WO2004084758A1 - Photopolymerization unit - Google Patents

Abstract

A photopolymerization unit comprising a light emitting diode emitting a light having a peak emission wavelength of 350-500 nm and secured tightly to the forward end part of a flexible heat dissipator contained in a curved hollow pipe. Accordingly, since optical loss incident to introduction of light to a limited place using a conventional optical fiber can be eliminated thoroughly and the light emitting diode can be used in close proximity to an object being irradiated, quantity of light can be increased substantially. Temperature of the light emitting diode can be lowered during to operation by a light emitting section having the hollow pipe containing the flexible heat dissipator secured tightly to the back of the light emitting diode in order to increase optical output therefrom, current supply can be increased over a rated current in a short time, , the quantity of emitted light can be increased by increasing the input power to the light emitting diode and reliability of the light emitting diode is not damaged by thermal deterioration.

Description

 Specification

Photopolymerizer

Technical field

 The present invention relates to a visible light polymerization irradiator for uniformly curing and curing a dental composite resin filler by irradiating light emitted from a light emitting diode with high power, high uniformity and high uniformity. Background art

 In the basic structure of the light source part of a light polymerization irradiator using an optical fiber, in order to efficiently cause light emitted from a light emitting element of a light emitting diode to be incident on a light guiding fiber conventionally Various structures have been proposed as disclosed in Japanese Patent Application Laid-Open No. 10 2 3 8, Japanese Patent Application Laid-Open No. 7 2 0 4 5 5 3 6, Japanese Patent Application Laid-Open No. 1 1 2 1 6 0 8 8, etc. There is. As shown in FIG. 10 as an example, according to Japanese Patent Application Laid-Open No. 11-219680, a plurality of resin-lens type light-emitting diodes 101 can be used to emit light in the same direction. The light is directed to the light emitting surface side by a tapered tapered light condensing body 1 0 3 in which a metal reflection layer 1 0 4 is arranged on the front side of the light emitting diode 1 0 1 and arranged in a tapered manner. It is possible to condense the light from the plurality of light emitting diodes 101 by connecting the optical fiber to the tapered condensing part, that is, the outgoing part, and to make the light enter the optical fiber 105. It has been tried. Furthermore, when JP-A-09-19023 8 is described with reference to FIG. 11, a transparent, conical surface formed of a wedge-shaped quadric surface whose light emitting surface is formed with one end surface on one side is a metallic reflective layer. A plurality of resin lens type light emitting diodes 1 1 1 are disposed on the convex surface so that light can be emitted in a direction perpendicular to the tangent of the convex secondary surface in the conical light guide 1 1 2 attached with The light is condensed in a cylindrical light guide 1 1 3 1 4, so that the light from the light emitting surface side of the cylindrical light guide 1 1 3 passes through the conical light guide 1 1 2. A structure that emits light to the outside is known. Then, as a conventional example of a photopolymerization illuminator using the basic structure of these light source parts, a small photopolymerization irradiation apparatus shown in FIG. 12 is disclosed in Japanese Patent Application Laid-Open No. 2000-215115. As shown in the figure, a large number of light emitting diodes 1 2 1 are arranged on a light emitting diode support 1 2 2 composed of a spherical surface, and the light emitting diodes can be condensed at the incident end of the optical fiber 1 2 3 . It is possible that a handy photopolymerization irradiator is put into practical use by storing the circuit for controlling the optical system thus configured and the drive power source 125 together with the handpiece 126. It is well known.

However, in JP-A-09-90238, light from a plurality of light emitting diodes can be efficiently incident on an optical fiber by providing a condensing point in the optical fiber through the light guide. However, the uniformity of the light was poor, and the light emitted from the first optical fiber was also poor in uniformity. And, as the diameter of the optical fiber to be guided becomes smaller as the variation of the light distribution characteristic of the shell type light emitting diode becomes larger, it becomes very difficult to condense a large number of light emitting diodes at the same point. Due to the inherent light distribution variation of the diode and the optical axis variation, it is necessary to individually adjust the optical positions of the light emitting diodes individually, and as a light guide, a transparent and conical metal layer is required for dimensional accuracy. Needs a conical quadric surface, etc. There was a great difficulty in practical use. Furthermore, the arrangement of a large number of light emitting diodes makes the substantial size of the light source too large, and the use of a large number of light emitting diodes further increases the power consumption and the storage battery capacity. There is a practical problem such as handling being too bad or heavy in a device aiming to reduce the size and weight by affecting the size of the entire device, such as an increase in the size of the DC power supply unit. In JP-A-11-219608, although the light from the light emitting diode is condensed by the transparent tapered light guide, the light attenuation due to the light reflection or the light guiding fiber 1. Since the taper angle can not be increased in order to place the incident angle of the incident light within the specified angle, ie, within the critical angle, the taper angle becomes substantially smaller, and the light emitting diode can be used to That is, although the distance from the incident end of the light guiding fiber is long and light attenuation due to the distance is large, light leakage from the optical system is small, but the irradiation distance becomes long in addition to light reflection and refraction loss. Caused problems such as increased light attenuation. On the other hand, if the taper angle is made large and the practical length is made short in order to reduce the size from a practical point of view, the light of the light emitting diode is largely refracted by the taper surface, so that the reflection loss becomes large and the efficiency is reduced. It was not good. For this reason, as in the case of the former conventional example, there is no change in that it uses a large number of light emitting diodes, and the apparatus is practically large in size, and the power consumption is large. As described above, in the conventional technology, the basic configuration is a light source for a high light output fiber by optically devising using a large number of light emitting diodes in order to measure an increase in light emitted from one optical fiber. In the present situation, there have been problems in putting it to practical use, such as downsizing of the device, low power consumption and high cost. Furthermore, in the handy apparatus shown in Japanese Patent Application Laid-Open No. 2001-215, as an example using the basic structure of these light source units, basically, as described above, a number of light emitting diodes are basically used. Although it is handy and handy, its size was large and there was a problem in practical use.

 An object of the present invention is to provide a lightweight, compact and highly reliable photopolymerization irradiation apparatus capable of efficiently irradiating light from a light emitting diode onto an object to be irradiated and having no irradiation spot. Disclosure of the Invention A semiconductor device such as a light emitting diode has an absolute maximum rating in terms of electrical temperature, and its use beyond this should not be done in order to reduce the life of the light emitting element, and the absolute maximum rating is exceeded. If it is not used, its lifetime is guaranteed to be tens of thousands to hundreds of thousands of hours or more.

 However, if such a long life is not required, it is considered that the characteristics can be greatly improved by using it beyond the absolute maximum rating.

 At present, halogen lamps are the main light source for dental photopolymerizers, but their service life is at most several dozen hours to several hundred hours, and they are sufficiently used for practical use. From this point of view, it can be said that the lifetime of the light emitting diode is sufficient if it is several hundred hours to several thousand hours.

 -The practical irradiation time of the dental light polymerizer should be short, but the maximum is up to 1 minute.

From the above viewpoint, when examining with a light emitting diode currently marketed, a sufficiently large radiator is attached to the light emitting diode, within 1.5 times the absolute maximum rating value of the average current of the light emitting element, It was found that if the conduction time is less than 1 minute, even if the junction temperature exceeds the absolute maximum rating of the element, it has a life of several thousand hours or more.

 In addition, if the average value of the current supplied to the light emitting element is within 1.5 times the absolute maximum rated value of the average value current of the light emitting element, the junction temperature can be lowered by decreasing the duty ratio, which is larger It turned out that the current could flow.

 The relationship between the conduction time and the current value is shown in Fig. 3 after the current has been supplied to the element for a while and then thermally stabilized. The relation between the conduction time and the junction temperature is shown in Fig. 4.

 That is, Iave (max) is the absolute maximum rating of the average current of the light emitting element, Iave (ext) is the average current that can be flowed for 1 minute without any significant loss of the life of the light emitting element, and D is the duty ratio. Assuming that the flowing current value is Ipeak, and the time during which the current flows in the device (sec), it is confirmed that the following equation holds.

 1.5 lave vmax) lave (ext) ≤ Ipeak 氺 D. · · · i

D = Ton / (Ton + Toff) · · · ₂

 Ton + Toff≤ 60 · · · · 3

 For example, when Iave (max) = 0.35 A, D = 0.4, the maximum current and time can be calculated easily from the above equation.

1.5 * 0.35 = 0.4 氺 Ipeak

0.4 = Ton / (Ton + Toff)

Ton + Toff = 60

From this, Ton = 24 sec, Toff = 36 sec, Ipeak = 1.3 A can be obtained.

That is, a light emitting diode with an absolute maximum rating of 350mA for average current can be used for up to 24 seconds at a current of 1.3A.

It is possible to flow between them. The light output from the light emitting diode increased approximately in proportion to the current, and in the above example, the light output could be obtained about 3.5 times the maximum light output obtained when used within the rating.

 Fig. 5 shows the relationship between the irradiation time and the thickness of the cured film by irradiating the light obtained at this time to a commonly used dental composite resin. . The emission wavelength of the light emitting diode at this time is 470 nm.

 It hardened 3 mm by 5 seconds irradiation, and 4.3 mm by 10 seconds irradiation, and it turned out that it is fully within the practical range. By such a method, the characteristics which could not be obtained unless a plurality of light emitting diodes are conventionally obtained can be obtained by using only one light emitting diode, so the degree of freedom in mounting the light emitting diode is increased and various advantages are obtained. It came to be obtained.

 For example, by attaching a single light emitting diode to the end of the H-shaped hollow pipe, the light guide which has always been necessary is not required, the cost is reduced significantly, and the light loss due to the light guide is eliminated. It has become possible to increase the output.

 In addition, when the light emitting diode is mounted inside the main body, it can be mounted in the immediate vicinity of the light guide because there is no need to collect light with a lens or the like, which offers the advantages of cost reduction and efficiency improvement.

As described above, the relationship between the lighting current of the light emitting diode, the lighting time and the rest time, and the junction temperature of the light emitting diode 'and the temperature rise value on the rear surface side of the light emitting diode are examined in detail. As a result, as shown above, it was confirmed that it could be practically used even under lighting conditions above the rated current.

In order to increase the light output of the light emitting diode, it is essential to provide a heat dissipating member with a heat radiation effect closely fixed to the back of the light emitting diode, which can reduce the operating temperature of the light emitting diode. It is possible to increase the current that can be conducted by limiting the constant time, and as a result, the input power to the light emitting diode is increased and the emitted light output is measured, but also for a short time. Therefore, even if an excessive current is applied, the heat radiation effect of the heat sink does not significantly impair the reliability of the light emitting diode due to the thermal deterioration. BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a first embodiment of the present invention will be described with reference to FIG. 1 and FIG. In FIG. 1, reference numeral 1 1 denotes a light emitting element which emits 4 70 nm or 4 90 nm light mounted on a heat dissipation substrate 12, and around the light emitting element to improve the light extraction efficiency from the light emitting element And, in order to protect the light emitting element, it is covered with a convex transparent silicon resin or transparent epoxy resin 13. The electrode 14 ab on the light emitting element is electrically connected to the cathode lead 15 and the anode lead 16 by a gold wire 17 a, respectively, and the light emitting element emits light when current flows between the leads. It has a light structure. As shown in FIG. 2 using such a light emitting diode, one side of the heat dissipating member 23 is a copper metal rod whose surface is electrically insulated on the back surface of the heat dissipating substrate 22 of the light emitting diode 21 as shown in FIG. It is in close contact via the thermally conductive bonding material 24 to the end of the. The current is supplied to the light emitting diode 21 from the two electric wires 25 a and b and electrically connected to the anode and the cathode lead 26 ab from the light emitting diode 21 and along the heat sink 23. Wired to the power supply unit. With such a configuration, the heat emitted from the light emitting diode 21 is dissipated directly to the outside by the heat dissipator 23, and the heat generated when the light emitting diode is lit is dissipated to the outside by the heat dissipator. Can do. As shown in FIG. 6 as the practical structure described above, a sewing wire obtained by bundling small diameter wires of copper metal, the surface of which is electrically insulated on the back surface of the heat dissipation substrate 6 2 of the light emitting diode 61. It is in close contact with one end of a flexible flexible heat sink 63 via a thermally conductive bonding material 64. This flexible heat sink 63 is embedded in a hollow pipe 65 made of stainless steel. The light emitting diode 61 is housed in a resin light emitting diode holder 66 airtightly bonded and fixed to one end of a hollow pipe, and the gap between the light emitting diode holder 65 and the light emitting diode 61 is Sealing resin 60 is filled and sealed. Further, the current supply to the light emitting diode 61 is electrically connected to the anode and the cathode lead 6 8 ab which are made from the two electric wires 6 7 a and b and are emitted from the light emitting diode 6 1. It is wired along a flexible heat sink 63 consisting of a loose wire, and one of the wires enables an airtight and sealed electrical connection to the other end of the hollow pipe 65 and is airtight. It is connected to feed through terminals 6 and 9 that can be electrically energized while maintaining the characteristics. The other electric wire is fixed so as to be pressed against the inner surface of the hollow pipe made of stainless steel in the hollow pipe 65 by the flexible heat dissipating body, and is substantially electrically connected to the hollow pipe 65. Also, here Although a loose wire made of a thin wire of copper metal is used as the heat dissipating material, although it is expensive, it is easily conceivable that the same effect can be expected using soft copper or soft iron (pure iron).

 Also, although the object of the present invention is aimed at dental photopolymerization, another object according to the basic constitution of the present invention, that is, mounting of a light emitting diode having an emission wavelength exceeding the range of 350 to 500 nm Therefore, it can be easily considered to be applied to industrial endoscopes, medical endoscopes, various illumination devices, and light sources for various vehicles. Furthermore, using a light fiber light guide made of a multi-core bundle or single-core hollow rod glass as shown in FIG. 7, a light emitting diode 71 is disposed in the vicinity of the incident end 74 of the optical fiber. As a result, the light emitted from the light emitting diode 71 can be guided to the light emitting end 75 of one of the optical fibers, so that the light can be efficiently utilized. At this time, in order to dissipate the heat generated from the light emitting diode 71 to the rear side, the radiator 76 is disposed in close contact with the rear surface of the S photodiode 7 1 via the heat conductive adhesive 73. .

 As described above, in any of the configurations of the entire configuration of the two devices as described above, the conduction current condition to the light emitting diode does not change. Furthermore, although a single light emitting diode was used in the present embodiment, it is easily conceivable that the above conditions do not change even if a plurality of these are used. FIG. 8 shows an embodiment of the whole apparatus based on claim 2.

 A light emitting unit 81, a control unit 82 for storing on / off of the light emitting unit 81, which is stored in a main body 86, and an absolute maximum rating value of average current in the light emitting unit is 1.5 times or less It consists of a current source unit 83 that supplies current, a battery unit 8 that supplies power to the current source unit, and a power supply unit 85 that supplies power to the battery in the main unit.

Since the light emitting unit 81 and the main unit 86 can be separated, the light emitting unit 81 can be easily removed and disinfected after use.

 In addition, since the battery is stored in the main unit 86, the main unit and the power supply unit 8 5 can be separated at the time of use, which is a so-called cordless state, which is very convenient.

 It is not necessary to store the battery in the main body 86, but it is also possible to remove the battery and connect the power supply 85 directly to the current source. In this case, the main body and the power supply unit 85 are connected at the time of use, so that the cost can be reduced and further downsizing can be achieved. An embodiment of the entire apparatus is shown in FIG. 9 based on claim 3.

 In the light guide 92 for emitting the light from the light emitting diode 91 to the outside and in the main body 93, the light emitting diode 91 attached near the light guide incident end and the heat radiation for emitting the heat of the light emitting diode 91 A current source unit 95 that supplies an electric current to the body 94 and the light emitting diode 91, and a battery unit that supplies electric power to the current source unit. And a power supply unit 97 for supplying power to the battery in the main unit 93.

As in the fourth embodiment, since the battery 1 is built in the main body, the main body and the power supply unit 97 can be separated at the time of use, and the so-called cordless state is obtained, which is very convenient. It is not necessary to have a built-in battery in the main body 93, so remove the battery It is also possible to connect the power supply unit 97 directly to the current source unit. In this case, the main body and the power supply unit 97 are connected at the time of use, which makes it possible to reduce the size and further reduce the size. Industrial Applicability

 As described above, according to the basic configuration of the present invention, the back surface side of the light emitting diode that emits light of 350 to 500 nm is closely fixed to the tip of the heat sink and the light emitting diode is energized. By setting the current to 1.5 times or less of the rated current, and by further limiting the continuous conduction time to 60 seconds or less, the amount of light from the fluorescent diode is enhanced without significantly reducing the reliability such as the life. It was possible. Brief description of the drawings

FIG. 1 is a schematic structural cross-sectional view of a light emitting diode according to the present invention.

Fig. 2 shows the basic structure of the light emitting unit of this unit.

Fig. 3 shows the measurement results of the relationship between the current application time and the current value.

FIG. 4 is a diagram showing the relationship between the current application time and the junction temperature.

FIG. 5 shows the results of curing experiments in Example 1.

FIG. 6 is a diagram for explaining the construction of the second embodiment.

FIG. 7 is another practical structural explanatory diagram in the second embodiment.

FIG. 8 is a diagram for explaining the construction of the third embodiment.

FIG. 9 is a diagram for explaining the construction of the fourth embodiment.

Figure 10 is a conventional example

Figure 11 is a conventional example

Figure 12 is a conventional example

Claims

The scope of the claims 1. In a photopolymerizer using a light emitting diode, the average value of the current flowing to the light emitting diode is set to 1.5 times or less of the absolute maximum rating value of the average current of the light emitting diode, and the conduction time is set to 60 seconds or less A photopolymerization device characterized in that it is used above the absolute maximum junction temperature of diode.  2. The photopolymerizer comprises a light emitting part, a main body, and a power supply part, and the light emitting part is a hollow pipe bent in a letter shape and the light emission sealed and attached to one end of the hollow pipe. A hollow pipe having a diode, a rod-shaped heat dissipating member attached to the rear surface of the light emitting diode, a conductor for supplying power to the light emitting diode, and a terminal for electrically connecting to the conductor. The photopolymerization device according to claim 1, characterized in that the terminal portion sealed at one end is capable of being detached and rotated from the main body.  3. The photopolymerization device includes a light guide for guiding the light from the light emitting diode to the outside, the light emitting diode facing the light guide incident end and closely or closely disposed on the light emitting surface side, and the light emission The photopolymerization device according to claim 1, further comprising a heat sink for releasing the heat of the diode.  4. A photopolymerization irradiator according to claim 3, wherein said light guide is made of multi-core bonded glass fiber or quartz solid rod.  5. The photopolymerization irradiator according to claim 1, wherein the light emitting diode comprises a plurality of light emitting elements.