JP4599781B2 - Thin film optical device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a thin film optical device having a light amount adjustment function.
[0002]
[Prior art]
In an imaging device such as a camera, the amount of light entering the lens is adjusted so that proper exposure is obtained by opening and closing the aperture blades. That is, when the light is strong, the diaphragm is strengthened to reduce the amount of light incident on the lens. Conversely, when the light is weak, the diaphragm is weakened to increase the amount of light incident on the lens. Here, since the diaphragm adjustment mechanism is a mechanical part such as a diaphragm blade, there is a current situation in which wear of a mechanical sliding portion or the like greatly affects the life of an imaging device such as a camera.
[0003]
As an optical device expected as a light amount adjustment mechanism without mechanical wear, for example, Japanese Patent Application Laid-Open No. 9-90436 has an optical filter using a redox reaction of a redox reaction substance. This optical filter fills the interior of the cell with electrodes on the inner surface with a reaction solution containing a reactive substance that undergoes a reversible oxidation-reduction reaction, and controls the light transmittance by the oxidation-reduction reaction of the reactive substance in the cell. Is what you do.
[0004]
The cell of such an optical filter includes, for example, a disk-shaped first transparent substrate on which an electrode (hereinafter referred to as ITO electrode) made of indium tin oxide, which is a transparent conductive material, and a silver plate electrode are formed. It consists of a second transparent substrate having substantially the same shape as the one transparent substrate, and an annular spacer disposed between the first transparent substrate and the second transparent substrate. The first transparent substrate and the second transparent substrate are arranged so as to face each other via a spacer, and the reaction solution is placed in a portion surrounded by the first transparent substrate, the second transparent substrate, and the spacer. It is charged. As the reaction solution filled in the cell, for example, a solution containing AgCl which is a reaction material that undergoes a reversible oxidation-reduction reaction is used.
[0005]
When controlling the light transmittance with such an optical filter, by causing a potential difference between the ITO electrode and the silver plate electrode, an oxidation-reduction reaction is caused in the reaction solution to deposit Ag on the ITO electrode. Dissolve. That is, when the light transmittance is lowered, Ag is deposited on the ITO electrode by an oxidation-reduction reaction, and when the light transmittance is increased, Ag on the ITO electrode is dissolved by the oxidation-reduction reaction.
[0006]
However, in such an optical filter using a redox reaction substance, when the redox reaction becomes dull due to deterioration of the reaction substance due to aging, etc., Ag adhering to the ITO electrode is removed by dissolution due to the redox reaction. There is a possibility that it may remain without being completed, and there is a problem that a good light quantity adjustment function cannot be maintained.
[0007]
[Problems to be solved by the invention]
Therefore, the first electrode layer, the optical multilayer film, and the second electrode layer are sequentially laminated on the transparent substrate, and an air gap is provided between the first electrode layer and the optical multilayer film, and applied between the electrodes. The inventors have developed a thin film optical device that adjusts the amount of light by changing the multiple interference condition of light by deforming the air gap by electrostatic attraction generated between the electrodes by controlling the voltage. .
[0008]
In this thin film optical device, one optical thin film element is constituted by the first electrode layer, the optical multilayer film, the second electrode layer, and one air gap. When this thin film optical device is incorporated as an aperture adjustment mechanism of an imaging device, for example, a large number of optical thin film elements are arranged along the surface of the optical lens, and each optical thin film element is driven so that a desired light amount can be obtained in total. In addition, the multiple interference condition of light of each optical thin film element is controlled.
[0009]
However, when the optical thin film elements are driven all at once, the mechanical movement of the individual optical thin film elements may generate a large vibration (resonance) as a whole, which may adversely affect the light amount adjustment. Hereinafter, the vibration (resonance) generated by the mechanical movement of the optical thin film element and the acceleration applied by an external impact will be referred to as vibration applied to the thin film optical device.
[0010]
The present invention has been proposed in view of such conventional circumstances, and provides a thin film optical device capable of suppressing vibration applied to the thin film optical device and obtaining an optical function such as stable light amount adjustment. It is intended to do.
[0011]
[Means for Solving the Problems]
In order to solve such a problem, the thin film optical device of the present invention includes a plurality of optical thin film elements that control the multiple interference condition of light by changing the interval between the opposing surfaces of the first thin film and the second thin film. In the thin film optical device, the detecting means for detecting the vibration applied to the thin film optical device, and the control for causing the optical thin film element to generate vibration for canceling the vibration applied to the thin film optical device based on the detection result of the detecting means Means.
[0012]
Further, in the present invention, a vibration for canceling the vibration applied to the thin film optical device by the control means is generated in a predetermined part of the optical thin film element.
[0013]
Furthermore, the present invention is configured such that the detecting means detects the vibration applied to the thin film optical device by detecting the distance between the opposing surfaces.
[0014]
Further, in the present invention, the first thin film and the second thin film are each provided with an electrode layer that generates an electrostatic attractive force when energized.
[0015]
In the present invention, the first thin film and the second thin film each include a thin film coil that generates a magnetic force when energized.
[0016]
That is, the present invention detects vibration applied to the thin film optical device, and controls the thin film optical device to generate vibration having an antiphase of the detected vibration. It is possible to suppress the optical function such as stable light quantity adjustment.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0018]
FIG. 1 is a plan view showing a thin film optical device according to an embodiment of the present invention.
[0019]
As shown in the figure, the thin film optical device 101 includes a base portion 10 such as optical glass or an optical lens, and a plurality of optical thin film elements 11 arranged uniformly on the surface of the base portion 10. .
[0020]
2 and 3 show the configuration of the optical thin film element 11. As shown in these figures, a first thin film coil 2, a first insulating layer 3 and a first electrode layer 4 are sequentially formed on a transparent substrate 1 such as optical glass which is the base portion 10 of FIG. They are stacked. On the first electrode layer 4, a first SiN layer 5, a second electrode layer 6, a second insulating layer 7, and a second thin film coil 8 are sequentially laminated. An air gap 13 is formed between one SiN layer 5 and the other.
[0021]
In addition, a third electrode layer 9 and a second SiN layer 10 are sequentially stacked on the first electrode layer 4 via a spacer SiN layer 12. A space corresponding to the thickness of the spacer SiN layer 12 is secured between the third electrode layer 9 and the first electrode layer 4, and the space between the first electrode layer 4 and the first electrode layer 4 is secured in this space. A multilayer film composed of the first SiN layer 5, the second electrode layer 6, the second insulating layer 7, and the second thin film coil 8 forming the air gap 13 is accommodated therebetween.
[0022]
Here, the 1st electrode layer 4, the 2nd electrode layer 6, and the 3rd electrode layer 9 are comprised by the electrode (ITO electrode) which consists of indium tin oxide which is a transparent conductive material, for example. For example, SiO2 is used as a material for the first insulating layer 3 and the second insulating layer 7.
[0023]
As shown in FIG. 1, a flexible printed circuit board 15 provided with conductor wirings 14 electrically connected to the thin film coils 2, 8 and the electrode layers 4, 6, 9 is provided on the outer periphery of the base body 10. It is attached. One end of each conductor wiring 14 of the flexible printed board 15 is connected to the controller 16.
[0024]
Next, the operation principle of the optical thin film element 11 will be described with reference to FIG.
[0025]
The optical thin film element 11 functions as, for example, an optical switch that switches light transmittance. 4A and 4B show two states of the optical thin film element 11 having different light transmittances. Thus, by varying the distance between the opposing surfaces of the first electrode layer 4 and the first SiN layer 5, that is, the height of the air gap 13, the multiple interference condition of light is controlled and the light transmittance is adjusted. Is done.
[0026]
In order to vary the height of the air gap 13, the controller 16 controls the voltage applied to the three electrode layers 4, 6, 9 to generate a desired electrostatic attractive force P between the electrodes. Further, in this embodiment, the first thin film coil 2 and the second thin film coil 8 are arranged so as to face each other above and below the air gap 13, and the thin film coils 2 and 8 are energized. The height of the air gap 13 is varied using the magnetic force generated by the above.
[0027]
Such a thin film optical device 101 can be used in an optical system as shown in FIG. 5, for example. A thin film optical device 101 used in this optical system is configured with an optical lens 109 as a base portion. In this optical system, light emitted from a light source 103 is applied to a subject 107 through an optical lens 105, and reflected light from the subject 107 whose transmitted light amount is limited by the thin film optical device 101 is received by a light receiving element through optical lenses 109 and 111. This is a system for converting into an electrical signal by the detecting unit 113 configured.
[0028]
Next, operations represented by the thin film optical device 101 will be described.
[0029]
As shown in FIG. 1, in the example of this embodiment, of the entire optical thin film element 11 of the thin film optical device 101, for example, the optical thin film element 11 in the outer peripheral portion A is applied to the thin film optical device 101. It is used as the optical thin film element 11 for canceling the (disturbance) and for generating a vibration having a phase opposite to that of the disturbance. The optical thin film element 11 in the outer peripheral portion A may be an area determined so as not to use the optical function of the optical thin film element 11 from the beginning. The driving of each optical thin film element 11 in the outer peripheral portion and the driving of each optical thin film element 11 in the inner peripheral portion B can be controlled separately by the controller 16.
[0030]
In order to detect the vibration applied to the thin film optical device 101, the thin film optical device 101 of this embodiment, for example, detects disturbance vibration due to resonance or the like of one or more optical thin film elements 11 in the inner periphery B. A vibration detector 17 is provided for detecting the change in the induced voltage of the coil 2 or the second thin film coil 8 or the like. This disturbance vibration can also be detected from a change in capacitance between the electrodes.
[0031]
The disturbance signal detected by the vibration detection unit 17 is applied to the controller 16, and the controller 16 generates an antiphase voltage of the disturbance signal, which is generated by the optical thin film element 11 of the outer peripheral part A, for example, all of the outer peripheral part A. A drive voltage is applied to the optical thin film element 11 or a part of the optical thin film element 11 near the inner periphery of the outer peripheral portion A. In this way, by driving the optical thin film element 11 in the outer peripheral portion A by the antiphase voltage of the disturbance signal, vibration applied to the thin film optical device, that is, accompanying the mechanical movement of each optical thin film element 11 in the inner peripheral portion B. The effect of suppressing the vibration (resonance) generated and the acceleration applied by the impact from the outside can be expected.
[0032]
Note that the thin film optical device of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.
[0033]
【The invention's effect】
As described above, according to the present invention, the vibration applied to the thin film optical device is detected, and the thin film optical is controlled by causing the optical thin film element to generate the vibration having the opposite phase of the detected vibration. Vibration applied to the apparatus can be suppressed, and an optical function such as stable light amount adjustment can be obtained.
[Brief description of the drawings]
FIG. 1 is a plan view showing a thin film optical device according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view showing a configuration of an optical thin film element of this embodiment.
3 is a diagram showing a configuration of a drive circuit for the optical thin film element of FIG. 2. FIG.
4 is a diagram for explaining the operating principle of the optical thin film element of FIG. 2; FIG.
FIG. 5 is a diagram showing a configuration of an optical system employing the thin film optical device of this embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Board | substrate 2 1st thin film coil 3 1st insulating layer 4 1st electrode layer 5 1st SiN layer 6 2nd electrode layer 7 2nd insulating layer 8 2nd thin film coil 9 3rd electrode layer DESCRIPTION OF SYMBOLS 10 Base part 11 Optical thin film element 13 Air gap 15 Flexible printed circuit board 16 Controller 17 Vibration detection part 101 Thin film optical apparatus

Claims (1)

In a thin film optical device having a plurality of optical thin film elements that control the multiple interference condition of light by changing the distance between the opposing surfaces of the first thin film and the second thin film,
Detecting means for detecting vibration applied to the thin film optical device;
Control means for causing the optical thin film element to generate vibration for canceling vibration applied to the thin film optical device based on the detection result of the detection means ,
A thin-film optical device that causes a predetermined part of the optical thin-film element to generate vibration for canceling out vibration applied to the thin-film optical device by the control means .

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