JPH0248631A - Method and device for scanning light beam - Google Patents

Abstract

PURPOSE:To attain light beam scanning at high speed and with high accuracy by oscillating a light source unit by controlling an applied voltage of an electrostrictive element. CONSTITUTION:When position information corresponding to a set value of a setting part 23 is supplied through a CPU 20 and a D/A converter 26, an electrostrictive element driving circuit 27 of a power amplifier integrates a voltage which considers a hysteresis corresponding to the unit displacement quantity at a prescribed time interval until reaching the designated displacement quantity and applies it to an electrostrictive element 17. As a result, a light source unit 14 which is pressed by the element 17 through a displacing member 10 by a supporting member 11 is oscillated by the element 17. Subsequently, a light beam is displaced with satisfactory responsiveness and a light beam is scanned at high speed and with high accuracy by small power consumption without generating noise.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a light beam scanning method and apparatus used in various measuring instruments and electronic devices.

[Conventional technology]

Surface inspection device 1 For example, in a light beam scanning device for measuring the shape (distance) of an object to be measured, a light beam scanning mechanism used in a barcode reader, laser printer, facsimile, etc. is applied to irradiate a light beam, A method is used in which the distance to the object to be measured is measured by creating a light spot on the object to be measured using the light beam, and focusing this light spot on the light receiving surface of the semiconductor device detector using a light receiving lens. is possible.

FIG. 16 schematically shows a light beam scanning device that applies the optical system of a laser printer. A laser beam generated by a semiconductor laser 101 and passed through a projection lens 102 passes through a cylindrical lens 103 and rotates into a polygon. Scanned by reflection from mirror 104, spherical lens 105. f
A light beam is scanned over the surface of the object to be measured 107 through the θ lens 106 .

FIG. 17 shows a light beam scanning device using a galvanometer, in which a mirror 112 is fixed to the rotating shaft of the galvanometer 111, and the mirror 112 is rotated by the vibration of the galvanometer 111, and the light beam is scanned from a light source (not shown). scanning the light beam.

In this way, conventionally considered light beam scanning devices use a semiconductor laser 101. Light projection lens 102. Cylindrical lens 103. Polygon mirror 104 or mirror 1129 of galvanometer 111 spherical lens 105. It was common to use a light beam scanning mechanism composed of an fθ lens 106 or the like.

[Problem to be solved by the invention]

However, in all of these light beam scanning devices, the light beam is scanned by rotating a mirror, so there is a problem that not only is there a limit to scanning and controlling the light beam at high speed and with high precision, but also the rise time is slow. was there.

Furthermore, the mechanism is complex, and it is difficult to assemble the unit for aligning the optical axis and angle of the light source and mirror with high precision, and a large amount of assembly requires many man-hours, resulting in high costs. be.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a light beam scanning device that is capable of high-speed and highly accurate light beam scanning with a simple mechanism.

(Means for Solving the Problems) In order to achieve the above object, a light beam scanning method according to the present invention supports a light source unit that emits a light beam in a swingable manner, To the point,
The other end of a displacement member fixed at one end, which has an electrostrictive element that generates dimensional distortion according to an applied voltage, is pressed into contact with the other end, and a voltage corresponding to a unit displacement of the electrostrictive element is applied for a predetermined time until a predetermined displacement is reached. It is integrated and applied at intervals.

Further, a light beam scanning device according to the present invention is a device for implementing the above method, and includes a light source unit that emits a light beam, a support member that swingably supports the light source unit while changing the irradiation direction. It has an electrostrictive element that is interposed between the support member and the light source unit and generates dimensional distortion according to an applied voltage, and a biasing means that presses the light source unit against the electrostrictive element, and the displacement of the electrostrictive element is The light source unit is swung to scan the light beam.

Furthermore, a support member having a head connected to one end via the neck, a tail at the other end, and an electric current interposed between the head and the tail of the support member to generate dimensional distortion according to the applied voltage. It has a strain element and a light source unit that emits a light beam attached to the tip of the head, and it is also possible to scan the light beam by swinging the light source unit using the neck as a fulcrum by displacement of the electrostrictive element. It is.

[For production]

With the above configuration, when a voltage is applied to the electrostrictive element, the electrostrictive element is displaced in accordance with the voltage, the light source unit is brought into contact, and the irradiation direction of the light beam is changed.

Since the dimensions of the electrostrictive element change accurately depending on the magnitude of the applied voltage, the light beam can be scanned over a desired range at high speed and with high accuracy by controlling this applied voltage.

By using a laminated piezoelectric element as the electrostrictive element, it is possible to obtain a light beam scanning device with quick response, no noise, and low power consumption.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to FIGS. 1 to 6 of the accompanying drawings, but prior to this.

The electrostrictive element used in this invention will be briefly explained using FIG. 7.

Two types of electrostrictive elements, bimorph piezoelectric elements and laminated piezoelectric elements, have been put into practical use as electrostrictive elements that generate dimensional distortion in response to applied voltage.

The former has electrodes 1a on both the front and back sides, as shown in FIG. 7(a).
, ib formed thereon, the piezoelectric plates 2a and 2b each formed with 111
A voltage is applied between the poles 1a and lb, and a relatively large strain can be generated with a low voltage.
The drawbacks are that the response speed is slow, the generated force is small, and the conversion efficiency of input electrical energy into mechanical energy is low.

On the other hand, the latter has electrodes 3a on both sides, as shown in FIG.
, 5b are stacked and bonded together using an adhesive or the like, and a voltage is applied between the electrodes 3a, ``)b'' on both sides of each piezoelectric body 4.

This laminated piezoelectric element has a smaller strain than a bimorph piezoelectric element, but its accuracy is high, the generated stress is large, the response is fast, the generation of heat and noise is extremely small, and the input electrical energy is very low. Since the energy conversion efficiency is high, the power consumption is low, and furthermore, by reducing the distance between the electrodes, it is possible to lower the driving voltage. Therefore, it is desirable to use this laminated piezoelectric element as the electrostrictive element also in the embodiments described below.

FIGS. 1 and 2 show an embodiment of the present invention.

This light beam scanning device has a frame 11 mounted on a support member 11.
8.11a are provided protrudingly in parallel to each other, and the frames 11a,
An end plate 12 is fixed to the tip of the frame 11a, and a shaft hole 13 is provided at a corresponding position near the tip of the frame 11a, lla.
．． 13, rotary shafts 15, 15 are rotatably fitted into the shaft holes 13, 13 with pointed ends 15a in the direction of the arrow in FIG. 2, and the pointed ends 15a form a light source unit that generates a light beam. The rotating shaft 15.15 is supported by a bearing portion 14d provided on the side surface of the outer cylinder 14c of No. 14, and the rotating shaft 15.15 is attached to the frame lla, l?
It is engaged with an elastic E-ring 150 or the like on the outer surface of a to prevent play of the rotation shaft.

Further, a compression spring 1 is provided between the light source unit 14 and the end plate 12.
6 (preferably provided on the axis of the displacement member 10, which will be described later), the light source unit 14 is biased in the right rotation direction in FIG. here.

The compression spring 16 may be a leaf spring or a coil spring that biases the displacement member 10.

Further, one end of an electrostrictive element 17 having external electrodes 17a and 17b is fixed to the support member 11 via a pedestal 18', and a driving member 19 is integrated with the other end via a pedestal 18.
A spherical part 19a is formed at the tip of this driving member, and the spherical part 19a is brought into contact with the side surface of the light source unit 14 from the radial direction, and the light source unit 14 is moved around the rotation axis 15 by the displacement of the electrostrictive element 17. It is designed so that it can be swayed as it is.

The support member 11 is made of a material such as high-strength Invar, which is extremely strong, rigid, and has the same coefficient of thermal expansion as the electrostrictive element 17, and is attached to a fixed part (not shown) through the mounting hole 11b using the positioning part 11c as a guide. By fixing it, its rigidity can be further increased.

When actually assembling, first, the flat sides of the pedestals 18° 18', each having a U-shaped cross section, are attached to both ends of the electrostrictive element 17 in the longitudinal direction by gluing, and then one pedestal 18 is attached using a jig. ', fit the other end of the prismatic drive member 19 into the groove 18a of the other pedestal 18, and while applying preload, drive the drive member 19.
is attached to the pedestal 18 and integrated with the electrostrictive element 17 to form the displacement member 10.

The displacement member 10 having such a configuration is positioned with respect to the support member 11 using an appropriate jig, the groove 18a of the pedestal 18' is fitted into the protrusion 11d of the support member 11, and a preload is applied from the drive member 19 side. cradle 18' and support member 11.
to braze.

Next, the frame lla of the support member 11, the shaft hole 15 of 11a
, 15, the rotation shaft 15° 15 of the light source unit 14 is rotatably fitted, a compression spring 1B is engaged between the light source unit 14 and the end plate 12, and the side surface of the light source unit 14 is attached to the drive member 19. is brought into pressure contact with the tip spherical surface portion 19a.

The light source unit 14 includes, for example, a semiconductor laser 14a, a projection lens 14b that focuses divergent light emitted from the semiconductor laser 14a, and an outer cylinder 14G that holds these together, as shown in FIG. Bearing part 1 on the side of 14c
4d and 14d are provided.

Further, it is necessary to select the material of the drive member in consideration of thermal expansion of each component due to changes in environmental temperature.

In other words, a material (for example, invar) having a coefficient of thermal expansion such that the elongation of the displacement member 10 per unit temperature is approximately equal to the elongation of the support member 11 with respect to the distance X from the displacement member mounting surface to the shaft hole 13 is selected. By doing so, the influence of temperature changes can be removed.

FIG. 4 shows an overall block diagram including the control means of this embodiment, in which a semiconductor laser 14a is connected to a light emission signal output port 21 provided in a microcomputer (CPU) 20 via a semiconductor laser drive circuit 22. , laser light can be irradiated at predetermined timing.

Further, the scanning command value set by the setting unit 23 is inputted to the CPU 20 from the input port 24, and the output data from the output port 25 is converted into an analog signal by the D/A converter 2B, and the electrostrictive element drive circuit 27 By applying a voltage to the electrodes 17a and 17b of the electrostrictive element 17, the electrostrictive element 17 of the displacement member 10 is given an elongation corresponding to the applied voltage, and the light beam emitted from the light source unit 14 is scanned over a required range. I'm trying to get it.

5 and 6 show another embodiment of the present invention, in which a support member 31 of this light beam scanning device is made of a strong material such as invar, and a body portion 31a has a head portion 31c2 at the top. A tail portion 31d is provided, and a body portion 31a and a head portion 3
A neck 318 is formed between the head 31c and the neck 31c.
It is designed to be able to wipe within an elastic range using 1e as a fulcrum.

A plurality of mounting holes 31f are provided in the lower part of the body part 31a so that the head part 31c can be firmly fixed to a fixed part (not shown).
An electrostrictive element 17. is provided between the leg portion 31d and the foot portion 31d as in the previous embodiment. cradle 18, 18' and drive member 3 days (head 31
A displacement member 30 is constructed, and the side surface of the light source unit 14 is integrally fixed to the tip of the head "tIQ" with a hook or the like.

From this point on, the head E51Q is caused by the displacement of the electrostrictive element 17.
By wiping the light source unit 14, the neck 31e
The light beam can be scanned by wiping using the fulcrum.

FIG. 9 shows an optical path diagram of the optical beam scanning device according to the present invention.

Here, W: Planar object A to be scanned with the light beam: Center of oscillation θ of the light source unit 14: Deflection angle D of the light source unit 14: Vertical distance Δd from the center of oscillation A of the light source unit 14 to the displacement member 10 : Displacement amount Q of the displacement member 10 with natural length d: Swing width L of the light spot: Distance from the center of vibration A to the flat object W, and the light beam when the displacement member 10 has the natural length d is the flat object W. Assuming that the angle θ is perpendicular to the angle θ and that the angle θ is sufficiently small, a linear equation holds true.

Δd = tan θ#θ Q Δd D Δd Ω= ・L Now, for example, by applying a voltage of 150 V to the electrostrictive element 17 with d”=20 mm, it is possible to obtain Δd=20 μm.

When D=1mm, L=l OOmm, then Q=2mmL=200mm
Then, Q = 4 mmL = 400 mm, then Q
=8mm, and by changing the distance ML, the displacement member 10
The fluctuation width of the light spot is determined by the slight displacement of the light spot.

That is, it can be seen that the scanning range can be set arbitrarily.

Next, the actual light beam scanning procedure will be explained in detail with reference to FIGS. 10 to 12.

The amplitude Q of the light beam on the planar object W is scanned by n light spots S1*S2+...+5ffl-□, Sn, and the corresponding displacement of the electrostrictive element 17 is expressed as a unit displacement. With reference to the amount Δd/n, Δd/n.

2Δd/n + ”'”'! Δd (Fig. 11 (
d)). Δd and n are set values that are set in advance by the setting unit 23 shown in the block diagram of FIG.

11024, and is read into the CPU 20 at the time of initialization.

On the other hand, within the CPU 20, the displacement Δd/n.

2Δd/n, ..., Δd is position information Pt
e pz +..., Pk,..., P
It is recognized as n.

This positional information Pi+Pz+...,Pn is a digital quantity and is generally an integer value. For example, the displacement (k·Δd/n) can be obtained from this position information Pk as follows.

First, position information Pk is output from the CPU 20 via the I/O 25, and converted from a digital amount to an analog amount using a D/A converter. This analog quantity is transferred to the electrostrictive element drive circuit 27.
The electrostrictive element 17 is driven as an input signal to the electrostrictive element 17.

If the output voltage of the D/A converter 2nd, that is, the input voltage of the electrostrictive element drive circuit 27 is vl k, and the driving voltage of the electrostrictive element 17 is Vzk, then the electrostrictive element driving circuit 27 outputs from the input voltage Vl k. This is a power amplifier circuit that obtains voltage Vzk. In this way, the electrostrictive element 17 is driven with a voltage of VZ k to obtain a predetermined displacement k·Δd/n.

By the way, the electrostrictive element 17 has hysteresis,
The relationship between the voltage applied to the electrostrictive element 17 and the displacement is shown in FIG.
) as shown.

That is, in order to obtain a predetermined displacement k・Δd/n, there are cases where the applied voltages V2 k and VZ k' are required, but even with this hysteresis, as can be seen from Fig. 8(a), , when positioning the electrostrictive element 17 in the direction of increasing the applied voltage v2, that is, while determining the position while charging;
By distinguishing between the direction in which the voltage is lowered, that is, the position is determined while discharging the charge of the electrostrictive element 17, it becomes possible to make the applied voltage and displacement correspond one-to-one.

Therefore, the CPU 20 has two systems for position information; one system determines the position while charging, and the other system determines the position while discharging.

PL+P2+ location information for determining location while charging
......, Pk, ......, Pn, the position information Pk is l in the order of pi + P2 *......
1025, and the electrostrictive element 17 receives V 21
+ V 22 r...Vzk...,
The voltage is applied in a direction that gradually increases in the order of VZ n, and the displacement amount Δd/n, 2Δd/n, ......, Δ
d/n, ..., Δd is determined.

On the other hand, the position information of the system that determines the position while discharging is Pt
'y P2'”...HPk' ・=-,
If Pn', position information Pk' is Pn', Pn-1'
The voltage v2 applied to the electrostrictive element 17 is V2n' (=V
2 n LV2 n −1' , ..., VZ
Displacement Δd, (nt) Δd, while decreasing as k'.
. . . , Δdn, . . . The position corresponding to Δdn is determined.

Hereinafter, the position information will be described as Pk in terms of the direction of charging, but the same can be said of the direction of discharging.

In this way, the relationship between the position information Pk and the displacement Δdn is determined, but a relational expression that directly connects the position information Pk and the displacement amount Δdn can be obtained by the following procedure.

In FIG. 8(b), the area [■] is a characteristic diagram showing the relationship between the applied voltage v2 and the displacement amount Δd. Here, voltage v2 is applied to the electrostrictive element 17, and the light source unit 14 vibrates.
The relationship between the applied voltage (2) and the amount of displacement Δd of this device is determined by the applied voltage displacement characteristics of the electrostrictive element 17 and the like.

Region (m) in FIG. 8(b) is the characteristic of the electrostrictive element drive circuit 27 showing the relationship between the input voltage Vl and the applied voltage v2.

V2/Vl is the amplification factor of the electrostrictive element drive circuit 27, and in general, 1 and v2 have a nonlinear relationship.

Region (IV) in FIG. 8(b) shows the characteristics of the D/A converter 26. A voltage v1 is obtained by inputting digital position information P. Position information P and voltage V! The characteristics are determined by the resolution, linearity, etc. of the D/A converter. 8th
Area (1) in figure (b) is the location information Pk that you ultimately want to know.
The relational expression is Δd/n for displacement.

The characteristics shown in FIG. 8(b) (II), Cm), and (IV) are determined through experiments. To obtain position information Pk and displacement amount Δd/n from those characteristics,
For example, in FIG. 8(b), the displacement amount Δd is arbitrarily divided into multiple equal parts and taken on the axis of the displacement amount in FIG. 8(b), the characteristic diagram is used in the direction of the arrow in the figure, and the applied voltage v2 decide.

Similarly, input voltage v1 is obtained by plotting from applied voltage v2 in the direction of the arrow, and position information P corresponding to this is also obtained.

The relationship between the position information P and the displacement Δd thus obtained can be plotted on the area [1) in FIG. 8(b), and the desired characteristics can be obtained.
Δd/n,...kΔd/n,...
. . . .DELTA.d is set at equal intervals for convenience of explanation, but it is also possible to set only the necessary spots finely among the n spots.

In Figure 11 (a), (b), (c), (d),
Light spot 51tS2y..., Q/
Position information P1+P2+ when moving at equal intervals by n
..., shows the output timing of Pn (each curve is the 8th
In Figure (a), the waveform when O→a is shown, and the waveform when a→O is omitted). Here, Δ is the charging current to the electrostrictive element 17.

FIG. 12 shows a specific example of the electrostrictive element drive circuit 27, which includes two transistor switches 41 and 42 connected in series between the drive power supply vB and the ground, and two transistor switches 41 and 42 that control their on/off, respectively. It consists of comparators 43 and 44, a changeover switch 45 that switches and applies the input voltage v1 to the comparator 43 or 44, resistors 46 and 47, and the like.

Then, when the selector switch 45 is switched to the a side, #!
The electrostrictive element 1 is connected via the transistor 41 by the dynamic power source VB.
7 can be charged and driven with a voltage V2 corresponding to the input voltage v1.

Furthermore, when the selector switch 45 is switched to the b side, the electrostrictive element 17 can be driven by discharging the charge through the transistor switch 42 and the resistors 46 and 47.

By the way, in order to move the light spot at equal intervals, it is necessary to divide it into parts. Then, the applied voltage v2 of the electrostrictive element 17
The displacement amount Δd is determined in FIG. 8(a).

On the other hand, as mentioned above, it is preferable to use a laminated piezoelectric element as the electrostrictive element, but this laminated piezoelectric element electrically corresponds to a capacitor and has a large capacity because it is made of one layer.

The amount of displacement is approximately proportional to the amount of charge stored in the electrostrictive element, and the change in capacitance over time is similar to the charging curve of a capacitor.

In order for the displacement amount to change from Δd/n to (k+1)Δd/n and the light spot to move, the applied voltage Vz
must be increased from Vzk to Vz(k+IH,-).

It can be seen from FIG. 8(a) that as the amount of displacement approaches Δd, the applied voltage v2 that should be raised becomes smaller. Therefore, the current flowing through the electrostrictive element 17 also becomes
At first, a large current flows, and as the amount of displacement approaches Δd, it becomes smaller.

Figure 11(a) shows such a relationship.

These are shown in (b), (c), and (d). Output voltage v
1 and the applied voltage v2 have a linear relationship in most of their ranges, as can be seen from the characteristic diagram shown in the region [IIr) of FIG. 8(b), and the waveforms of the output voltage Vz and the applied voltage v2 are approximately The curve will be similar.

In the embodiment of the present invention, the CPU 20 is used, and the output voltage Vl of the D/A converter 26 does not change continuously.

It changes in steps.

The waveforms of the applied voltage v2 and the charging current ■ are the waveforms of the electrostrictive element 1.
7 can be electrically approximated as a capacitor, so the 11th
As shown in Figures (c) and (d), it becomes an exponential function.

That is, as shown in FIGS. 11(a), (b), (c), and (d), in order to move the light spot at equal intervals, the order of time jl + j2 +..., tn is required. At the point in time when the time interval gradually increases, the position information P1eP2t
. . . can be realized by outputting Pn via l1025.

The embodiment shown in FIG. 1 (center A of the light source unit 14) has been described above, but even when the light source unit 14 swings about the neck 31a as a fulcrum as in the embodiment shown in FIG. Similarly, each correlation curve as shown in FIG. 8(b) may be obtained experimentally, and the position information of the CPU 20 may be outputted from this through the l1025.

FIG. 13 is a flowchart showing the processing of the CPU 20 during optical spot scanning according to the embodiment of FIG. 4, in which the semiconductor laser drive circuit 22 (FIG. 4)
Let a emit light (step ■).

The position of the light spot S is determined (step ■), and a voltage corresponding to the position is applied to the electrostrictive element 17 (step ■).

Furthermore, it is determined whether or not to continue scanning depending on whether the applied voltage has reached a predetermined voltage (Step 2). To continue scanning, steps 2 to 3 are repeated, and to end scanning, the semiconductor laser 14a to stop emitting light (step ■).

In this way, according to each of the embodiments described above, the amount of displacement of the electrostrictive element 17 can be freely controlled in accordance with the voltage applied to the electrostrictive element 17 with an extremely simple configuration, and thereby the light source unit 14 can be oscillated. It becomes possible to scan and position the optical spot at high speed (on the order of several KHz) and with high accuracy by moving the optical fiber.

In each of the above embodiments, a case has been described in which the light beam is scanned in the same plane, but the light source units are designed to be able to swing independently and perpendicular to each other, and to scan two light beams perpendicular to each rotation axis. By providing two displacement members, the light beam can be scanned in the x-y direction.

Also, light ij! 14a is not limited to a semiconductor laser, and a light emitting element such as an LED may be used.

Next, an application example in which the light beam scanning device according to the present invention is applied to an optical distance measuring device will be described with reference to FIGS. 14 and 15.

In FIG. 16, reference numeral 14 denotes a light source unit in which a semiconductor laser 14a and a light projecting lens 14b are integrally held by an outer cylinder 140, and is swingable around the principal point A of the light projecting lens 14b. It is driven by the displacement of a displacement member 10 having a natural length d and spaced apart from the center of motion A.

40 is the principal point B located at a distance of 1IiC directly to the side from the swing center A.
41 is a semiconductor device detector (hereinafter abbreviated as rPsDJ) provided horizontally at a distance F from the principal point B of the light receiving lens 40.

For convenience of illustration, only the light-receiving surface is shown.

Now, with no voltage applied to the electrostrictive element of the displacement member 10, a light beam is vertically irradiated from the light source unit 14, and the light beam generates a light spot P1 on the object W to be measured. PS by the light receiving lens 40
When an image is formed on point Q1 on the light receiving surface of D41, if the distance from the fixed point QO where the optical axis of the light receiving lens 40 intersects with the light receiving surface of PSD 41 to point Q1 is xl, then as shown in FIG. , the distance Ll from the swing center A to the object W to be measured is expressed by the following equation.

That is, by knowing the position of point Q1 on PSD 41, the distance to object W can be measured.

Further, from this state, a voltage is applied to the electrostrictive element to extend the displacement member 10 by the displacement amount Δd, and the light source unit 14 is swung around the oscillation center A, with the light beam being swung by an angle θ. , a light spot P2 is generated at a distance Q from point P1 on the object W to be measured, and the image of this light spot P2 is projected by the light receiving lens 40 at a distance X from a fixed point QO on the light receiving surface of the PSD 41.
If the image is focused on point Q2 of 2, then from Fig. 17,
From these equations (2) and (3), the distance tlLz to point P2 is expressed by the following equation.

C·F

That is, by applying each voltage shown in FIG. 11(a) to the electrostrictive element and scanning the light beam.

It becomes possible to recognize the surface shape of the object W to be measured.

〔Effect of the invention〕

As described above, the light beam scanning device according to the present invention is an extremely simple device that only requires an electrostrictive element to be interposed between a light source unit that generates a light beam and a support member that swingably supports this light source unit. Due to its structure, it has good dust resistance, low manufacturing cost, and is easy to assemble.

In addition, since scanning of the light beam is performed by swinging the light source unit, a large amplitude of the light spot can be obtained by slight displacement of the electrostrictive element, making it possible to scan the light beam at high speed and with high precision. Become.

Note that if a laminated piezoelectric element is used as the electrostrictive element,
It is possible to obtain a light beam scanning device that generates little heat, is noiseless, has good responsiveness, and has good efficiency in converting input electrical energy into mechanical energy, so it consumes little power.

[Brief explanation of the drawing]

Fig. 1 is a front view showing an embodiment of the present invention, Fig. 2 is a plan view thereof, Fig. 3 is a sectional view showing the structure of the light source unit, and Fig. 4 shows the entire planting of this embodiment. FIG. 5 is a front view showing another embodiment of the invention, and FIG. 6 is a plan view thereof. Figures 7(a) and (b) are perspective views showing the structures of different electrostrictive elements, Figure 8(a) is a diagram showing the relationship between applied voltage and displacement of the electrostrictive element, and (b) 9 is a correlation curve diagram showing the relationship between CPU position information and displacement amount, and FIG. 9 is an optical path diagram of the embodiment shown in FIGS. 1 to 4. FIG. 10 is an explanatory diagram illustrating a light beam scanning method according to this embodiment. FIG. 11 (a) is a diagram showing the output voltage of the D/A converter in relation to the elapsed time, (b) is a diagram showing the current to be supplied to the electrostrictive element in relation to the elapsed time, ( C) is a diagram showing the voltage to be applied to the electrostrictive element in relation to the elapsed time, (d) is a diagram showing the amount of displacement of the electrostrictive element in relation to the elapsed time, and Figure 12 is the diagram shown in Figure 4. 13 is a flow diagram showing the processing of the CPU 20 during light beam scanning according to the implementation of FIG. 4, and FIG. 14 is an application of the light beam scanning device according to the present invention. A perspective view showing an example, and FIG. 15 is an optical path diagram. FIGS. 18 and 17 are explanatory diagrams showing different examples of conventional light beam scanning devices. 10.50...Displacement member 11.31...Support member 14...Light source unit 1 day...Compression spring (biasing means) 17...Electrostrictive element 19,39...Driving member 20... Microcomputer (CPU) 22...
Semiconductor laser drive circuit 26...D/A converter 27...Electrostrictive element drive circuit 1 Fig. 5 Fig. 6 Fig. 7 Fig. 7 (Q) (b) Fig. 9 H1-+ Fig. 10 Figure 11 Figure 12 Drive power supply V port Figure 13 Figure 16

Claims (1)

[Scope of Claims] 1. One end that swingably supports a light source unit that emits a light beam, and has an electrostrictive element that generates dimensional distortion in accordance with an applied voltage at a point away from the center of swing of the light source unit. A light beam operation characterized in that the other end of a fixed displacement member is brought into pressure contact with the electrostrictive element, and a voltage corresponding to the unit displacement of the electrostrictive element is integrated and applied at predetermined time intervals until the required displacement is reached. Method. 2. A light source unit that emits a light beam, a support member that swingably supports the light source unit in a variable irradiation direction, and a support member that is interposed between the support member and the light source unit and generates dimensional distortion according to the applied voltage. and an urging means for pressing the light source unit against the electrostrictive element, and the light source unit is oscillated by displacement of the electrostrictive element to scan the light beam. Features a light beam scanning device. 3. A support member having a head connected via a neck at one end and a tail at the other end, and an electrostrictive member that is interposed between the head and tail of the support member and generates dimensional distortion according to applied voltage. Motoko and
A light source unit that emits a light beam is attached to the tip of the head, and the light boom is scanned by swinging the light source unit using the neck as a fulcrum by displacement of the electrostrictive element. A light beam scanning device.