JPH0727999A - Laser type pointer - Google Patents

Abstract

PURPOSE:To prevent the indicating point of light from being fluctuated due to camera shake. CONSTITUTION:X, Y, and Z coordinates fixed on a pointer 1 are defined as shown in figure C. Rotating angular velocity dthetaX, dthetaY, in the directions of X, Y are detected by a rate (angular velocity) sensor 6. Sensor output are integrated by an integrator 7, and are changed into rotation angle signals thetaX,thetaY, and are inputted to a control part 4. The control part 4 supplies control signals VX, VY to a light direction varying part 3 so as to change the light of a laser emitting part 2 in the directions of X, Y by -thetaX, -thetaY. The light direction varying part 3 can be constituted of light X/Y direction varying parts 3a, 3b. The varying parts 3a, 3b are held by a base 31 fixed on a cabinet at angles alphaX, alphaY to the base 31 respectively, and it can be composed of a mirror 32 on which a laser beam is reflected, and a piezo-element 33 extended/contracted corresponding to the control signals VX, VY and which varies the angles alphaX, alphaY. A high frequency vibration component due to camera shake can be cut off by providing a high-pass filter at the control part 4 or applying negative feedback to the integrator 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pointer (pointer) for an overhead projector used in conferences and the like, and more particularly to a laser type pointer used in a large screen.

[0002]

2. Description of the Related Art A conventional rod-shaped object or a pointer (indicator) using laser light has been used for pointing on a screen of an overhead projector. The laser pointer is suitable for a large screen when it cannot be reached with a stick-shaped object, and has an advantage that it can be pointed without reaching for it.

[0003]

A conventional laser pointer is held by a hand and used for pointing, and when a large screen is used, the distance between the pointing point and the hand is long. The point that was pointed out was erratic (especially when the explainer was an elderly person, etc.), and there was a drawback that it was very difficult to see.

SUMMARY OF THE INVENTION The present invention eliminates the conventional drawbacks and provides a laser type pointer in which the pointing point of light does not fluctuate even if the hand fluctuates.

[0005]

[Means for Solving the Problems]

(1) A laser pointer according to the invention of claim 1 has a laser emitting portion, a standard emission direction of light from the laser emitting portion is a Z-axis direction, and a coordinate origin is provided in a holding portion of the casing. When the orthogonal X, Y, and Z coordinates fixed to are used, a light direction variable unit that receives the light of the laser emission unit and changes the optical axis thereof in the X-axis and Y-axis directions and emits the light, A rate sensor for detecting rotational angular velocities dθ _X and dθ _Y in the axial and Y-axis directions,
The rotational angular velocities dθ _X and dθ _Y are input, integrated, and X
The integrator that outputs rotation angle signals θ _X and θ _Y in the axis and Y-axis directions and the rotation angle signals θ _X and θ _Y are input, and the X-axis and Y-axis
A control unit that controls the light direction changing unit so that the light direction changes in the axial direction by −θ _X and −θ _Y , respectively;
The high pass filter is added to the control unit and cuts low frequency components included in the rotation angle signals θ _X and θ _Y.

(2) In the invention of claim 2, in the invention of (1), the transfer function K ₁ + K ₂ / s (K ₁ , K ₂ is a constant instead of providing a high-pass filter in the control unit 4). ,
s is a Laplace variable) and is inserted between the rate sensor and the integrator, and a feedback unit for feeding back the rotation angle signals θ _X and θ _Y on the output side of the integrator to the input side of the control unit. The subtraction unit for subtracting the output of the feedback unit from the outputs dθ _X and dθ _{Y of the} rate sensor and inputting the subtracted output to the integrator is added.

(3) According to a third aspect of the invention, in the laser pointer according to the above (1) or (2), the light direction changing unit is an optical X direction changing unit and an optical Y direction changing unit. The optical X or Y direction variable part is configured and the angle (α _X or α _Y ) with respect to the base fixed to the housing.
And an output control signal V _X or V of the control unit, which is held obliquely with a mirror for reflecting the output light of the laser emission unit.
Expand and contract in response to _Y, those having a, a piezo element for changing the angle (alpha _X or alpha _Y) relative to the base of the mirror.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure and block diagram of the present invention are shown in FIG. 1
Is a laser type indicator of the present invention. Reference numeral 2 denotes a laser emitting section, which can be easily obtained as a general commercial product. Reference numeral 3 is a light direction variable unit. Standard direction of laser light (Z axis direction)
The direction is changed to the X and Y axis directions that are perpendicular to. The XYZ Cartesian coordinates are fixed to the housing, and the origin of the XYZ orthogonal coordinates is provided in the grip portion 1a of the pointer 1. Reference numeral 4 is a control unit for the light direction changing unit 3. Reference numeral 5 is a laser beam. Reference numeral 6 denotes a biaxial rate (angular velocity) sensor, which is used in the X-axis direction and Y direction of the laser type indicator 1.
Measure the sway in the axial direction. 1 axis rate sensor for X axis and Y
It may be attached to the shaft. 7 is an integrator. The X-axis and Y-axis direction rate signals dθ _X and dθ _Y of the shake of the indicator obtained by the rate sensor 6 are integrated to generate rotation angle signals θ _X and θ _Y of the shake of the indicator. That is,

[0009]

[Equation 1] 4 is a control unit, optical X or Y-direction changing unit 3a so that the optical axis of the laser beam 5 is changed to the X-axis or Y-axis direction by - [theta] _X or - [theta] _Y, 3b to the control voltage V _X, V _Y Supply each. FIG. 1B is a detailed view of the optical X-direction changing unit 3a. 31
Is a base and is fixed to the indicator 1. A mirror 32 reflects the laser light 5. The light can be changed in the X direction by changing the angle α of the mirror 32 with respect to the base 31. Three
Reference numeral 3 is a piezo element, which expands and contracts when a control voltage V _X is applied. The configuration of the light Y direction variable unit 3b is also the same as above. Obtaining a rotation angle theta _X of indicator 1 around the X axis by integrating the rate obtained X-axis angular velocity around the sensor 6 (rate) signal d [theta] _X at the integrator 7.

The control unit 4 controls the voltage V so that the angle α formed with the base 31 of the mirror 32 changes by θ _X / 2, and as a result, the optical axis of the laser beam 5 changes by -θ _{X in the} X direction. _The piezo element 33 is driven by _X. The same applies to the case of using the light Y direction variable unit 3b, and the rotation angle of the laser light in the Y axis direction is corrected. In this way, the angle change of the indicator θ _X , θ
_Since the optical axis of the laser beam changes in the direction opposite to Y, even if the X and Y directions of the indicator 1 change, the pointing point of the light on the screen remains stationary.

By the way, if the integrator 7 is a normal integral calculation, the pointing point of light remains stationary on the screen even when the user intentionally changes the pointing direction of the pointer. As a countermeasure, consider as follows. The movement of the indicator 1 having a relatively high vibration frequency is unintentional shake, and the movement in one direction or the movement of a considerably low vibration frequency is an intentional change of the indication point. Therefore, the pointing point of light is made stationary for high-frequency movement, and the pointing point of light is made to follow the indicator for low-frequency (including movement in one direction) movement. Therefore, a high-pass filter 4a is provided in the control unit 4 to cut high frequency components and pass low frequency components.

As another method, there is a method in which the output of the integrator 7 is negatively fed back to the input side through the feedback section 8. The transfer function is shown in FIG. 2A. The transfer function G (s) of the integrator 7 is simplified to be G (s) = 1 / s (1). s is a Laplace variable. Further, the transfer function H (s) of the feedback section 8 is set to H (s) = K ₁ + K ₂ / s (2). The subtractor 9 outputs the output dθ of the rate sensor 6.
It is inserted to subtract the output of the feedback section 8 from _x (or dθ _Y ). If the transfer function of these feedback circuits is T (s), then 1 / T (s) = 1 / G (s) + H (s) (3) Equation (1), (2) Substituting the formula, 1 / T (s) = s + K ₁ + K ₂ / s = (s ² + K ₁ s + K ₂ ) / s If the right side is factored, = (s−s ₁ ) (s−s ₁ ^* ) / s (4) where s ₁ and s ₁ ^* are expressed as complex numbers,

[0013]

[Equation 2] As is clear from the equation (4), s ₁ and s ₁ ^* are zero points of the anti-transmission function 1 / T (s), and s = 0 and s = ± j∞ are attenuation poles. FIG. 2B shows these zeros and attenuation poles on the s plane (Laplace plane). However, the zero point is represented by a circle, the attenuation pole is represented by a cross, and s = σ + jω (7), the real axis is represented by σ, and the imaginary axis is represented by jω. The gain frequency characteristic of the negative feedback circuit of FIG. 2A in which the zero point and the attenuation pole are arranged as shown in FIG. 2B is as shown in FIG. 2C. -K ₁
As can be seen from FIG. 2B, / 2 gives damping to the vibration component having the angular frequency ω ₁ of the negative feedback circuit output, and the frequency characteristic near ω ₁ can be adjusted.

[0014]

According to the present invention, a rate sensor (angular velocity meter) is attached to a conventional display, and a rotational angular velocity d applied to the display is applied.
Since θ _X and d θ _Y are measured and the pointing point is moved in the opposite direction of this angular velocity, the pointing point is spatially stable (apparently stationary) even if the pointer vibrates, and the effect of camera shake can be prevented. it can.

[Brief description of drawings]

FIG. 1A is a block diagram showing an embodiment of the present invention, B is a principle configuration diagram of an optical X-direction variable unit 3a of A, and C is X, Y, Z fixed to a laser type pointer 1 of A. FIG. 6 is a perspective view for defining Cartesian coordinates.

FIG. 2A shows a feedback section 8 and a subtraction section 9 in the integrator 7 of FIG. 1A.
Is a diagram showing a negative feedback circuit formed by adding a transfer function, and B is a reciprocal of the transfer function of the entire negative feedback circuit of A (anti-transmission function) 1 / T (s), and the attenuation pole is represented by s. The figure shown on the plane (Laplace plane), C is a figure which shows the outline of the gain frequency characteristic of the circuit of A. FIG.

Claims (3)

[Claims] 1. A laser emitting section, and a standard emission direction of light from the laser emitting section is defined as a Z-axis direction,
When the orthogonal X, Y, Z coordinates fixed to the housing are used and the origin of the coordinates is in the grip portion of the housing, the light of the laser emitting portion is received and the optical axes thereof are the X-axis and the Y-axis. A light direction variable part that variably outputs in the axial direction, a rate sensor that detects the rotational angular velocities dθ _X and dθ _Y in the X-axis and Y-axis directions, and the rotational angular velocities dθ _X and dθ _Y are input and integrated. , X
Rotation angle signal axis and Y-axis direction theta _X, an integrator for outputting a theta _Y, the angle of the rotation angle signal theta _X, enter the theta _Y, X-axis and Y-axis direction - [theta] _X, - [theta] _Y A control unit that controls the light direction changing unit so that the light direction changes, and a high-pass filter that is added to the control unit and that cuts low frequency components included in the rotation angle signals θ _X and θ _Y. ,
A laser-type pointer, comprising: 2. A laser emitting section, and a standard emission direction of light of the laser emitting section is a Z-axis direction,
When the orthogonal X, Y, Z coordinates fixed to the housing are used and the origin of the coordinates is in the grip portion of the housing, the light of the laser emitting portion is received and the optical axes thereof are the X-axis and the Y-axis. A light direction variable part that variably outputs in the axial direction, a rate sensor that detects the rotational angular velocities dθ _X and dθ _Y in the X-axis and Y-axis directions, and the rotational angular velocities dθ _X and dθ _Y are input and integrated. , X
Rotation angle signal axis and Y-axis direction theta _X, an integrator for outputting a theta _Y, the angle of the rotation angle signal theta _X, enter the theta _Y, X-axis and Y-axis direction - [theta] _X, - [theta] _Y A control unit for controlling the light direction variable unit so that the light direction changes, and a transfer function K ₁ + K ₂ / s (K ₁ , K ₂ are constants, s is a Laplace variable), and Angle signal θ on the output side of the device
A feedback unit that feeds back _X and θ _Y to the input side, and is inserted between the rate sensor and the integrator, subtracts the output of the feedback unit from the outputs dθ _X and dθ _{Y of the} rate sensor, and A laser type pointer, comprising: a subtraction unit for inputting to an integrator. 3. The laser type pointer according to claim 1 or 2, wherein the light direction variable section is composed of a light X direction variable section and a light Y direction variable section, and the light X or Y direction variable section is provided. A base fixed to the housing, a mirror that is held obliquely with respect to the base at an angle (α _X or α _Y ) and reflects the output light of the laser emitting unit, and an output control signal V _{X of the} control unit Or a piezo element that expands and contracts according to V _Y and changes the angle (α _X or α _Y ) of the mirror with respect to the base.