JP2006313238A - Light deflector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To deflect light in a two dimensional direction in a light deflector utilizing a liquid crystal. <P>SOLUTION: A liquid crystal layer 3 is disposed between a first transparent substrate 4a on which a first transparent electrode 1a is formed, and a second transparent substrate 4b on which a second transparent electrode 1b is formed via a pair of facing alignment films 2a, 2b. Different voltages are applied to terminals 11a, 11b formed at facing side ends of the first transparent electrode by a first voltage application means 5. Different voltages are applied to terminals 12a, 12b formed at facing side ends of the second transparent electrode 1b in the direction perpendicular to the direction between the terminals 11a, 11b by a second voltage application means 6. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an optical deflecting device having a liquid crystal layer, and more particularly to an optical deflecting device that deflects light by applying a voltage to the liquid crystal layer.

  Conventionally, an optical deflecting device used in various apparatuses deflects light by mechanical movement such as a polygon mirror, a hologram scanner, and a vibrating mirror. An apparatus that deflects light by such a mechanical movement has a problem that a mechanism is complicated, an assembling work is difficult, and power consumption is large.

Therefore, various types of optical deflecting devices using liquid crystals that can deflect light without using such mechanical movement have been proposed (for example, Patent Document 1).
Japanese Patent Laid-Open No. 63-240534 (Claims, page 2, FIGS. 1 to 3)

  However, the proposed light deflecting device can deflect light only in a one-dimensional direction, and its application is limited.

  The present invention has been made in view of such conventional problems, and an object of the present invention is to enable light to be deflected in a two-dimensional direction in an optical deflecting device using liquid crystal.

  An optical deflecting device according to the present invention that achieves the above-described object provides a pair of opposing orientations between a first transparent substrate on which a first transparent electrode is formed and a second transparent substrate on which a second transparent electrode is formed. An optical deflecting device in which a liquid crystal layer is sandwiched through a film, the first voltage applying means for applying a voltage between terminals formed on opposite side edges of the first transparent electrode, and formed on the first transparent electrode And a second voltage applying means for applying a voltage between terminals formed on opposite side ends of the second transparent electrode in a direction orthogonal to the direction between the formed terminals.

  According to another aspect of the present invention, there is provided an optical deflecting device comprising a pair of opposing alignment films between a first transparent substrate on which a first transparent electrode is formed and a third substrate on which a second transparent electrode is formed. An optical deflecting device in which a liquid crystal layer is sandwiched, wherein a reflection layer for reflecting light is formed between a second transparent electrode and a third substrate, and between terminals formed on opposite side edges of the first transparent electrode A voltage is applied between the first voltage applying means for applying a voltage to the terminal and the terminal formed on the opposite end of the second transparent electrode in the direction orthogonal to the direction between the terminals formed on the first transparent electrode. And a second voltage applying means.

  Here, from the viewpoint of always keeping the average refractive index of the entire liquid crystal layer constant, the first transparent electrode is set so that the effective voltage applied to a predetermined point of the first transparent electrode and the second transparent electrode is constant. It is preferable to control the voltage applied to the second transparent electrode.

  Further, from the viewpoint of increasing the light deflection in the two-dimensional direction, it is preferable to set the electric resistance values of the first transparent electrode and the second transparent electrode in the range of 100Ω to 1MΩ.

  In the optical deflecting device according to the present invention, the opposite side of the second transparent electrode between the terminals formed on the opposite side ends of the first transparent electrode and in the direction orthogonal to the direction between the terminals formed on the first transparent electrode. Since a voltage is applied between terminals formed at the ends, light can be deflected in a two-dimensional direction. As a result, the optical deflection apparatus of the present invention can be suitably used for an optical disc tracking mechanism or the like.

  In the optical deflecting device according to another aspect of the present invention, a reflection layer is further added to the configuration of the optical deflecting device according to the above invention so that the liquid crystal layer is transmitted twice, so that a larger optical deflection can be obtained. become.

  When the voltage applied to the first transparent electrode and the second transparent electrode is controlled so that the effective voltage applied to a predetermined point of the two transparent electrodes is constant, the average refractive index of the entire liquid crystal layer becomes constant, Light can be deflected without affecting the optical path length of the optical axis of the entire optical system.

  Hereinafter, the present invention will be described with reference to the drawings, but the present invention is not limited to these embodiments.

  FIG. 1 is a perspective view showing an example of a light deflection apparatus according to the present invention, and FIG. 2 is a schematic view of the light deflection apparatus shown in FIG. As can be understood from FIG. 2, in this optical deflecting device, the first transparent substrate 4a and the second transparent substrate 4b are disposed so as to face each other, and the first transparent substrate 4a and the second transparent substrate 4b are opposed to each other. The first transparent electrode 1a and the second transparent electrode 1b are respectively formed. The periphery is sealed with a sealing agent S between the first alignment film 2a formed on the first transparent electrode 1a and the second alignment film 2b formed on the second transparent electrode 1b. The liquid crystal layer 3 is formed by enclosing a liquid crystal agent in the space.

  FIG. 3 shows a plan view of the first transparent electrode 1a and the second transparent electrode 1b. As shown in FIG. 2A, terminals 11a and 11b are formed at the side edges of the first transparent electrode 1a in the vertical direction. Further, as shown in FIG. 5B, terminals 12a and 12b are formed at the lateral ends of the second transparent electrode 1b. In FIG. 3, the terminals are formed in the vertical direction in the first transparent electrode 1a and in the horizontal direction in the second transparent electrode 1b. However, the present invention is not limited to this, and the first transparent electrode 1a and the first transparent electrode 1b It suffices if the forming directions of the terminals of the two transparent electrodes 1b are orthogonal to each other.

  As the high electrical resistance first transparent electrode 1a and second transparent electrode 1b used in the present invention, for example, a zinc oxide film doped with one or more elements such as gallium, aluminum, silicon, yttrium, and indium; Examples thereof include a tin oxide film doped with one or more elements such as silicon, antimony, indium, and gallium; an undoped zinc oxide film, a tin oxide film, and an ITO film. Among these, a zinc oxide film doped with indium and a tin oxide film not doped are preferable. The electric resistance value of these electrode films is preferably in the range of 100Ω to 1MΩ.

As shown in FIG. 2, the first voltage applying means 5 is connected to the terminals 11a and 11b (shown in FIG. 3) of the first transparent electrode 1a, and the terminals 12a and 12b (shown in FIG. 3) of the second transparent electrode 1b. ) Is connected to the second voltage applying means 6. Here, for example, when light is deflected in the vertical direction, different voltages V ₁₁ and V ₁₂ are respectively applied to the terminals 11a and 11b of the first transparent electrode 1a by the first voltage applying means 5, as shown in FIG. Apply. Then, since the first transparent electrode 1a is a high-resistance film, a potential gradient that changes linearly from the terminal 11a to the terminal 11b is formed. On the other hand, the rising angle of the liquid crystal molecules increases as the potential difference increases. Since the refractive index with respect to the light beam (abnormal light) deflected along the major axis direction of the liquid crystal molecules decreases as the rising angle of the liquid crystal molecules increases, the potential gradient as described above is formed in the first transparent electrode 1a. Thus, the refractive index of the liquid crystal layer 3 is low at the top and high at the bottom. By forming such a refractive index distribution in the liquid crystal layer 3, the light incident horizontally on the liquid crystal layer 3 is deflected downward and emitted, and the same effect as the prism is achieved.

  Similarly, when the light is deflected in the left-right direction, different voltages may be applied to the terminals 12a and 12b of the second transparent electrode 1b by the second voltage applying means 6. Thus, the light can be deflected in a two-dimensional direction by applying different voltages to the terminals 11a and 11b and the terminals 12a and 12b by the first voltage applying means 5 and the second voltage applying means 6, respectively. It becomes like this.

Next, the voltage applied between the terminals will be specifically described. As shown in FIG. 5, the terminals 11a and 11b formed at the upper and lower ends of the first transparent electrode 1a have a wavelength and a reference voltage V ₂ (shown in FIG. 3) at the center position of the second transparent electrode 1b. Voltages V ₁₁ and V ₁₂ having the same phase and different amplitudes are applied. As a result, a potential gradient is formed in the direction between the terminals of the first transparent electrode 1a (vertical direction in FIG. 3), and as described above, the refractive index of the liquid crystal layer 3 changes in the vertical direction and deflects light in the vertical direction. To be able to. When the voltage applied to the terminals 11a and 11b is changed, that is, when the potential gradient between the terminals is changed, the potential V _{10 at the} center in the vertical direction (solid line in FIG. 5) is applied to both terminals 11a and 11b so as not to change. It is desirable to set the voltage to be used. The effect of this voltage setting will be described later.

The terminals 12a and 12b formed at the left and right ends of the second transparent electrode 1b have a constant potential V ₂₀ (see the solid line in FIG. 5 and FIG. 3B) at the center in the left-right direction as shown in FIG. In such a manner, voltages V ₂₁ and V _{22 that} are line symmetrical about the potential V ₂₀ are applied. As a result, a potential gradient is formed in the direction between the terminals of the second transparent electrode 1b (the left-right direction in FIG. 3), the refractive index of the liquid crystal layer 3 changes in the left-right direction, and light can be deflected in the left-right direction. become.

When the voltage as described above is applied to the first transparent electrode 1a and the second transparent electrode 1b, as shown in FIG. 7, the potential difference (V ₁ −V) between the center points of the first transparent electrode 1a and the second transparent electrode 1b. ₂ ) is always constant even when the applied voltage is changed. As a result, the average refractive index of the entire liquid crystal layer 3 can be made constant at all times, and light can be deflected without affecting the optical path length on the optical axis of the entire optical system in which the optical deflecting device of the present invention is used. To be able to.

  Next, an optical deflecting device according to another invention will be described. The optical deflecting device of the present invention differs from the optical deflecting device of the previous invention in that a reflective layer 7 is provided between the second transparent electrode 1b and the third substrate 4c. In other words, the point that the light transmitted through the liquid crystal layer 3 is reflected by the reflective layer 7 and is transmitted through the liquid crystal layer 3 again is different from the above-described optical deflecting device. Due to this difference, the third substrate 4c is used instead of the second transparent substrate 4b. That is, in the optical deflecting device of the present invention, a non-transparent substrate can be used as the substrate on which the second transparent electrode 1b is formed. Hereinafter, the optical deflection apparatus of the present invention will be described with reference to the drawings. However, the same members and parts as those of the optical deflection apparatus according to the above-described invention are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 8 is a schematic configuration diagram showing an example of an optical deflection apparatus according to the present invention. In the optical deflecting device of FIG. 8, the first transparent substrate 4a and the third substrate 4c are disposed so as to face each other. A first transparent electrode 1a is formed on the surface of the first transparent substrate 4a, and a first alignment film 2a is laminated thereon. On the other hand, the reflective layer 7 is formed on the surface of the third substrate 4c, and the second transparent electrode 1b and the second alignment film 2b are laminated on the reflective layer 7 in this order. And the liquid crystal agent is enclosed in the space sealed with the sealing agent S between the first transparent substrate 4a and the third substrate 4c, and the liquid crystal layer 3 is formed.

  When the same voltage as above is applied to the first transparent electrode 1a and the second transparent electrode 1b by the first voltage applying means 5 and the second voltage applying means 6, a refractive index distribution is formed in the vertical and horizontal directions of the liquid crystal layer 3. The light incident on the liquid crystal layer 3 is deflected in a two-dimensional direction. Then, the light emitted from the liquid crystal layer 3 is reflected by the reflection layer 7, enters the liquid crystal layer 3 again, and is deflected in a two-dimensional direction. As described above, in the optical deflecting device of the present invention, the light passes through the liquid crystal layer 3 twice, so that it is possible to obtain a deflection effect twice that of the above-described optical deflecting device, or the deflection effect is equivalent. If so, the thickness of the liquid crystal layer 3 can be reduced, and the responsiveness can be remarkably improved.

  The reflective layer 7 used in the present invention is not particularly limited as long as it reflects light, and examples thereof include those in which an insulating metal film is formed on the surface of the third substrate 4c.

It is a perspective view which shows an example of the optical deflection apparatus based on 1st invention. FIG. 2 is a schematic diagram of the light deflection apparatus in FIG. 1. It is a top view of the 1st transparent electrode and 2nd transparent electrode which are used with the optical deflection apparatus of FIG. It is a figure explaining an effect | action at the time of applying a voltage to a 1st transparent electrode. It is an example of a voltage waveform diagram applied between the terminals of the first transparent electrode. It is an example of a voltage waveform diagram applied between the terminals of the second transparent electrode. It is an example of a voltage waveform diagram applied between the center points of the first transparent electrode and the second transparent electrode. It is a schematic diagram which shows an example of the optical deflection apparatus based on 2nd invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a 1st transparent electrode 1b 2nd transparent electrode 2a 1st alignment film 2b 2nd alignment film 3 Liquid crystal layer 4a 1st transparent substrate 4b 2nd transparent substrate 4c 3rd substrate 5 1st voltage application means 6 2nd voltage application means 7 Reflective layer 11a, 11b terminal 12a, 12b terminal

Claims (4)

An optical deflecting device in which a liquid crystal layer is sandwiched between a first transparent substrate on which a first transparent electrode is formed and a second transparent substrate on which a second transparent electrode is formed via a pair of opposing alignment films. Because
First voltage applying means for applying a voltage between terminals formed on opposite side edges of the first transparent electrode, and the second transparent electrode facing each other in a direction orthogonal to the direction between the terminals formed on the first transparent electrode An optical deflecting device comprising: a second voltage applying means for applying a voltage between terminals formed at the side ends. An optical deflecting device in which a liquid crystal layer is sandwiched between a first transparent substrate on which a first transparent electrode is formed and a third substrate on which a second transparent electrode is formed via a pair of opposing alignment films. There,
A reflective layer for reflecting light is formed between the second transparent electrode and the third substrate;
First voltage applying means for applying a voltage between terminals formed on opposite side edges of the first transparent electrode, and the second transparent electrode facing each other in a direction orthogonal to the direction between the terminals formed on the first transparent electrode An optical deflecting device comprising: a second voltage applying means for applying a voltage between terminals formed at the side ends.   The voltage applied to the first transparent electrode and the second transparent electrode is controlled so that the effective voltage applied to a predetermined point of the first transparent electrode and the second transparent electrode is constant. Optical deflection device.   The optical deflection apparatus according to any one of claims 1 to 3, wherein the first transparent electrode and the second transparent electrode have an electric resistance value in a range of 100Ω to 1MΩ.

Images