JPH0820308B2 - Optical variable wavelength filter device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention is designed to select and pass light having a specific wavelength from light diffracted by, for example, a diffraction grating.
The present invention relates to an optical variable wavelength filter device capable of variably setting a central wavelength of passing light and a passing wavelength bandwidth.

[Prior Art] FIG. 7 shows an apparatus for variably setting a central wavelength and a passing wavelength bandwidth of passing light when a specific wavelength is selected and passed from light diffracted by a diffraction grating or the like. Such an optical variable wavelength filter device is known.

This device has a fine movement table 21, equipped with micrometer heads 23, 24, so that each of the slits 20, 20 can be driven independently.
The slits 20 and 20 are attached to 22 and the fine movement tables 21 and 22 are
In contrast, the slits 20 and 20 are arranged so as to face each other.When the central wavelength and the passing wavelength bandwidth of the light passing through the slits 20 and 20 are variable, for example, a white light source and an optical spectrum analyzer are used. Use the knob 23 of the micrometer head 23, 24 while always measuring the state of the passing light.
This has been dealt with by manually rotating a and 24a to control the movement of fine movement tables 21 and 22.

[Problems to be Solved by the Invention] However, in the above-described conventional device, the central wavelength and the passing wavelength bandwidth of the passing light are set by using other devices such as a white light source and an optical spectrum analyzer in combination. Since the user must constantly monitor the condition, it takes time and effort to set the adjustment, which is not efficient. Further, it is difficult to maintain the set value against the influence of external fluctuation such as vibration after the adjustment, and there is a problem that the set value after the adjustment lacks reliability.

Therefore, the present invention has been made in view of the above-mentioned problems, and the purpose thereof is to be able to perform setting in a short time without requiring time and effort for adjustment by an extremely simple operation, and to be affected by external fluctuation after adjustment. An object of the present invention is to provide an optical variable wavelength filter device that can obtain a desired passing light without causing any change.

[Means for Solving the Problems] In order to achieve the above object, a variable wavelength filter device according to the present invention includes a pair of slits 1a and 1b for separating incident light and selectively passing the separated light. In the optical variable wavelength filter device, a setting unit 2 for inputting a set value for determining a central wavelength of passing light and a passing wavelength bandwidth, and an L-shaped frame 12 symmetrically arranged with a fulcrum F at one end A lever 11 mounted on an extension of the piezoelectric actuator 10, a piezoelectric actuator 10 for opening and closing the lever about the fulcrum, one of the slits is attached to the other end of the lever, the operation of the piezoelectric actuator A drive unit 6 for driving each of the pair of slits, which includes a drive mechanism 7a, 7b including a leaf spring 13 that is displaced so as to change the distance between the slits according to the amount, and a leaf spring 13 provided on the leaf spring. The displacement amount detection unit 15 for detecting the displacement amount of the slit is compared with the output of the displacement amount detection unit and the set value, and the piezoelectric actuator is driven so as to cancel the deviation due to this comparison. And a control unit 5 for correcting and controlling the displacement amount of the drive unit.

[Operation] When the incident light is split and the split light is selectively passed, when the set value for determining the center wavelength and the pass wavelength bandwidth of the pass light is input by the setting unit 2, a fulcrum is provided at one end. The lever 11 on the frame 12 symmetrically arranged with F is opened and closed by the piezoelectric actuator 10 about the fulcrum F of the frame 12. The leaf springs 13 are bent and displaced in response to the opening / closing of the lever 11 so that the slits 1a, 1b
The interval of changes. At that time, the displacement amount detection unit 15 provided in the leaf spring 13 detects the displacement amount of the slits 1a, 1b,
The control unit 5 drives the piezoelectric actuator 10 so as to cancel the deviation between the detected value and the set value by the setting unit 2 and controls the displacement amount of the drive unit 6 by self-correction. As a result, passing light adjusted to a desired center wavelength and passing wavelength bandwidth can be obtained.

[Embodiment] FIG. 1 is a block configuration diagram showing an embodiment of the overall configuration of an optical variable wavelength filter device according to the present invention.

The optical variable wavelength filter device according to this embodiment uses a displacement magnifying mechanism having a piezoelectric actuator for the opening / closing mechanism of the two slits 1, and controls the opening / closing of each slit 1 independently. 3, a storage unit 4, a control unit 5, and a drive unit 6 are provided.

The setting unit 2 numerically sets the center wavelength and the passing wavelength bandwidth as a wavelength setting signal in order to determine the center wavelength and the passing wavelength bandwidth of the passing light, and the data by this input is output to the control unit 5. . More specifically, as shown in FIG. 2, the setting unit 2 is provided separately for setting either the center wavelength or the pass wavelength bandwidth.
It is equipped with a plurality of setting switches 2a, 2b and an encoder knob 2c whose setting value is increased / decreased by rotating the setting switches 2a, 2b after being pushed and operated, and the encoder knob 2c is rotated by one notch. 1 nm, and the set value at that time is displayed on the display unit 3 which separately displays the set values of the center wavelength and the passing wavelength bandwidth.

The storage unit 4 is composed of upper slit data storage means 4a and lower slit data storage means 4b, and each storage means 4a, 4
In b, as shown in the drawing, data indicating the distortion value for each wavelength of the upper and lower slits 1a and 1b is stored.

The control unit 5 includes a wavelength calculation unit 5a and an upper slit strain value calculation unit.
5b, a lower slit distortion value calculation means 5c, an upper slit control section 6a and a lower slit control section 6b.

The wavelength calculator 5a calculates the wavelength in each of the upper slit 1a and the lower slit 1b based on the data of the center wavelength and the passing wavelength bandwidth input by the setting operation of the setting unit 2.

The upper slit strain value calculation means 5b and the lower slit strain value calculation means 5c are each slit calculated by the wavelength calculation means 5a.
The distortion values corresponding to the wavelengths of 1a and 1b are calculated, and each distortion value data by this calculation is output to the drive unit 6 of each slit 1a and 1b.

The drive unit 6 has a displacement magnifying mechanism 7 as two sets of drive mechanisms that independently drive the pair of slits corresponding to the slits 1a and 1b, and the upper slit control unit 6a and the lower slit control unit 6b are A distortion value which is composed of an amplifier 8 and a comparator 9 and is calculated by each slit distortion value calculating means 5b, 5c, and each slit 1 in the displacement magnifying mechanism 7 which will be described in detail later.
a, 1b is compared with a strain value detected by a later-described strain gauge 15 to calculate the deviation, and the applied voltage of the piezoelectric actuator 10 described below in each slit 1a, 1b is independently set so that this deviation is offset. Is adjusted and drive control is performed.

The displacement magnifying mechanism 7 is an upper slit displacement magnifying mechanism 7a and a lower slit displacement magnifying mechanism corresponding to the upper and lower slits 1a and 1b.
7b, the displacement magnifying mechanisms 7a, 7b are composed of the same component and are arranged opposite to each other. More specifically, each displacement magnifying mechanism 7a, 7b is a piezoelectric actuator 10.
The amount of displacement of the piezoelectric actuator 10 is magnified by the principle of leverage, and as shown in FIG. 3, the frame 12 including the two levers 11, 11 having a substantially L shape is in contact with the one end 10a of the piezoelectric actuator 10. It is arranged so as to cover the periphery of the piezoelectric actuator 10. A leaf spring 13 is fixedly mounted on the tip of each lever 11, 11 so that the amount of displacement of the piezoelectric actuator 10 is transmitted and the displacement is expanded. Further, the leaf spring 13 is provided with a mounting portion 14, and the mounting portion 14 is mounted with a slit 1 (1a, 1b) having a metal reflection film deposited on a glass plate, for example. Further, on the front and back surfaces of the leaf spring 13, four strain gauges 15 forming a displacement amount detecting portion are adhered and fixed. Among these strain gauges 15, the strain gauge adhered and fixed to the surface of the leaf spring 13 has a resistance value which is reduced when a voltage is applied to the piezoelectric actuator 10 and the curvature of the leaf spring 13 is largely displaced. On the other hand, the resistance value of the other strain gauge fixed to the adhesive is increased, and when the equivalent circuit is constructed with these four strain gauges 15, it becomes as shown in FIG. 4, and the curvature of the leaf spring 13 changes. The output voltage from the strain gauge 15 changes accordingly. As a result, a voltage is output from the strain gauge 15 corresponding to the amount of displacement of the slit 1.

Therefore, the displacement magnifying mechanisms 7a and 7b described above are driven independently based on the signals from the slit control units 6a and 6b, and the DC voltage is applied to the lead wire 16 from the state where the piezoelectric actuator 10 is not operating. When the voltage is applied, the piezoelectric actuator 10 extends in the direction of arrow E in the figure, and the two levers 11, 1 with the point F in the figure as a fulcrum by the lever principle of the frame 12.
1 move closer to each other and the curvature of the leaf spring 13 is largely displaced, whereby the slit 1 moves in the direction of arrow G in the figure. A strain value is output from the strain gauge 15 to the control unit 5 in accordance with the amount of displacement of the slit 1.

Next, the operation of the optical variable wavelength filter device configured as described above will be described.

First, when one of the setting switches 2a and 2b of the setting unit 2 is pushed and the center wavelength or the passing wavelength bandwidth is set by the encoder knob 2c, the wavelength calculation means 5a causes the upper slit 1a to be set based on this setting data. And the wavelength of the lower slit 1b is calculated. Next, based on the calculated wavelength data, the strain values corresponding to the respective data are stored in the respective slit data storage means.
Read from 4a and 4b. The respective strain value data read out are the strain gauges 1 provided in the corresponding displacement magnifying mechanisms 7a and 7b.
The respective deviations are calculated by comparing with the distortion value detected by 5. Then, the applied voltage of the corresponding piezoelectric actuator 10 is adjusted so as to cancel each deviation, and the drive thereof is controlled.

By the above control, the diffracted light is selectively passed through the upper slit 1a and the lower slit 1b.

Here, the diffracted light is light with a short wavelength on the side of the upper slit 1a,
Further, since long wavelength light is vertically dispersed on the lower slit 1b side, the upper slit 1a cuts the short wavelength side of the diffracted light and the lower slit 1b cuts the long wavelength side of the diffracted light. .

At this time, as shown in FIG. 5, each slit 1a, 1
When b is controlled to move in the opposite direction, each slit 1a, 1b is opened / closed around the center position (shown by the one-dot chain line in the figure) to change slit width l, and the central wavelength of the passing light passes without changing. Only the wavelength bandwidth is variable.

Further, as shown in FIG. 6, when the respective slits 1a and 1b are controlled to move in the same direction, the slit width 1 of each of the slits 1a and 1b does not change, and only the slit center position is changed.
Only the center wavelength is variable without changing the passing wavelength bandwidth of the passing light.

In this way, the setting of the center wavelength and the passing wavelength bandwidth of the passing light described above is performed by the setting switches 2a, 2 in the setting unit 2.
It is performed by an extremely simple switch operation by pushing the b button and adjusting the rotation of the encoder knob 2c, and the set value is instantly displayed on the display unit 3. Therefore, visually check the numerical value displayed on the display unit 3. Only by rotating and adjusting the encoder knob 2c, it is possible to obtain passing light having a desired center wavelength and passing wavelength bandwidth.

Further, in the above-described embodiment, since the displacement magnifying mechanism 7 including the piezoelectric actuator 10 is used to control the movement of the upper and lower slits 1a and 1b, the mechanism is simple and the device is compact and inexpensive. be able to. Furthermore, since the upper and lower slits 1a and 1b are independently controlled to move, the slit width 1 and the slit center position can be changed by combining the operations shown in FIG. 5 and FIG. It is possible to arbitrarily variably control the center wavelength and the passing wavelength bandwidth of the light to be emitted.

By the way, the setting switches 2a and 2b of the setting unit 2 in the above-described embodiment have been described as being separately provided for each of the center wavelength and the passing wavelength bandwidth of the set passing light, but one switch is also used. Alternatively, the center wavelength and the passing wavelength bandwidth may be set first.

[Advantages of the Invention] As described above, according to the optical variable wavelength filter device of the present invention, adjustment is performed by an extremely simple operation without using other devices such as a white light source and an optical spectrum analyzer as in the related art. It is possible to set the central wavelength of the passing light and the passing wavelength bandwidth in a short time without taking time and effort. Further, since the displacement amount of the drive mechanism is detected and the displacement amount of the drive unit is self-corrected, desired passing light can be obtained without being affected by external fluctuation after adjustment as in the conventional case.

[Brief description of drawings]

FIG. 1 is a block configuration diagram showing an embodiment of the overall configuration of an optical variable wavelength filter device according to the present invention, FIG. 2 is a perspective view showing the appearance of the device, and FIG. 3 is a slit opening / closing mechanism in the device. FIG. 4 is a perspective view showing the equivalent circuit diagram of a strain gauge in the same device, FIG. 5 is a diagram showing the operation of the slit when the wavelength band of passing light is changed in the same device, and FIG. FIG. 7 is a diagram showing the operation of the slit when the central wavelength of light is varied, and FIG. 7 is a diagram showing an example of a conventional optical variable wavelength filter device. 1 ... slit, 1a ... upper slit, lower slit, 2 ...
… Setting section, 5 …… Control section, 6 …… Drive section, 7 (7a, 7b)
…… Displacement magnifying mechanism, 10 …… Piezoelectric actuator, 15 ……
Strain gauge (displacement detector).

Claims (1)

[Claims] 1. A variable optical wavelength filter device having a pair of slits (1a, 1b) for separating incident light and selectively passing the separated light, and determining a central wavelength and a passing wavelength bandwidth of the passing light. Setting section (2) for inputting the set value for the lever, and a lever (11) mounted on an extension of an L-shaped frame (12) symmetrically arranged with a fulcrum (F) at one end.
A piezoelectric actuator (10) for opening and closing the lever about the fulcrum, and one of the slits is attached to the other end of the lever, and the slit of the slit is provided in accordance with the operation amount of the piezoelectric actuator. A drive mechanism (7) including a leaf spring (13) that is displaced so as to change the distance.
and a drive unit (6) for driving the pair of slits, a displacement amount detection unit (15) provided in the leaf spring for detecting the displacement amount of the slit, and And a control unit (5) for comparing the output of the amount detection unit with the set value and driving the piezoelectric actuator so as to cancel the deviation due to the comparison and correcting and controlling the displacement amount of the drive unit. An optical variable wavelength filter device characterized by: