JPH10125991A - Solid-state laser oscillator and laser marker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the optical path effectively and to reduce the size and weight by providing an optical member for bending the optical path of an induced emission light, between a laser chamber and a Q switch. SOLUTION: An optical path for an induced emission light to be emitted from a mirror holder 60 becomes a path which folds back in the reverse direction an induced emission light emitted from a laser chamber 2, at a position shifted in the directions of the height and width of a base 1, and on this folded back optical path a total reflection mirror 4 and a Q switch 7 are arranged. And the optical path of the induced emission light going and returning between an output mirror 3 and the total reflection mirror 4 is bent by bending mirrors 6, 6 arranged between the laser chamber 2 and the Q switch 7, and it becomes possible to shorten the longitudinal dimension L of the base 1. Moreover, it becomes possible to reduce the width dimension W of the base 1, since the laser chamber 2 and the Q switch 7 arranged on both sides of this folded back position are arranged at positions different in the upward and downward directions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a solid-state laser oscillator such as a YAG laser and a laser marking apparatus using the same.

[0002]

2. Description of the Related Art A laser marking apparatus for irradiating a surface of various articles with a laser beam to mark a pattern such as a character or a figure can form an indelible pattern. Responsible Liability Act) has been receiving attention with the enforcement of the
A laser marking device using a solid-state laser typified by a G (yttrium, aluminum, garnet) laser provides high laser output, is easy to focus on a small spot, and can be used for metal, resin, ceramics, etc. It is widely used in various industrial fields as an apparatus capable of forming a fine pattern under non-contact irrespective of a material of an article.

[0003] Laser marking with a solid-state laser is performed by irradiating the surface of a target article with a beam of a solid-state laser emitted from a laser oscillator while appropriately scanning by the operation of a scanning optical system. A laser oscillator that generates a YAG laser as a representative of a solid-state laser includes a laser rod that is a rod-shaped crystal body of YAG doped with an appropriate amount of Nd (neodymium) and a laser chamber containing a lamp for exciting the laser rod, The main components are an output mirror and a total reflection mirror which are arranged opposite to each other at a predetermined distance along the optical path of the stimulated emission light emitted from the rod.

[0004] The output mirror and the total reflection mirror are formed so that a dielectric multilayer film is formed on the surface of a glass substrate to obtain a desired reflectance. The reflectivity of the total reflection mirror is set so that substantial total reflection is possible, while the reflectivity of the output mirror is set so as to allow a part of the irradiation light to pass therethrough. , The stimulated emission light emitted from both ends of the laser rod is amplified during multiple reflections between the output mirror and the total reflection mirror, passes through the output mirror, and incorporates a scanning optical system. Output to the scanning head.

[0005] An aperture (mode selector) is arranged between the output mirror and the total reflection mirror that perform the above-described amplifying action. The aperture is a shielding plate having an opening smaller than the diameter of the laser rod, and the opening is set at the center of the optical path of the stimulated emission light, and during the multiple reflection between the output mirror and the total reflection mirror. In addition, a mode selection action for suppressing oscillation of an unnecessary mode deviating from the regular optical path is performed. This mode selection is important for improving the quality of the marking.

Further, many of the above laser oscillators are:
A Q switch is provided on the optical path between the output mirror and the total reflection mirror. This is to cut off the optical path of the stimulated emission light reciprocating between the two mirrors in a short cycle, increase the merit number (Q value) as a resonator, and take out a laser beam in a desired mode. In particular, an acousto-optic Q switch configured to apply compression waves of several tens of MHz to a fused silica block to generate compression waves and diffract light passing through the block is a continuous excitation type YAG laser. In the laser marking device used, it is a substantially essential component.

[0007]

As described above, in the oscillator of the YAG laser, the laser chamber, the aperture and the Q are arranged on the optical path of the stimulated emission light emitted from the laser chamber.
An output mirror and a total reflection mirror are arranged opposite to each other with a switch interposed therebetween, and it is necessary to secure a predetermined optical path length therebetween. The output mirror and the total reflection mirror are connected together with a laser chamber, a Q switch and an aperture. There is a problem that the supporting base becomes long.

Further, in order to enable stable operation, the Q switch, the aperture, the output mirror, and the total reflection mirror must be correctly positioned on the optical path of the stimulated emission light emitted from the laser chamber. It is necessary to secure sufficient rigidity to the base, which causes a problem that the weight of the laser oscillator including the base becomes large.

An increase in the length and weight of a laser oscillator causes an inconvenience that the application of the object to be marked to a production facility of a device using the laser oscillator, for example, a laser marking device, is restricted. In order to expand the applicable range of the laser marking device, it is important to reduce the size and weight of the laser oscillator.

[0010] As described above, the reason for the increase in the size of the laser oscillator is that a predetermined optical path length is secured between the output mirror and the total reflection mirror, and necessary members such as a laser chamber, a Q switch, and an aperture are provided on this optical path. In order to perform positioning, a long base having high rigidity is required.

In JP-A-63-43884 and JP-A-2-113354, an optical member (generally a total reflection mirror) is disposed at an appropriate position between an output mirror and a total reflection mirror. A solid-state laser oscillator is disclosed in which the optical path between both mirrors is appropriately bent to shorten the optical path length in the direction along the optical axis of the laser chamber, thereby reducing the size and weight of the base. However, these publications do not refer to necessary members such as a Q switch and an aperture, so that a desired shortening effect cannot be obtained in order to secure the arrangement positions thereof.

Further, as described above, it is important to reduce the weight of the laser oscillator and to reduce the planar occupied area in order to expand the range of application of the laser marking device to production equipment for various articles. This is very important.
However, JP-A-63-43884 and JP-A-2-133
In the laser oscillator disclosed in No. 54, the optical path is bent on the surface of the base, and the direction along the optical path of the stimulated emission light, that is, the longitudinal dimension of the base is reduced. However, since the dimension in the direction perpendicular to the optical path, that is, in the width direction of the base is increased, there is a problem that the planar occupied area of the base cannot be reduced.

The present invention has been made in view of the above-mentioned circumstances, and by bending the optical path of the stimulated emission light between the output mirror and the total reflection mirror at an appropriate position and in an appropriate direction, the above-mentioned object is achieved. An object of the present invention is to provide a solid-state laser oscillator that effectively shortens an optical path, is small and lightweight, and has a small planar occupation area, and a laser marking device using the same.

[0014]

A solid-state laser oscillator according to the present invention is provided with a laser chamber containing a laser rod and an excitation lamp, and a predetermined distance along the optical path of stimulated emission light emitted from the laser chamber. In a solid-state laser oscillator including an output mirror and a total reflection mirror disposed opposite to each other, and a Q switch disposed between one of them and the laser chamber, the optical member that bends the optical path of the stimulated emission light is It is provided between the laser chamber and the Q switch.

According to the present invention, the optical path between the output mirror and the total reflection mirror is provided with a bulky part of the parts to be juxtaposed on the optical path, that is, between the laser chamber and the Q switch. The laser beam is bent by the disposed optical members, and the laser chamber is positioned on one side of the bending position, and the Q switch is positioned on the other side, thereby effectively reducing the optical path length.

Further, the bending of the optical path is a folding in which the traveling direction of the stimulated emission light before and after the bending is reversed.

In the present invention, the bending of the optical path by the optical member is performed so as to be reversed, thereby reducing the planar occupied area of each member disposed on the optical path.

The arrangement position of the laser chamber and the arrangement position of the Q switch are vertically different from each other.
Further, they are characterized in that they are different in the lateral direction.

In these inventions, the laser chambers and the Q switches located on both sides of the bending position are vertically shifted from each other, and the optical path passing therethrough is bent or turned back in the height direction of the base, thereby forming the base. To reduce the occupied planar area. In addition, the laser chamber and the Q switch, which are shifted up and down, are further shifted in the horizontal direction, so that they can be seen without overlapping from the front side and the upper side, so that their attachment, removal and adjustment do not interfere with each other. Be able to do it.

In addition, the laser chamber and the Q
The base supporting the switch and the switch integrally include a support member rising from the upper surface thereof, and the laser chamber and the Q
One of the switches is attached to the support member, and the support member is a plate extending in a direction along the optical path.

In these inventions, one of the laser chamber and the Q switch is attached to the base, and the other is attached to a support member that stands up integrally from the base, and the above-described arrangement of both is realized with high accuracy. . Further, the support member is made of a plate extending in the direction along the optical path of the stimulated emission light, that is, in the longitudinal direction of the base, and acts as a rib for increasing the rigidity of the base itself, thereby reducing the thickness of the base. Plan.

Further, a laser marking apparatus according to the present invention is characterized in that the solid-state laser oscillator having the above-described configuration is provided as a source of a laser beam for marking.

In the present invention, the use of the laser oscillator having the above-described configuration realizes a small and lightweight laser marking device including a scanning optical system for outputting a laser beam.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings showing the embodiments. FIG. 1 is a front view of a laser marking device provided with a solid-state laser oscillator according to the present invention,
FIG. 2 is a plan view thereof, and FIG. 3 is a sectional view taken along line III-III of FIG.

As shown in the figures, the solid-state laser oscillator according to the present invention has a laser chamber 2 containing a laser rod and a lamp for exciting the laser rod and a predetermined distance along the optical path of stimulated emission light emitted from the laser chamber. An output mirror 3 and a total reflection mirror 4 which are arranged to face each other are provided on the base 1.

The base 1 is a rectangular flat plate having an appropriate thickness, as shown in FIGS. 1 and 2, and has end walls 10 and 11 along both longitudinal edges on the surface of the base 1. However, the support wall 12 is erected substantially perpendicularly to the surface, and a support wall 12 is erected along the side edge of the base 1 between them. The support wall
The base end of the base 12 is continuously provided at a position shifted to one side in the width direction of the surface of the base 1 so as to be substantially perpendicular to the surface of the base 1.

The laser chamber 2 is fixed on the surface of the base 1, and the optical path of the stimulated emission light emitted from the laser chamber 2 is located at a position close to the surface of the base 1, as shown by a dashed line in the figure. It is positioned so as to be substantially parallel to the longitudinal direction of the surface. On the surface of the base 1, a mirror base 30 is erected at a position separated by a predetermined distance from the mounting position of the laser chamber 2 on one end wall 10 side, and between the mirror base 30 and the laser chamber 2. An aperture base 50 is provided upright, the output mirror 3 is mounted on the mirror base 30, and the aperture 5 is mounted on the aperture base 50, respectively.

The output mirror 3 is a mirror having a reflectivity capable of partially transmitting light, and is attached to the optical path of the stimulated emission light emitted from the laser chamber 2 with the center of the mirror surface facing directly. The aperture 5 is a shielding plate having a small-diameter opening corresponding to the diameter of the laser rod contained in the laser chamber 2, and the center of the opening is attached so as to match the optical path of the stimulated emission light.

A scanning head 8 having a built-in scanning optical system is mounted on the outer surface of the end wall 10.
The stimulated emission light emitted from is transmitted through the output mirror 3 and is output as a marking laser beam to the scanning head 8 through an opening 13 formed in the end wall 10. At this time, the aperture 5 suppresses oscillation of an unnecessary mode deviating from the optical path, and performs a mode selection operation for optimizing the mode of the laser beam.

A mirror holder 60 having a rectangular box shape is mounted on the inner surface of the other end wall 11 of the base 1. The mirror holder 60 has a pair of openings at both ends in the longitudinal direction of one surface thereof, one opening at the lower position is directly opposed to the optical path of the stimulated emission light, and the other opening at the upper position is provided. Is formed in such a state that its forming end is inclined toward the support wall 12 side.

Inside the mirror holder 60, a pair of bending mirrors 6 and 6 are attached to the inside of the pair of openings, respectively. These are individually
The mirrors are inclined at an angle of 45 °, have mirror surfaces facing each other inside the mirror holder 60, and stimulated emission light emitted from the laser chamber 2 is introduced into an opening below the mirror holder 60, and After being bent at a substantially right angle by one of the bending mirrors 6 inside the opening, and traveling inside the mirror holder 60 in the longitudinal direction, the other bending mirror 6
Is bent again at a substantially right angle, and is sent out from the other opening in the opposite direction, that is, toward the end wall 10.

That is, the optical path of the stimulated emission light emitted from the mirror holder 60 is inverted at the position shifted in the height direction and the width direction of the base 1 from the optical path of the stimulated emission light emitted from the laser chamber 2. The optical path is folded in the direction (hereinafter referred to as a folded optical path), and the total reflection mirror 4 and the Q switch 7 are arranged on the folded optical path.

The total reflection mirror 4 has a mirror surface capable of substantially total reflection, and the mirror base 40 erected on the inner wall surface of the support wall 12 has the center of the mirror surface forward to the folded optical path. It is attached to it. The total reflection mirror 4 arranged in this manner is composed of the folding mirrors 6, 6 arranged as described above.
, And the stimulated emission light emitted from the laser chamber 2 is amplified during multiple reflection between the output mirror 3 and the total reflection mirror 4.

The Q switch 7 has a merit number (Q) as a resonator between the output mirror 3 and the total reflection mirror 4.
Value) to generate an inverted population of excited atoms and extract a high-power laser pulse, and is mounted on the wall surface of the support wall 12 so as to be correctly positioned on the folded optical path.

In the solid-state laser oscillator configured as described above, the stimulated emission light emitted from the laser chamber 2 acts on the aperture 5 and the Q switch 7 while reciprocating between the output mirror 3 and the total reflection mirror 4. The scanning head 8 is sent to the scanning head 8 via the output mirror 3 and scanned by the operation of an optical system built in the scanning head 8.
The object is irradiated through a condenser lens 80 attached to a part (the lower part in FIG. 1) of the scanning head 8.

In the present invention, as described above, the optical path of the stimulated emission light that reciprocates between the output mirror 3 and the total reflection mirror 4 is a bending mirror disposed between the laser chamber 2 and the Q switch 7. It is bent by 6 and 6, and the longitudinal dimension L of the base 1 can be shortened. In particular, since the folding mirrors 6 and 6 are arranged between the laser chamber 2 having a large bulk and the Q switch 7 among the components which need to be arranged on the optical path, the longitudinal dimension L Is effectively shortened, and the base 1 can be reduced in size and weight.

The bending of the optical path by the bending mirrors 6 and 6 is performed in such a manner as to be folded in the opposite direction.
Further, since the laser chamber 2 and the Q switch 7 arranged on both sides of the turnback position are arranged at different positions in the vertical direction, the width dimension W of the base 1 can be reduced, and the longitudinal dimension L can be reduced. In addition, the planar occupied area of the base 1 is reduced, and the base 1 is more effectively reduced in size and weight.

Further, since the laser chamber 2 and the Q switch 7 are arranged at different positions also in the width direction of the base 1, each of them is viewed from the front (see FIG. 1) and the plan view (see FIG. 2).
Can be seen without overlapping. Therefore, mounting, removing and adjusting the laser chamber 2 from above the base 1 and mounting, removing and adjusting the Q switch 7 from the front side of the base 1 can be easily performed without interference.

The Q switch 7 and the total reflection mirror 4
However, it is attached to a support wall 12 as a support member that rises from the base 1, and positioning with respect to the folded optical path is realized with high accuracy. Further, since the support wall 12 extends in the direction along the optical path of the stimulated emission light, that is, in the longitudinal direction of the base 1, and acts as a rib for increasing the bending rigidity of the base 1, it is sufficient. The base 1 can be made thinner while maintaining high rigidity, and the base 1 can be further reduced in weight.

As shown in FIGS. 2 and 3, the back surface of the support wall 12 is used as a mounting surface of a control board 9a for controlling the operation of a scanning optical system (galvano mirror) built in the scanning head 8. I have. Furthermore, on the base side of the support wall 12,
As shown in FIG. 3, a parallel portion is provided at a position distant from the surface of the base 1, and the drive substrate 9b of the scanning optical system is fixed to the upper surface of the base 1 below the parallel portion.

Since the temperature of the laser chamber 2 becomes high due to the supply of a large current to the excitation lamp, the inside of the laser chamber 2 is cooled by continuously supplying cooling water to the inside thereof. A humid environment is inevitable. In the solid-state laser oscillator shown in FIGS.
Due to the above-described arrangement of the control substrate 9a and the drive substrate 9b of the scanning optical system, they are isolated from the space in which the laser chamber 2 is provided. Operation can be prevented beforehand.

A drive board 9b that generates heat when power is supplied to the scanning optical system is fixed to the upper surface of the base 1, and the heat is effectively emitted to the outside through the base 1 and the mounting surface thereof. And the thermal expansion of the base 1 can be suppressed to a small extent, and the occurrence of displacement due to the thermal expansion of each member positioned on the optical path of the stimulated emission light on the surface of the base 1 is prevented. it can. As a result, stable operation can be performed over a long period of time.

As described above, in the solid-state laser oscillator and the laser marking device according to the present invention, the optical member (bending mirrors 6 and 6) for bending the optical path of the stimulated emission light emitted from the laser chamber 2 includes the laser chamber 2 and the Q switch 7 And the base 1 supporting them can be reduced in size and weight.

The bending of the optical path in the laser oscillator is as follows.
Not only the embodiment shown in FIGS. 1 to 3 but also the embodiment shown in FIGS. 4 to 7 is possible. These all show only the arrangement of necessary members on the optical path, and in each of the drawings,
(A) is a front view, (b) is a plan view, and (c) is a side view.

In FIG. 4, the folding mirrors 6 and 6 are arranged between the laser chamber 2 and the Q switch 7 so as to be folded on the surface of the base 1 (not shown). In this configuration, the effect of shortening the longitudinal dimension L of the base 1 can be obtained, but the width dimension W of the base 1 is larger than in the configuration shown in FIGS.

In FIG. 5, the folding mirrors 6 and 6 are arranged between the laser chamber 2 and the Q switch 7 so as to turn the base 1 (not shown) in the height direction. In this configuration, both the longitudinal dimension L and the width dimension W of the base 1 can be shortened, and the size and weight of the base 1 can be effectively reduced, but the laser chamber 2 and the Q switch 7 are vertically overlapped. The arrangement makes it difficult to attach, remove and adjust them.

6 and 7, a single bending mirror 6 is used for bending the optical path. FIG.
The Q switch 7 and the total reflection mirror 4 are arranged on the optical path bent upward at right angles by the bending mirror 6, and according to this configuration, the longitudinal dimension L and the width dimension W of the base 1 can be reduced. This is achieved, but this results in an increase in the height of the device in order to ensure a certain distance between the folding mirror 6 and the total reflection mirror 4. FIG. 7 shows a configuration in which the Q switch 7 and the total reflection mirror 4 are arranged on the optical path that is turned obliquely upward by the bending mirror 6, and according to this configuration, the longitudinal dimension L and width of the base 1 are While the dimension W can be shortened and the height of the device is kept small,
The positioning of the Q switch 7 and the total reflection mirror 4 on the bent optical path becomes slightly difficult.

In the above embodiment, the bending mirrors 6 and 6 are used as optical members for bending the optical path. However, it goes without saying that other optical members such as prisms can be used. In the embodiment shown in FIGS. 1 to 3, the laser chamber 2 is fixed to the surface of the base 1,
The switch 7 is fixed to the side surface of the support wall 12, but these fixing positions are reversed, that is, the Q switch 7 is fixed to the surface of the base 1, and the laser chamber 2 is fixed to the side surface of the support wall 12. The configuration may be fixed.

[0049]

As described above in detail, in the solid-state laser oscillator and the laser marking device according to the present invention, the optical path of the stimulated emission light emitted from the laser chamber is formed by the bulk of the components arranged side by side on this optical path. Is bent between the laser chamber and the Q-switch mirror, which has a large diameter, so that the longitudinal dimension of the base can be effectively reduced, and the device including the base can be reduced in size and weight.

Further, since the arrangement positions of the laser chamber and the Q switch on the bent optical path are different in the height direction and the width direction of the base, the width of the base can be reduced. In addition, the laser chamber and the Q switch can be mounted, removed, and adjusted without interference.

Further, since one of the laser chamber and the Q switch is mounted on a support member erected on the base, it can be accurately positioned on the optical path, and the support member extends in a direction along the optical path. The present invention has excellent effects, for example, the base plate can be made thin and the base can be made thinner while securing sufficient strength, and the weight of the device including the base can be reduced. To play.

[Brief description of the drawings]

FIG. 1 is a front view of a laser marking device provided with a solid-state laser oscillator according to the present invention.

FIG. 2 is a plan view of a laser marking device provided with a solid-state laser oscillator according to the present invention.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is an explanatory diagram showing another embodiment of the solid-state laser oscillator according to the present invention.

FIG. 5 is an explanatory diagram showing another embodiment of the solid-state laser oscillator according to the present invention.

FIG. 6 is an explanatory diagram showing another embodiment of the solid-state laser oscillator according to the present invention.

FIG. 7 is an explanatory diagram showing another embodiment of the solid-state laser oscillator according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 base 2 laser chamber 3 output mirror 4 total reflection mirror 5 aperture 6 bending mirror 7 Q switch 60 mirror holder

Claims (7)

[Claims] 1. A laser chamber containing a laser rod and an excitation lamp, an output mirror and a total reflection mirror disposed opposite to each other at a predetermined distance along an optical path of stimulated emission light emitted from the laser chamber. A solid state laser comprising a Q switch disposed between the laser chamber and the laser chamber, wherein an optical member for bending an optical path of the stimulated emission light is provided between the laser chamber and the Q switch. A solid-state laser oscillator. 2. The solid-state laser oscillator according to claim 1, wherein the bending of the optical path is a bending in which the traveling direction of the stimulated emission light before and after the bending is reversed. 3. An arrangement position of said laser chamber and said Q
3. The solid-state laser oscillator according to claim 1, wherein an arrangement position of the switch is vertically different. 4. An arrangement position of said laser chamber and said Q
4. The solid-state laser oscillator according to claim 3, wherein a position at which the switch is provided is different in a lateral direction. 5. A base for supporting the laser chamber and the Q switch, wherein the base integrally includes a support member rising from an upper surface thereof, and one of the laser chamber and the Q switch is attached to the support member. The solid-state laser oscillator according to claim 3 or 4. 6. The solid-state laser oscillator according to claim 5, wherein said support member is a plate extending in a direction along said optical path. 7. A laser marking device comprising the solid-state laser oscillator according to claim 1 as a source of a laser beam for marking.