sectional view of the variable focal length optical element of FIG. 1A deformed by applying a driving voltage. 2B to 2E are data comparison diagrams of the radius of curvature and the ideal radius of curvature of the variable focus optical element of FIG. 2A when different driving voltages are applied. Fig. 2F is a graph showing the relationship between the deformation of the piezoelectric film and the simulation data of the driving voltage of Fig. 2A. Fig. 3 is a schematic top view of another variable focal length optical element according to an embodiment of the present invention. 4 to 6 are schematic cross-sectional views of different variable focal length optical elements according to embodiments of the present invention.

100: Variable focal length optics

110: First substrate

111: first surface

112: second surface

113: first cavity

120: Piezo film

120a: outer surface

120b: inner surface

130: optical liquid

140: Carrier layer

150: drive electrode

151: first drive electrode

152: second drive electrode

160: light-transmitting layer

170: second substrate

171: The second cavity

180: elastic membrane

CA: Luminous area

PS: protruding structure

IL1: first insulating layer

IL2: second insulating layer

WF: Wafer layer

Claims (12)

A variable focal length optical element, including: A first substrate having a first surface and a second surface opposite to each other, the first substrate having a first cavity, wherein the first cavity penetrates the first surface and the second surface; A carrier layer is located on the first surface of the first substrate and has a light-passing area penetrating the carrying layer. The carrying layer has a protruding structure that encloses the light-passing area. The extension structure extends from the first surface of the first substrate to the center of the light-passing area in the radial direction of the light-passing area; A piezoelectric film located on the carrier layer; A driving electrode located on the carrying layer for driving the piezoelectric film, wherein the driving electrode applies a driving voltage to the piezoelectric film to cause the piezoelectric film to stretch and deform and pull the protruding structure to bend and deform; as well as A light-transmitting layer is overlapped and arranged on the protruding structure, and the light-transmitting layer covers the light-passing area. The variable focal length optical element according to claim 1, wherein the variable focal length optical element further includes a second substrate and an elastic film, and the second substrate is located on the second surface of the first substrate and has at least one A second cavity, the at least one second cavity communicates with the first cavity of the first substrate, and the second substrate is located between the elastic film and the first substrate, and the elastic film covers the second substrate And the elastic coefficient of the elastic film is smaller than the elastic coefficient of the light-transmitting layer. The variable focus optical element according to claim 1, wherein the bearing layer includes: A first insulating layer; A second insulating layer arranged to overlap the first insulating layer; and A wafer layer is located between the first insulating layer and the second insulating layer, wherein the piezoelectric film is disposed on the first insulating layer, and the light-transmitting layer is disposed on the piezoelectric film. The variable focal length optical element according to claim 1, wherein the material of the light-transmitting layer comprises a polymer material or glass. The variable focal length optical element according to claim 1, wherein the light-transmitting layer is a first insulating layer, the carrier layer includes a second insulating layer and a wafer layer, and the first insulating layer is laminated on the wafer And the wafer layer is located between the second insulating layer and the light-transmitting layer. The variable focus optical element according to claim 1, wherein the carrier layer includes a first insulating layer and a wafer layer, the light-transmitting layer is a second insulating layer, and the wafer layer is located on the first insulating layer Between the transparent layer and the transparent layer, the transparent layer is located between the first substrate and the wafer layer, wherein the variable focus optical element further includes an auxiliary piezoelectric film, and the auxiliary piezoelectric film is disposed on the transparent Layer up. The variable focus optical element according to claim 1, wherein the carrier layer includes a second insulating layer and a wafer layer, the second insulating layer is located between the first substrate and the wafer layer, and the light-transmitting layer The layer is located between the wafer layer and the piezoelectric film, and the piezoelectric film covers the light-passing area, wherein the material of the light-transmitting layer includes polymer material or glass. The variable focal length optical element according to claim 1, wherein the shape of the driving electrode is a ring, and the driving electrode surrounds the light transmission area. The variable focal length optical element according to claim 1, wherein the driving electrode includes a plurality of arc-shaped electrodes, the arc-shaped electrodes are arranged on an annular area, the annular area surrounds the light transmission area, and The polarity direction of the driving voltage of any one of the arc-shaped electrodes is opposite to the polarity direction of the driving voltage applied by the adjacent arc-shaped electrodes. The variable focus optical element according to claim 9, wherein the driving voltage ranges from 0 to 50 volts. The variable focal length optical element according to claim 1, wherein the piezoelectric film has an opening area, and the boundary of the opening area is the same as the boundary of the light transmission area. The variable focal length optical element according to claim 1, wherein the variable focal length optical element further comprises an optical liquid suitable for filling the first cavity, wherein the light-transmitting layer directly contacts the optical liquid.

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