JP3190746B2 - Laser pointer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser pointer for pointing a predetermined point or a straight line position on an object by projecting a visible laser beam onto the object by, for example, rotating, scanning, and stopping the laser beam.

[0002]

2. Description of the Related Art In a conventional laser pointer, the actual working angle is 1-1.
As disclosed in Japanese Patent No. 58908, a large and heavy He-Ne gas laser has been used as a laser light source.
Further, as disclosed in JP-A-63-179208, an invisible semiconductor laser is used as a light source. In recent years, a visible semiconductor laser that emits a visible laser having a wavelength of 700 nm or less has been put into practical use, and a relatively small laser pointer has been constructed. The above-mentioned conventional visible semiconductor laser is driven continuously and emits light continuously.

[0003]

The laser pointer is often used outdoors, and it is desirable that the laser pointer be small and lightweight, have excellent portability, and have a long life of the power supply battery section. In particular,
Since the use of visible semiconductor lasers, the miniaturization and long life of the power supply battery section of the laser pointer have had a large effect on the size and weight of the entire laser pointer device, Current laser pointers still require improvement in this respect.

[0004] The present invention has been made in view of such a problem of a conventional laser pointer, and has been made to save power.
It is an object of the present invention to provide a laser pointer in which a power supply battery unit is small and lightweight and the power supply battery unit has a long life.

[0005]

According to the present invention, there is provided a laser pointer which has a built-in power supply and projects a visible laser beam to indicate a predetermined position, a visible semiconductor laser, and a pulse drive circuit for pulse-driving the visible semiconductor laser. A laser beam optical system for directing a laser beam emitted from the visible semiconductor laser toward an object, and the response speed of the human eye is 30 m.
This is a laser pointer that performs ON / OFF drive faster than sec.

[0006]

The output characteristics of a visible semiconductor laser are non-linear with respect to the drive current. When the output current exceeds a threshold current, the drive current becomes almost constant, and the response speed of the human eye is about 30 msec. The power saving is realized based on the fact that repetitive pulsed light faster than that is perceived as light having continuous temporal average light intensity.

That is, when the peak light output is Pmax and the duty is D, the average light output Pave is expressed by Pave = Pmax × D (1). On the other hand, the average current Iave when the pulse drive is performed with the drive current I and the duty D is as follows: Iave = I × D (2) Optical output P-drive current of the visible semiconductor laser As shown in FIG. 8, the relationship of I becomes substantially constant when the drive current I exceeds the threshold current It, and the drive current I in the equation (2) can be treated as being substantially constant. Accordingly, from the equations (1) and (2), when trying to obtain the same average light output Pave, the average current Iave can be reduced by increasing the peak light output Pmax and decreasing the duty D. For example, when pulse driving is performed at ON-OFF with a duty of 50%, as shown in FIG. 2, in order to obtain the same light output P1, twice as much light output P2 as continuous light emission is required. However, the driving current I1 for obtaining the optical output P1 and
The driving current I2 for obtaining the optical output P2 is almost the same.

That is, in order to obtain the optical output P1, the second
The doubled pulse drive light output P2 must be generated by the drive current I2, but the drive current I1 and the drive current I2 for obtaining the light output P1 are almost the same. / 2, the power consumption is about 1/2 of continuous light emission, and power saving is achieved. In practice,
The reason for such power saving effect is that
0% or less.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a reciprocating laser scanning system will be described below with reference to the drawings. Laser pointer 1
As shown in FIG. 1, a pulse driving circuit 2 that includes an oscillator and an LD driving circuit and performs pulse driving at ON / OFF with a duty of 50%, and a visible semiconductor laser 3. As described above, the driving is performed at the duty of 50%, so that the power consumption can be reduced. In this reciprocating laser scanning system, the driving at a duty of 50% also serves as a modulation signal for detecting a reflection unit described later. On the optical axis O of the laser beam emitted from the visible semiconductor laser 3, there is provided a collimator lens 4, an inclination correction system 6, a reflecting mirror 8, a beam expander 9, and a hole 7 through which the optical axis O passes. A perforated mirror 8 and a beam rotation system 10 are arranged. The optical system of the reciprocating laser scanning system can be configured without including the tilt angle correction system 6.

The tilt angle correction system 6 is a part of an optical system that reflects a laser beam emitted from the laser light source 2 so as to always maintain a vertical position regardless of the tilt of the main body (not shown). 20, an oil bath 24 having a liquid back surface 22, a sealing glass 26, and a pair of prism members 3
The optical axis adjusting system 34 and the beam expander 9, which are composed of 0 and 32 and polarize the optical axis O, are configured by arranging a pair of lenses 36 and 38 having different focal lengths at predetermined intervals, and Extend the width of.

The beam rotating system 10 is an optical system that reflects a laser beam incident vertically upward so as to rotate and scan in a horizontal plane.
Is arranged. An encoder 44 for detecting the rotation direction of the rotary support 40 is attached to an intermediate portion of the rotary support 40. A gear 4 is provided at the lower part of the rotary support 40.
6 is mounted, and an output gear 50 of a motor 48 serving as a rotation drive source of the rotation support base 40 meshes with the gear 46.
The rotational drive of the motor 48 is controlled by a control system 100 which is a CPU. The control system 100 is connected to the encoder 44 and a photoelectric conversion element 86 of a laser beam detection system 80 described later.

As shown in FIG. 3, the reflecting means 60 which is disposed on the object to be measured, ie, the object, and reflects the laser beam,
A first reflecting member 66 in which two vertically extending reflecting zones 62 and 64 are arranged at an interval. The laser beam detection system 80 includes a condenser lens 82, a pinhole plate 84, and a photoelectric conversion element 8 on the reflection optical axis 00 of the perforated mirror 8.
6 are arranged at an appropriate interval.

The electrical system of the reciprocating laser scanning system is shown in FIG.
As shown in (1), the oscillator 102 includes an LD driving circuit 104 to which an output of the oscillator 102 is input, and an LD light emitting unit 106 to which an output of the LD driving circuit 104 is input. The electric system further includes a photoelectric conversion element 86 that receives the laser beam reflected from the reflection means 60, a motor 48, and a control system 100.
And The output of the encoder 44 is controlled by the control system 10.
Enter 0.

The control system 100 has a structure for facilitating the visual recognition of the laser light beam by reciprocally scanning the laser light beam only in the angular range of the two reflecting means 60. The control system 100 includes, as shown in FIG.
Signal detection unit 1 connected to the output of the amplifier and amplifying the input signal
12 and a chattering prevention circuit unit 114 to which the output of the modulation signal detection unit 112 is connected.

The output of the chattering prevention circuit 114 is
Motor drive circuit 134 via waveform shaping section 116, double pulse discriminating section 118 and forward / reverse signal generating section 120
It is connected to the. The output of the waveform shaping section 116 is also connected to the double pulse determining section 118 via the distance determining section 130. The output of the double pulse discriminating unit 118 is sent to the motor drive circuit 13
4 is connected. The outputs of the distance determination unit 130 and the double pulse determination unit 132 are connected to the chattering prevention circuit unit 114.

The chattering prevention circuit 114 is for preventing chattering from occurring by adjusting the time constant of the RC filter circuit.
30 includes two vertical reflection zones 62, 6 of the reflection means 60.
The distance between the main body (not shown) and the object is determined based on the interval between the double pulse signals generated by the step 4, and the time constant of the chattering prevention circuit 114 is switched. If the time from the input of the first pulse to the input of the second pulse is within the predetermined time set for the search and scan, respectively, the double pulse determination unit 118 determines that the reflection unit 60 is used, and Is output to the forward / reverse signal generator 120 and the search / scan determiner 132.

The search / scan judging section 132 judges whether the search is a scan or a scan based on the output signal from the double pulse judging section 118, and outputs the resulting pulse signal to the chattering prevention circuit 114. The forward / reverse signal generating section 120 is constituted by a frequency dividing circuit, and switches between the forward / reverse signal and the inverting signal each time a signal for determining the reflection means 60 is input from the double pulse determining section 118 and outputs a motor drive circuit. 134.

The motor drive circuit 134 controls the rotation direction of the motor 48 based on the normal rotation signal and the reverse signal from the normal / reverse signal generator 112,
The rotation speed is controlled by the search or scan signal from the control unit 2, that is, the rotation speed at the time of search is controlled to be higher than the rotation speed at the time of scanning. Although this embodiment has been described with respect to the reciprocating laser scanning system, the present invention can be applied to a laser scanning system having a rotation, reciprocating, and stop function.
Furthermore, it is clear that the method can be applied to a pointer indicating a position.

[0019]

Since the present invention is configured as described above, it is possible to provide a laser pointer which is power-saving, has a small and lightweight power supply battery section, and has a long lifespan. Further, in the above embodiment, by lowering the scanning speed of the laser beam on the object, the substantial energy of the laser beam on the object is increased, and the laser beam can be easily recognized. .

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a laser pointer including a reciprocating laser scanning system according to an embodiment of the present invention.

FIG. 2 is a club chart of a light emitting car driving current characteristic of a visible semiconductor laser.

FIG. 3 is a front view of the reflection means according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram of the principle of the present invention.

[Explanation of symbols]

 O, OO Optical axis 2 Pulse drive circuit 3 Visible semiconductor laser 4 Collimator lens 6 Inclination angle correction system 9 Beam expander 10 Beam rotation system 24 Compensator 34 Optical axis adjustment system 40 Rotation support 42 Pentaprism 44 Encoder 48 Motor 100 Control system 102 Oscillator 114 Chattering prevention circuit unit 120 Forward / inverted signal generation unit 130 Distance judgment unit

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-123183 (JP, A) JP-A-3-60015 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01C 15/00-15/14 G02B 27/18-27/20 G09B 19/00 H05B 37/00-39/10

Claims (3)

(57) [Claims] 1. A laser pointer which has a built-in power supply and projects a visible laser beam to indicate a predetermined position.
A visible semiconductor laser, a pulse driving circuit for pulse driving the visible semiconductor laser, and a laser light beam optical system for directing a laser light beam emitted from the visible semiconductor laser to an object, and a response speed of a human eye. Than 30ms
Laser point characterized by fast ON / OFF drive
Ta. 2. The laser pointer according to claim 1, wherein the pulse driving circuit drives the visible semiconductor laser so as to be ON / OFF at a duty of 70% or less. 3. The wavelength emitted by a visible semiconductor laser is ON.
/ 700nm or less for power saving effect by / OFF drive
2. The laser pointer according to claim 1, wherein the wavelength is a visible laser wavelength .