JP2014228764A - Liquid crystal lens element and camera module using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal lens element in which a driving voltage can be reduced with less variance in optimal driving frequency and an optical axis of transmission light can be tilted, and to provide a camera module using the same.SOLUTION: A liquid crystal lens element 100 includes a first side surface electrode 41 connected to a first circular electrode 21, a second side surface electrode 42 connected to a first common electrode 31, and a plurality of third side surface electrodes 43a to 43d connected to a plurality of first peripheral electrodes 11a to 11d. A first liquid crystal layer 70 is smaller in thickness than a first substrate 50 and a second substrate 51, and the first circular electrode 21 and the plurality of first peripheral electrodes 11a to 11d are located between one principal surface of the first substrate 50 and the first liquid crystal layer 70, and the first common electrode 31 is located between a principal surface of the second substrate 51, which faces the first substrate 50, and the liquid crystal layer 70.

Description

  The present invention relates to a liquid crystal lens element and a camera module using the same.

  The liquid crystal lens is a new optical element that can change the focal length of the lens by applying an AC voltage, and it is expected to be put to practical use as a next-generation optical element that replaces the conventional focus control mechanism such as an actuator that requires a mechanical drive part. Has been.

  As such a liquid crystal lens, for example, in Patent Document 1, a first electrode, a second electrode, a third electrode, a liquid crystal layer disposed between the second electrode and the third electrode, A first insulating layer disposed between the electrode and the second electrode; a second insulating layer disposed between the second electrode and the third electrode; disposed outside the first electrode. In addition, there has been proposed a liquid crystal lens including a third insulating layer and a fourth insulating layer disposed outside the third electrode.

  In the liquid crystal lens of Patent Document 1, an effective voltage of 20 Vrms is applied between the first electrode and the third electrode, and an effective voltage of 70 Vrms is applied between the second electrode and the third electrode to form a convex lens. An effective voltage of 90 Vrms is applied between the first electrode and the third electrode, and an effective voltage of 30 Vrms is applied between the second electrode and the third electrode to function as a concave lens. In addition, the liquid crystal lens of Patent Document 1 is composed of four electrodes in which the second electrode is divided vertically and horizontally, and the two second electrodes divided into these four and the third electrode are divided. By applying 75 Vrms between the electrodes and 70 Vrms between the remaining two second and third electrodes, the direction of deflection of the incident light and the focal position of the image are perpendicular to the optical axis. It is disclosed that about 40 μm can be changed.

  On the other hand, in Patent Document 2, a liquid crystal is sealed between a first substrate on which a common electrode is formed and a second substrate on which a plurality of segment electrodes including a peripheral electrode hollowed out are formed. There has been proposed a liquid crystal optical element that is provided with a plurality of electrode terminals that are exposed to the outside at a plurality of corners on the side surface of the liquid crystal optical element.

JP 2010-113029 A JP 2012-088394 A

  However, in the structure of the conventional liquid crystal lens described in Patent Document 1, insulating layers are arranged between the first electrode and the second electrode and between the second electrode and the third electrode. The distance between the electrodes is increased. For this reason, the potential drop of the electric field between the electrodes increases, and in order to obtain an electric field curve necessary for the liquid crystal layer to exhibit lens characteristics, the voltage applied between the electrodes, that is, the effective voltage required for driving is several tens. It needs to be as high as Vrms. Therefore, there is a problem that it cannot be used for a camera module mounted on a mobile device driven by a battery, such as a small camera or a mobile phone for personal computers that requires low power consumption.

  In addition, the liquid crystal lens described in Patent Document 1 does not mention anything about the power feeding structure to the first to third electrodes, and depending on the way of wiring, between the electrodes due to the capacitance between the lines of the wiring. The technical problem remains that the capacitive reactance fluctuates and the optimum drive frequency of the applied voltage varies.

  On the other hand, in the liquid crystal optical element described in Patent Document 2, a plurality of segment electrodes are composed of a circular second transparent electrode and a third transparent electrode having a circular notch at the center, and thus transmitted light is transmitted. There was a problem that the optical axis could not be tilted.

  Accordingly, the present invention has been made in view of such circumstances, and a liquid crystal lens element capable of tilting the optical axis of transmitted light with a low driving voltage while reducing variations in the optimum driving frequency. Another object is to provide a camera module using the same.

  The liquid crystal lens element according to the present invention electrically insulates the first substrate, the second substrate, and the first circular electrode provided on one main surface of the first substrate on the same plane. A plurality of first peripheral electrodes divided in such a manner, a first common electrode provided on a main surface of the second substrate facing the first substrate, a first circular electrode, and a plurality of first electrodes An element body having a first liquid crystal layer disposed between the peripheral electrode and the first common electrode, and a plurality of side electrodes provided on an outer surface of the element body, The outer surface has two main surfaces facing each other and a plurality of side surfaces connecting the two main surfaces, and the plurality of end surface electrodes are respectively provided on any one of the plurality of side surfaces of the element body. A first side electrode connected to the first circular electrode and a second side electrode connected to the first common electrode And a plurality of third side electrodes connected to the plurality of first peripheral electrodes, wherein the first liquid crystal layer is thinner than the thickness of the first substrate and the thickness of the second substrate. The first circular electrode and the plurality of first peripheral electrodes are disposed between one main surface of the first substrate and the first liquid crystal layer, and the first common electrode is formed on the second substrate. The first liquid crystal layer is disposed between the main surface facing the first substrate and the first liquid crystal layer.

  According to the present invention, the liquid crystal lens element includes a first circular electrode and a plurality of first peripheral electrodes divided so as to be electrically insulated from each other on the same plane. Thereby, the optical axis of the transmitted light can be tilted by giving a gradient to the voltage applied to the plurality of first peripheral electrodes.

  In the liquid crystal lens element according to the present invention, the first liquid crystal layer is thinner than the thickness of the first substrate and the thickness of the second substrate, and the first circular electrode and the plurality of first peripheral electrodes are the first. The first common electrode is disposed between one main surface of the substrate and the first liquid crystal layer, and the first common electrode is disposed between the main surface of the second substrate facing the first substrate and the first liquid crystal layer. Is arranged. For this reason, since the distance between the first circular electrode and the first common electrode and the distance between the plurality of first peripheral electrodes and the first common electrode approach, the potential drop of the electric field between the electrodes Is minimized, and the voltage required for driving the liquid crystal lens element can be reduced. As a result, it can be used for a camera module mounted on a mobile device driven by a battery.

  Furthermore, in the liquid crystal lens element according to the present invention, a plurality of end surface electrodes are provided on any one of a plurality of side surfaces of the element body, respectively, and a first side electrode connected to the first circular electrode, A second side electrode connected to the common electrode, and a plurality of third side electrodes connected to the plurality of first peripheral electrodes. As a result, fluctuations in the capacitive reactance between the electrodes can be suppressed, and variations in the optimum driving frequency can be reduced.

  Preferably, the plurality of first peripheral electrodes are radially divided so that the central angles of the dividing lines are substantially equal, and the first common electrode may have a substantially circular shape. In this case, since the areas of the plurality of first peripheral electrodes divided radially are substantially equal, the capacitance values depending on the areas of the electrodes are substantially equal, and as a result, the optimum driving of each electrode is achieved. The occurrence of variations in frequency can be reduced.

  Preferably, the areas of the regions where the plurality of first peripheral electrodes and the first common electrode overlap each other when viewed from the optical axis direction are substantially equal, and the plurality of first peripheral electrodes and the first common electrode The entire overlapping region may overlap with the first liquid crystal layer. In this case, since the variation in the capacitance formed between the plurality of first peripheral electrodes and the first common electrode is suppressed, it is possible to further reduce the variation in the optimum driving frequency. .

  Preferably, the first circular electrode has a part of the electrode extending to the periphery of the element body and connected to the first side electrode, and the first common electrode has a part of the electrode extending to the periphery of the element body. The plurality of first peripheral electrodes are connected to the second side electrode, and each of the plurality of first peripheral electrodes is connected to at least one of the plurality of third side electrodes by extending a part of the electrode to the periphery of the element body. The electrode and a part of the electrode extending to the periphery of the element body of the plurality of first peripheral electrodes and the part of the electrode extending to the periphery of the element body of the first common electrode do not overlap each other when viewed from the optical axis direction. Good. In this case, a short circuit between the electrodes is prevented, and electrical conduction between the electrodes and the side electrodes can be ensured.

  Preferably, the first side surface electrode, the second side surface electrode, and the plurality of third side surface electrodes are located on two opposing side surfaces of the plurality of side surfaces of the element body, and are formed on both main surfaces of the element body. It is good to extend continuously. In this case, since it is possible to minimize the influence of variations in capacitance between the side electrodes, it is possible to further reduce the occurrence of variations in the optimum driving frequency for each electrode. Here, in the liquid crystal lens element, either one of the two main surfaces of the element body is disposed opposite to the mounting surface of the circuit board, but each side electrode is continuous so as to reach both the main surfaces of the element body. Since the electrical connection between each side electrode and the circuit board becomes possible directly, it is possible to realize a connection without using a lead wire with a deformation of the shape, and the capacitance between the electrodes is reduced. The variation can be reduced, and the occurrence of variation in the optimum driving frequency for each electrode can be further reduced.

  More preferably, the element body includes a second circular electrode provided on the other main surface of the first substrate and a plurality of second peripheral electrodes divided so as to be electrically insulated from each other on the same plane. A third substrate, a second common electrode provided on a main surface of the third substrate facing the first substrate, a second circular electrode, a plurality of second peripheral electrodes, and a second A second liquid crystal layer disposed between the common electrode and the second liquid crystal layer, wherein the second liquid crystal layer is thinner than the thickness of the first substrate and the thickness of the third substrate. And the plurality of second peripheral electrodes are disposed between the other main surface of the first substrate and the second liquid crystal layer, and the second common electrode is opposed to the first substrate of the third substrate. A pair of element bodies of a plurality of first peripheral electrodes and a plurality of second peripheral electrodes as viewed from the optical axis direction. May electrodes are located are connected to the same third aspect electrodes.

  By adopting such a configuration, one of the plurality of first peripheral electrodes and one of the plurality of second peripheral electrodes positioned at the diagonal of the element body connected to the same third side electrode Since the same potential voltage can be applied, the optical axes of the transmitted light of the first liquid crystal layer and the second liquid crystal layer are tilted by the same amount in the same direction without increasing the number of side electrodes. Can do. Therefore, the optical performance as a liquid crystal lens element can be further improved.

  A camera module according to the present invention is characterized in that the liquid crystal lens element is used as a part of a lens. According to the present invention, it is possible to provide a camera module capable of tilting the optical axis of transmitted light with a low drive voltage while reducing the occurrence of variations in the optimum drive frequency.

  According to the liquid crystal lens element of the present invention and the camera module using the liquid crystal lens element, it is possible to tilt the optical axis of the transmitted light with a low driving voltage while reducing the variation in the optimum driving frequency.

1 is a perspective view illustrating a configuration of a liquid crystal lens element according to a first embodiment of the present invention. It is a top view which shows the structure of the liquid-crystal lens element which concerns on 1st Embodiment of this invention. It is a side view which shows the structure of the liquid-crystal lens element which concerns on 1st Embodiment of this invention. FIG. 2b is a cutaway end view taken along the cutting line AA ′ in FIG. 2a. It is a graph which shows the relationship between the electrostatic capacitance in a liquid crystal lens element, and the optimal drive frequency. It is a top view which shows the structure of the modification of the liquid crystal lens element which concerns on 1st Embodiment of this invention. It is a side view which shows the structure of the modification of the liquid crystal lens element which concerns on 1st Embodiment of this invention. It is a perspective view which shows the structure of the liquid-crystal lens element which concerns on 2nd Embodiment of this invention. It is a top view which shows the structure of the liquid-crystal lens element which concerns on 2nd Embodiment of this invention. It is a cut part end view which follows the cutting line BB 'line in FIG. 5b. It is a bottom view which shows the structure of the liquid-crystal lens element which concerns on 2nd Embodiment of this invention. It is the elements on larger scale which expand and show the area | region A in the liquid-crystal lens element shown to FIG. It is a perspective view which shows the structure of the camera module which concerns on this embodiment. It is a graph which shows the lens power with respect to the applied voltage of an Example and a comparative example.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined. Furthermore, in the description, the same elements or elements having the same function are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
First, the configuration of the liquid crystal lens element 100 according to the first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a perspective view showing the configuration of the liquid crystal lens element according to the first embodiment of the present invention. FIG. 2A is a top view showing the configuration of the liquid crystal lens element according to the first embodiment of the present invention. FIG. 2B is a side view showing the configuration of the liquid crystal lens element according to the first embodiment of the present invention. FIG. 2c is an end view of the cut portion along the cutting line AA 'in FIG. 2a. However, in FIG. 2a, the second substrate 51 is omitted for convenience of explanation.

  As shown in FIG. 1, the liquid crystal lens element 100 includes an element body 10, a first side electrode 41 provided on the outer surface of the element body 10, a second side electrode 42, and a plurality of third electrodes. Side electrodes 43a to 43d are provided.

  The element body 10 has a substantially quadrangular prism shape, and the first main surface 10za and the second main surface 10zb, the first main surface 10za, and the second main surface 10zb that face each other are formed as outer surfaces. The first side surface 10xa and the second side surface 10xb that are connected and face each other, and the third side surface 10ya and the fourth side surface 10yb that connect the first main surface 10za and the second main surface 10zb and face each other. And have. In addition, the element body 10 has a circular liquid crystal lens opening 9 at substantially the center when viewed from the opposing direction of the first main surface 10za and the second main surface 10zb. Here, the opposing direction of the first main surface 10za and the second main surface 10zb is the optical axis direction of the liquid crystal lens element 100. When the liquid crystal lens element 100 is mounted on the circuit board, either the first main surface 10za or the second main surface 10zb of the element body 10 is disposed to face the mounting surface of the circuit board.

  2a and 2b, the element body 10 includes a first substrate 50, a second substrate 51, a first liquid crystal layer 70, a first peripheral electrode 11, a first circular electrode 21, 1 common electrode 31.

  The first substrate 50 and the second substrate 51 are each composed of a transparent glass substrate, and as shown in FIG. 2 c, one main surface of the first substrate 50 and one main surface of the second substrate 51. Are arranged to face each other. The thickness of the first substrate 50 is about 200 μm, and the thickness of the second substrate 51 is about 150 μm.

  As shown in FIG. 2 c, the first liquid crystal layer 70 is configured by sealing a liquid crystal material between the first substrate 50 and the second substrate 51. The first liquid crystal layer 70 is thinner than the thickness of the first substrate 50 and the thickness of the second substrate 51, and the thickness is 10 to 100 μm. Here, the first liquid crystal layer 70 is disposed in a region surrounded by a sealing material (not shown) between the first substrate 50 and the second substrate 51.

  The first peripheral electrode 11 is made of indium tin oxide (ITO) and is provided on one main surface of the first substrate 50 as shown in FIG. 2c. Specifically, the first peripheral electrode 11 is disposed between one main surface of the first substrate 50 and the first liquid crystal layer 70. In the present embodiment, as shown in FIG. 2a, the first peripheral electrodes 11 have a circular hole, are electrically insulated from each other on the same plane, and the central angle of the dividing line is substantially the same. It consists of a plurality of first peripheral electrodes 11a to 11d (four in this embodiment) that are radially divided so as to be equal. In addition, when the 1st peripheral electrode 11 is comprised from four 1st peripheral electrodes 11a-11d, the center angle of a parting line will be 90 degrees. The first peripheral electrode 11 a extends toward a third side surface 10 ya that is a part of the electrode that is the periphery of the element body 10. The first peripheral electrode 11 b extends toward the fourth side surface 10 yb, in which a part of the electrode is the periphery of the element body 10. The first peripheral electrode 11 c extends toward the first side surface 10 xa where a part of the electrode is the periphery of the element body 10. The first peripheral electrode 11 d extends toward the first side surface 10 xa, where a part of the electrode is the periphery of the element body 10.

  The first circular electrode 21 is made of indium tin oxide, and a plurality of first peripheral electrodes 11a to 11d are formed in the central portion on one main surface of the first substrate 50 as shown in FIG. 2c. It is arranged in an electrically insulated state. Specifically, the first circular electrode 21 is disposed between one main surface of the first substrate 50 and the first liquid crystal layer 70. The first circular electrode 21 has a substantially circular shape with a diameter of about 2 mm and coincides with the region of the liquid crystal lens opening 9 when viewed from the optical axis direction. The first circular electrode 21 extends toward the second side surface 10 xb, which is a part of the electrode body 10, which is the periphery of the element body 10.

  The first common electrode 31 is made of indium tin oxide, and is disposed on the main surface of the second substrate 51 facing the first substrate 50, as shown in FIG. 2c. Specifically, the first common electrode 31 is between the main surface of the second substrate 51 facing the first substrate 50 and the first liquid crystal layer 70, and the first liquid crystal layer 70 is formed between the first liquid crystal layer 70 and the first liquid crystal layer 70. The first peripheral electrodes 11a to 11d and the first circular electrode 21 are arranged so as to face each other when viewed from the optical axis direction. That is, the first liquid crystal layer 70 is disposed between the first circular electrode 21 and the plurality of first peripheral electrodes 11 a to 11 d and the first common electrode 31. The first common electrode 31 has a substantially circular shape, and has a region overlapping the plurality of first peripheral electrodes 11 a to 11 d and the first circular electrode 21 when viewed from the optical axis direction. The areas of the overlapping regions of the first common electrode 31 and the plurality of first peripheral electrodes 11 a to 11 d when viewed from the optical axis direction are substantially equal, and the entire region overlaps the first liquid crystal layer 70. The first common electrode 31 extends toward the second side face 10xb, which is a part of the electrode body, that is the periphery of the element body 10.

  In the present embodiment, a part of the electrode extending toward the third side surface 10ya that is the periphery of the element body 10 of the first peripheral electrode 11a is the first common electrode as shown in FIG. 2a. No part of the electrode extending toward the second side surface 10xb, which is the periphery of the element body 10, is overlapped when viewed from the optical axis direction. A part of the electrode extending toward the fourth side surface 10yb, which is the periphery of the element body 10 of the first peripheral electrode 11b, is formed on the element body 10 of the first common electrode 31 as shown in FIG. A part of the electrode extending toward the second side surface 10xb, which is the periphery, does not overlap as viewed from the optical axis direction. A part of the electrodes extending toward the first side face 10xa, which is the periphery of the element body 10 of the first peripheral electrodes 11c and 11d, are element bodies of the first common electrode 31 as shown in FIG. 2a. 10 does not overlap with a part of the electrode extending toward the second side surface 10xb which is the periphery of the optical axis 10 when viewed from the optical axis direction. A part of the electrode extending toward the second side surface 10xb that is the periphery of the element body 10 of the first circular electrode 21 is formed on the element body 10 of the first common electrode 31 as shown in FIG. A part of the electrode extending toward the second side surface 10xb, which is the periphery, does not overlap as viewed from the optical axis direction. That is, a part of the plurality of first peripheral electrodes 11 a to 11 d and the first circular electrode 21 that extend to the periphery of the element body 10 and a part of the first common electrode 31 that extends to the periphery of the element body 10. Are not overlapped with each other when viewed from the optical axis direction. Note that a conductive material (not shown) is provided between the second substrate 51 and a part of the plurality of first peripheral electrodes 11a to 11d and the first circular electrode 21 extending along the periphery of the element body 10. Filled. In addition, a conductive material (not shown) is filled between the first substrate 50 and a part of the first common electrode 31 extending along the periphery of the element body 10.

Further, as shown in FIG. 2c, an insulating film (not shown) generally provided between the plurality of first peripheral electrodes 11a to 11d and the first circular electrode 21 and the first liquid crystal layer 70 is used. ) And a high resistance film may be formed. The insulating film is preferably made of silicon dioxide (SiO ₂ ). The high resistance film is preferably composed of a ternary oxide semiconductor containing zinc oxide (ZnO) as a main component and added with aluminum oxide (Al ₂ O ₃ ) and magnesium oxide (MgO). In addition, an alignment film (not shown) whose main component is polyimide resin may be formed on both main surfaces of the first liquid crystal layer 70. This alignment film is a rubbing process in a certain direction in order to regularly arrange the liquid crystal molecules in the first liquid crystal layer 70, that is, one of the alignment film processing methods. For example, the alignment performance of the first liquid crystal layer 70 is added by rubbing.

  The first side surface electrode 41 is disposed on the second side surface 10xb of the element body 10. The first side surface electrode 41 is connected to a part of the electrode extending toward the second side surface 10 xb that is the periphery of the element body 10 of the first circular electrode 21.

  The second side electrode 42 is disposed on the second side surface 10 xb of the element body 10. The second side electrode 42 is connected to a part of the electrode extending toward the second side surface 10 xb which is the periphery of the element body 10 of the first common electrode 31. In the present embodiment, the first side surface electrode 41 and the second side surface electrode 42 are the second side surface 10xb of the element body 10 in the direction from the third side surface 10ya to the fourth side surface 10yb. The side electrode 42 and the first side electrode 41 are arranged in this order.

  The third side surface electrode 43 a is disposed on the third side surface 10 ya of the element body 10. The third side surface electrode 43a is connected to a part of the electrode extending toward the third side surface 10ya which is the periphery of the element body 10 of the first peripheral electrode 11a. The third side surface electrode 43 b is disposed on the fourth side surface 10 yb of the element body 10. The third side surface electrode 43b is connected to a part of the electrode extending toward the fourth side surface 10yb which is the periphery of the element body 10 of the first peripheral electrode 11b. The third side electrodes 43 c and 43 d are disposed on the first side surface 10 xa of the element body 10. The third side surface electrode 43c is connected to a part of the electrode extending toward the first side surface 10xa that is the periphery of the element body 10 of the first peripheral electrode 11c. The third side surface electrode 43d is connected to a part of the electrode extending toward the first side surface 10xa, which is the periphery of the element body 10 of the first peripheral electrode 11d. In the present embodiment, the third side surface electrodes 43c and 43d are arranged in the direction from the third side surface 10ya to the fourth side surface 10yb in the first side surface 10xa of the element body 10. The third side electrodes 43c are arranged in this order. The first side surface electrode 41, the second side surface electrode 42, and the plurality of third side surface electrodes 43 a to 43 d are electrically insulated from each other on each side surface of the element body 10.

  Next, referring to FIG. 3, the relationship between the change in capacitance between the plurality of first peripheral electrodes 11 a to 11 d of the liquid crystal lens element 100 and the first common electrode 31 and the optimum driving frequency will be described in detail. explain.

  First, the optimum driving frequency of the AC voltage applied between the electrodes of the liquid crystal lens element 100 will be considered. The maximum value of the lens power obtained in the liquid crystal lens element 100 is determined depending on the effective voltage of the alternating voltage applied between the electrodes of the liquid crystal lens element 100 and the driving frequency. Here, the lens power is one of indices indicating the performance of the lens, and the value increases as the function of the lens increases. This lens power is also one of the indices indicating the performance of the lens, and corresponds to the reciprocal of the focal length, the value of which tends to decrease as the function of the lens for bending light increases, and the unit is diopter. It is represented by [1 / m]. As the effective voltage and driving frequency of the applied AC voltage increase, the lens power obtained in the liquid crystal lens element 100 also increases. On the other hand, if the effective voltage and driving frequency become too large, the wavefront aberration of light increases. As a result, the optical performance deteriorates. For this reason, the driving frequency of the AC voltage applied between the electrodes of the liquid crystal lens element 100 is fixed to the driving frequency (optimum driving frequency) at which the largest lens power is obtained with the wavefront aberration within the limit value in the allowable range. Control is performed such that the effective voltage of the alternating voltage applied between the electrodes of the liquid crystal lens element 100 is appropriately changed to obtain a desired lens power. However, if this optimum drive frequency is to be controlled, the circuit scale increases and the manufacturing cost tends to increase. Therefore, it is necessary to reduce the variation in the optimum driving frequency and set the driving frequency to a fixed value (for example, 1 kHz).

  Next, a method for keeping the optimum driving frequency of the AC voltage applied between the electrodes of the liquid crystal lens element 100 at a constant value will be considered. The capacitance between the plurality of first peripheral electrodes 11a to 11d and the first common electrode 31 is changed by changing the thickness of the first liquid crystal layer 70 of the liquid crystal lens element 100 according to the present embodiment. The change of the optimal driving frequency was measured. At this time, the plurality of first peripheral electrodes 11a to 11d were set to the same potential in order to simplify the measurement.

The measurement results are shown in FIG. FIG. 3 is a graph showing the relationship between the capacitance and the optimum drive frequency in the liquid crystal lens element. In FIG. 3, the horizontal axis represents capacitance × 10 ⁻¹¹ [F], and the vertical axis represents the optimum drive frequency [kHz].

As shown in FIG. 3, it was confirmed that the optimum driving frequency tends to increase as the capacitance value increases. Therefore, in order to keep the optimum driving frequency of the AC voltage applied between the electrodes of the liquid crystal lens element 100 at a constant value, the static between the plurality of first peripheral electrodes 11a to 11d and the first common electrode 31 is maintained. It is necessary to keep the electric capacity uniform. That is, it is necessary to minimize the variation in electrostatic capacitance between the plurality of first peripheral electrodes 11 a to 11 d and the first common electrode 31. Here, the capacitance C between electrodes arranged in parallel is equal to the electrode area S, the vacuum dielectric constant ε ₀ , the dielectric constant ε _{r of} the dielectric filled between the electrodes, the electrode If the distance between them is d, the capacitance C is expressed by the following formula (1).
C = ε ₀ × ε _r × S / d Formula (1)
From the relationship of the formula (1), in the liquid crystal lens element 100 according to the present embodiment, the respective areas and electrodes overlapping with the first common electrode of the plurality of first peripheral electrodes 11a to 11d when viewed from the optical axis direction. The capacitance can be kept uniform by equalizing the distance between the electrodes and the relative dielectric constant of the first liquid crystal layer 70 filled between the electrodes.

  As described above, the liquid crystal lens element 100 according to the present embodiment includes the first circular electrode 21 and the plurality of first peripheral electrodes 11a to 11d divided so as to be electrically insulated from each other on the same plane. I have. Thereby, the optical axis of the transmitted light can be tilted by giving a gradient to the voltages applied to the plurality of first peripheral electrodes 11a to 11d.

  Further, in the liquid crystal lens element 100 according to the present embodiment, the first liquid crystal layer 70 is thinner than the thickness of the first substrate 50 and the thickness of the second substrate 51, and the first circular electrode 21 and the plurality of first electrodes. Peripheral electrodes 11 a to 11 d are arranged between one main surface of the first substrate 50 and the first liquid crystal layer 70, and the first common electrode 31 is connected to the first substrate 50 of the second substrate 51. Arranged between the opposing main surface and the first liquid crystal layer 70. For this reason, the distance between the first circular electrode 21 and the first common electrode 31 and the distance between the plurality of first peripheral electrodes 11a to 11d and the first common electrode 31 approach each other. The potential drop of the electric field between them is minimized, and the voltage required for driving the liquid crystal lens element 100 can be lowered. As a result, it can be used for a camera module mounted on a mobile device driven by a battery.

  Further, in the liquid crystal lens element 100 according to the present embodiment, a plurality of end surface electrodes are provided on any one of the plurality of side surfaces of the element body 10 and are connected to the first circular electrode 21. 41, a second side electrode 42 connected to the first common electrode 31, and a plurality of third side electrodes 43a to 43d connected to the plurality of first peripheral electrodes 11a to 11d. Yes. As a result, fluctuations in the capacitive reactance between the electrodes can be suppressed, and variations in the optimum driving frequency can be reduced.

  In the present embodiment, the plurality of first peripheral electrodes 11a to 11d are radially divided so that the center angles of the dividing lines are substantially equal, and the first common electrode 31 has a substantially circular shape. For this reason, since the areas of the plurality of first peripheral electrodes 11a to 11d that are radially divided are substantially equal, the capacitance values that depend on the area of each electrode are substantially equal, and as a result, the optimum for each electrode is obtained. It is possible to reduce the variation in the driving frequency.

  In the present embodiment, the areas of the regions where the plurality of first peripheral electrodes 11a to 11d and the first common electrode 31 overlap when viewed from the optical axis direction are substantially equal, and the plurality of first peripheral electrodes 11a. All the overlapping regions of ˜11d and the first common electrode 31 overlap with the first liquid crystal layer 70. For this reason, the variation in the capacitance formed between the plurality of first peripheral electrodes 11a to 11d and the first common electrode 31 is suppressed, so that the variation in the optimum drive frequency is further reduced. be able to.

  In the present embodiment, the first circular electrode 21 includes a part of the electrode that extends to the periphery of the element body 10 and is connected to the first side electrode 41, and the first common electrode 31 includes a part of the electrode. The plurality of first peripheral electrodes 11a to 11d extend to the periphery of the element body 10 and extend to the periphery of the element body 10, and are connected to the second side electrode 42. A part of the first common electrode 31 and a part of an electrode connected to at least one of the electrodes 43a to 43d and extending to the periphery of the element body 10 of the first circular electrode 21 and the plurality of first peripheral electrodes 11a to 11d Some of the electrodes extending to the periphery of the main body 10 do not overlap each other when viewed from the optical axis direction. In this case, a short circuit between the electrodes is prevented, and electrical conduction between the electrodes and the side electrodes can be ensured.

(Modification of the first embodiment)
Next, with reference to FIG. 4, a configuration of a modification of the liquid crystal lens element 100 according to the first embodiment of the present invention will be described. FIG. 4A is a top view showing a configuration of a modification of the liquid crystal lens element according to the first embodiment of the present invention. FIG. 4B is a side view showing the configuration of a modification of the liquid crystal lens element according to the first embodiment of the present invention. However, in FIG. 4a, the second substrate 51 is omitted for convenience of explanation.

  The configuration of the first substrate 50, the second substrate 51, the first liquid crystal layer 70, the first circular electrode 21, the first common electrode 31, the first side electrode 41, and the second side electrode 42 is the first configuration. This is the same as the liquid crystal lens element 100 according to the embodiment. In the present modification, the number and arrangement of the first peripheral electrodes 111 and the third side electrodes 143 are different from those of the liquid crystal lens element 100 according to the first embodiment. Hereinafter, a description will be given focusing on differences from the first embodiment.

  Similar to the first peripheral electrode 11, the first peripheral electrode 111 is made of indium tin oxide and is provided on one main surface of the first substrate 50. Specifically, the first peripheral electrode 111 is disposed between one main surface of the first substrate 50 and the first liquid crystal layer 70. In this modification, as shown in FIG. 4a, the first peripheral electrodes 111 have circular holes, are electrically insulated from each other on the same plane, and the center angles of the dividing lines are substantially equal. The plurality of first peripheral electrodes 111a to 111h (eight in the present modification example) divided radially so as to be configured. In addition, when the 1st peripheral electrode 111 is comprised from the 8 1st peripheral electrodes 111a-111h like this modification, the center angle of a parting line will be 45 degrees. The first peripheral electrodes 111a and 111h extend toward the third side surface 10ya that is a part of the electrode that is the periphery of the element body 10. The first peripheral electrodes 111b and 111c extend toward the second side surface 10xb, which is a part of the periphery of the element body 10, of the electrodes. The first peripheral electrodes 111 d and 111 e extend toward the fourth side surface 10 yb that is a part of the electrode that is the periphery of the element body 10. The first peripheral electrodes 111f and 111g extend toward the first side surface 10xa, in which a part of the electrodes is the periphery of the element body 10.

  The 3rd side surface electrode 143 is arrange | positioned at each side surface of the element main body 10, as FIG. 4B shows. In the present modification, as shown in FIG. 4a, the third side electrodes 143a to 143h (eight in the present modification) are configured. The third side surface electrode 143a is disposed on the third side surface 10ya of the element body 10, and is a part of an electrode extending toward the third side surface 10ya that is the periphery of the element body 10 of the first peripheral electrode 111a. Connected with. The third side surface electrode 143b is disposed on the second side surface 10xb of the element body 10, and is a part of an electrode extending toward the second side surface 10xb that is the periphery of the element body 10 of the first peripheral electrode 111b. Connected with. The third side surface electrode 143c is disposed on the second side surface 10xb of the element body 10, and is a part of the electrode extending toward the second side surface 10xb that is the periphery of the element body 10 of the first peripheral electrode 111c. Connected with. The third side surface electrode 143d is disposed on the fourth side surface 10yb of the element body 10, and is a part of an electrode extending toward the fourth side surface 10yb that is the periphery of the element body 10 of the first peripheral electrode 111d. Connected with. The third side surface electrode 143e is disposed on the fourth side surface 10yb of the element body 10, and is a part of the electrode extending toward the fourth side surface 10yb that is the periphery of the element body 10 of the first peripheral electrode 111e. Connected with. The third side surface electrode 143f is disposed on the first side surface 10xa of the element body 10, and is a part of the electrode extending toward the first side surface 10xa that is the periphery of the element body 10 of the first peripheral electrode 111f. Connected with. The third side surface electrode 143g is disposed on the first side surface 10xa of the element body 10, and is a part of the electrode extending toward the first side surface 10xa that is the periphery of the element body 10 of the first peripheral electrode 111g. Connected with. The third side surface electrode 143h is disposed on the third side surface 10ya of the element body 10 and a part of the electrode extending toward the third side surface 10ya that is the periphery of the element body 10 of the first peripheral electrode 111h. Connected with. As described above, since the present modification includes a plurality of first peripheral electrodes 111 and third side electrodes 143 (eight in this modification), the optical axis of transmitted light is tilted with higher accuracy. be able to.

(Second Embodiment)
Next, the configuration of the liquid crystal lens element 200 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5a is a perspective view showing a configuration of a liquid crystal lens element according to the second embodiment of the present invention. FIG. 5 b is a top view showing the configuration of the liquid crystal lens element according to the second embodiment of the present invention. FIG. 5c is a cut end view taken along the line BB 'in FIG. 5b. FIG. 5d is a bottom view showing the configuration of the liquid crystal lens element according to the second embodiment of the present invention. FIG. 5e is a partially enlarged view showing a region A in the liquid crystal lens element shown in FIG. 5d in an enlarged manner. However, in FIG. 5b, the second substrate 51 is omitted for convenience of explanation. In FIG. 5d, the third substrate 52 is omitted for convenience of explanation.

  5a and 5b, the liquid crystal lens element 200 includes an element body 20, a first side electrode 41 provided on the outer surface of the element body 20, a second side electrode 42, and a plurality of Third side electrodes 243a, 243b, 43c, 43d are provided. The element body 20 includes a first substrate 50, a second substrate 51, a third substrate 52, a first liquid crystal layer 70, a second liquid crystal layer 270, a first peripheral electrode 211, and a first circular electrode 21. , The first common electrode 31, the second peripheral electrode 212, the second circular electrode 222, and the second common electrode 232. Here, the first substrate 50, the second substrate 51, the first liquid crystal layer 70, the first circular electrode 21, the first common electrode 31, the first side electrode 41, the second side electrode 42, The configuration of the third side electrodes 43c and 43d is the same as that of the liquid crystal lens element 100 according to the first embodiment. In the present embodiment, the arrangement of the first peripheral electrode 211 and the third side surface electrodes 243a and 243b, the third substrate 52, the second liquid crystal layer 270, the second peripheral electrode 212, the second circular electrode 222, The second common electrode 232 is different from the liquid crystal lens element 100 according to the first embodiment in that the second common electrode 232 is provided. Hereinafter, a description will be given focusing on differences from the first embodiment.

  The first peripheral electrode 211 is made of indium tin oxide like the first peripheral electrode 11 and is provided on one main surface of the first substrate 50 as shown in FIG. 5c. Yes. Specifically, the first peripheral electrode 211 is disposed between one main surface of the first substrate 50 and the first liquid crystal layer 70. In the present embodiment, as shown in FIG. 5b, the first peripheral electrodes 211 have circular holes, are electrically insulated from each other on the same plane, and the central angle of the dividing line is substantially the same. It consists of a plurality of first peripheral electrodes 211a to 211d (four in this embodiment) that are radially divided so as to be equal. When the first peripheral electrode 211 includes four first peripheral electrodes 211a to 211d, the center angle of the dividing line is 90 °. The first peripheral electrodes 211a and 211b extend toward the second side surface 10xb, which is a part of the electrode body, which is the periphery of the element body 20. The first peripheral electrodes 211 c and 211 d partially extend toward the first side surface 10 xa that is the periphery of the element body 20.

  The third side surface electrode 243a is disposed on the second side surface 10xb of the element body 20, and is a part of an electrode extending toward the second side surface 10xb that is the periphery of the element body 20 of the first peripheral electrode 211a. Connected with. The third side surface electrode 243b is disposed on the second side surface 10xb of the element body 20, and is a part of an electrode extending toward the second side surface 10xb that is the periphery of the element body 20 of the first peripheral electrode 111b. Connected with. In the present embodiment, the third side surface electrodes 243a and 243b, the first side surface electrode 41, and the second side surface electrode 42 are arranged on the second side surface 10xb of the element body 20 from the third side surface 10ya to the fourth side electrode. In the direction toward the side surface 10yb, the third side surface electrode 243b, the first side surface electrode 41, the second side surface electrode 42, and the third side surface electrode 243a are arranged at substantially equal intervals in this order. Similarly to the liquid crystal lens element 100 according to the first embodiment, the third side surface electrodes 43c and 43d are directed from the third side surface 10ya to the fourth side surface 10yb in the first side surface 10xa of the element body 20. In the direction, the third side electrode 43d and the third side electrode 43c are arranged in this order. That is, the first side surface electrode 41, the second side surface electrode 42, and the plurality of third side surface electrodes 243 a, 243 b, 43 c, 43 d are the first side surface 10 xa and the second side surface that are the opposite side surfaces of the element body 20. It is located on the side surface 10xb. The first side surface electrode 41, the second side surface electrode 42, and the plurality of third side surface electrodes 243a, 243b, 43c, 43d are formed on both main surfaces of the element body 20, as shown in FIGS. 5b and 5d. It extends continuously so as to reach (first main surface 10za and second main surface 10zb). Furthermore, the first side electrode 41, the second side electrode 42, and the plurality of third side electrodes 243a, 243b, 43c, 43d are electrically insulated from each other.

  The third substrate 52 is composed of a transparent glass substrate. As shown in FIG. 5 c, one main surface of the third substrate 52 is arranged to face the other main surface of the first substrate 50. The thickness of the third substrate 50 is about 150 μm.

  As shown in FIG. 5 c, the second liquid crystal layer 270 is configured by sealing a liquid crystal material between the first substrate 50 and the third substrate 52. The second liquid crystal layer 270 is thinner than the first substrate 50 and the third substrate 52 and has a thickness of 10 to 100 μm. Here, the second liquid crystal layer 270 is disposed in a region surrounded by a sealing material (not shown) between the first substrate 50 and the third substrate 52.

  The second peripheral electrode 212 is made of indium tin oxide, and is provided on the other main surface of the first substrate 50 as shown in FIG. 5c. Specifically, the second peripheral electrode 212 is disposed between the other main surface of the first substrate 50 and the second liquid crystal layer 270. In the present embodiment, as shown in FIG. 5d, the second peripheral electrodes 212 have circular holes, are electrically insulated from each other on the same plane, and the central angle of the dividing line is substantially the same. A plurality of second peripheral electrodes 212 a to 212 d (four in this embodiment) that are radially divided so as to be equal to each other, and a plurality of second peripheral electrodes provided at four corners on the other main surface of the first substrate 50. It consists of two peripheral electrodes 212e to 212h (four in this embodiment). The central angle of the dividing line of the four second peripheral electrodes 212a to 212d is 90 °.

  The second circular electrode 222 is made of indium tin oxide, and a plurality of second peripheral electrodes 212a to 212h are formed at the center on the other main surface of the first substrate 50, as shown in FIG. 5c. A main surface portion 222a disposed in an electrically insulated state, and a terminal connection portion 222b disposed at an end portion on the second side surface 10xb side on the other main surface of the first substrate 50. Has been. Specifically, the second circular electrode 222 is disposed between the other main surface of the first substrate 50 and the second liquid crystal layer 270. The main surface portion 222a of the second circular electrode 222 has a substantially circular shape with a diameter of about 2 mm, and coincides with the region of the liquid crystal lens opening 9 when viewed from the optical axis direction.

  The second common electrode 232 is made of indium tin oxide and is disposed on the main surface of the third substrate 52 facing the first substrate, as shown in FIG. 5c. Specifically, the second common electrode 232 is between the second liquid crystal layer 270 between the main surface of the third substrate 52 facing the first substrate and the second liquid crystal layer 270. The plurality of second peripheral electrodes 212a to 212d and the main surface portion 222a of the second circular electrode 222 are disposed so as to face each other when viewed from the optical axis direction. That is, the second liquid crystal layer 270 is disposed between the second circular electrode 222 and the plurality of second peripheral electrodes 212 a to 212 d and the second common electrode 232. The second common electrode 232 has a substantially circular shape, and has a region that overlaps the plurality of second peripheral electrodes 212a to 212d and the main surface portion 222a of the second circular electrode 222 when viewed from the optical axis direction. The areas of the overlapping regions of the second common electrode 232 and the plurality of second peripheral electrodes 212a to 212d when viewed from the optical axis direction are substantially equal, and the entire region overlaps the second liquid crystal layer 270. The second common electrode 232 is a second side surface in which a part of the electrode extends toward the second side surface 10 xb that is the periphery of the element body 20 and is disposed on the second side surface 10 xb of the element body 20. It is connected to the electrode 42.

  On the other main surface of the first substrate 50, as shown in FIG. 5d, a wiring pattern region 15 is provided along the outer periphery of the second peripheral electrodes 212a to 212d. That is, the wiring pattern region 15 is formed so as to be able to go around the outer periphery of the second peripheral electrodes 212a to 212d. Further, the wiring pattern region 15 is a region extending from the surrounding region toward the plurality of second peripheral electrodes 212e to 212h, the main surface portion 222a of the second circular electrode 222, and the terminal connection portion 222b of the second circular electrode 222. Have. In the wiring pattern region 15, a plurality of linear wirings 15a to 15e are arranged.

  The second peripheral electrode 212a is connected to the second peripheral electrode 212e through a linear wiring 15a disposed on the wiring pattern region 15. Specifically, as shown in FIG. 5d, the wiring 15a is formed by connecting the wiring pattern region 15 from the position of the end of the second peripheral electrode 212a on the third side surface 10ya side as viewed from the center of the element body 20. After turning around, it is provided so as to reach the position of the second peripheral electrode 212e through the wiring pattern region 15 extending to the second peripheral electrode 212e. The second peripheral electrode 212e is connected to the third side electrode 43c disposed on the first side surface 10xa of the element body 20. That is, the second peripheral electrodes 212a and 212e are connected to the third side surface electrode 43c. Therefore, the electrodes of the first peripheral electrode 11c and the second peripheral electrode 212a located at the diagonal of the element body 20 when viewed from the optical axis direction are connected to the same third side surface electrode 43c.

  The second peripheral electrode 212b is connected to the second peripheral electrode 212f via a linear wiring 15b disposed on the wiring pattern region 15. Specifically, as shown in FIG. 5d, the wiring 15b is formed by extending the wiring pattern region 15 from the end of the second peripheral electrode 212b on the second side face 10xb side as viewed from the center of the element body 20. After turning around, it is provided so as to reach the position of the second peripheral electrode 212f through the wiring pattern region 15 extending to the second peripheral electrode 212f. The second peripheral electrode 212f is connected to the third side surface electrode 43d disposed on the first side surface 10xa of the element body 20. That is, the second peripheral electrodes 212b and 212f are connected to the third side electrode 43d. Therefore, the electrodes of the first peripheral electrode 11d and the second peripheral electrode 212b that are located diagonally to the element body 20 when viewed from the optical axis direction are connected to the same third side surface electrode 43d.

  The second peripheral electrode 212c is connected to the second peripheral electrode 212g via a linear wiring 15c arranged on the wiring pattern region 15. Specifically, as shown in FIG. 5d, the wiring 15c has a wiring pattern region 15 extending from the end position on the fourth side surface 10yb side of the second peripheral electrode 212c as viewed from the center of the element body 20. After turning around, it is provided so as to reach the position of the second peripheral electrode 212g through the wiring pattern region 15 extending to the second peripheral electrode 212g. The second peripheral electrode 212g is connected to the third side surface electrode 243a disposed on the second side surface 10xb of the element body 20. That is, the second peripheral electrodes 212c and 212g are connected to the third side electrode 243a. Therefore, the electrodes of the first peripheral electrode 11a and the second peripheral electrode 212c located at the diagonal of the element body 20 as viewed from the optical axis direction are connected to the same third side electrode 243a.

  The second peripheral electrode 212d is connected to the second peripheral electrode 212h via a linear wiring 15d disposed on the wiring pattern region 15. Specifically, as shown in FIG. 5d, the wiring 15d has a wiring pattern region 15 extending 135 from the position of the end of the second peripheral electrode 212d on the first side face 10xa side as viewed from the center. After turning around, it is provided so as to reach the position of the second peripheral electrode 212h through the wiring pattern region 15 extending to the second peripheral electrode 212h. More specifically, as shown in FIG. 5e, the wiring 15d is drawn out to the wiring pattern 15 from the end of the second peripheral electrode 212d on the first side face 10xa side, and the wiring pattern area 15 has the wiring 15a. , 15e so as to circulate while being separated. The second peripheral electrode 212h is connected to the third side surface electrode 243b disposed on the second side surface 10xb of the element body 20. That is, the second peripheral electrodes 212d and 212h are connected to the third side electrode 243b. Therefore, the electrodes of the first peripheral electrode 11b and the second peripheral electrode 212h that are located diagonally to the element body 20 when viewed from the optical axis direction are connected to the same third side electrode 243b.

  As shown in FIG. 5d, the main surface portion 222a of the second circular electrode 222 is connected to the terminal connection portion 222b of the second circular electrode 222 via a linear wiring 15e disposed on the wiring pattern region 15. Has been. More specifically, as shown in FIG. 5e, the wiring 15e is connected to the first side surface 10xa between the second peripheral electrode 212c and the second peripheral electrode 212d from the main surface portion 222a of the second circular electrode 222. The wiring pattern 15 is provided so as to circulate while being separated from the wirings 15a and 15d. The terminal connection portion 222b of the second circular electrode 222 is connected to the first side electrode 41 disposed on the second side surface 10xb of the element body 20. That is, the second circular electrode 222 is connected to the first side electrode 41.

  As described above, in the liquid crystal lens element 200 according to the present embodiment, the first side electrode 41, the second side electrode 42, and the plurality of third side electrodes 243a, 243b, 43c, 43d It is located on two opposing side surfaces of the plurality of side surfaces, and extends continuously so as to reach both main surfaces of the element body 20. In this case, since it is possible to minimize the influence of variations in capacitance between the side electrodes, it is possible to further reduce the occurrence of variations in the optimum driving frequency for each electrode. Here, in the liquid crystal lens element 200, either one of the two main surfaces of the element body 20 is disposed to face the mounting surface of the circuit board, but each side electrode reaches the both main surfaces of the element body 20. If it is continuously extended, each side electrode and the circuit board can be directly connected to each other, so that a connection without using a lead wire with deformation of the shape can be realized, and the electrostatic connection between the electrodes can be realized. It is possible to further reduce the variation in capacitance and the occurrence of variation in the optimum driving frequency in each electrode.

  In the present embodiment, the element body 20 includes a plurality of divided circular electrodes 222 provided on the other main surface of the first substrate 50 so as to be electrically insulated from each other on the same plane. Second peripheral electrodes 212a to 212h, a third substrate 52, a second common electrode 232 provided on the main surface of the third substrate 52 facing the first substrate 50, and a second circular electrode 222 and a plurality of second peripheral electrodes 212a to 212d and a second liquid crystal layer 270 disposed between the second common electrode 232, and the second liquid crystal layer 270 includes the first liquid crystal layer 270 The second circular electrode 222 and the plurality of second peripheral electrodes 212a to 212h are thinner than the thickness of the substrate 50 and the third substrate 52, and the other main surface of the first substrate 50 and the second liquid crystal. The second common electrode 23 is disposed between the layer 270 and the second common electrode 23. Is disposed between the main surface of the third substrate 52 facing the first substrate 50 and the second liquid crystal layer 270, and the plurality of first peripheral electrodes 11a to 11d and the plurality of first peripheral electrodes 11a to 11d when viewed from the optical axis direction. The electrodes of the second peripheral electrodes 212a to 212d located at the diagonal of the element body 20 are connected to the same third side surface electrodes 243a, 243b, 43c, 43d. With such a configuration, one and a plurality of first peripheral electrodes 11a to 11d, which are located diagonally to the element body 20 connected to the same third side surface electrodes 243a, 243b, 43c, and 43d, are provided. Since the same potential voltage can be applied to one of the second peripheral electrodes 212a to 212d, the first liquid crystal layer 70 and the second liquid crystal layer can be formed without increasing the number of side electrodes. The optical axis of the transmitted light 270 can be tilted by the same amount in the same direction. Therefore, the optical performance as the liquid crystal lens element 200 can be further improved.

  Next, a configuration of a camera module 300 using the liquid crystal lens element 200 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 6 is a perspective view showing the configuration of the camera module according to the present embodiment.

  As shown in FIG. 6, the camera module 300 includes an electronic circuit board 314 on which a lens system 310, a driver IC 313, and an image sensor (not shown) are mounted.

  The lens system 310 includes a liquid crystal lens element 200, an optical lens system 311, and a spacer 312, and is mounted on an electronic circuit board 314. Here, the liquid crystal lens element 200 according to the second embodiment is used as the liquid crystal lens element.

  The optical lens system 311 is disposed so as to overlap the liquid crystal lens element 200 so as to face the liquid crystal lens opening 9 of the liquid crystal lens element 200. This optical lens system 311 is configured by combining a plurality of lenses formed using a transparent material typified by glass or polyolefin plastic, and emits or reflects from a subject existing at a long distance or a short distance. It has the function of capturing the emitted light and forming the image on the image sensor with high quality. In the present embodiment, the optical lens system 311 is overlapped and fixed using the thickness of the unpolished cylindrical surface (edge surface) around each lens. This eliminates the need for a cylindrical housing that is mounted to fix the lens system at a desired position with respect to the image sensor. As a result, the cost of the camera module 300 can be reduced.

  The spacer 312 is disposed so as to overlap the optical lens system 311. The spacer 312 is for increasing the distance between the optical lens system 311 and the image sensor with high accuracy, and has an annular shape of a substantially quadrangular prism with a hollow inside. The spacer 312 may be integrated with the optical lens system 311.

  In the present embodiment, each side electrode of the liquid crystal lens element 200 continuously extends along the optical lens system 311 and the spacer 312 and extends to the electronic circuit board 314 on which the lens system 310 is mounted. Therefore, the liquid crystal lens element 200 and the electronic circuit board 314 can be directly connected to each other, and an individual AC voltage can be applied to each side electrode.

  The driver IC 313 is mounted on the electronic circuit board 314. The driver IC 313 receives control information from an arithmetic processing unit (not shown) that controls the entire system via serial interface communication means (not shown), and based on the information, a plurality of first ICs of the liquid crystal lens element 200 are provided. Different effective values for the peripheral electrodes 11 a to 11 d, the first circular electrode 21, the first common electrode 31, the plurality of second peripheral electrodes 212 a to 212 d, the second circular electrode 222, and the second common electrode 232. The AC voltage is applied to drive the liquid crystal lens element 200. Note that the driver IC 313 has a structure in which the frequency of multiplication such as 1k, 2k, and 4k is switched in the element by a switch corresponding to the control signal. The driver IC 313 itself is driven by a DC power supply voltage that is used to drive an image sensor or the like.

  As described above, the camera module according to the present embodiment uses the liquid crystal lens element 200 as a part of the lens. Therefore, it is possible to provide the camera module 300 capable of tilting the optical axis of the transmitted light with a low driving voltage while reducing the occurrence of variations in the optimum driving frequency. The camera module 300 can automatically correct blurring and vibration caused by camera shake, which has been a problem in conventional compact cameras, by tilting the optical axis that enters the lens at high speed according to the movement of the image. It becomes.

  Hereinafter, the fact that the drive voltage can be reduced according to the present embodiment is specifically shown by examples and comparative examples. However, the present invention is not limited to these. In Examples and Comparative Examples, the lens power with respect to the voltage applied to each electrode was measured.

  In the example, the liquid crystal lens element 100 according to the first embodiment described above was used. In the comparative example, an insulating layer is disposed between the circular electrode (first electrode) and the plurality of peripheral electrodes (second electrode), and between the plurality of peripheral electrodes and the common electrode (third electrode). A liquid crystal lens element (structure disclosed in Patent Document 1) in which an insulating layer is disposed was used.

  Here, the same materials were used for the substrates, electrodes, and liquid crystal layers in the examples and comparative examples. In the liquid crystal lens element 100 of the example, the thickness of the first substrate 50 is 200 μm, the thickness of the second substrate 51 is 150 μm, and the thickness of the first liquid crystal layer 70 is 30 μm. That is, in the liquid crystal lens element 100 of the embodiment, the distance between the first circular electrode 21 and the first common electrode 31 and the distance between the plurality of first peripheral electrodes 11 a to 11 d and the first common electrode 31. The distance is 30 μm. Furthermore, in the liquid crystal lens element of the comparative example, the thickness of the first substrate (third insulating layer) is 200 μm, the thickness of the second substrate (fourth insulating layer) is 150 μm, and the liquid crystal layer (first liquid crystal layer) ) Of 60 μm, the thickness of the insulating layer (first insulating layer) between the circular electrode and the plurality of peripheral electrodes is 70 μm, and the insulating layer (second insulating layer) between the plurality of peripheral electrodes and the common electrode ) Was 700 μm. That is, in the liquid crystal lens element of the comparative example, the distance between the circular electrode and the common electrode is 830 μm, and the distance between the plurality of peripheral electrodes and the common electrode is 760 μm.

  For Examples and Comparative Examples, the lens power obtained when functioning as a convex lens and the lens power obtained when functioning as a concave lens were measured. The measurement results are shown in FIG.

  The graph shown in FIG. 7 is a graph showing the lens power with respect to the applied voltage of the example and the comparative example. In FIG. 7, the horizontal axis represents the voltage [Vrms] applied to the circular electrode and the plurality of peripheral electrodes, and the vertical axis represents the lens power [1 / m]. In FIG. 7, when the lens power shows a positive value, the lens functions as a convex lens, and when the lens power shows a negative value, the lens functions as a concave lens. Here, in FIG. 7, the voltage applied to the circular electrode and the plurality of peripheral electrodes is set equal to the initial value driven by the liquid crystal lens element, and then only the voltage applied to the circular electrode is decreased to function as a convex lens. The lens power in case was measured. In FIG. 7, the voltage applied to the circular electrode and the plurality of peripheral electrodes is set equal to the initial value driven by the liquid crystal lens element, and then only the voltage applied to the plurality of peripheral electrodes is decreased to function as a concave lens. The lens power was measured.

  First, consider the case where the liquid crystal lens element functions as a convex lens. As shown in FIG. 7, in order to drive the liquid crystal lens element 100 according to the embodiment as a convex lens, the initial value of the voltage applied to the first circular electrode 21 and the plurality of first peripheral electrodes 11a to 11d is 3. In contrast to 5 [Vrms], in order to drive the liquid crystal lens element in the comparative example as a convex lens, the initial value of the voltage applied to the circular electrode and the plurality of peripheral electrodes is 90.0 [Vrms]. It was confirmed that the example can be driven at a lower voltage than the comparative example. In addition, when the lens power of 6.8 [1 / m] is obtained when the lens is functioned as a convex lens, in the embodiment, the voltage applied to the first circular electrode 21 of the liquid crystal lens element 100 is 1.0 [Vrms. In contrast, in the comparative example, the voltage applied to the circular electrode of the liquid crystal lens element is 35.0 [Vrms]. In the example, the applied voltage is much lower than that in the comparative example. It was confirmed that the same lens power could be obtained.

  Next, a case where the liquid crystal lens element functions as a concave lens will be considered. As shown in FIG. 7, in order to drive the liquid crystal lens element 100 in the embodiment as a concave lens, the initial value of the voltage applied to the first circular electrode 21 and the plurality of first peripheral electrodes 11a to 11d is 2. In contrast to 5 [Vrms], in order to drive the liquid crystal lens element in the comparative example as a concave lens, the initial value of the voltage applied to the circular electrode and the plurality of peripheral electrodes is 100.0 [Vrms]. It was confirmed that the example can be driven at a lower voltage than the comparative example. In addition, when an attempt is made to obtain a lens power of −5.5 [1 / m] when functioning as a concave lens, in the embodiment, the voltage applied to the plurality of first peripheral electrodes 11 a to 11 d of the liquid crystal lens element 100 is In contrast to 0.8 [Vrms], the voltage applied to the plurality of peripheral electrodes of the liquid crystal lens element is 47.0 [Vrms] in the comparative example, and the embodiment is compared with the comparative example. It was confirmed that the same lens power could be obtained with a remarkably low applied voltage. From the above, the effectiveness of the present embodiment was confirmed.

  The present invention has been described based on the embodiments. It will be understood by those skilled in the art that the embodiments are illustrative, and that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. By the way. Accordingly, the description and drawings herein are to be regarded as illustrative rather than restrictive.

  The liquid crystal lens element according to the present invention is used by being mounted on a camera shake correction mechanism of a camera module for a portable device such as a mobile phone or other small camera.

  DESCRIPTION OF SYMBOLS 9 ... Liquid crystal lens opening part 10, 20, ... Element main body, 10xa ... 1st side surface, 10xb ... 2nd side surface, 10ya ... 3rd side surface, 10yb ... 4th side surface, 10za ... 1st main surface, 10zb: second main surface, 11, 111, 211 ... a plurality of first peripheral electrodes, 11a-11d, 111a-111h, 211a-211d ... first peripheral electrodes, 15 ... wiring pattern region, 15a-15e ... Wiring, 21 ... first circular electrode, 31 ... first common electrode, 41 ... first side electrode, 42 ... second side electrode, 43,143 ... a plurality of third side electrodes, 43a to 43d, 143a to 143h, 243a, 243b ... third side electrode, 50 ... first substrate, 51 ... second substrate, 52 ... third substrate, 70 ... first liquid crystal layer, 80 ... thin film layer, 100, 200 ... Liquid crystal lens element, 212 ... Plural Second peripheral electrode, 212a to 212h, second peripheral electrode, 222, second circular electrode, 222a, main surface portion of second circular electrode, 222b, terminal connection portion of second circular electrode, 232, second Two common electrodes, 270 ... second liquid crystal layer, 300 ... camera module, 310 ... lens system, 311 ... optical lens system, 312 ... spacer, 313 ... driver IC, 314 ... electronic circuit board.

Claims (7)

A first substrate, a second substrate, and a first circular electrode provided on one main surface of the first substrate, and a plurality of portions divided so as to be electrically insulated from each other on the same plane A first peripheral electrode; a first common electrode provided on a main surface of the second substrate facing the first substrate; the first circular electrode; and the plurality of first peripheral electrodes; A device main body having a first liquid crystal layer disposed between the first common electrode and the first common electrode;
A plurality of side electrodes provided on the outer surface of the element body,
The element body has, as the outer surface, two main surfaces facing each other, and a plurality of side surfaces connecting the two main surfaces,
The plurality of end surface electrodes are provided on any one of the plurality of side surfaces of the element body, and are connected to the first side electrode connected to the first circular electrode and the first common electrode. A second side surface electrode, and a plurality of third side surface electrodes connected to the plurality of first peripheral electrodes,
The first liquid crystal layer is thinner than the thickness of the first substrate and the thickness of the second substrate,
The first circular electrode and the plurality of first peripheral electrodes are disposed between one main surface of the first substrate and the first liquid crystal layer,
The liquid crystal lens element, wherein the first common electrode is disposed between a main surface of the second substrate facing the first substrate and the first liquid crystal layer.   The plurality of first peripheral electrodes are radially divided so that the center angles of the dividing lines are substantially equal, and the first common electrode has a substantially circular shape. The liquid crystal lens element described.   The areas of the regions where the plurality of first peripheral electrodes and the first common electrode overlap each other when viewed from the optical axis direction are substantially equal, and the plurality of first peripheral electrodes and the first common electrode 3. The liquid crystal lens element according to claim 2, wherein the entire overlapping region overlaps with the first liquid crystal layer. 4. The first circular electrode has a part of the electrode extending to the periphery of the element body and connected to the first side electrode,
The first common electrode has a part of the electrode extending to the periphery of the element body and connected to the second side electrode,
Each of the plurality of first peripheral electrodes is connected to at least one of the plurality of third side electrodes by extending a part of the electrode to the periphery of the element body;
A portion of the first circular electrode and the plurality of first peripheral electrodes that extend around the periphery of the element body and a portion of the first common electrode that extends around the periphery of the element body have an optical axis The liquid crystal lens element according to claim 1, wherein the liquid crystal lens elements do not overlap each other when viewed from a direction.   The first side electrode, the second side electrode, and the plurality of third side electrodes are located on two opposing side surfaces of the plurality of side surfaces of the element body, The liquid crystal lens element according to claim 1, wherein the liquid crystal lens element extends continuously so as to reach the surface. The element body includes a second circular electrode provided on the other main surface of the first substrate, a plurality of second peripheral electrodes divided so as to be electrically insulated from each other on the same plane, A third substrate; a second common electrode provided on a main surface of the third substrate facing the first substrate; the second circular electrode; and the plurality of second peripheral electrodes; A second liquid crystal layer disposed between the second common electrode and the second common electrode,
The second liquid crystal layer is thinner than the thickness of the first substrate and the thickness of the third substrate,
The second circular electrode and the plurality of second peripheral electrodes are disposed between the other main surface of the first substrate and the second liquid crystal layer,
The second common electrode is disposed between a main surface of the third substrate facing the first substrate and the second liquid crystal layer,
Electrodes located at the diagonal of the element body of the plurality of first peripheral electrodes and the plurality of second peripheral electrodes as viewed from the optical axis direction are connected to the same third side electrode. The liquid crystal lens element according to claim 5.   A camera module comprising the liquid crystal lens element according to claim 1 as a part of a lens.

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