JP2958779B2 - Speckle pattern movement detection method and position specification device using the same - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a speckle pattern movement detecting method for detecting speckle pattern movement information generated by scattering of a coherent electromagnetic wave on a rough surface of an object, and a method of using the method. The present invention relates to an improvement of a position designation device (a position designation device useful when a position is designated on a display screen in a computer terminal, a workstation, a personal computer, or the like, or when a position is designated for various control objects).

[Conventional technology]

As a conventional position specifying device for computer input, a so-called mouse is widely used from the viewpoint of low cost, excellent operability, and high position specifying accuracy.

At present, the mainstream mechanical mouse has a ball that can be rotated in any direction protruding from a part of the housing, and detects the direction and amount of movement based on the direction and amount of rotation of the ball. Thus, the position to be designated is specified.

[Problems to be solved by the invention]

However, such a conventional mechanical mouse utilizes mechanical contact rotation of a ball, which is difficult in terms of durability and has a limit in improving the positional accuracy.

As a solution to such a drawback of the mechanical mouse, an optical mouse that optically detects movement information without contact has already been provided.

An optical mouse of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 57-107929.
No. 57-207930, as disclosed in JP-A-57-207930, a main body in which a light source and a photodetector are stored, and the main body is moved on a dedicated underlay on which a regular lattice pattern is engraved. The movement information is detected by counting the number of grids on the special underlay that traverses.

However, in this type of optical mouse, a dedicated underlay is indispensable, which not only limits the degree of freedom of use, but also makes the dedicated underlay dirty or damaged, making it unusable. The point is not enough, and the resolution of the movement information detection is determined by the fineness of the grid engraved on the dedicated underlay. Therefore, it is not easy to increase the resolution of the movement information without increasing the cost.

In order to solve such a problem, the present inventor detects movement information of a so-called speckle pattern,
We have already provided a position designation device that can easily increase the resolution of moving information detection without using a special underlay, while reducing the cost of the device itself, improving operability and durability (Japanese Patent Application No. Sho 63). -116878).

And, in the above-mentioned prior art, from the viewpoint of further improving the operability of the above-described position specifying device, in order to enable fine position specification or rough position specification according to the application, For example, by making the average size of speckles variable, the ratio of the movement amount of the movable body of the position designation device to the movement amount of the designated object (position designation movement rate)
Has already been disclosed.

However, the present inventor has further studied the dynamic technology for changing the position designation movement rate. As a result, depending on the average size of speckles, the position designation movement rate may not be dynamically changed. However, it has not been sufficiently solved how to set the average size of the speckles in order to surely perform the operation of changing the position designation movement rate.

In addition, such a problem is caused not only by the above-mentioned mouse but also by various devices (movement detecting device, speed detecting device, etc.) utilizing the detection of the movement information of the speckle pattern, including a position specifying device such as a robot. The same can occur under the demand that the operation of changing the detection movement rate be performed reliably.

SUMMARY OF THE INVENTION The present invention has been made in view of the above viewpoints, and has a speckle pattern movement detection method capable of reliably performing a change operation of a speckle pattern detection movement rate, and position designation using the same. An object of the present invention is to provide a position specifying device capable of surely performing a change operation of a movement rate.

[Means for solving the problem]

◎ Experimental analysis to solve the problem In order to solve the above problems, the present inventors conducted the following experiment in order to investigate the relationship between the average size of speckle and the detection movement rate or the position designation movement rate. went.

(1) Content of experiment When speckles of a predetermined size are moved under predetermined conditions, the movement information of the speckle pattern is appropriately processed by a processing system, and based on the processed data, for example, a display of a personal computer is displayed. An experimental system (FIG. 2) for moving the cursor on the screen is constructed, and the cursor movement rate K (the actual cursor movement amount with respect to the rough surface movement amount for generating the movement speckle pattern) corresponding to the position designation movement rate Ratio)
And the average size of speckles were investigated.

(2) Experimental system In FIG. 2, reference numeral 10 is a He-Ne laser, and 11 is a laser.
A condenser lens for condensing the beam Bm from 10, 12 in a predetermined direction at a predetermined velocity v _d with laser beams Bm, which is condensed by the condenser lens 11 is irradiated (the x direction in this example) A rough moving plate 13 that moves by a predetermined amount _xd , 13 is a rough moving plate 12
Scattered, a pair of photo die auto 13a which is arranged along the x direction in order to detect the speckle pattern SP moves by x _s at a moving speed v _s, detector consisting 13b at, 14
(Specifically, 14a, 14b) is an amplifier for amplifying the output ( _fds : frequency _fds , M: number of vibrations [number of signal peaks]) of the detector 13, and 15 (specifically, 15a, 15b) Is a binarizing circuit for binarizing the output from each amplifier 14 with an appropriate threshold.

Reference numeral 16 denotes a personal computer, and a display screen
An arithmetic processing unit 19 is provided for performing arithmetic processing on how to move the cursor 18 on 17. This arithmetic processing unit 19
Receives the output from each binarization circuit 15, determines the direction of movement of the cursor 18 from the sign of the phase difference τ between them, and counts up or counts the number of pulses of the binarized signal according to the direction of movement. Equipped with an up-down counter that counts down,
The cursor 17 is moved by N to a position corresponding to the counter output.

(3) Experimental conditions In FIGS. 2 and 3, laser beam wavelength λ: 632.8 nm Photodiode interval: 0.3 mm Photodiode aperture size: 0.295 mm Radius ω ₀ of beam waist Bw: 9.7 μm Speckle rigidity η : 10 However, the speckle translation distance L _T, the speckle average size when as D, is _{η = L T / D ... (} 1).

Here, the speckle translation distance L _T, as shown in FIG. 4, the spatial cross-correlation function at each of the speckle pattern SP before and after the movement Peak height of the spatial displacement amount) (amount of movement x [0 speckle _{<x 1 <x 2 <x} 3 < changed by x ₄ <x _5]) of the peak of the cross correlation function of the stationary speckle 1 / e of height γ _P0
(E: base of natural logarithm) means the amount of speckle movement (N.Takai, T.Iwai & T.Asakura, Applied Optics)
Vol22 No.1 (1983) pages 170-177 'Correlation dista
nce of dynamic speckles'), L _T = ∞ when the speckle moves without deformation, and L _T = 0 when the speckle only moves without deformation. Therefore, the speckle modulus η obtained by normalizing the speckle translation distance L _T speckle average size D is made to the index indicating the deformation resistance in the speckle.

According to the above-mentioned document, in the case of a so-called Gaussian speckle which is generated when a so-called Gaussian beam is scattered into irregularities sufficiently deeper than the wavelength, the specification of the diffraction field (scattering in free space not via an imaging system) The speckle translation distance L _T is given by: L _T = (1 + R / ρ) ω (2) where R is the speckle pattern SP from the rough moving plate 12.
Is the radius of curvature of the wavefront of the laser beam Bm on the rough moving plate 12, and ω is the distance to the detection surface position of the rough moving plate 12.
Is the spot radius of the laser beam Bm.

The average speckle size D corresponds to the average speckle radius, and is represented by D = λR / πω (3).

Therefore, when the equations (2) and (3) are substituted into the equation (1), η = (1 + R / ρ) ω / (λR / πω) = (πω ² / λ) (1 / R + 1 / ρ) (4) Here, assuming that | 1 / R | << | 1 / ρ |, that is, | R | >> | ρ | (5), the above equation (4) can be expressed as η ≒ πω ² / (λρ) (( 4 ').

Also, the beam waist Bw narrowed down by the condenser lens 11
If the distance from to the rough moving plate 12 is z, a = πω ₀ ² / λ, Substituting equations (6) and (7) into the above equation (4 '), Here, assuming that the z is sufficiently large, (a / z) ²
≪1, and considering the above equation (7), the above equation (5) usually holds when | ρ | ≒ | z |, | R | >> | z | (9) It is.

In summary, the rough surface is far from the beam waist Bw,
In addition, when the distance R between the rough surface and the detection surface is sufficiently longer than the beam waist Bw to the distance z between the rough surfaces, it can be said that the speckle rigidity η is proportional to the above z.

In this experiment, the average speckle size D is expressed by the above equation (3).

Here, assuming that the z is sufficiently large, 1 << (λz / πω ₀ ² ) ² (10)

Therefore, from equations (6) and (10), ω ≒ ω ₀ · (λz / πω ₀ ² ) = λz / πω ₀ (11) holds.

Therefore, when this equation (11) is substituted into the above equation (3), it can be approximated as D ≒ (λR / π) · (πω ₀ / λz) = Rω ₀ / z (12)

In summary, when the rough surface is far from the beam waist Bw, the average speckle size D is proportional to the distance R between the rough surface and the detection surface regardless of the wavelength λ, and is inversely proportional to the distance z between the beam waist Bw and the rough surface. I can say that.

In this experiment, by appropriately adjusting R and z based on the above equations (3) and (4), the speckle rigidity η was uniquely set and the numerical value of the average speckle size D was variably set. did.

(4) Experimental Results FIG. 5 shows the relationship between the average speckle size D and the cursor movement rate K.

According to the figure, the average speckle size D is 0 to 600μ.
It is understood that the cursor movement rate K tends to increase proportionally up to about m, and the cursor movement rate K is kept substantially constant from around the point where the average speckle size D exceeds 600 μm.

This means that the average speckle size D is 0-600 μm
Variably set in the area E, it means that the cursor movement rate K changes substantially proportionally according to the average size D of the speckles.

◎ Theoretical analysis to solve the problem (1) Basic model system FIG. 6 is a model of the experimental system in FIG.

In the following analysis, the speckle pattern SP
When considering only the amount of movement without considering the direction of movement, there is essentially no difference from using only one photodiode as a detector, so consider using only one photodiode as a detector. , And speckle deformation is considered negligible.

By doing so, in the theoretical analysis of the model system,
This makes it possible to make the movement information of an image that is not deformed equivalent to that detected by a spatial filter. In order to apply the velocity measurement method using the spatial filter, in the analysis, instead of the cursor movement amount, the speckle movement amount, and the rough surface movement amount, the cursor speed, the speckle speed, and the
Consider the rough surface speed, and if a moving amount is necessary, integrate the speed over time.

In the figure, the cursor speed p is: p = K ・ v _d (13) where K = K ₁ · K ₂ · K ₃ (14)

Here, K: car loss transfer rate K ₁ : ratio of speckle speed / rough surface speed (referred to as speckle transfer rate) K ₂ : ratio of average frequency of detector signal / speckle speed K ₃ : cursor speed / detector signal Represents the ratio of the average frequency of

By integrating the above equation (13), the following equation of the cursor movement amount N is obtained.

N = K · x _d (15) where x _d is the amount of movement of the rough surface.

(2) speckle mobile ratio K ₁ for each coefficient of the cursor movement ratio (2-a) K _1, K ₃ is the characteristic of dynamic speckles,
In the case of Gaussian speckle, it is usually given by the following equation.

K ₁ = 1 + R / ρ (16) Here, considering the above equation (9), | ρ | ≒ | z |, | R | >> | z |, the above equation (16) becomes K ₁ ≒ 1 + R / z ≒ R / z… (17)

That is, under the above approximation, the speckle movement rate K
₁ is the distance R from the rough surface to the detection surface without being affected by the wavelength.
, And is inversely proportional to the beam waist Bw to the rough surface distance z.

Also, K ₃ is a constant determined by the interface of a computer.

K ₂ for (2-b) K ₂ is representative of the characteristic of the spatial filter of the detector.

Now, if not to take into account the deformation of the speckle, speed v _s
The output of the detector placed in the speckle that moves with is based on the theory of velocity detection by a spatial filter, Ψ (f _ds ) = Φ (f _ds / v _s ) · Ω (f _ds / v _s )… (18) It is represented by

Where Ψ (f _ds ) is the time-frequency power spectrum of the output signal of the detector, Φ (ξ) is the spatial frequency power spectrum of speckle, Ω (ξ) is the spatial frequency power spectrum of the detector, and f _ds is the time. Frequency and ξ indicate spatial frequencies, respectively.

Then, according to equation (18), the overlap of the time frequency power spectrum of the speckle and the time frequency power spectrum of the detector is obtained as the output signal of the detector.

Therefore, as shown in FIG. 7, when the size of the speckle S is sufficiently smaller than the opening d of the detector 13,
In other words, as shown in FIG. 8, if the spread of the spatial frequency power spectrum Φ (ξ) of the speckle is sufficiently larger than the spread of the spatial frequency power spectrum Ω (ξ) of the detector, the output signal is determined by the spatial frequency power spectrum of the velocity v _s and the detector speckle Ω (ξ), it does not depend on the spatial frequency power spectrum of the speckle Φ (ξ).

On the other hand, assuming that the aperture of the detector is a one-dimensional rectangular aperture, Φ (ξ) = a ₁ sinc ² (d · ξ) (19) Here, a ₁ is a constant.

Therefore, the spread of the spatial frequency power spectrum of the detector is proportional to 1 / d, and eventually, the spread of the time frequency power spectrum of the output signal of the output signal of the detector is v _s
It will be proportional to / d.

Therefore, K ₂ is Becomes Here, ▲ ▼ is the time average of f _ds .

(3) Conclusion When the cursor movement rate K is calculated based on each coefficient of the cursor movement rate K described in detail in the above (2), the following is obtained.

That is, from equations (14), (17), and (20), K = K ₁ · K ₂ · K ₃ ∝ (R / z) · (1 / d) · K ₃ = (K ₃ / d) · ( R / z) ... (21)

Here, since both K ₃ and d are constants, the cursor movement rate K satisfies the relationship K∝R / z (22).

Further, from the above equation (12), the average speckle size D
Is because it is D = Rω ₀ / z, the equation (22) becomes _{KαR / zαRω 0 / z = D} ... (23).

In summary, it has been theoretically supported that when the average size D of the speckles is sufficiently smaller than the opening size d of the detector 13, the cursor movement rate K is proportional to the average size D of the speckles.

The present inventors have devised the present invention through the above-described experimental analysis and theoretical analysis.

That is, in the method for detecting the movement of a speckle pattern according to the present invention, as shown in FIG. 1 (a), the movement information M of a speckle pattern SP generated by scattering of a coherent electromagnetic wave Bm on an object rough surface 1 is detected by light. Upon detection by the detector 2, the average size D of the speckle in the speckle pattern SP on the light receiving surface of the photodetector 2, the relative movement information of the photodetector 2 with respect to the object rough surface 1, and the information of the photodetector 2 The average size D of the speckles is varied in an area E in which the detected mobility J changes almost proportionally to the average size D of the speckles in relation to the detected mobility J indicating the ratio to the output movement information. It is characterized in that it is set.

In such a method invention, the movement information M of the speckle pattern SP is not limited to only the movement amount, but widely includes movement speed, movement acceleration, and the like. For this reason, as an object to which the method invention can be applied, in addition to a position specifying device described later, a moving amount detecting device necessary for performing position control of a self-propelled bogie or the like, a speed detecting device such as a speed sensor, or the like is used. No.

FIG. 1 (a) shows a speckle pattern SP.
As shown in (1), only a speckle of a so-called diffraction field without an imaging system caused by scattering of the object rough surface 1 is targeted, and the scattered light of the object rough surface 1 is imaged on a predetermined portion by an imaging lens. by the so-called object-field speckle, since the speckle velocity / rough surface speed (corresponding to K ₁ theoretical formula) is that different from those described above, not subject.

Further, the photodetector 2 may be appropriately selected as long as it can detect the movement information of the speckle pattern SP, and a signal processing system from the photodetector 2 is also a target device. The design may be changed appropriately according to the requirements.

Here, as for the photodetector 2, from the viewpoint of easy real-time processing and accurate determination of the movement information M including the positive and negative of the moving direction of the speckle pattern SP, FIG. As shown in FIG. 1), at least one set of photodetectors 2a and 2b is arranged side by side for one dimensional component necessary for detecting the movement information M, and as shown in FIG. It is preferable to detect the phase difference τ of the output signals from the photodetectors 2a and 2b.

In this case, when detecting one-dimensional movement information, one set of the light detection elements 2a and 2b is used for one direction component.
May be arranged side by side, for example, a pair of photodetectors 2a, 2b
If two or three sets of photodetectors 2a and 2b are used such that straight lines connecting each other are orthogonal to each other, two-dimensional or three-dimensional movement information can be detected.

Further, a processing system for processing an output signal from the photodetector 2 including the pair of photodetectors 2a and 2b may be appropriately selected, but the obtained phase difference τ may correspond to the speckle pattern SP. From the viewpoint of reducing the influence of errors caused by irregularities, the phase difference τ obtained from each set of photodetectors 2a and 2b by using a plurality of sets of photodetectors 2a and 2b per dimension. Taking an average, taking a time average of the phase difference τ obtained from the pair of photodetectors 2a, 2b,
It is preferable to adopt a configuration that uses both of them.

In addition, as shown in FIG. 1 (d), the position specifying device using the speckle pattern movement detection method according to the present invention includes a movable body 3 movable with respect to an object rough surface 1,
And an electromagnetic wave source 4 for irradiating a coherent electromagnetic wave Bm to the object rough surface 1 from a predetermined portion of the movable body 3 and a spec generated from the object rough surface 1 accompanying the irradiation of the electromagnetic wave Bm to the movable body 3 Detector 2 for detecting relative movement information of the light pattern SP with respect to the movable body 3, an average size D of speckles in a speckle pattern SP on a light receiving surface of the light detector 2, and an object roughness of the light detector 2. In relation to the detected movement rate J indicating the ratio of the relative movement information to the surface 1 and the output movement information of the photodetector 2, the detected movement rate J
And a speckle size changing means 5 for variably setting the average size D of the speckles in a region E in which the average size D of the speckles changes substantially proportionally. A position to be designated is specified based on the movement information.

In such a device invention, the photodetector 2 may be appropriately selected in the same manner as described in the method invention described above, and the signal of the output signal detected by the photodetector 2 may be selected. The location of the processing system may be selected as appropriate, such as an external device, the movable body 3 or a device connected to the external device. However, from the viewpoint of sharing with various external devices, the inside of the movable body 3 may be selected. It is preferable to provide a signal processing system.

As the speckle size changing means 5, if the average size D of the speckles can be arbitrarily set during the position specifying operation, the electromagnetic wave source 4 can be used to set the rough surface 1 of the object.
The design may be changed as appropriate, for example, the distance to the object may be variably set, or the distance between the rough object surface 1 and the photodetector 2 may be variably set.

[Action]

In the technical means as described above, according to the method invention shown in FIG. 1A, the average size D of speckles on the light receiving surface of the photodetector 2 is variably set within the predetermined area E. The moving rate J detected by the photodetector 2 changes substantially proportionally according to the average size D of the speckles.

In particular, a set of photodetectors 2 as shown in FIG.
If the photodetector 2 composed of a and 2b (the distance between the centers thereof is g) is used, the speckle pattern SP (the deformation is assumed to be extremely small) moves at a constant speed v in the direction of the arrow. In this case, the signal intensity detected by one of the light detection elements 2a located at the preceding stage in the movement direction is substantially the same as the light detection element 2b located at the latter stage in the movement direction of the speckle pattern by a certain time τ earlier. .

In this case, as shown in FIG. 1 (c), the time variation curves of the output signals of the pair of photodetectors 2a and 2b are similar to each other and shifted by a phase difference τ. τ = g /
Determined by v.

Therefore, from the information of the phase difference τ, the speckle pattern
From SP movement information, for example, τ sign to spec pattern
The sign of the moving direction of the SP can be determined, the magnitude of the moving speed v can be determined from its absolute value, and the speckle pattern SP can be determined by counting the rise and fall of the output signal. Can be obtained.

According to the position designation device invention shown in FIG. 1 (d), the electromagnetic wave source 4 such as a laser irradiates the object rough surface 1 with the electromagnetic wave Bm, and the movable body 3 moves with respect to the object rough surface 1 with the velocity v _d in If you moved by u _d, so that the object rough surface 1 is relatively moved by u _d at a speed v _d relative to the movable body 3.

At this time, the speckle pattern SP scattered by the object rough surface 1 is moved proportionally u _s at a speed v _s on the light receiving surface of the photodetector 2 with the relative movement of the object rough surface 1 .

Therefore, the photodetector 2 has the speckle pattern
By detecting the SP movement information at a predetermined detection movement rate J, the relative movement amount of the object rough surface 1 is indirectly detected, and the position of the designated object is determined based on this detection information. It is specified.

At this time, the speckle size changing means 5 determines the average size of speckles on the light receiving surface of the photodetector 2 by a predetermined area E.
, The movement rate J detected by the photodetector 2 changes in accordance with the average size of the speckles, and the movement rate of position designation changes accordingly.

〔Example〕

Hereinafter, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

FIGS. 9 and 10 show the case where the present invention is applied to a computer input mouse.

In the figure, reference numeral 30 denotes a rough surface of an object, 31 denotes a movable housing having a pressing pad 32 for sliding at a bottom portion, 33 denotes a semiconductor laser as an electromagnetic wave source stored in the movable housing 31 and irradiating a laser beam Bm; Reference numeral 34 denotes a condensing lens made of a plastic lens, a Fresnel lens, or the like for guiding the beam Bm from the semiconductor laser 33 to the irradiation portion Q of the rough object surface 30 with a predetermined spot radius ω, and 35 denotes an optical path length of the detection optical system. A reflecting mirror for appropriately reflecting the reflected beam from the object rough surface 30, is disposed at the optical path end position of the detection optical system,
A detector 37 for detecting movement information of the speckle pattern SP generated in the reflected beam from the object rough surface 30; a signal processing system 37 for converting the output signal from the detector 36 into a movement control signal for computer input; Is an input switch for performing a position designation operation, and 39 is a harness for connection to an external device (not shown).

Reference numeral 40 also moves the position of the reflection mirror 35 up and down, thereby changing the optical path length R from the beam irradiation part of the object rough surface 30 to the detector 36 via the reflection mirror 35, and changes the movement rate of the cursor 53 described later. A button body 40a to which the reflection mirror 35 is attached and which is vertically movably disposed at the top insertion hole 31a of the movable housing 31, a button body 40a, and a position of the reflection mirror 35. Button body 40a to return the
And a return spring 40b for biasing the return spring.

In this embodiment, the detector 36 is, in particular, an eleventh embodiment.
As shown in the figure, light receiving cells 36a to 36d made of photodiodes are arranged side by side at predetermined intervals along the x direction and the y direction, which are movement reference directions.

In this case, the condenser lens 34 is for obtaining an appropriate radius ω ₀ of the beam waist Bw, the beam waist radius ω ₀ , the distance z between the beam waist Bw and the object rough surface 30, and the object rough surface 30. Regarding the distance R between the detectors 36, the average size of speckles on the detectors 36 (meaning the radius of the speckles in this case) is the detector 36 regardless of the position of the reflection mirror 35 in any position within the movable range. Are set to be equal to or smaller than the openings of the respective light receiving cells 36a to 36d.

In addition, as shown in FIG. 12, the signal processing system 37 is arranged in the y direction with an x component signal processing system 37x for processing signals from the light receiving cells 36a and 36b arranged in the x direction. And a y-component signal processing system 37y for processing signals from the light receiving cells 36a and 36c.

In this embodiment, the signal processing system 37 includes an amplifier 41 that amplifies the output of a corresponding set of light receiving cells 36a, 36b or 36a, 36c, and removes a DC component, a noise, and a high frequency component of the output of the amplifier 41. And a binarization circuit 43 for binarizing the output of the cut filter 42 with a threshold value of 0
Consists of

Further, in this embodiment, the signal from the signal processing system 37 is input to the arithmetic processing unit 51 in the computer 50, and the arithmetic processing unit 51 outputs the x component and the y component of the output from the binarization circuit 43. The direction of movement is determined from the signs of the phase differences τ _x and τ _y, the number of pulses of the binary signal is counted up or down according to the direction of movement, and the speckle pattern SP The relative movement information with respect to the object rough surface 30 is determined, and the position of the cursor 53 on the display screen 52 is specified in accordance with the movement information.

Next, the operation of the position specifying device according to this embodiment will be described.

Now, the laser beam Bm emitted from the semiconductor laser 33 is reflected on the rough surface 30 of the object and then reaches the detector 36,
On this detector 36, a speckle pattern SP is generated.

In this state, the movable housing 31 is
When moved on 30, the speckle pattern SP on each of the light receiving cells 36a to 36d of the detector 36 moves correspondingly. The x-direction component of the movement of the speckle pattern SP is represented by a pair of 36a and 36b arranged side by side along the x-direction.
Further, the y-direction component of the movement of the speckle pattern SP is detected by a pair of light receiving cells 36a and 36c arranged in parallel along the y-direction.

Here, since the operation of detecting each movement component of the speckle pattern SP is substantially the same, the operation of detecting the movement of the x-direction component will be described below.

That is, in FIG. 12, the above speckle pattern
When the SP moves from the light receiving cell 36a to the light receiving cell 36b, the light receiving cell
The output signal of 36a fluctuates according to the movement of the speckle pattern SP.

At this time, if the deformation of the speckle pattern SP is negligible, the adjacent light receiving cell 36b has the same form as the output signal of the light receiving cell 36a for a time τ _x as shown in FIG. 13 (a). A delayed signal is obtained.

This output signal is input to the x-component signal processing system 37x,
After being amplified by the amplifier 41, as shown in FIG.
The cut filter 42 converts the signals into m and n two-system signals crossing the zero line. Thereafter, as shown in FIG. 13 (c), the binarization circuit 43 uses the m and n two-system signals based on the zero line. It is converted to a binary signal. Then, the binarized signal is input to the arithmetic processing unit 51.

In this case, the time delay τ _x is equal to the light receiving cell 36a.
And determined by the moving speed of the distance and speckle pattern SP between the 36b, tau _x sign in speckle pattern SP for
The positive / negative of the moving direction of the light receiving cells 36a, 36b can be determined.
In order to correspond to the number of speckle grains passing over the surface, by counting the number of the peaks, it is possible to detect the magnitude of the movement of the speckle pattern SP, thereby obtaining movement information. Can be. The above-described arithmetic processing unit 51 performs the speckle pattern SP based on the above-described principle.
The moving direction and the moving amount of the
Set the movement direction and movement amount of 53.

The arithmetic processing unit 51 is exactly the same as a conventional mechanical mouse or optical mouse. Normally, since this type of arithmetic processing unit 51 is incorporated in the interface of the computer 50, the binary processing in the case of the present embodiment is performed. The conversion signal can be directly input to a conventional mouse interface.

In the mouse according to this embodiment, the moving rate variable button 40 is depressed by a predetermined amount, and the cursor 53 is pressed.
After examining the change in the movement rate of the
It has been confirmed that the moving rate of the cursor 53 decreases substantially proportionally according to the amount of depression of.

For this reason, when using the mouse according to this embodiment, if it is desired to move the cursor 53 finely, the movement rate variable button 40 is appropriately depressed, and if it is desired to move the cursor 53 roughly, The mouse may be operated in a state where the mouse is set at the initial position where the depression amount is 0.

Further, in this embodiment, a plurality of sets of light receiving cells (not shown) are used as the detector 36 in the x direction and the y direction.
Can be arranged and the signal processing unit 37 can average the phase difference information based on the output from each set, so that the dispersion of the phase difference information based on the irregularity of the speckle pattern SP can be reduced. It is.

Further, the movement rate variable button 40 according to this embodiment is configured to change the distance R between the object rough surface 30 and the detector 36, but is not limited to this. For example, the beam waist Bw to the object rough surface 30 The distance z may be changed.

In this case, the average size of the speckle is inversely proportional to z (see the formula (12) in the section of the means for solving the problem), so if z is reduced, the average size of the speckle increases. The cursor 53 can be roughly moved by the amount that can be set, and if z is increased, the cursor 53 can be finely moved by the amount that the average speckle size can be set small. .

〔The invention's effect〕

As described above, according to the speckle pattern movement detection method according to claim 1, the average size of speckles on the light receiving surface of the photodetector is changed within a predetermined area,
Since the detection movement rate by the photodetector is changed substantially proportionally according to the average size of the speckles, the operation of changing the detection movement rate by the photodetector can be reliably realized, and various movement information can be obtained. The detection resolution can be adjusted dynamically.

In particular, according to the method for detecting movement of a speckle pattern according to claim 2, a time variation of the speckle pattern is detected by at least one set of photodetectors arranged side by side in the moving speckle pattern. Since the movement information of the speckle pattern can be detected by simple processing such as finding the phase difference of the speckle pattern, real-time processing is easy, and various movement information including the moving direction of the speckle pattern can be easily obtained.

According to the position specifying device of the third aspect, the relative movement information of the speckle pattern generated from the rough surface of the object with respect to the rough surface of the object is detected and the position to be specified is specified. This eliminates the necessity, which makes the operability more convenient, and reduces the durability associated with mechanically movable parts such as conventional mechanical mice, and limits the use of dirt and damage to the dedicated underlay. And the durability of the device itself can be further improved, and the movement information can be set by appropriately setting the optical system harameter between the electromagnetic wave source and the photodetector without being affected by the grid density of the dedicated underlay. The resolution of detection can be increased, and the position designation accuracy can be improved.

Further, according to the position specifying device of the third aspect,
The speckle size changing means variably sets the average size of the speckles in a predetermined region, so that the detection movement rate by the photodetector is surely changed in a substantially proportional relationship according to the average size of the speckles. Therefore, it is possible to surely change the movement rate of the designated object that moves according to the detection signal of the photodetector in a substantially proportional relationship.

For this reason, even when fine position specification accuracy is required or rough position specification accuracy is required, it is possible to reliably set the movement amount of the position specification object to a fine or rough position according to the request. It is possible to further improve the operability of the position specifying device.

[Brief description of the drawings]

FIG. 1A is an explanatory view showing the principle of a method for detecting movement of a speckle pattern according to the present invention, and FIGS. 1B and 1C are explanatory views showing an embodiment of a photodetector and an explanation of its detection operation. FIG. 1 (d) is an explanatory view showing a schematic configuration of one designation device according to the present invention, FIG. 2 is an explanatory view showing an experimental system performed in devising the present invention, and FIG. FIG. 2 is a detailed view of part III, FIG. 4 is an explanatory view showing the concept of the speckle translation distance, and FIG. 5 is a diagram showing the relationship between the average speckle size and the cursor movement rate obtained by the experimental system of FIG. FIG. 6 is an explanatory diagram modeling the experimental system of FIG. 2,
FIG. 7 is a schematic explanatory view showing a relationship between speckles and detectors according to the present invention, and FIG. 8 is a graph showing a relationship between spatial frequency power spectra of speckles and detectors according to the present invention. FIG. 9 is an explanatory view showing one embodiment of a mouse to which the present invention is applied;
FIG. 10 is a partially cutaway bottom view, FIG. 11 is an explanatory view showing a configuration of a detector according to the embodiment, FIG. 12 is a block diagram showing a signal processing system of the detector according to the embodiment, and FIG. 6 is a timing chart showing operation timing of a signal processing system. [Explanation of Signs] SP: Speckle pattern Bm: Electromagnetic wave M: Movement information 1: Rough surface of object 2: Photodetector 2a, 2b: Photodetector 3: Movable body 4: Electromagnetic wave source 5 ... Speckle size variable means

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) G06F 3/033 G01P 3/36

Claims (3)

(57) [Claims] 1. A photodetector (2) for detecting movement information (M) of a speckle pattern (SP) generated by scattering of a coherent electromagnetic wave (Bm) on a rough surface (1) of an object. Average size (D) of speckles in the speckle pattern (SP) on the light receiving surface of the detector (2), relative movement information of the photodetector (2) with respect to the rough object surface (1), and the photodetector (2) In the area (E) where the above-mentioned detected movement rate (J) changes almost proportionally to the average speckle size (D) in relation to the detected movement rate (J) indicating the ratio to the output movement information. A speckle pattern movement detecting method, wherein the average size (D) of the speckle is variably set. 2. The photodetector (2) according to claim 1, wherein the photodetector (2) includes at least one set of photodetectors (2a, 2b) arranged in one dimension, and one set of photodetectors (2a, 2b). 2b)
And detecting a phase difference (τ) of an output signal from the speckle pattern. A movable body (3) movable with respect to the object rough surface (1); and a movable part (3) incorporated into the movable body (3) to move a predetermined portion of the movable body (3) to the object rough surface (1). An electromagnetic wave source (4) for irradiating a coherent electromagnetic wave (Bm); and a speckle pattern (SP) which is incorporated in the movable body (3) and is generated from the rough surface (1) of the object due to the irradiation of the electromagnetic wave (Bm). A light detector (2) for detecting relative movement information with respect to the movable body (3); an average size (D) of speckles in a speckle pattern (SP) on a light receiving surface of the light detector (2); In the relationship between the detection movement rate (J) indicating the ratio of the relative movement information of the detector (2) to the object rough surface (1) and the output movement information of the photodetector, the detection movement rate (J) is speckle. In the area (E) that changes approximately proportionally to the average size (D) of the A speckle size varying means (5) for variably setting the average size (D) of the knuckle, wherein a position to be designated is specified based on the relative movement information detected by the photodetector (2). A position specifying device characterized by the above-mentioned.