JPH06137869A - Laser pointer - Google Patents

Abstract

PURPOSE:To save the power, perform downsizing, reduce weight, and prolong the lifetime of a laser pointer by providing a circuit for pulse-driving a visible semi-conductor laser and a laser flux optical system for directing the laser flux output from a laser to an object. CONSTITUTION:A laser pointer has a pulse driving circuit 2, which includes an oscillator and an LD driving circuit and which pulse-drives with ON-OFF of a duty at 50%, and a visible semi-conductor laser 3. Since the visible semi-conductor laser 3 is driven by a duty at 50%, power can be saved. Drive by a duty at 50% also works as the modulating signal for detecting a reflecting means in this reciprocating laser scanning system. As a laser flux optical system, a collimator lens 4, an inclination angle correcting system 6, a reflecting mirror 8, a beam expander 9, a hole opened mirror 8 having a hole 7, which an optical axis O passes through, and a beam rotating system 10 are arranged on the optical axis O of the laser flux radiated from the visible semi-conductor laser 3. With this structure, a device is downsized, lightened, and the power thereof can be saved.

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 the visible laser beam onto the object by rotationally scanning, stopping or the like.

[0002]

2. Description of the Related Art In a conventional laser pointer, an actual Kaihei 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 light 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 continuously.

[0003]

The laser pointer is often used outdoors, and it is desirable that the laser pointer is small and lightweight, has excellent portability, and has a long battery life. In particular,
Since the introduction of visible semiconductor lasers, the miniaturization and longevity of the power source battery of the laser pointer has a large impact on the overall size and weight of the laser pointer device. The current laser pointer is still required to be improved in this respect.

The present invention has been made in view of the above problems of the conventional laser pointer, and is power saving.
An object of the present invention is to provide a laser pointer in which the power supply battery unit is small and lightweight and the power supply battery unit has a long life.

[0005]

According to the present invention, in a laser pointer for projecting a visible laser beam to indicate a predetermined position, a visible semiconductor laser, a pulse drive circuit for pulse-driving the visible semiconductor laser, and the visible semiconductor laser described above. And a laser light beam optical system for directing a laser light beam emitted from the laser beam to an object.

[0006]

Principle of the invention The output characteristic of a visible semiconductor laser is non-linear with respect to the drive current, and when the threshold current is exceeded, the drive current becomes almost constant, and the response speed of the human eye is about 30 msec. Reducing the power consumption is realized based on the fact that the repetitive pulsed light faster than that is sensed as light of 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 pulse-driving with the drive current I and the duty D is: Iave = I × D (2) Optical output P of visible semiconductor laser P-drive current As shown in FIG. 8, the relationship of I becomes almost constant when the drive current I exceeds the threshold current It, and the drive current I of the equation (2) can be treated as almost constant. Therefore, when the same average light output Pave is to be obtained from the equations (1) and (2), 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, a light output P2 that is twice as high as that of continuous light emission is required. However, the drive current I1 for obtaining the optical output P1 and
The drive current I2 for obtaining the optical output P2 is almost the same.

That is, in order to obtain the optical output P1, part 2
The double 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. In this case, the drive current I2 has a light emission time of 1 The power consumption is 1/2, and the power consumption is about half that of continuous light emission, thus saving power. In fact,
The effect of such power saving is shown in the duty 7
It is 0% or less.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example 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, it has a pulse drive circuit 2 including an oscillator and an LD drive circuit and pulse-driven with ON / OFF at a duty of 50%, and a visible semiconductor laser 3. As described above, the driving is performed with the duty of 50%, and the power consumption can be reduced. In this reciprocating laser scanning system, the driving with the duty of 50% also serves as a modulation signal for detecting the reflecting means described later. A collimator lens 4, an inclination angle correction system 6, a reflecting mirror 8, a beam expander 9, and a hole 7 through which the optical axis O passes are provided on the optical axis O of the laser beam emitted from the visible semiconductor laser 3. 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 for reflecting the laser beam emitted from the laser light source 2 so as to always keep the vertical direction regardless of the tilt of the main body (not shown), and is a sealed glass. 20, an oil bath 24 having a liquid rear surface 22, a sealed 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 rotation system 10 is an optical system that reflects a laser light beam incident vertically upward so as to rotate and scan in a horizontal plane, and a pentaprism 42 on a rotation support base 40.
It will be arranged. An encoder 44 for detecting the rotation direction of the rotation support base 40 is attached to an intermediate portion of the rotation support base 40. At the bottom of the rotary support 40, the gear 4
6 is attached, and an output gear 50 of a motor 48, which serves as a rotation drive source of the rotary support 40, meshes with a gear 46.
The rotation drive of the motor 48 is controlled by a control system 100 which is a CPU, and the control system 100 is connected to the encoder 44 and a photoelectric conversion element 86 of a laser light flux detection system 80 described later.

The reflecting means 60 arranged on the object to be measured, that is, the object, for reflecting the laser beam, as shown in FIG.
This is a first reflecting member 66 in which two vertically extending reflecting zones 62, 64 are arranged at intervals. 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 apertured mirror 8.
6 and 6 are arranged at appropriate intervals.

The electrical system of the reciprocating laser scanning system is shown in FIG.
As shown in FIG. 3, the oscillator 102, the LD drive circuit 104 to which the output of the oscillator 102 is input, and the LD light emitting unit 106 to which the output of the LD drive circuit 104 is input. The electric system further includes a photoelectric conversion element 86 that receives the laser light flux reflected by the reflection means 60, the motor 48, and the control system 100.
Have and. The output of the encoder 44 is the control system 10
Enter 0.

The control system 100 has a structure for facilitating visual recognition of the laser light flux by reciprocally scanning the laser light flux only in the angular range of the two reflecting means 60. As shown in FIG. 4, the control system 100 includes a photoelectric conversion element 86.
Signal detection unit 1 that is connected to the output of the
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 section 114 is
The motor drive circuit 134 is passed through the waveform shaping section 116, the double pulse determination section 118, and the forward / reverse signal generation section 120.
It is connected to the. The output of the waveform shaping section 116 is also connected to the double pulse determination section 118 via the perspective determination section 130. The output of the double pulse discrimination unit 118 is output to the motor drive circuit 13 via the search / scan discrimination unit 132.
4 is connected. The chattering prevention circuit unit 114 is connected to the outputs of the perspective determination unit 130 and the double pulse determination unit 132.

The chattering prevention circuit section 114 is for preventing the occurrence of chattering by adjusting the time constant of the RC filter circuit.
30 denotes two vertical reflection zones 62, 6 of the reflection means 60.
The distance between the main body (not shown) and the object is discriminated by the interval of the double pulse signal generated by 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 the scan, the double pulse determination unit 118 determines that the reflection means 60 is the pulse. The pulse signal for generating one pulse is output to the forward / reverse signal generator 120 and the search / scan determiner 132.

The search / scan discriminating unit 132 discriminates whether it is a search or a scan based on the output signal from the double pulse discriminating unit 118, and outputs the resulting pulse signal to the chattering prevention circuit 114. The forward / reverse signal generator 120 is composed of a frequency divider circuit, and switches the forward / reverse signal every time a signal for determining that the reflection means 60 is input from the double pulse determiner 118 is switched to the motor drive circuit. Output to 134.

The motor drive circuit 134 controls the rotation direction of the motor 48 by the normal rotation signal and the reverse rotation signal from the normal rotation / reverse rotation signal generation section 112, and the search / scan determination section 13 is controlled.
The rotation speed is controlled by the search or scan signal from 2, that is, the rotation speed at the time of search is controlled to be higher than the rotation speed at the time of scan. Although the present embodiment shows the reciprocating laser scanning system, it can be used for a laser scanning system having a rotating, reciprocating and stopping function.
Furthermore, it is obvious that it 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 unit, and has a long life power supply battery unit. In addition, in the above-described embodiment, by slowing the scanning speed of the laser light flux on the object, the substantial energy of the laser light flux on the object is increased, and it is easy to visually recognize the laser light flux. .

[Brief description of 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 diagram of a light emitting Kerr driving current characteristic of a visible semiconductor laser.

FIG. 3 is a front view of the reflecting 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 Tilt angle correction system 9 Beam expander 10 Beam rotation system 24 Compensator 34 Optical axis adjustment system 40 Rotation support 42 Penta prism 44 Encoder 48 Motor 100 Control system 102 Oscillator 114 Chattering prevention circuit section 120 Forward / inverted signal generation section 130 Far-near discrimination section

Claims (6)

[Claims] 1. A laser pointer for projecting a visible laser beam to indicate a predetermined position, a visible semiconductor laser, a pulse drive circuit for pulse-driving the visible semiconductor laser, and a laser emitted from the visible semiconductor laser. A laser pointer having a laser beam optical system for directing a laser beam to an object. 2. The laser pointer according to claim 1, wherein the pulse drive circuit is an ON / OFF drive. 3. The pulse drive circuit comprises a duty 70
2. The laser pointer according to claim 1, which is ON / OFF drive of less than or equal to%. 4. The laser pointer according to claim 1, wherein the visible semiconductor laser emits a laser beam having a wavelength of 700 nm or less. 5. The laser beam optical system projects the convergent laser beam toward an object.
Laser pointer described. 6. The laser light flux optical system projects a parallel laser light flux toward an object.
Laser pointer described.