JP2006091049A - Light quantity controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-efficiency light quantity controller which is made extremely thinner in shape, and improved in responsibility. <P>SOLUTION: The light quantity controller is provided with a 1st substrate having a 1st light transmissive part, a 2nd substrate having a 2nd light transmissive part, and arranged facing the 1st substrate so that the 1st light transmissive part and the 2nd light transmissive part may face each other, and opaque liquid 3 sandwiched between the 1st substrate and the 2nd substrate. The 2nd substrate is piezoelectric, and provided with electrodes 4a and 4b for exciting acoustic surface wave on the surface facing the 1st substrate of the 2nd substrate. The controller is provided with a flow-in suppressing means for suppressing the opaque liquid from flowing in between the 1st light transmissive part and the 2nd light transmissive part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a light amount adjusting device mainly used for a camera or the like for the purpose of adjusting an incident light amount.

  In recent years, with the rapid spread of camera-equipped mobile phones, there is a strong demand for smaller and thinner devices. In addition, regarding camera functions mounted on devices, from the viewpoint of added value of the camera, higher functions such as an aperture function, an AF (autofocus) function, an optical zoom function, and a camera shake prevention function are required. However, miniaturization and high functionality of devices are in a trade-off relationship, and until now, miniaturization was given priority due to the nature of mobile devices such as mobile phones, and camera functions remained low.

  Conventionally, mechanical diaphragm devices have been mainly used for the diaphragm function, which is one of the enhancements. However, the mechanical aperture requires a mechanical mechanism for operating the mechanical aperture, which causes the increase in size and cost of the camera and the restriction on the degree of freedom in design.

  As a conventional technique, a method of adjusting the light quantity by moving a diaphragm blade or the like by an electromagnetic actuator is well known. However, downsizing of the diaphragm device by the electromagnetic actuator is reaching its limit. In order to solve these problems, many aperture devices that do not use electromagnetic actuators have been recently proposed.

  As an example, in Patent Document 1, a diaphragm blade is mechanically operated by exciting a surface acoustic wave on a piezoelectric substrate and moving a moving body in pressure contact with the piezoelectric substrate by a frictional force. A method is disclosed. In this method, the main mechanical mechanisms are only the piezoelectric substrate on which the electrodes are deposited and the moving body that is in pressure contact with the piezoelectric substrate. Therefore, the method is smaller and thinner than conventional electromagnetic actuators. I can plan.

  In addition, as another conventional technique for the purpose of downsizing the diaphragm device, there is a method in which the diaphragm blade is sucked and discharged without using a mechanical mechanism for the diaphragm blade as described above. As an example, the technique is disclosed in Patent Document 2, and will be described with reference to FIGS.

In FIGS. 7A and 7B, 3 and 4 are lenses, 5 is a sealed chamber, 6 is a light shielding fluid intake / exhaust pipe, 9 is a light shielding fluid, and 10 is an intake / exhaust pump. In FIG. 7A, the suction / exhaust pump 10 discharges the light shielding fluid 9, whereby the light shielding fluid 9 is filled in the sealed chamber 5 between the lenses 3 and 4 to block light. Further, in FIG. 7B, when the suction / discharge pump 10 absorbs the light shielding fluid 9, the light shielding fluid 9 in the sealed chamber 5 between the lenses 3 and 4 moves backward toward the suction / discharge pump 10 and takes in light. Can do. As described above, since the mechanical mechanism is not used for the aperture blade, the aperture device can be downsized.
JP 2001-255570 A JP-A-4-56934

  However, the above conventional techniques have the following problems. First, in the method of moving a moving body that is in pressure contact with a piezoelectric substrate on which surface acoustic waves are excited by frictional force, in order to excite surface acoustic waves that are not affected by the surface roughness of the piezoelectric substrate, etc. Since it is necessary to input relatively large electric power to the electrodes, there is a big problem in overall efficiency. Further, since the diaphragm blades are indirectly operated through friction, there are problems of reliability due to wear, and further problems such as unstable operation of the diaphragm speed.

  Next, in the method of sucking and discharging the shading fluid with the pump, the mechanical mechanism such as the diaphragm blades can be reduced, but the pump and the device that drives the pump are required. Can't plan. Moreover, since the light shielding fluid is moved by the pump, it seems that there is a problem in response.

  An object of the present invention is to solve the above-described conventional problems, and to provide a light amount adjusting device that is ultra-thin, highly efficient, and excellent in responsiveness.

  In order to solve the above-described problems, a light amount adjustment device of the present invention includes a first substrate having a first light transmission part, a second light transmission part, and the first light transmission part and the second light transmission part. A second substrate disposed to face the first substrate so that the light transmission portion faces, and an opaque liquid sandwiched between the first substrate and the second substrate, The second substrate has piezoelectricity, and has an electrode for exciting the surface acoustic wave on the surface of the second substrate facing the first substrate, and the opaque liquid is the first substrate of the first substrate. And an inflow suppressing means for suppressing inflow between the light transmitting portion of the second substrate and the second light transmitting portion of the second substrate.

  According to the present invention, an opaque liquid can be moved between substrates by applying a high-frequency voltage to an electrode and exciting a surface acoustic wave, and an ultra-thin light amount adjusting device can be provided.

  DESCRIPTION OF EMBODIMENTS Hereinafter, a light amount adjusting device of the present invention will be described in detail according to a preferred embodiment with reference to the drawings.

(Embodiment 1)
FIG. 1 is a top view of a light amount adjusting apparatus showing Embodiment 1 of the present invention.

  In FIG. 1, an opaque liquid 3 is sealed between a substrate 1 having piezoelectricity and a substrate 2 (not shown). An optical path 5 indicates a region through which light incident from the outside is transmitted when the opaque liquid 3 is not present. On the surface of the substrate 1 and the substrate 2 facing each other, a thin film 6 having water repellency with respect to the opaque liquid 3 is disposed in the region of the optical path 5. Here, the substrate 1 and the substrate 2 are transparent at least inside the optical path 5. The thin film 6 is also transparent. The opaque liquid 3 and the distance between the substrate 1 and the substrate 2 are set so that the surface tension of the opaque liquid 3 does not spread within the substrates 1 and 2 as long as some action is not applied from the outside and can maintain a constant state. . In addition, the preferable space | interval of the board | substrate 1 and the board | substrate 2 is 100 micrometers or less. Further, as the opaque liquid 3, a material having excellent light shielding properties such as mercury is used.

  Electrode groups 4a, 4b, 4c, and 4d composed of a plurality of parallel linear electrodes are arranged around the optical path 5 on the surfaces of the substrates 1 and 2 having piezoelectricity on the side in contact with the opaque liquid 3. Has been. The individual electrodes of the electrode groups 4a, 4b, 4c, and 4d are grounded at every other electrode row, and an AC voltage having a predetermined frequency, amplitude, and phase is applied to the other electrodes. Thereby, surface acoustic waves are excited on the surfaces of the substrate 1 and the substrate 2 having piezoelectricity.

  In addition, it is desirable to apply to the electrode groups 4a, 4b, 4c, and 4d an alternating voltage having the same phase at a frequency of 1 to 100 MHz.

  Further, the electrode groups 4a, 4b, 4c, and 4d are configured such that the electrode crossing width gradually decreases from the center part to the end part in the arrangement direction of the individual electrodes of each electrode group. The electrode crossing width means the length of the portion of each electrode facing the adjacent electrode.

  With such a configuration, the electrode groups 4a, 4b, 4c, and 4d can be efficiently arranged on the surfaces of the substrate 1 and the substrate 2, and the opaque liquid 3 can be smoothly moved toward the center of the optical path 5. It becomes possible to move.

  Next, a specific operation principle will be described with reference to FIGS.

  2A and 2B are cross-sectional views of the light amount adjusting device taken along A-A ′ in FIG. 1. First, in FIG. 2A, no AC voltage is applied to the electrode groups 4a, 4b, 4c, and 4d, and surface acoustic waves are not excited on the surfaces of the substrate 1 and the substrate 2 having piezoelectricity. . Therefore, the force generated in the opaque liquid 3 is only the surface tension, cannot be present in the region where the thin film 6 having water repellency is formed, and the optical path 5 is fully open.

  Next, in FIG. 2 (b), as described above, every other electrode of the electrode groups 4a, 4b, 4c, and 4d is grounded or AC voltage having a predetermined frequency and phase. Is applied, and surface acoustic waves are excited on the surfaces of the substrate 1 and the substrate 2 having piezoelectricity. At this time, the opaque liquid 3 receives pressure due to the surface acoustic wave in addition to the surface tension, moves to the inside of the optical path 5 to a state that balances with the water repellent effect by the thin film 6, and suppresses the amount of light transmitted through the optical path 5. It becomes a state. That is, by arbitrarily adjusting the frequency, amplitude, phase, and the like of the alternating voltage applied to the individual electrodes of the electrode groups 4a, 4b, 4c, and 4d, the amount of light that can be taken in from the optical path 5 can be freely adjusted. .

  Note that the AC voltage waveform applied to each electrode of the electrode groups 4a, 4b, 4c, and 4b is preferably a sine wave waveform in order to excite a surface acoustic wave with high efficiency, but other triangular wave waveforms and square wave waveforms. Even in the sawtooth waveform, it is possible to fulfill the function as the light amount adjusting device.

(Embodiment 2)
Next, a light amount adjusting device showing Embodiment 2 of the present invention will be described with reference to FIG.

  FIG. 3 is a cross-sectional view of the light amount adjusting device showing the present embodiment. In FIG. 3, a convex portion 7 is formed in the region of the optical path 5 of the substrate 1 and the substrate 2 so that the distance between the substrates becomes narrower toward the center of the optical path 5.

  With this configuration, the surface tension in the region of the optical path 5 can be arbitrarily set, and the same effect as the thin film 6 in Embodiment 1 can be obtained.

  In addition, if the convex part 7 makes it play the role of an optical lens, a number of parts can be reduced and cost reduction can be implement | achieved.

  The same effect can be obtained even if the convex portion 7 is provided only on at least one of the substrate 1 and the substrate 2.

(Embodiment 3)
Next, a light amount adjusting apparatus showing Embodiment 3 of the present invention will be described with reference to FIG.

  FIG. 4 is a cross-sectional view of the light amount adjusting device showing the present embodiment. In the substrate 1 and the substrate 2 of FIG. 4, a substrate 8 made of a material different from that of the substrate 1 and the substrate 2 is disposed on a portion including at least the optical path 5 on the inner surface of the substrate 1 and the substrate 2. With this configuration, the material of the substrate 8 can be selected so that the thin film 6 can be easily disposed regardless of the materials of the substrate 1 and the substrate 2. Furthermore, it is also possible to select a material that can be easily processed with high accuracy to serve as an optical lens.

(Embodiment 4)
Next, a light amount adjusting apparatus showing Embodiment 4 of the present invention will be described with reference to FIG.

  FIG. 5 is a top view of the light amount adjusting apparatus showing the present embodiment. The components in FIG. 5 are the same as those in FIG. 1 showing the first embodiment.

  In FIG. 5, the direction in which the piezoelectricity of the substrate 1 or the substrate 2 is maximum is taken as the X axis, and the direction orthogonal to the X axis and having the smallest piezoelectricity is taken as the Y axis. At this time, when the X (β) axis and the Y (β) axis are respectively shifted by a predetermined angle β with respect to the X axis and the Y axis, the electrode groups 4a and 4b are parallel to the X (β) axis. Electrode groups 4c and 4d are arranged in parallel to the Y (β) axis. Β is preferably about 30 to 60 degrees.

  With this configuration, even if the substrate 1 or the substrate 2 is a piezoelectric substrate with the alignment direction aligned in one direction, a predetermined AC voltage is applied to the electrode groups 4a, 4b, 4c, and 4d to generate surface acoustic waves. By exciting, the opaque liquid 3 can be moved toward the center of the optical path 5 in a well-balanced manner, and a low-cost and stable light quantity adjusting device with reduced manufacturing variations is possible.

  In addition, the said effect can be fully utilized by making (beta) 45 degrees.

(Embodiment 5)
Next, a light amount adjusting apparatus showing Embodiment 5 of the present invention will be described with reference to FIG.

  FIG. 6 is a top view of a light amount adjusting apparatus showing Embodiment 5 of the present invention. In FIG. 6, substrates 1a, 1b, 1c, and 1d are substrates having piezoelectricity, respectively, and directions in which the piezoelectricity is maximum are directions of arrows Pa, Pb, Pc, and Pd. The electrode groups 4a, 4b, 4c, and 4d are arranged so that the individual electrodes are orthogonal to the directions of arrows Pa, Pb, Pc, and Pd.

  By adopting such a configuration, it is possible to realize a light amount adjusting device with higher efficiency compared to the fourth embodiment.

  The present invention is not limited to the camera light amount adjusting device described in the above embodiment, and can be applied to all devices that adjust the light amount.

  Further, in the embodiment described above, the substrate 1 and the substrate 2 are both substrates having piezoelectricity, and the parallel electrodes for generating the surface acoustic wave are provided on each substrate. At least one of 2 may be a substrate having no piezoelectricity. In that case, the substrate having no piezoelectricity is not particularly limited, and any substrate such as inorganic glass or transparent resin may be used.

  The present invention is applied to a light amount adjusting device for a camera as described in the above embodiment. Further, the present invention is not limited to the camera and is applied to all devices that adjust the light amount.

The top view of the light quantity adjustment apparatus which shows Embodiment 1 of this invention Sectional view along A-A 'in FIG. Sectional drawing of the light quantity adjustment apparatus which shows Embodiment 2 of this invention Sectional drawing of the light quantity adjustment apparatus which shows Embodiment 3 of this invention The top view of the light quantity adjustment apparatus which shows Embodiment 4 of this invention. The top view of the light quantity adjustment apparatus which shows Embodiment 5 of this invention. Explanatory drawing of conventional light quantity adjustment device

Explanation of symbols

1, 1a, 1b, 1c, 1d, 2 Piezoelectric substrate 3 Opaque liquid 4a, 4b, 4c, 4d Electrode 5 Optical path 6 Thin film 7 Protruding portion 8 Substrate

Claims (8)

A first substrate having a first light transmission part;
A second substrate having a second light transmission portion, and disposed opposite to the first substrate so that the first light transmission portion and the second light transmission portion are opposed to each other;
An opaque liquid sandwiched between the first substrate and the second substrate;
The second substrate has piezoelectricity, and has an electrode for exciting a surface acoustic wave on a surface of the second substrate facing the first substrate,
Inflow suppression means for suppressing the opaque liquid from flowing between the first light transmission part of the first substrate and the second light transmission part of the second substrate. A characteristic light amount adjusting device. As the inflow suppressing means, the surface of the first light transmission part on the second substrate side or the surface of the second light transmission part on the first substrate side is repelled against the opaque liquid. The light quantity adjusting device according to claim 1, which has water. 2. The light amount adjusting device according to claim 1, wherein an interval between the first light transmission unit and the second light transmission unit is reduced as the inflow suppression unit is moved toward a central portion of the light transmission unit. 2. The light amount adjusting device according to claim 1, wherein the first or second substrate is made of a material that constitutes the light transmission part and is different from other parts. The electrode includes a plurality of electrode groups including a plurality of linear electrodes arranged in parallel to each other, and the linear electrode is directed from the peripheral portion of the substrate toward the center of the first and second light transmission portions. The light amount adjusting device according to claim 1, wherein the light amount adjusting device is arranged in an array. The light amount adjusting device according to claim 5, wherein the opposing width of the linear electrodes adjacent to each other is gradually narrowed from the central portion of the electrode group in the arrangement direction of the linear electrodes toward the end portion. . The said 2nd board | substrate has piezoelectricity in a predetermined | prescribed direction, and the said predetermined | prescribed direction cross | intersects the direction of the said linear electrode at the angle of (beta) (30 degrees <beta <60 degrees). Light quantity adjustment device. The second substrate includes a plurality of portions having different piezoelectric directions, and each of the plurality of portions has a piezoelectric direction parallel to a direction of the linear electrode disposed in the plurality of portions. The light quantity adjusting device according to claim 5.

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