JP4917282B2 - Liquid crystal optical element, camera using the same, and optical pickup device - Google Patents

Description

  The present invention relates to a liquid crystal optical element used for a variable focus lens of a digital camera, an aberration correction optical element for performing aberration correction when information recording or information reproduction is performed on an information recording medium such as an optical disk, and the liquid crystal optical element. The present invention relates to a camera using a lens as a lens, and an optical pickup device using the liquid crystal optical element.

  FIG. 6 shows a liquid crystal optical element conventionally used for an aberration correction optical element for correcting aberration when information recording or information reproduction is performed on an information recording medium such as a variable focus lens of a digital camera or an optical disk. It has been known.

  6A and 6B are diagrams showing main electrodes of the liquid crystal optical element. FIG. 6A is a plan view and FIG. 6B is a cross-sectional view. The liquid crystal layer 11 is sandwiched between the upper glass 12 and the lower glass 10, the entire surface electrode 132 is provided on the upper glass 12, and a plurality of concentric transparent electrodes 120, 122, 124 are provided on the lower glass 10. In this liquid crystal optical element, the liquid crystal optical element is used as a variable focus lens or an aberration correction optical element by changing the applied voltage to the concentric transparent electrode group to change the optical refractive index of the portion of the liquid crystal layer 11. ing.

JP 2001-176108 A

  However, in the above-described liquid crystal optical element, the concentric segment electrodes 120, 122, and 124 shown in FIG. 6A are configured by a single transparent electrode, and therefore the gaps 126 and 128 are provided between the concentric segment electrodes. In addition, it is necessary to pull out the wiring group 130 for connection with the drive unit to the glass end. For this reason, in the portions corresponding to the gaps 126 and 128 and the connecting wiring group 130, image distortion occurs when used as a camera lens, and information due to failure in aberration correction when used as an aberration correction optical element. Recording or playback errors may occur. Such a problem becomes more serious due to an increase in the number of pixels of a digital camera and an increase in the density of an information recording medium.

  Therefore, in the liquid crystal optical element for correcting aberration, two layers of concentric segment electrode side transparent electrodes are provided, one of the two layers forms a concentric segment electrode, and the other one layer forms the concentric circle. The gap between the concentric segment electrodes shown in FIG. 6 is obtained by providing an electrode that complements the gap between the segment electrode segments and applying the same drive voltage as one of the concentric segment electrodes adjacent in plan view. There is a technique for improving the accuracy of aberration correction at 126 and 128 (see, for example, Patent Document 1).

  However, even with this proposal, there remains a problem that aberration correction is impossible and distortion of the image occurs in the connection wiring group 130 shown in FIG. 6, and the aberration correction optical element for high-density information recording medium, digital camera However, the lens did not exhibit sufficient characteristics.

  The present invention has been made in view of the above-described problems of the prior art, eliminates image distortion when used as a variable focus type liquid crystal lens, and improves aberration correction accuracy when used as an aberration correction. It is an object of the present invention to provide a liquid crystal optical element that can be used, a camera using the same, and an optical pickup device.

The present invention relates to first and second transparent substrates arranged opposite to each other, a plurality of segment electrodes arranged on the first transparent substrate and arranged concentrically, and a liquid crystal layer sandwiched between the first and second transparent substrates A plurality of wiring electrodes formed between the segment electrodes and the first transparent substrate and electrically connected to each of the segment electrodes, and a wiring corresponding to each of the segment electrodes The adjacent segment electrodes have different height positions from the first transparent substrate, and are located on the first transparent substrate side among the adjacent segment electrodes. When viewed from the opposing direction of the first and second transparent substrates, the segment electrode has a recess formed in a part of its edge so as to avoid an electrical short circuit with the contact portion of the adjacent segment electrode , Side by side Between two concentric segment electrodes and is characterized in that a segment electrodes so that there is no planar gap than the gap to prevent a short circuit between the recess and the contact portion.

  The liquid crystal optical element of the present invention includes a first transparent electrode layer on one of the first and second transparent substrates, and a second transparent electrode layer on the first transparent electrode layer. The third transparent electrode layer is provided on the second transparent electrode layer, and one of the adjacent concentric segment electrodes is used as the second transparent electrode layer, and the other is used as the third transparent electrode layer. Further, the wiring electrode is provided in the first transparent electrode layer portion, and electrical connection is established by the corresponding concentric segment electrode and the contact portion.

  The liquid crystal optical element of the present invention is characterized in that the contact portions are randomly arranged in a plane.

The liquid crystal optical element of the present invention is characterized in that at least one of the first and second transparent substrates has a substantially circular shape.

  The camera of the present invention is characterized by using the liquid crystal optical element as a lens.

  The optical pickup device of the present invention is characterized by using the liquid crystal optical element.

  According to the present invention, it is possible to eliminate image distortion and aberration correction error caused by gaps between concentric segment electrodes and wiring portions, and when using a liquid crystal lens and a blue laser in a zoom multi-pixel digital camera. It is possible to achieve a quality of a practical level for the first time with an optical pickup device for a high-density storage medium.

[Example 1]
1 to 3 are views showing a first embodiment of the liquid crystal optical element of the present invention. FIG. 1 is a diagram showing an outline of a liquid crystal optical element according to the present invention. FIG. 1 (a) is a plan view of electrodes on a larger transparent substrate constituting the liquid crystal optical element, and FIG. 1 (b) is a smaller transparent figure. The top view of the electrode on a board | substrate and FIG.1 (c) have shown sectional drawing.

In FIG. 1A, on the larger transparent substrate 10 constituting the liquid crystal optical element, as shown in the figure, ring-shaped concentric segment electrodes 14, 16, 18, 20, 22 and the concentric segment electrode group. Wiring electrodes 24, 26, 28, 30, and 32 that provide drive signals are formed. Each concentric segment electrode and each wiring electrode are connected to each other by a contact portion described later. The concentric segment electrodes 14, 16, 18, 20, and 22 are arranged without a gap when viewed from the opposing direction of the transparent substrates 10 and 12. Further, a common terminal electrode 13 for applying a drive signal to the electrode on the smaller transparent substrate 12 is also formed. Furthermore, concavities 15 and 17 are formed in the concentric segment electrodes 16 and 20.

  In FIG. 1B, a transparent electrode is formed on the entire surface of the smaller transparent substrate 12 constituting the liquid crystal optical element as shown in the figure, and although not shown, it is shown in FIG. A drive signal is given from the common terminal electrode 13 through a seal portion described later.

  FIG. 1C is a cross-sectional view of the liquid crystal optical element according to the present invention. A full transparent electrode 34 is formed on the smaller upper transparent substrate 12, and the first lower transparent substrate 10 has a first transparent electrode 34 formed thereon. A transparent electrode layer 42, a second transparent electrode layer 40 above the first transparent electrode layer 42, and a third transparent electrode layer 38 above the second transparent electrode layer 40 are formed. . A first insulating layer 44 is provided between the first transparent electrode layer 42 and the second transparent electrode layer 40, and between the second transparent electrode layer 40 and the third transparent electrode layer 38. A second insulating layer 46 is provided. Each of these layers is a substantially parallel plane.

  The upper transparent substrate 12 and the lower transparent substrate 10 provided with the transparent electrode layer are bonded by a seal portion 36, and the liquid crystal layer 11 is held in the formed space.

  The third transparent electrode layer 38 includes, for example, odd-numbered electrode groups of concentric segment electrode groups 14, 16, 18, 20, and 22, and the second transparent electrode layer 40 includes, for example, concentric segment electrode groups 14 16, 16, 18, 20, and 22, the wiring electrode groups 24, 26, 28, 30, and 32 are arranged on the third transparent electrode layer 38 and the third transparent electrode layer 38. Each concentric segment electrode can be arranged so as to remove the gap between the segment electrodes, and the influence of the wiring electrode group can also be removed.

  The concavities 15 and 17 on the concentric segment electrodes 16 and 20 are provided in order to avoid an electrical short circuit at the contact portion. By providing such a concavity, the diameter of the contact portion is a concentric segment. Even if it is larger than the width of the electrode, it can be configured such that the entire surface of the liquid crystal optical element is filled with a doughnut-shaped electrode of approximately 360 degrees in a plan view (when viewed from the opposing direction of the transparent substrates 10 and 12). Therefore, the entire liquid crystal layer 11 is controlled by the applied voltage applied from the concentric segment electrodes 14, 16, 18, 20, 22. The recesses 15 and 17 will be described in detail with reference to FIG.

  Therefore, when used as a camera lens, image distortion (asymmetry) can be removed, and when used as an aberration correction optical element, the possibility of information recording or reproduction errors due to aberration correction failure can be eliminated.

  The number of concentric segment electrodes may be set in accordance with desired characteristics required for the lens and required characteristics of the aberration correction element.

FIG. 2 shows an example in which the electrodes on the lower transparent substrate 10 are shown for each transparent electrode layer 38, 40, 42.
2A is an electrode formed on the third transparent electrode layer 38, FIG. 2B is an electrode formed on the second transparent electrode layer 40, and FIG. 2C is a first transparent electrode layer. The electrode formed in 42 is shown.

  FIG. 2A is an electrode diagram of the third transparent electrode layer 38, and the electrode patterns of the odd-numbered electrode groups 14, 18, 22 among the concentric segment electrode groups 14, 16, 18, 20, 22 are formed. Has been.

FIG. 2B is an electrode diagram of the second transparent electrode layer 40, and concentric segment electrode groups 14, 1.
An electrode pattern having concave portions of even-numbered electrode groups 16 and 20 among 6, 18, 20, and 22 is formed. Here, the concentric segment electrodes 16 and 20 formed on the second transparent electrode layer 40 are segment electrodes positioned on the substrate side.

  One of the concentric segment electrodes adjacent to each other as described above is provided in the second transparent electrode layer portion 40, and the other is provided in the third transparent electrode layer portion 38.

  FIG. 2C is an electrode diagram of the first transparent electrode layer 42 in which electrode patterns of wiring electrode groups 24, 26, 28, 30, 32 are formed. As is apparent from the drawing, the wiring electrodes 24, 26, 28, 30, and 32 are provided corresponding to the concentric segment electrodes 14, 16, 18, 20, and 22, respectively. Further, a common terminal electrode 13 is provided for connection to the entire transparent electrode of the smaller transparent substrate shown in FIG.

  In this way, the odd-numbered electrode group among the concentric segment electrode groups by layer, the even-numbered electrode group among the concentric segment electrode groups, the wiring electrode group, and the segment electrode located on the substrate side Since the concave portion was provided to avoid the contact portion of the segment electrode on the liquid crystal layer side, the entire surface of the liquid crystal optical element was filled with almost 360-degree donut-shaped electrodes in a plan view without causing an electrical short circuit between the electrodes. We were able to.

  FIG. 3 is an enlarged view of an electrode portion of the liquid crystal optical element according to the present invention. FIG. 3A is a diagram showing the concentric segment electrode in FIG. 1A, and FIG. 3B is a diagram further enlarging the vicinity of the contact portion 21 shown in FIG. 3A. .

  In FIG. 3A, concentric segment electrodes 14, 18, and 22 are electrodes disposed on the third transparent electrode layer 38 shown by 38 in FIG. 1, and concentric segment electrodes 16 and 20 are those shown in FIG. The concentric segment electrode is connected to the wiring electrode arranged in the first transparent electrode layer 42 shown in FIG. 1 by the contact portion. There is a need. Conventionally, there was no problem even if the number of concentric segment electrodes was small, so the width of the concentric segment electrodes could be made larger than the diameter of the contact portion. As a result, it is necessary to increase the number of concentric electrodes, and as a result, the diameter of the contact portion exceeds the width of the concentric segment electrodes.

  In FIG. 3 (a), 19 and 21 indicate the sizes of the contact portions between the concentric segment electrodes 18 and 22 and the wiring electrodes, respectively. The sizes of the contact portions 19 and 21 indicate the reliability of electrical connection. It is difficult to reduce the size to ensure

  The contact portions connected to the concentric segment electrodes 16 and 20 arranged in the third transparent electrode layer 38 and the wiring electrodes arranged in the first transparent electrode layer 42 need to pass through the second transparent electrode layer 40. Therefore, if the concentric segment electrodes 14, 16, 18, 20, and 22 are arranged without gaps in a plane, they are electrically short-circuited at the contact portion, and the concentric segment electrodes are approximately 360 degrees in a plane. It has become impossible to fill the entire surface of the liquid crystal optical element with a donut-shaped electrode.

  FIG. 3B is an enlarged view of the periphery of the contact portion 21 shown in FIG. 3A. The concentric segment electrode 16 is provided with a recess 17 to avoid the concentric segment electrode 18 contact portion. . On the other hand, the concentric segment electrode 18 has a convex portion 25 due to the contact portion and a gap 23 for preventing a short circuit with the contact portion.

As described above, in the present invention, among the concentric segment electrodes adjacent to each other, the segment electrode located on the substrate side is formed with a recess at a part of the edge thereof, and therefore other than the gaps 23 in part around the contact part. The portion can be configured to fill the entire surface of the liquid crystal optical element with a 360-degree donut-shaped electrode.

Therefore, when used as a camera lens, image distortion (asymmetry) can be removed, and when used as an aberration correction optical element, the possibility of information recording or reproduction errors due to aberration correction failure can be eliminated.
[Example 2]

  FIG. 4 is a plan view showing a second embodiment of the liquid crystal optical element according to the present invention. FIG. 4 is a diagram showing the arrangement of the contact portions. The contact portions 100, 98, 104, 102, and 96 have concentric segment electrodes 14, 16, 18, 20, and 22 and wiring electrodes 24, 26, 28, and 30, respectively. , 32 is shown.

  As is clear from FIG. 4, the contact portions are randomly arranged in a plan view. In the contact portion, there is a gap 23 shown in FIG. 3B, and the gap 23 affects the optical characteristics of the liquid crystal layer, so that the contact portion has a specific shape such as a straight line or a circle. If it is disposed in the position, particularly when used as a camera lens, it is recognized as an image disturbance.

When the contact portions are randomly arranged in a planar manner as in the present invention, the disturbance of the image is not recognized and the effect is great.
[Example 3]

  FIG. 5 is a plan view showing a third embodiment of the liquid crystal optical element according to the present invention. FIG. 5 is a plan view showing the outer shape of the liquid crystal optical element according to the present invention. The smaller transparent substrate remains a quadrangle, while the larger transparent substrate is substantially circular.

A zoom digital camera also has a cylindrical lens barrel, and it is important and difficult to make it easy to store the components that can be stored in the lens barrel and to match the optical axes. For this reason, it is very effective for the liquid crystal optical element to have a substantially circular outer shape.
Since the liquid crystal optical element only needs to be substantially circular, for example, a polygon having five or more corners is also included in the concept of “substantially circular”.

  In the embodiment shown in FIG. 5, the example in which the smaller transparent substrate is used in the form of a square is shown. However, it is of course more effective if the smaller transparent substrate is also formed in a substantially circular shape.

  Although the camera according to the present invention is not shown in the drawing, the liquid crystal optical element according to the present invention is used, so that an image without distortion can be taken. , Small size, light weight and low price.

  Furthermore, although the optical pickup device according to the present invention is not shown in the drawing, since the liquid crystal optical element according to the present invention is used, an aberration correction error can be eliminated, and an optical pickup of a high-density storage medium using a blue laser. As a device, it can be of a practical level.

It is a figure which shows the outline | summary of the 1st Example of the liquid crystal optical element by this invention. FIG. 5 is a partial view of the first embodiment of the liquid crystal optical element according to the present invention, showing the electrodes on the lower transparent substrate for each transparent electrode layer. It is an enlarged view of the electrode part of the liquid crystal optical element by this invention. It is a top view which shows the 2nd Example of the liquid crystal optical element by this invention. It is a top view which shows the 3rd Example of the liquid crystal optical element by this invention. It is a figure which shows the conventional liquid crystal optical element.

Explanation of symbols

14, 16, 18, 20, 22 Concentric segment electrodes 10, 12 Transparent substrate 11 Liquid crystal layer 24, 26, 28, 30, 32 Wiring electrodes 19, 21, 96, 98, 100, 102, 104 Contact portion 15, 17 Concave portion 42 First transparent electrode layer 40 Second transparent electrode layer 38 Third transparent electrode layer

Claims (6)

First and second transparent substrates arranged opposite to each other, a plurality of segment electrodes provided on the first transparent substrate and arranged concentrically, a liquid crystal layer sandwiched between the first and second transparent substrates, In a liquid crystal optical element having
A plurality of wiring electrodes formed between the segment electrode and the first transparent substrate and electrically connected to each of the segment electrodes;
The segment electrodes, and contact portions connected to the wiring electrodes corresponding to the segment electrodes,
The adjacent segment electrodes have different height positions from the first transparent substrate,
Of the adjacent segment electrodes, the segment electrode located on the first transparent substrate side is in contact with the contact portion of the adjacent segment electrode when viewed from the opposing direction of the first and second transparent substrates . In order to avoid an electrical short circuit , a recess is formed on a part of its edge ,
The liquid crystal optical system, wherein the segment electrode is disposed between the two adjacent concentric segment electrodes so that there is no planar gap other than a gap for preventing a short circuit between the concave portion and the contact portion. element. A first transparent electrode layer on one of the first and second transparent substrates, a second transparent electrode layer on top of the first transparent electrode layer, and the second transparent electrode layer A third transparent electrode layer is provided on the top of
One of the concentric segment electrodes adjacent to each other is provided in the second transparent electrode layer portion, and the other is provided in the third transparent electrode layer portion,
2. The liquid crystal optical element according to claim 1 , further comprising a wiring electrode provided on the first transparent electrode layer portion and electrically connected by the corresponding concentric segment electrode and the contact portion. The liquid crystal optical element according to one of claims 1-2, characterized in that arranged at random in a planar manner to the contact portion. The liquid crystal optical element according to one of claims 1 to 3, characterized in that at least one of said first and second transparent substrates was approximately circular. Camera using the lens of the liquid crystal optical element according to one of claims 1-4. Optical pickup device using a liquid crystal optical element according to one of claims 1-4.

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