JP2015225166A - Optical element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element that allows a moving or small detection object to be detected even when the detection object moves or is small by optimizing a shape of an electrode, and can sufficiently exert a function as the optical sensor.SOLUTION: An optical element 1 comprises: a first glass plate 3 that has a first electrode 2; a second glass plate 5 that has a plurality of second electrodes 4; and a liquid crystal layer 6 that lies between the first glass plate 3 and the second glass plate 5. The optical element 1 causes potential to generate between the first electrode 2 and the second electrode 4, and controls an orientation of a liquid crystal molecule. A gap area 4b present between respective inner side ends 4a in the plurality of second electrodes 4 is shaped into a non-circular form, and thereby light passing through the gap area 4b cannot be converged at a focus position. Thus, even when a detection object moves or is small, the optical element can accurately detect such the detection object, and a function as the optical element is sufficiently exerted.

Description

  The present invention relates to an optical element that can change the traveling direction of light with a simple structure.

  Optical elements utilizing the characteristics of liquid crystals continue to make remarkable progress as thin and light flat elements. In general, a liquid crystal called a nematic liquid crystal has fluidity like a liquid, and has a property that liquid crystal molecules are aligned in the direction of an electric field when a voltage is applied to the liquid crystal. Various voltage variable optical elements have been proposed by utilizing this property.

  As a flat plate type optical element using liquid crystal, for example, there is a liquid crystal lens disclosed in Patent Document 1 below. The liquid crystal lens includes a first substrate having a first electrode, a second substrate having a second electrode in which a circular hole is formed on a surface facing the first electrode, and the first substrate and the second substrate. And a liquid crystal layer accommodated opposite to the first electrode. The second electrode is divided into a plurality of portions in the radial direction of the holes formed in the second electrode. A third electrode is disposed on the opposite surface of the second substrate.

  In this liquid crystal lens, a voltage is applied to the second electrode, and another voltage independent of the voltage applied to the second electrode is applied to the third electrode, whereby the first electrode is applied to the third electrode. A potential difference different from the potential difference generated between the electrode and the second electrode is generated, thereby controlling the alignment of the liquid crystal molecules in the liquid crystal layer. That is, the focal length of the liquid crystal lens is changed by controlling the voltage applied to the third electrode. In addition, since the second electrode is divided into a plurality of portions in the radial direction of the hole, the focal position of the liquid crystal lens changes if the voltage applied to the second electrode is controlled. Therefore, the liquid crystal lens controls the movement of the focal position three-dimensionally by controlling the voltage applied to the second electrode and the third electrode, respectively.

JP 2006-91826 A

  By the way, in the liquid crystal lens of the above-mentioned patent document 1, it is possible to detect the detection target at the focal position with high sensitivity. In this case, it is possible to detect the detection target by moving the focal position by adjusting the voltage applied to the electrode and aligning the focal position with the detection target, but the detection target moves. When the detection object is small or the detection object is small, it is difficult to adjust the focus position to the detection object. For this reason, the liquid crystal lens of Patent Document 1 cannot sufficiently exhibit the function as an optical sensor, and it is substantially impossible to use this as an optical sensor.

  In the present invention, in view of the above circumstances, by optimizing the shape of the electrode, even when the detection target moves or even when the detection target is small, this can be detected appropriately. An object of the present invention is to provide an optical element that can sufficiently function as an optical sensor.

  This invention made | formed in order to solve the said subject is between the 1st glass substrate which has a 1st electrode, the 2nd glass substrate which has several 2nd electrode, and a 1st glass substrate and a 2nd glass substrate. An optical element that includes an intervening liquid crystal layer, generates a potential difference between the first electrode and the second electrode, and controls the orientation of liquid crystal molecules, and includes an inner end portion of each of the plurality of second electrodes. The gap region between them is characterized by a non-circular shape.

  According to such a configuration, by controlling the voltage applied to the second electrode, in the liquid crystal layer interposed between the first electrode and the second electrode according to the potential difference between the second electrodes. The orientation of the liquid crystal molecules can be locally controlled to change the traveling direction of light transmitted through the liquid crystal layer. In this case, the gap region formed by the inner ends of the plurality of second electrodes formed in the optical element is non-circular, so that the light transmitted through the liquid crystal layer is collected at the focal position. There is nothing. Therefore, even when the detection object moves or when the detection object is small, it can be detected appropriately. Therefore, the function as an optical sensor is sufficiently exhibited.

  In the above configuration, it is preferable that each inner end portion of the plurality of second electrodes is linear.

  In this way, the gap region can be easily and surely made non-circular.

  In this case, the gap region may have a polygonal shape.

  In this way, the degree of freedom of changing the traveling direction of the light transmitted through the liquid crystal layer is increased, and the traveling direction of the light can be freely changed.

  The number of the second electrodes is preferably 8 or less.

  In this way, it is possible to reliably prevent the gap region formed at the inner end portion of the gap between the plurality of second electrodes from being circular. That is, if the number exceeds eight, the gap region approaches a circular shape, and thus the above-described effect due to the non-circular gap region may not be sufficiently secured. However, if it is 8 or less, such a problem can be avoided reliably.

  Further, the gap region may be formed in a line shape.

  If it does in this way, the 2nd electrode can be constituted by two pieces, and the composition of the 2nd electrode can be simplified.

  In the above configuration, the gap region may be linear.

  In this way, the gap region can be formed very easily.

  As described above, according to the present invention, the gap region existing between the inner ends of the plurality of second electrodes is made noncircular, so that the light transmitted through the liquid crystal layer is condensed at the focal position. There is nothing to do. Therefore, even when the detection object moves or when the detection object is small, it can be appropriately detected, and the function as an optical sensor can be sufficiently exhibited.

FIG. 1A is a longitudinal front view of the optical element according to the first embodiment of the present invention, and FIG. 1B is a plan view of the optical element of FIG. It is a side view of the optical element of FIG. It is an optical element which concerns on 2nd embodiment of this invention, Comprising: It is a top view which shows the formation pattern of a 2nd electrode. It is an optical element which concerns on 3rd embodiment of this invention, Comprising: It is a top view which shows the formation pattern of a 2nd electrode. It is a vertical front view which shows the modification of the optical element which concerns on one Embodiment of this invention.

  Hereinafter, an optical element according to an embodiment of the present invention will be described with reference to the drawings.

  Fig.1 (a) has illustrated the longitudinal front view of the optical element 1 which concerns on 1st embodiment of this invention. As shown in the figure, the optical element 1 includes, as main components, a first glass substrate 3 having a first electrode 2, a second glass substrate 5 having a second electrode 4, a first glass substrate 3, and And a liquid crystal layer 6 that changes a traveling direction of light transmitted through the second glass substrate 5.

  A transparent first electrode 2 having translucency is formed on the upper surface of the first glass substrate 3, and a transparent second electrode 4 having translucency is formed on the lower surface of the second glass substrate 5. Has been. The first electrode 2 and the second electrode 4 are for applying a voltage to cause a potential difference in the liquid crystal layer 6 to align liquid crystal molecules. Due to the orientation of the liquid crystal molecules, the light L1 transmitted through the liquid crystal layer 6 is refracted. Examples of the constituent material of the first electrode 2 and the second electrode 4 include translucent conductive members such as indium tin oxide (hereinafter referred to as ITO), tin oxide, and zinc oxide.

  In addition, an alignment film (not shown) that aligns liquid crystal molecules in one direction is disposed on the surface of the first electrode 2 in contact with the liquid crystal layer 6, and a transparent surface is disposed on the surface of the second electrode 4 that faces the liquid crystal layer 6. An insulating layer 7 is arranged, and a high resistance film 8 is arranged inside the insulating layer 7. An alignment film (not shown) is also disposed on the surface of the insulating layer 7 in contact with the liquid crystal layer 6. The alignment film disposed on the first electrode 2 and the alignment film disposed on the insulating layer 7 are formed so that the alignment directions thereof are different when the liquid crystal molecules are aligned.

  Between the 1st electrode 2 and the insulating layer 7, the liquid crystal layer formation body 9 which forms the liquid crystal layer 6 of the upper and lower layers between the 1st glass substrate 3 and the 2nd glass substrate 5 is arrange | positioned. The liquid crystal layer forming body 9 incorporated in the optical element 1 of the present embodiment is formed in a state where three types of two transparent glass plates 9a and 9b are laminated. More specifically, the liquid crystal layer forming body 9 is composed of a perforated glass plate 9a in which a long hole-like (oval-shaped) through hole 9c is formed, and a partition glass plate 9b in which the through hole 9c is not formed. The two perforated glass plates 9a are joined to the upper and lower surfaces via the partition glass plate 9b, and two through holes 9c having the same shape and the same area are formed on the upper and lower surfaces of the partition glass plate 9b. It is arranged.

  By setting the liquid crystal layer forming body 9 in such a configuration, the first glass substrate 3 and the second glass substrate 5 are bonded together while maintaining a predetermined thickness, and the lower surface side of the partition glass plate 9b and the first glass substrate 9b. Spaces for sealing the liquid crystal are formed between the glass substrate 3 and the surface on which the first electrode 2 is formed and between the upper surface side of the partition glass plate 9 b and the insulating layer 7. By sealing the liquid crystal in these two spaces, two liquid crystal layers 6 are formed between the first glass substrate 3 and the second glass substrate 5.

  Moreover, aluminum etc. are vapor-deposited by sputtering on the joining surface with the liquid crystal layer formation body 9 in the 1st glass substrate 3 and the 2nd glass substrate 5, for example. Therefore, a voltage is applied to the first electrode 2 and the second electrode 4 under a predetermined condition and anodic bonding is performed, so that the first glass substrate 3 and the second glass substrate 5 are separated via the liquid crystal layer forming body 9. Are joined together.

  FIG. 1B is a plan view of the optical element 1 according to the first embodiment of the present invention. As shown in the figure, in the optical element 1, two second electrodes 4 are formed on a second glass substrate 5, and are arranged on the left and right sides, respectively. A gap region 4b existing between the inner end portions 4a of the second electrodes 4 has a non-circular shape. More specifically, the two second electrodes 4 are each rectangular and have the same area, and the inner end portions 4a of these electrodes are formed in a straight line and between the inner end portions 4a. The gap region 4b is formed in a line shape, particularly in a straight line shape. Further, the first electrode 2 and the two second electrodes 4 are slightly exposed from the second glass substrate 5, and by applying a voltage to this portion, the first electrode 2 and the second electrode 4 A potential difference occurs between them. In the optical element 1 according to this embodiment, the first electrode 2 functions as a ground.

  Next, the effect of changing the traveling direction of light using the optical element 1 having the above configuration will be described.

As shown in FIG. 1A, the first electrode 2 formed on the first glass substrate 3 is grounded, and the two second electrodes 4 on both the left and right sides of the second glass substrate 5 are respectively connected to the first glass substrate 3. Re voltage _V L, it is applied to _{V R.} In the figure, the voltage V _L is applied to the second electrode 4 on the left side, applying a voltage V _R to the second electrode 4 on the right side. The voltage V _L, is supplied from the V _R Wazorezo Re separate voltage supply unit.

Thus, between the first electrode 2 and the second electrode 4 on the left, along with the potential difference V _L occurs between the first electrode 2 and the right side of the second electrode 4, the potential difference V _R occurs. By controlling the potential differences V _L and V _R , the alignment of the liquid crystal molecules in the liquid crystal layer 6 with respect to the gap region 4b existing between the inner ends 4a of the second electrodes 4 becomes the potential differences V _L and V _R. It changes locally according to. Therefore, the light L1 which enters from the lower side of the optical element 1, when passing through the liquid crystal layer 6, the potential difference V _L, is refracted by the liquid crystal molecules oriented in accordance with the V _R.

At this time, the gap region 4b existing between the inner end portions 4a of the two second electrodes 4 formed on the second glass substrate 5 has a linear shape, and therefore light transmitted through the liquid crystal layer 6 (hereinafter referred to as refraction). The light L2) is not condensed at the focal position. That is, as shown in FIG. 2, the light L <b> 1 entering from the lower side of the optical element 1 toward the gap region 4 b passes through the liquid crystal layer 6, and the voltage difference V between the first electrode 2 and the second electrode 4. _L, refracted by the liquid crystal molecules oriented due to V _R, the refracted light is without condensed at the focal position, travels straight refracted direction. Further, the difference between the voltage V _L, V _R applied to the second electrode 4, it is possible to change the traveling direction of the refracted light L2 to the left and right (see Fig. 1).

Thus, the optical element 1 according to a first embodiment of the present invention, the voltage V _L applied to the second electrode 4 formed on the left and right sides of the second glass substrate _5, and controls the V _R, the first electrode potential difference V _L between 2 and second electrode _4, causing V _R, by aligning the liquid crystal molecules in the liquid crystal layer 6, it is possible to refract light L1 transmitted through the liquid crystal layer 6. At this time, the voltage V _L applied to the second electrode _4, by changing the difference between V _R, it is possible to change appropriately the traveling direction of the refracted light L2 in the lateral direction. Accordingly, the optical element 1 according to the present invention is practical as an optical sensor, and can be applied to various uses such as a human sensor, a distance detection sensor, and a shape measurement sensor.

FIG. 3 is a plan view illustrating the formation pattern of the second electrode 4 in the optical element 1 according to the second embodiment of the invention. The optical element 1 according to the second embodiment of the present invention is different from the optical element 1 according to the first embodiment in that four second electrodes 4 are formed on the second glass substrate 5 and each second electrode is formed. 4 is that the gap region 4b existing between the inner end portions 4a is substantially square. As shown in the figure, the second electrode 4 is disposed on each of the left and right sides and the upper and lower sides of the second glass substrate 5, and the inner end 4a of each second electrode 4 is linear. Is formed. Thereby, the light L1 that has entered from the lower side of the optical element 1 has a traveling direction in the left-right direction depending on the voltage applied to each second electrode 4 (in this case, the voltages V _L , V _R , V _U , V _D ). In addition, it can be changed not only in the vertical direction, but the degree of freedom in changing the traveling direction of light can be increased. That is, the traveling direction of light can be freely changed. Therefore, the practicality of the optical element 1 according to the present invention as an optical sensor is further enhanced, and the application range of the optical element 1 can be expanded. Since the other components are the same as those of the first embodiment described above, the same reference numerals are given to the components common to both, and the description thereof is omitted.

FIG. 4 is a plan view illustrating the formation pattern of the second electrode 4 in the optical element 1 according to the third embodiment of the invention. The optical element 1 according to the third embodiment of the present invention is different from the optical element 1 according to the first embodiment and the second embodiment in that six second electrodes 4 are formed on the second glass substrate 5. The gap region 4b existing between the inner end portions 4a of the respective second electrodes 4 is a substantially regular hexagon. As shown in the figure, three second electrodes 4 are formed on the upper side of the second glass substrate 5. Voltages V _UL , V _U , and V _UR are applied to the three second electrodes 4, respectively. Similarly, three second electrodes 4 are formed on the lower side of the second glass substrate 5, and voltages V _DL , V _D , and V _DR are applied to the three second electrodes 4, respectively. . As described above, when the number of the second electrodes 4 is increased, the degree of freedom in changing the traveling direction of light is further increased by controlling the voltage applied to each second electrode 4 as described above. It is possible to change the traveling direction of light more freely.

  Here, the number of the second electrodes 4 formed on the second glass substrate 5 is 8 or less, so that the gap formed at the inner end portion 4a of the gap between the second electrodes 4 is formed. It is possible to reliably prevent the region 4b from being circular. That is, when the number of the second electrodes 4 exceeds 8, the gap region 4b approaches a circular shape, so that the refracted light L2 is easily collected at the focal position, and the gap region 4b is non-circular. The effects described above cannot be secured sufficiently. Therefore, by setting the number of the second electrodes 4 formed on the second glass substrate 5 to 8 or less, such a problem can be avoided reliably. In addition, the number of the 2nd electrodes 4 formed in the 2nd glass substrate 5 becomes like this. Preferably it is 2, 4, or 6, More preferably, it is 2 or 4. In addition, since it is the same as 1st embodiment and 2nd embodiment as stated above about another component, the same code | symbol is attached | subjected about the component which is common to both, and the description is abbreviate | omitted.

  FIG. 5 illustrates a state where a concave cylindrical lens 10 as a diffusion lens is disposed on the second glass substrate 5 of the optical element 1 according to an embodiment of the present invention. As shown in the figure, by arranging the concave cylindrical lens 10 on the second glass substrate 5 of the optical element 1 according to the embodiment of the present invention, the refracted light L2 refracted by the optical element 1 is further reduced. The light is refracted, and the traveling direction of light can be changed more greatly. As the diffusion lens, in addition to the concave cylindrical lens 10, for example, a concave lens or the like can be used as appropriate. Since the other components are the same as those of the above-described embodiment, the components common to both are denoted by the same reference numerals and the description thereof is omitted.

  In addition to this, the optical element 1 according to the first embodiment of the present invention may be one in which a liquid crystal layer 6 is formed between the first glass substrate 3 and the second glass substrate 5 ( (Not shown). In this case, for example, the porous glass plate 9 a described above is disposed as the liquid crystal layer forming body 9 between the first electrode 2 and the insulating layer 7. If it does in this way, the 1st glass substrate 3 and the 2nd glass substrate 5 can be joined, maintaining predetermined thickness with the perforated glass plate 9a, and formation of the 1st electrode 2 in the 1st glass substrate 3 will be carried out. The liquid crystal layer 6 is sealed between the first glass substrate 3 and the second glass substrate 5 by sealing the liquid crystal in a space between the surface and the insulating layer 7 disposed on the second glass substrate 5. It is formed. When the liquid crystal layer 6 is a single layer, the light L1 incident on the optical element 1 is transmitted only once through the liquid crystal layer 6, so that the amount of change in the light traveling direction is small, but the structure of the optical element 1 is simplified. Can be

  Moreover, the shape of the through-hole 9c formed in the perforated glass plate 9a constituting the liquid crystal layer forming body 9 is a rectangular shape, a circular shape, a polygonal shape, or the like other than the long hole shape (oval shape). It can be appropriately changed according to the shape of the glass substrate 5.

DESCRIPTION OF SYMBOLS 1 Optical element 2 1st electrode 3 1st glass substrate 4 2nd electrode 4a Inner edge part 4b Gap area | region 5 2nd glass substrate 6 Liquid crystal layer 7 Insulating layer 8 High resistance film 9 Liquid crystal layer formation body 9a Perforated glass plate 9b Partition Glass plate 9c through hole

Claims (6)

A first glass substrate having a first electrode, a second glass substrate having a plurality of second electrodes, and a liquid crystal layer interposed between the first glass substrate and the second glass substrate,
An optical element that generates a potential difference between the first electrode and the second electrode and controls the alignment of liquid crystal molecules to change the traveling direction of light,
An optical element, wherein a gap region existing between each inner end portion of the plurality of second electrodes has a non-circular shape.   2. The optical element according to claim 1, wherein each inner end portion of the plurality of second electrodes has a linear shape.   The optical element according to claim 2, wherein the gap region has a polygonal shape.   The optical element according to claim 3, wherein the number of the plurality of second electrodes is eight or less.   The optical element according to claim 1, wherein the gap region has a line shape. The optical element according to claim 5, wherein the gap region is linear.

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