JP2512249B2 - Optical beam heating device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light beam heating device capable of local heating by condensing light from a light emitting lamp, which comprises heating for soldering, film removal of a thin polyurethane wire, Alternatively, the present invention relates to a light beam heating device suitable for heat processing of resin.

[0002]

2. Description of the Related Art In recent years, light emitted from a light-emitting lamp is condensed, is incident on one end of an optical fiber, and the light emitted from the other end is condensed using an optical system to be heated near a condensing point. Light beam heating devices for heating objects are beginning to be widely used as non-contact local heating devices. In order to effectively utilize the light energy generated by the light emitting lamp, this device uses an elliptical reflecting mirror to collect light, and the light emitting part of the light emitting lamp is located at the first focal point and the optical fiber receives light at the second focal point. The end is located. Conventionally, this type of light beam device is shown in FIGS.
The structure shown in FIG. The configuration will be described below with reference to FIGS. 3 and 4. As shown in FIG. 3, a light emitting lamp 1 such as a xenon lamp is held by a lamp mounting mechanism 2 having a manual position adjusting function, and the light emitting portion is adjusted so as to be located at the first focal point 4 of the elliptical reflecting mirror 3. It The central part of the light receiving end of the optical fiber 5 is fixed by a fitting (not shown) so as to come to the position of the second focal point 6 of the elliptical reflecting mirror 3. The lens holder 7 is an optical fiber 5
An optical lens system for condensing the light emitted from the emission end of is incorporated. The power supply circuit 14 adjusts the input current to the light emitting lamp 1 according to the command value of the output command circuit 15. FIG.
Shows the structure of the lamp mounting mechanism 2.
The position of the light emitting lamp 1 can be adjusted by rotating each adjustment shaft in each of the front and rear directions as illustrated.

In the above structure, the lamp mounting mechanism 2 is adjusted so that the light emitting portion of the light emitting lamp 1 has the first focal point 4 of the elliptical reflecting mirror 3.
When the light receiving end of the optical fiber 5 is fixed to the second focal point 6 and the light emitting lamp 1 is turned on, the light emitting lamp 1 emits light by the current set by the output command circuit 15 and is condensed by the lens holder 7. The object to be heated (not shown) can be heated by being irradiated with the light.

[0004]

In such a conventional light beam heating apparatus, the output command circuit 15 only sets the drive current of the light emitting lamp 1 to the command value, and changes the temperature of the light emitting lamp 1 during use. When a change in the amount of emitted light and a change in the amount of emitted light due to stains on the glass portion of the light-emitting lamp 1, electrode deformation, or the like occur over time, the light energy incident on the light-receiving end of the optical fiber 5 decreases, and the object to be heated is heated. Light energy is reduced. Further, when the light emitting lamp 1 reaches the end of its service life due to electrode wear or the like and is replaced with another lamp, the light emitting characteristics with respect to the input current of the individual lamps differ, so that even if the setting of the output command circuit 15 is the same. The light energy incident on the light-receiving end of the optical fiber 5 changes greatly. As described above, when heating the object to be heated, even if the output command circuit 15 is set to the same condition, the light energy incident on the light receiving end of the optical fiber 5 changes, and the heating condition of the object to be heated changes. As a result, stable heating cannot always be performed. Therefore, in order to always reproduce the same construction conditions, the lens holder 7
Since the light beam output from the device must be measured while frequently measuring it with a power meter, etc., it was inefficient and could hardly be performed in practice, and the reproducibility of construction conditions was poor.

The present invention solves the above problems, and an object of the present invention is to provide a light beam heating apparatus which can ensure the reproducibility of heating work and has good operability and responsiveness.

[0006]

[Means for Solving the Problems]To achieve the above objectives
The present invention, Light-emitting lamp and elliptical reflection that collects the light
A mirror and a plurality of light-receiving ends that receive and transmit the collected light.
Fiber strandOptical fiber bundled with, The optical phi
Of the barAt least oneAt the light-receiving end of the fiber
And a light output of the photodetector
A photoelectric converter for photoelectrically convertingAt least oneNo
Fiber wireBased on placement at the fiber optic receiverRank
Location informationandOf the photoelectric converterDetection position of the photodetector
InOptical fiber receiving end from outputWhole surfaceLight incident on
A calculation circuit that calculates the total amount of energy and a heating output
Output command circuit that performs the setting, and the command value of the output command circuit
Error amplification circuit for performing error amplification with the output value of the arithmetic circuit
According to the output value of the error amplifier circuit.
Equipped with a power supply circuit that can set the power to be suppliedIt was
You.

[0007]

The operation will be described below with reference to the drawings. Figure 2 shows the distribution of the light intensity collected at the optical fiber receiving end when the light emitting part of the light emitting lamp is located at the first focal point of the elliptical reflecting mirror and the optical fiber receiving end is placed at the second focal point. ,
It is a bell-shaped distribution that is almost axisymmetric. In the drawing, the bell-shaped distribution is shown cut at the center. This bell-shaped distribution has a distribution shape that is almost similar to the Gaussian intensity distribution shown in FIG. The Gaussian intensity distribution curve is expressed by the following equation.

I (r) = I (0) exp (−2r ² / w ₀ ² ) ... (1) where I (r): strength, I (0): strength on central axis,
r: radial distance, w ₀ : Gaussian beam radius In FIG. 2, r at which the relative intensity is e ⁻² is normalized as w ₀ . Further, the total energy (P (r)) within the radius r is expressed by the following equation.

[0009] P therefore ^{_{(r) = (πw 0 2}} /2) I (0) [1-exp (-2r 2 / w 0 2)] ...... (2), r, I (0), is w ₀ Knowing this, the total amount of light energy incident on the optical fiber can be known. Let r be the radius of the optical fiber, measure the light intensity at the optical fiber receiving end and the detection position with a photodetector, set the maximum value to I (0), and further calculate w ₀ using equation (1) The incident energy of can be calculated. Further, if the distribution of the light intensity is separately measured, w ₀ is measured in advance, and I (0) is detected by the photodetector arranged at the center of the optical fiber receiving end, P (r) = a · I ( 0)
(A is a constant) and using this relationship, the optical energy incident on the optical fiber can be calculated by the arithmetic circuit. The error energy between the value of the optical energy incident on the light receiving end of the optical fiber measured in this way and the command value of the output command circuit is amplified, and the output value of the power supply circuit is changed according to the error,
By adjusting the power supplied to the light emitting lamp, the light energy incident on the optical fiber receiving end can be made constant, and therefore,
The heating condition of the object to be heated can be made constant, and the desired heating condition can always be reproduced.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The lamp mounting mechanism 2 has a light emitting lamp 1
The light emitting portion of the light emitting lamp 1 is located at the first focal point 4 of the elliptical reflecting mirror 3, and the second focal point 6 which is another focal point of the elliptic reflecting mirror 3 has a light receiving end of the optical fiber 5. Are arranged. Further, one fiber strand is taken out from the center of the light receiving end of the optical fiber 5 to form a photodetector 8, and the output of this photodetector 8 is input to a photoelectric converter 9 and converted into an electric quantity and then calculated. It is input to the circuit 10.
The arithmetic circuit 10 calculates the total amount of light energy incident on the optical fiber 5 described above, and the output thereof is the error amplification circuit 1
Connect to one end of the 3 input. The output of the output command circuit 15 for setting the heating output to a desired value is connected to the other end. The error signal of the error amplifier circuit 13 is connected to the power supply circuit 14 and changes its output current. This power circuit 1
The output current of No. 4 is supplied to the light emitting lamp 1 and changes the total amount of light emitting energy.

The operation of the above-described structure will be described. The light-emitting lamp 1 is turned on by being supplied with a current from the power supply circuit 14. The characteristics of the power supply circuit 14 are selected to be suitable for the type of the light emitting lamp 1. In this embodiment, a xenon lamp is used as the light emitting lamp 1, and the power supply characteristic is a constant current characteristic. Since the light emitting portion of the light emitting lamp 1 is at the first focal point 4 of the elliptical reflecting mirror 3, the generated light is emitted at the second focal point 6, that is, the optical fiber 5.
The light is condensed at the light receiving end of the with a bell-shaped light intensity distribution shown in FIG. As described above, this light intensity distribution is close to the Gaussian intensity distribution, and the Gaussian beam radius w ₀ has been measured in advance. Since the photodetector 8 is located at the center of the light receiving end of the optical fiber 5, it detects a value I ₀ according to the light intensity at the center of the light receiving end of the optical fiber 5. When the light emitting part of the light emitting lamp 1 has different light emitting characteristics due to heat change of the lamp, wear of electrodes, or individual lamp differences due to lamp replacement, the condensed light intensity distribution remains the same as the light distribution at the center of the light receiving end. The intensity changes, and the detection value of the photodetector 8 changes to I ₁ .

Light intensity at the center of the light receiving end of the optical fiber 5.
After the photodetector 8 detects the degree, the photoelectric converter 9
It is converted into a quantity and input to the arithmetic circuit 10.
Total amount of light energy incident on the light receiving end (P (r) = P
w) is calculated by the equation (2). Detection value of photodetector 8
Is I₀, I₁, The output value of the arithmetic circuit 10 is Pw.
₀, Pw₁However, it is input to one end of the error amplification circuit 13
The value of the output command circuit 15 is
A value (Pw corresponding to the light energy incident on the light receiving end of 5
₀). As a result, the error amplifier circuit 13 is
The detection value of the detector 8 is I₁Then, the error (ΔP = Pw₀−
Pw₁) Is input and the amplified output of the power supply circuit 14
It becomes an output control signal, and the power supply circuit is in the direction of reducing ΔP to zero.
14 output current is Pw₁-Pw₀It changes so that.

As described above, even when the light emitting portion of the light emitting lamp 1 has different light emitting characteristics due to heat change of the lamp, wear of electrodes, or individual lamp difference due to lamp replacement, the light always entering the light receiving end of the optical fiber 5. Since the total amount of energy can be controlled to be constant, the object to be heated can be heated under desired irradiation conditions. In this embodiment, one photodetector 8 is placed at the center of the light receiving end of the optical fiber 5, but a plurality of photodetectors 8 are placed around the center of the light receiving end, and if the position information is known, the above (1), (2 ) Is used to calculate the incident light energy to the optical fiber 5, and even if there is a difference between the light intensity distribution and the Gaussian intensity distribution at the light receiving end, the calculation processing of the calculation circuit 10 can be corrected. The irradiation output can be stabilized and reproduced with high accuracy.

[0014]

As is apparent from the above description, according to the present invention, at least one optical fiber located at the light receiving end of the optical fiber is located.
A value that corresponds to the light energy incident on the light receiving end of the optical fiber in the arithmetic circuit by detecting the light intensity and position information on the light receiving end surface of the optical fiber with the photodetector consisting of two fiber strands. Is calculated and the output of the power supply circuit that supplies the light-emitting lamp is changed so as to eliminate the error between this value and the command value set by the output command circuit, so the light irradiation output is stable and the work is performed when heating is performed. It is possible to provide a light beam heating device that can ensure reproducibility and has good operability and responsiveness when setting desired conditions.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a light beam heating apparatus according to an embodiment of the present invention.

FIG. 2 is a light intensity distribution and a Gaussian intensity distribution diagram at the light receiving end of the optical fiber when the light emitting portion of the light emitting lamp is on the first focal point of the elliptical reflecting mirror.

FIG. 3 is a block diagram showing a configuration of a conventional light beam heating device.

FIG. 4 is an external perspective view showing an example of a lamp position adjusting mechanism of the light beam heating device.

[Explanation of symbols]

 1 Light-Emitting Lamp 3 Elliptical Reflector 5 Optical Fiber 8 Photodetector 9 Photoelectric Converter 10 Operation Circuit 13 Error Amplifying Circuit 14 Power Supply Circuit 15 Output Command Circuit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-61-211978 (JP, A) JP-A-3-238185 (JP, A) JP-A-3-30452 (JP, U)

Claims (1)

(57) [Claims] 1. A light emitting lamp, an elliptical reflecting mirror for condensing the light, an optical fiber bundled with a plurality of fiber strands for receiving and transmitting the condensed light at a light receiving end , and at least one of the optical fibers. placement of a photodetector for detecting the light intensity in the light receiving end of the fiber strand, the light output of the light detector and the photoelectric converter for photoelectrically converting an optical fiber receiving end of the at least one fiber strand Based on the position information and the detection position of the photodetector of the photoelectric converter
An arithmetic circuit for calculating the total amount of light energy incident on the optical fiber receiving end entirely from the output of the error amplifier of an output command circuit for setting the heating output, the output value of the operational circuit and the command value of the output command circuit A light beam heating apparatus comprising: an error amplification circuit for performing the above; and a power supply circuit capable of setting the power supplied to the light emitting lamp according to the output value of the error amplification circuit.