JP2008053014A - Light irradiation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light irradiation device having a very large irradiation width, excelling in an illuminance distribution, and high in illuminance. <P>SOLUTION: This light irradiation device 1 includes: light irradiation parts 2 each composed by connecting a plurality of lamps 4 each comprising a microwave generation means 5, a rod-like electrodeless lamp 6 emitting light by microwaves from the microwave generation means 5, and a condensing mirror 7 condensing and emitting light of the electrodeless lamp 6 to one another in the longitudinal direction of the electrode lamps 6; and a light uniforming part 3 having a pair of reflecting mirrors 8, 8 arranged in the irradiation direction of the condensing mirrors 7 and extended in a predetermined length L along in the longitudinal direction of the electrodeless lamps 6 in the light irradiation part 2, wherein the reflecting surfaces of the reflecting mirrors 8, 8 are faced to each other at a predetermined distance D; and is characterized in that the focus position of the light emitted from the condensing mirror 7 is located at upper ends of the reflecting mirrors 8, 8, and at the center between the reflecting mirrors 8, 8. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light irradiation apparatus for producing an optical functional film used for a flat panel display or the like.

  In recent years, flat panel displays (liquid crystal displays, plasma displays, etc.) have become larger and lower in price, and accordingly, the display substrate at the time of manufacture has also increased in size. In 1870 × 2200 mm, the 7.5th generation is 2200 × 2400 mm). These display substrates require an optical functional film (hereinafter referred to as a film) such as an antireflection film as a constituent element, and this film also needs to be wide. Therefore, a light (mainly ultraviolet) irradiation device necessary for manufacturing this film also requires a wide irradiation surface.

  In order to obtain a wide irradiation surface, it is common to increase the light emission length of a lamp used in the light irradiation device. However, in the case of a lamp having a long light emission length, particularly an electroded lamp, various problems occur because the lamp is provided with electrodes at both ends of the lamp and discharged between the electrodes to emit light. That is, as the problem of the lamp performance, when the light emission length of the lamp is long, there are problems that the lamp hangs down by its own weight when the input density is high, or the arc of the lamp is not stable. Further, as a safety problem of the lamp, since the lamp voltage increases in proportion to the light emission length of the lamp, there is a problem that a very high voltage is required when the light emission length is long. As a problem in manufacturing the lamp, there is a problem that the manufacturing facility is enlarged because the lamp is long. Therefore, in the electroded lamp, the light emission length has a limit.

  For this reason, in particular, when the irradiation width exceeds 1500 mm, a light irradiation device using an electrodeless lamp as a light irradiation device and connecting a plurality of the lamps has come to be used. As such a lamp, Patent Document 1 describes a lamp 31 having a configuration as shown in FIG. That is, the lamp 31 includes a magnetron 33 having an oscillation frequency of 2.45 GHz, a waveguide 34 that transmits the generated microwave, and a microwave resonator 35 that resonates the transmitted microwave. And an electrodeless lamp 36 that emits light by resonating microwaves, and a reflector (condenser mirror) 37 that condenses the emitted light so that the focal position FP of the emitted light is outside.

  In the case of the electrodeless lamp 36, since there is no electrode, the connecting portion (the portion not emitting light) is as short as about 20 to 30 mm even when the lamp is connected. The decrease in illuminance at the part becomes the practical range (about 20%). Therefore, the length of one lamp of the electrodeless lamp 36 is short (generally about 250 mm, two wavelengths of the commonly used microwave frequency of 2.45 GHz), but by connecting a plurality of lamps 31, A wide irradiation surface can be obtained.

On the other hand, in the case of an electroded lamp, an electrode and a metal foil for secretly sealing it exist at both ends in the longitudinal direction of the lamp. Therefore, when the lamp is connected and used, a connecting portion of about 100 mm is required at the minimum, and the decrease in illuminance at the connecting portion greatly exceeds the practical range.
JP 2003-68490 A (paragraphs 0022 to 0025, FIGS. 1 to 3)

  However, since the optical functional film has recently been made thinner (some have a thickness of about 10 μm) in response to demands for thinner and lighter flat panel displays, a decrease in illuminance at the connecting part of the lamp has become a problem. It is coming. That is, even when a lamp using an electrodeless lamp is used, wrinkles may occur in the film due to a decrease in illuminance at the connecting portion of the lamp. If the irradiation surface position of the film is separated from the focal position of the lamp, the illuminance distribution is improved and the decrease in illuminance at the connecting portion is reduced, but the illuminance is decreased (see FIGS. 6 to 8).

  Therefore, the present invention was devised to solve such a problem, and its purpose is to provide a light irradiation device having a very large irradiation width, good illuminance distribution, and high illuminance. is there.

  In order to solve the above-mentioned problems, the invention according to claim 1 is directed to a microwave generating means, a rod-shaped electrodeless lamp that emits light by microwaves from the microwave generating means, and condensing light from the electrodeless lamp. A plurality of lamps each having a condensing mirror for irradiation in the longitudinal direction of the electrodeless lamp, and a longitudinal direction of the electrodeless lamp in the light irradiating unit, arranged in the irradiation direction of the condensing mirror. A pair of reflecting mirrors extending along a direction with a predetermined length (L), and a light uniformizing unit facing the reflecting surfaces of the reflecting mirrors with a predetermined distance (D), The focus position of the irradiation light from the said condensing mirror is comprised as a light irradiation apparatus which is the upper end part of the said reflective mirror, and is the center between the said reflective mirrors.

  According to the said structure, an irradiation width spreads by setting a light irradiation part as the structure which connected the some lamp. In addition, a light uniformizing unit (a pair of reflecting mirrors) is provided in the irradiation direction of the light irradiation unit, and the focal position of the irradiation light from the light irradiation unit (condensing mirror) is a predetermined position, thereby collecting light. Irradiation light from the mirror is reflected between the reflecting mirrors, and the illuminance reduction of the irradiation surface at the position corresponding to the connecting part of the lamp is suppressed, the illuminance distribution is improved, and the illuminance over the entire irradiation surface is also high. Maintained. Furthermore, since the light irradiation unit includes an electrodeless lamp, the light collecting property of the irradiation light from the light irradiation unit is improved, and the interval between the pair of reflection mirrors can be narrowed. ) Is reduced in illuminance.

  According to the light irradiation apparatus according to the present invention, the irradiation width is very large, the irradiation distribution is good, and the illuminance is high. Further, by limiting the interval between the reflecting mirrors, the illuminance distribution becomes even better and the illuminance becomes even higher.

  Embodiments of a light irradiation apparatus according to the present invention will be described in detail with reference to the drawings. 1 is a partially cut perspective view of the light irradiation device, FIG. 2 is a cross-sectional view along the longitudinal direction of the light irradiation device, and FIG. 3 is a cross-sectional view taken along the line ZZ of FIG.

As shown in FIGS. 1 to 3, the light irradiation device 1 includes a light irradiation unit 2 and a light uniformizing unit 3. Each configuration will be described below.
<Light irradiation part (lamp)>
The light irradiation unit 2 is formed by connecting a plurality of lamps 4 each having a microwave generating means 5, an electrodeless lamp 6, and a condenser mirror 7 in the longitudinal direction of the electrodeless lamp 6.

(Microwave generation means)
If the microwave generation means 5 can generate a microwave, the structure will not be specifically limited. For example, the microwave generation means 5 includes a magnetron 9, a waveguide 10, and a microwave resonator 11.

  The magnetron 9 is normally used to generate a microwave having a frequency of 2.45 GHz, and includes an antenna (the shape in the figure is an antenna cover) 14 for radiating the generated microwave to the waveguide 10. . The magnetron 9 is fixed in a state where the antenna 14 is inserted into the one end 10 a of the waveguide 10. The antenna 14 is a hollow tube formed of ceramic, preferably ceramic containing alumina: 92% by mass or more, and its tip is preferably formed in a hemispherical shape. In addition, since the dielectric loss can be reduced by containing alumina, it is possible to suppress a rapid temperature increase of the antenna 14 that occurs when the electrodeless lamp 6 is started up. In addition, by forming the tip portion into a hemispherical shape, stress concentration can be prevented and the antenna 14 can be prevented from being damaged by distortion caused by heating. As a result, the light irradiation apparatus 1 can use the electrodeless lamp 6 in an instant flashing manner.

  The waveguide 10 transmits a microwave generated by the magnetron 9 to the microwave resonator 11, and is a hollow tube formed of aluminum. The microwave is transmitted by joining the other end 10 b of the waveguide 10 and the closed surface 11 a of the microwave resonator 11. The waveguide 10 and the microwave resonator 11 are continuously connected in order to prevent the discharge of the microwave electric field generated at the junction between the waveguide 10 and the microwave resonator 11 or the leakage of the microwave. It is preferable to form them integrally. As a result, the light irradiation device 1 can suppress variations in light output for each lamp 4 and temporal degradation of the light output, and can stabilize the light output.

  The microwave resonator 11 radiates the microwave transmitted from the waveguide 10 to the electrodeless lamp 6 by resonance. The microwave resonator 11 is a box-shaped product formed of aluminum and has an opening surface that opens in the light irradiation direction. 11b and a closed surface 11a joined to the other end portion 10b of the waveguide 10. A microwave reflection mesh 12 that reflects the microwave toward the electrodeless lamp 6 is disposed on the opening surface 11b.

  The microwave resonator 11 is preferably provided with an antenna 15 in order to improve the radiation efficiency of microwaves to the electrodeless lamp 6. The antenna 15 extends from the other end 10 b side of the waveguide 10 to the microwave resonator 11, and a part of the antenna 15 is arranged in parallel to the electrodeless lamp 6 and the condenser mirror 7. One end of the antenna 15 is connected to the microwave resonator 11, and the other end is fixed in the waveguide 10. It is also possible to configure so that the antenna 15 is not provided.

(Electrodeless lamp)
The electrodeless lamp 6 is fixed in the microwave resonator 11. The electrodeless lamp 6 emits light when the light emitting medium enclosed in the electrodeless lamp 6 is excited by the microwave in the microwave resonator 11. The electrodeless lamp 6 is a cylindrical glass tube formed of quartz or the like, and mercury or the like is enclosed as a light emitting medium.

(Condenser mirror)
The condensing mirror 7 is a half-cylindrical concave mirror having a semi-elliptical cross section, and is formed of hard glass that transmits microwaves. The condensing mirror 7 reflects the light generated by the electrodeless lamp 6, guides the light to the opening surface 11 b of the microwave resonator 11, and condenses the light at the external focal position FP. It is disposed in the vessel 11.

  The light irradiation unit 2 may include a cooling fan 17 for the purpose of cooling the electrodeless lamp 6. The cooling fan 17 is disposed above the waveguide 10 (on the magnetron 9 side). In order to blow the cooling air sent from the cooling fan 17 onto the surface of the electrodeless lamp 6, a ventilation hole 16 is formed in the waveguide 10, and the lamp cooling nozzle 13 is a closed surface of the microwave resonator 11. 11a and the condensing mirror 7 are penetrated.

  The light irradiation unit 2 may include a light intensity detection sensor 18 in the lamp housing 4a. The light intensity detection sensor 18 detects the intensity of light from the electrodeless lamp 6, that is, the light emission state of the light emitting medium sealed in the electrodeless lamp 6, and controls the driving of the magnetron 9.

<Light uniformizing section>
The light uniformizing unit 3 includes a pair of reflecting mirrors 8 and 8 that are arranged in the irradiation direction of the light collecting mirror 7 and extend in the longitudinal direction of the light irradiation unit 2 with a predetermined length (L). The reflecting surfaces of the reflecting mirrors 8 and 8 face each other with a predetermined distance (D). The arrangement of the light uniformizing unit 3 with respect to the light irradiation unit 2 is defined by the focal position FP of the irradiation light from the condensing mirror 7, and the focal position FP is the upper end 8 a on the condensing mirror side of the reflection mirror 8. And it is necessary to be in the center between the reflecting mirrors 8 and 8. By arranging the pair of reflection mirrors 8 and 8 in this way, the illumination light reflected from the pair of reflection mirrors 7 is reflected between the pair of reflection mirrors, and the light irradiation unit 2 does not emit light. The illuminance lowering of the irradiation surface corresponding to the four connecting portions is suppressed, and the illuminance in the longitudinal direction becomes uniform.

  The predetermined length (L) of the reflection mirror 8 is set to be approximately the same as the length in the longitudinal direction of the light irradiation unit 2 in order to ensure the irradiation width as large as possible. The predetermined distance (D) that defines the distance between the pair of reflecting mirrors 8 and 8 is preferably 20 to 35 mm. When the distance (D) is less than 20 mm, the ratio of the light rays entering between the mirrors decreases, so that the total energy on the irradiation surface decreases. On the other hand, if the distance (D) exceeds 35 mm, the illumination intensity on the irradiated surface decreases.

  The reflection mirror 8 is preferably a plane mirror having a constant reflection direction, but does not hinder the use of a concave mirror. The reflecting mirror 8 is preferably composed of a single mirror, but a mirror having a predetermined size (length (L) × height (H)) is configured by combining a plurality of mirrors. May be. Further, the light uniformizing unit 3 may include a pair of reflecting mirrors 8 and 8 inside a box-shaped housing 19 having openings on the light irradiation unit 2 side and the workpiece W side.

  The operation principle of the light irradiation apparatus 1 configured as described above will be described. As shown in FIG. 3, in the light irradiation device 1, the microwave generated by the magnetron 9 housed in the lamp housing 4 a is radiated from the antenna 14 of the magnetron 9 to the waveguide 10. The microwave radiated to the waveguide 10 travels through the waveguide 10 and is radiated from the antenna 15 (see FIG. 2) to the microwave resonator 11. The microwave radiated from the antenna 15 resonates with the microwave resonator 11 and is absorbed by the electrodeless lamp 6. Mercury enclosed in the electrodeless lamp 6 becomes plasma by the absorbed microwave. When plasma is generated in the electrodeless lamp 6, light including ultraviolet rays is emitted from the electrodeless lamp 6. This light is reflected by the condensing mirror 7 and condensed at the focal position FP below the opening surface 11 b of the microwave resonator 11. The light collected at the focal position FP is input to the pair of reflection mirrors 8 and 8 and reflected between the reflection mirrors 8 and 8, thereby suppressing the decrease in illuminance at the connection portion of the lamp 4 and the work W. Irradiated. The reflection mirrors 8 and 8 are most suitably a dielectric multilayer film called a UV cold mirror in order to increase the reflectance (see FIG. 4).

Examples of the present invention will be described.
(Example)
In the example, the work was irradiated with ultraviolet rays using the light irradiation apparatus shown in FIGS. The illuminance (wavelength around 365 nm) on the workpiece irradiation surface at that time was measured to confirm the illuminance distribution. The result is shown in FIG. FIG. 5 is a graph showing the illuminance distribution of the light irradiation device.

  The light irradiating apparatus of the example uses a lamp in which three lamps are arranged as a light irradiating part, and magnetron 9 (two units for one lamp, oscillation frequency is about 2.45 GHz, as a microwave oscillation source in the micro generating means. The total energy of the microwave was about 6 kW for one lamp. Moreover, the light emission length of the electrodeless lamp was 250 mm, and the total length of the lamp was 265 mm. Further, a box-shaped housing is installed as a light uniformizing portion in the irradiation direction of the lamp (condensing mirror), and as shown in FIG. 1, a pair of opposed to the longitudinal direction (X direction) inside the housing 19. The reflecting mirror 8 (length (L) 700 × height 200 mm, spacing between reflecting mirrors (D) 20 mm) was accommodated. In addition, a pair of reflecting mirrors 8A (length 20 mm × height 200 mm) facing the short direction (Y direction) of the housing 19 was housed.

(Comparative Examples 1-3)
In Comparative Examples 1 to 3, the work was irradiated with ultraviolet rays using a light irradiation device in which three lamps shown in FIG. 9 were arranged. Then, the illuminance was measured and the illuminance distribution was confirmed in the same manner as in the example. The results are shown in FIGS. 6 to 8 are graphs showing the illuminance distribution of the light irradiation device.

  The light irradiation apparatus of Comparative Examples 1 to 3 was the same as the example except that the light uniformizing unit (one pair of reflection mirrors) was not installed. In Comparative Example 1, the irradiation surface position is a focal position, in Comparative Example 2, the irradiation surface position is A = 17 mm away from the focal position, and in Comparative Example 3, the irradiation surface position is A = 27 mm away from the focal position. It was.

In the light irradiation apparatus of the example, as shown in FIG. 5, the illuminance distribution on the irradiated surface was 90% or higher, and the illuminance was 2000 mW / cm ² or higher. In the light irradiation apparatus using the electroded lamp, the illuminance on the irradiation surface is about 1000 mW / cm ² , and 2000 mW / cm ² is a sufficiently high illuminance.

In the light irradiation apparatus of Comparative Example 1, as shown in FIG. 6, the illuminance on the irradiated surface was high but the illuminance distribution was poor (about 80%). Moreover, in the light irradiation apparatuses of Comparative Examples 2 and 3, as shown in FIGS. 7 and 8, the illuminance distribution was improved, but the illuminance decreased to 2000 mW / cm ² or less.

  Therefore, it was confirmed that the light irradiation apparatus (Example) according to the present invention can obtain a good illuminance distribution while maintaining a high illuminance as compared with the conventional light irradiation apparatuses (Comparative Examples 1 to 3). .

  As mentioned above, although embodiment of this invention was described, the light irradiation apparatus which concerns on this invention is not limited to the said embodiment (Example), It can change in the range which does not deviate from a claim. For example, a material other than aluminum may be applied as a constituent material of the waveguide and the microwave resonator.

It is a partial cutaway perspective view of the light irradiation apparatus concerning the present invention. It is sectional drawing along the longitudinal direction of the light irradiation apparatus which concerns on this invention. FIG. 3 is a sectional view taken along line ZZ in FIG. 2. It is a graph which shows the relationship between the reflectance of a UV cold mirror used for the light irradiation apparatus which concerns on this invention, and a wavelength. It is a graph which shows the illumination intensity distribution of the light irradiation apparatus which concerns on this invention. It is a graph which shows the illumination intensity distribution of the conventional light irradiation apparatus. It is a graph which shows the illumination intensity distribution of the conventional light irradiation apparatus. It is a graph which shows the illumination intensity distribution of the conventional light irradiation apparatus. It is a longitudinal cross-sectional view which shows the structure of the lamp used for the conventional light irradiation apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light irradiation apparatus 2 Light irradiation part 3 Light equalization part 4 Lamp 5 Microwave generation means 6 Electrodeless lamp 7 Condensing mirror 8 Reflection mirror L Length W Interval

Claims (1)

A lamp comprising: a microwave generating unit; a rod-shaped electrodeless lamp that emits light by microwaves from the microwave generating unit; and a condensing mirror that collects and irradiates light from the electrodeless lamp. A plurality of light irradiation sections connected in the longitudinal direction of the lamp;
A pair of reflecting mirrors arranged in the irradiation direction of the condenser mirror and extending a predetermined length (L) along the longitudinal direction of the electrodeless lamp in the light irradiation unit; And a light uniformizing unit facing each other at a predetermined interval (D),
The light irradiation apparatus, wherein a focal position of irradiation light from the condenser mirror is an upper end portion of the reflection mirror and a center between the reflection mirrors.

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