JP2016129093A - Light irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photoirradiation device capable of blocking light with a wavelength unnecessary for an irradiation region at a high degree of accuracy, by a configuration using a wavelength selection filter having incident angle dependence.SOLUTION: A wavelength selection filter 33 for allowing transmission of light including a wavelength necessary for an irradiation region is provided, and an absorbing filter 35 for absorbing light outside the range of the necessary wavelength is provided. The light transmitted through the wavelength selection filter 33 and the absorbing filter 35 is applied to a workpiece W that is the irradiation region.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a light irradiation apparatus that irradiates an irradiation region with light transmitted through a wavelength selection filter.

In general, photo-curing technology is known in which a photo-curing agent is applied to the surface of paper, plastic, etc., and this photo-curing agent is cured by irradiating light, sealing liquid crystal panels and bonding optical lens components. It is widely applied to adhesion of optical disks, temporary fixing of printed circuit board components, and the like. The light used for photocuring varies depending on the type of curing agent, curing conditions, and the like, and visible light or near infrared light may be used in addition to ultraviolet light (ultraviolet light).
As a light source of a light irradiation device used in the photocuring technique, a discharge lamp such as a high-pressure mercury lamp or a metal halide lamp is usually used when ultraviolet rays are used for photocuring (see, for example, Patent Document 1).
In order to avoid the thermal influence from the light source as much as possible, this type of light irradiation apparatus includes a heat ray cut filter that blocks unnecessary visible light and near infrared rays in the irradiation region (for example, Patent Documents). 2).

Japanese Patent No. 4642066 JP 2007-191543 A

  By the way, a wavelength selective filter in which a dielectric multilayer film is laminated on a transparent substrate is used as the cut filter, and the transmission characteristic has an incident angle dependency. For this reason, when the wavelength required for the irradiation region is adjusted only by the cut filter, there is a problem that unnecessary wavelength is transmitted through the light incident obliquely on the filter, and the irradiation region is irradiated.

  The present invention has been made in view of the above-described circumstances, and it is possible to block light with an unnecessary wavelength in an irradiation region with high accuracy with a configuration using a wavelength selection filter having incident angle dependency. It aims at providing a light irradiation apparatus.

  In order to achieve the above object, the present invention comprises a light source that emits light including a wavelength necessary for an irradiation region, and a wavelength selection filter that transmits light including the necessary wavelength. In the light irradiation apparatus that irradiates the irradiation region with light that has passed through a filter, the light irradiation device includes an absorption filter that absorbs light outside the necessary wavelength range, and the irradiation with the light that has passed through the wavelength selection filter and the absorption filter It is characterized by irradiating the area.

  In the light irradiation apparatus according to the present invention, the absorption filter is disposed so that light transmitted through the wavelength selection filter is incident thereon.

  Further, the present invention is characterized in that the light irradiation apparatus includes a reflecting mirror that reflects the light from the light source so that the light is incident on the wavelength selection filter in an angle range including an oblique incident angle.

  Further, the present invention is the above light irradiation apparatus, wherein the light source and the wavelength selection filter are accommodated in a box, and the irradiation opening provided in the box is a cover unit including the wavelength selection filter and the absorption filter. It is characterized by being blocked.

  In the light irradiation device according to the present invention, the cover unit includes a filter disposed between the wavelength selection filter and the absorption filter on the light source side of the wavelength selection filter and the absorption filter. A packing for shielding light incident on the other filter without passing through is inserted.

  According to the present invention, the irradiation area includes the wavelength selection filter that transmits light including the necessary wavelength, and includes the absorption filter that absorbs light outside the necessary wavelength range, and transmits the wavelength selection filter and the absorption filter. Since the irradiated light is irradiated to the irradiation region, it is possible to block light with a wavelength unnecessary for the irradiation region with high accuracy by using a wavelength selection filter having an incident angle dependency.

It is a figure which shows the light irradiation apparatus which concerns on embodiment of this invention. It is a figure which shows typically the irradiation unit of a light irradiation apparatus. It is a disassembled perspective view of the cover unit of a light irradiation apparatus. It is a figure which shows the spectral characteristics of a wavelength selection filter and an absorption filter.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a light irradiation apparatus 1 according to an embodiment.
This light irradiation apparatus 1 is an apparatus that irradiates visible light toward a substance that is cured by visible light, and is installed above a workpiece W that is an irradiation surface of an object, and visible from 390 nm to 500 nm with respect to the workpiece W. The apparatus is configured to irradiate light (light on the short wavelength side of visible light) substantially uniformly.
In the exterior body 2 constituting the exterior of the light irradiation apparatus 1, the irradiation unit 11, a cooling unit 21 for cooling the irradiation unit 11, and a cover unit 31 disposed between the irradiation unit 11 and the workpiece W are provided. And are stored.

FIG. 2 is a diagram schematically showing the irradiation unit 11.
The irradiation unit 11 includes a straight tube lamp 12 that constitutes a light source, and a reflection that reflects light emitted from the straight tube lamp 12 (light is indicated by a broken line in FIG. 2) downward (to the workpiece W side). And a mirror unit 13.
The straight tube lamp 12 is, for example, a gallium lamp in which a gallium halide is sealed in an arc tube and outputs a large wavelength region of 400 to 450 nm, and is a long straight tube extending substantially parallel to the workpiece W. A tube-type lamp is used. Various types of light sources can be widely applied to the straight tube lamp 12. For example, a high-pressure mercury lamp or other metal halide lamp may be applied. A lamp support 12 </ b> S that supports the straight tube lamp 12 is coupled to the cover unit 31.

  The reflecting mirror unit 13 is formed as a concave mirror that is recessed upward, surrounds the straight tube lamp 12 with a space directly below the straight tube lamp 12, and extends along the longitudinal direction of the straight tube lamp 12. The reflecting mirror unit 13 covers the entire length of the straight tube lamp 12 from above, and reflects direct light that is not radiated from the straight tube lamp 12 to the work W toward the work W. By providing the reflecting mirror unit 13, the amount of light irradiated onto the workpiece W can be increased, and the light use efficiency of the straight tube lamp 12 can be increased. The reflector unit 13 is slidably supported by a pair of rails 2R extending in the longitudinal direction of the straight tube lamp 12, and the reflector unit 13 can be easily moved to a position where maintenance such as replacement is easy. is there.

The exterior body 2 is formed of a metal box having an opening 2K that opens downward, and includes a cooling radiator 21A, a cooling unit 21B, a cooling blower 21C, and the like above the reflecting mirror unit 13. Yes. The cooling radiator 21A, the cooling unit 21B, and the cooling blower 21C are components constituting the cooling unit 21. The cooling blower 21C blows cooling air to the irradiation unit 11, and each part of the irradiation unit 11 (straight pipe) The mold lamp 12 and the reflector unit 13 are air-cooled.
Further, the cooling radiator 21 </ b> A and the cooling unit 21 </ b> B cool the cooling fluid respectively supplied to the plurality of holes 13 </ b> A provided in the reflecting mirror unit 13. The plurality of holes 13A extend in the longitudinal direction of the reflector unit 13, and the reflector unit 13 can be efficiently cooled by flowing a cooling fluid through each of the holes 13A.

  Thereby, each part (straight tube type lamp 12 and reflector unit 13 grade) of irradiation unit 11 can be forced-cooled, and temperature of straight tube type lamp 12 and reflector unit 13 grade by the influence of heat generation of straight tube type lamp 12 etc. The rise can be suppressed sufficiently. In addition, since the opening 2K of the lamp housing box 15 is covered with the cover unit 31, the lamp housing box 15 can be partitioned from the external space, and an independent cooling space is formed in the lamp housing box 15 by suppressing the thermal effect of the external space. be able to.

  The cover unit 31 is a lid member that covers the opening 2 </ b> K below the exterior body 2, and is formed in a rectangular thin cover that extends along the longitudinal direction of the straight tube lamp 12. In the cover unit 31, a rectangular opening 31A extending along the longitudinal direction of the straight tube lamp 12 is formed immediately below the straight tube lamp 12, and the opening 31A is formed in the straight tube lamp 12. The direct light and the indirect light reflected by the reflecting mirror unit 13 pass through and the work W is irradiated with light. That is, the opening 31 </ b> A of the exterior body 2 functions as an irradiation opening that irradiates light toward the workpiece W. Further, the cover unit 31 is easily detachably attached from the exterior body 2. Since the cover unit 31 supports the straight tube lamp 12 via the lamp support 12S, the cover unit 31 and the straight tube lamp 12 can be easily detached from the exterior body 2.

Here, the light from the straight tube lamp 12 also includes light having a wavelength that does not require irradiation of the workpiece W. In order to remove the light having this unnecessary wavelength, the opening 31A of the cover unit 31 includes: A wavelength selection filter 33 is attached so as to cover the opening 31A.
The wavelength selection filter 33 is an optical filter formed by laminating a dielectric multilayer film on a transparent substrate, and transmits only light having a wavelength (necessary wavelength) that is necessary to irradiate the workpiece W, and light having an unnecessary wavelength. Does not penetrate. Thereby, the wavelength selection filter 33 functions as a cut filter for removing light unnecessary for the workpiece W.

By the way, the wavelength selection filter 33 has an incident angle dependency in transmission characteristics. For this reason, the incident light is partially transmitted even at an unnecessary wavelength. In particular, in the light irradiation device 1 of the present embodiment, the plate-shaped wavelength selection filter 33 is disposed at a position away from the straight tube lamp 12, and the curved reflector unit 13 is used for the straight tube lamp 12. Since light is reflected, as shown in FIG. 2, there are a relatively large amount of light components incident obliquely on the wavelength selection filter 33, and light of unnecessary wavelengths that pass through the wavelength selection filter 33 tends to increase.
Therefore, in this configuration, an absorption filter 35 that absorbs light with an unnecessary wavelength is further provided, and only the light with the required wavelength that has passed through the wavelength selection filter 33 and the absorption filter 35 is irradiated onto the work W that is an irradiation region. ing.

FIG. 3 shows an exploded perspective view of the cover unit 31.
As shown in FIG. 3, the cover unit 31 includes a frame cover 32 that forms an opening 31 </ b> A, a wavelength selection filter 33, a packing 34, and an absorption filter 35 that are stacked on the frame cover 32, and these wavelength selection filters. 33, a packing 34, and an absorption filter 35 are provided with a filter retainer 36 for fixing the absorption filter 35 to the frame cover 32. The wavelength selection filter 33 and the absorption filter 35 are formed in a rectangular flat plate shape slightly larger than the opening 31A, and are formed in the same outer shape in this embodiment.

The frame cover 32 and the filter retainer 36 are formed of a rigid material such as metal or resin. On the upper surface of the frame cover 32, a ridge portion 32A is provided so as to form a rectangular frame continuous along the outer edge of the opening portion 31A, and the wavelength selection filter 33, packing 34, The filter holder 36 is arranged from above so as to sandwich the absorption filter 35, and the filter holder 36 is fixed to the frame cover 32 by a plurality of fastening members (fastening bolts in this configuration) 37. As a result, the wavelength selection filter 33, the packing 34, and the absorption filter 35 are sandwiched between the frame cover 32 and the filter holder 36.
In this configuration, since the wavelength selection filter 33 and the absorption filter 35 are formed integrally with the cover unit 31, it is easy to attach and remove the plurality of filters 33 and 35 to the irradiation unit 11. In addition, since the plurality of filters 33 and 35 are disposed so as to be substantially overlapped, the height of the cover unit 31 having the plurality of filters 33 and 35 can be suppressed, and an increase in the height of the light irradiation device 1 can be suppressed.

The packing 34 is a gap adjusting member for securing a gap between the wavelength selection filter 33 and the absorption filter 35 that are arranged in an overlapping manner, and has light shielding properties such as PTFE (polytetrafluoroethylene) and flexibility. Made of material. By providing a minute gap, contact between the filters 33 and 35 can be avoided even when an external force acts on one filter 33 or 35, and transmission of the external force can be suppressed.
In particular, when a transparent glass material (quartz glass, borosilicate glass, etc.) having an advantage of being an ultraviolet-resistant material and having high transmittance is used for the base material of the wavelength selection filter 33 and the absorption filter 35, the packing 34 is used. Even if these are provided in a stacked manner, damage to the glass material due to the influence of external force can be effectively suppressed.

  The packing 34 is formed in a frame shape along the outer edge of the wavelength selection filter 33 so that at least the gap around the wavelength selection filter 33 disposed on the straight tube lamp 12 side can be shielded from light. For this reason, it is possible to reliably prevent the light from the straight tube lamp 12 from leaking from the periphery of the wavelength selection filter 33 and entering the absorption filter 35 disposed on the workpiece W side.

Further, as shown in FIG. 3, the wavelength selection filter 33 on the straight tube lamp 12 side is configured as a multi-plate type in which a plurality of filters 33 A are arranged in the longitudinal direction of the straight tube lamp 12. There is a possibility that light from the straight tube lamp 12 may enter the small gap.
In this embodiment, the packing 34 is integrally provided with a boundary light shielding part 34A extending along the boundary part of the plurality of filters 33A (small pieces) constituting the wavelength selection filter 33, and light leaking from the boundary part is on the workpiece W side. So as not to be incident on the absorption filter 35 disposed in the position. That is, the packing 34 functions as a light shielding member that shields light incident on the absorption filter 35 without passing through the wavelength selection filter 33, and can suppress deterioration of the light absorption material of the absorption filter 35. Moreover, since the emitted light of the straight tube | pipe type lamp 12 contains ultraviolet light and it can suppress with the packing 34 that this ultraviolet light is irradiated to the absorption filter 35, the ultraviolet-ray deterioration of a light absorption material can be suppressed. . Thereby, the performance deterioration of the absorption filter 35 can be suppressed efficiently, and the lifetime can be extended.
The wavelength selection filter 33 may be configured as a single plate type. In the case of a single plate type, the boundary light shielding part 34A of the packing 34 may be deleted or may not be deleted. If not deleted, the gaps between the wavelength selection filter 33 and the absorption filter 35 can be more appropriately maintained as much as the number of boundary light shielding portions 34A.

FIG. 4 shows spectral characteristics of the wavelength selection filter 33 and the absorption filter 35. In FIG. 4, reference numeral f <b> 1 indicates the spectral characteristic of the wavelength selection filter 33, and reference numeral f <b> 2 indicates the spectral characteristic of the absorption filter 35. Note that the spectral characteristic of the wavelength selection filter 33 shown in FIG. 4 is a transmittance characteristic at normal incidence.
The wavelength selection filter 33 has a transmission wavelength region in which the maximum transmittance is 85% or more in a wavelength range of 390 to 500 nm and a wavelength range of 600 to 800 nm in the transmittance characteristic at normal incidence as indicated by reference numeral f1 in FIG. The maximum transmittance is 1% or less in at least a part of the wavelength range of 200 to 400 nm, and the cut wavelength region on the visible and near infrared light side where the maximum transmittance is 1% or less in at least a part of the wavelength range. And an ultraviolet cut wavelength region. Further, the heat resistance of the wavelength selection filter 33 is enhanced by forming the transparent substrate with quartz glass, which is a material having a relatively high heat resistance.

  Specifically, the wavelength selection filter 33 includes a first laminated body constituting a narrow band pass type (NBP type) filter and a broadband pass type (BBP type) filter on different surfaces of a quartz glass transparent substrate. The first laminated body has a transmission wavelength region in which the maximum transmittance is 85% or more in the wavelength range of 400 to 600 nm, and a transmittance on the short wavelength side of the transmission wavelength region is 85. % To 5% or less of the transmittance curve, and the transmittance curve slope of the long wavelength side transmittance to 85% to 5% or less. Furthermore, the NBP-type second laminate allows the visible and near-infrared light-side cut wavelength regions where the minimum transmittance is 1% or less in at least part of the wavelength range of 600 to 800 nm, and the wavelength range of 200 to 400 nm. An ultraviolet cut wavelength region having a minimum transmittance of 1% or less is formed in at least a part of these.

  The absorption filter 35 is an optical filter formed by dispersing a light absorbing material that absorbs light of a predetermined wavelength in a transparent substrate (quartz glass, borosilicate glass, etc.). It is formed in a rectangular flat plate shape covering the opening 31 </ b> A of the unit 31. As indicated by reference numeral f2 in FIG. 4, the absorption filter 35 transmits light in a wavelength range (390 to 500 nm) in which the transmittance of the wavelength selection filter 33 is set high, and other light having a predetermined wavelength, that is, , The characteristic of absorbing light having a wavelength unnecessary for the workpiece W is set. The absorption filter 35 has no incident angle dependency.

More specifically, the absorption filter 35 has a wavelength range of less than 390 nm as an absorption wavelength region and a wavelength range of 390 nm or more as a transmission wavelength region where the maximum transmittance is 90% or more. Thereby, light having a wavelength of less than 390 nm that is transmitted through the wavelength selection filter 33 by oblique incidence can be absorbed by the absorption filter 35.
As shown in FIG. 3, the absorption filter 35 is also configured as a multi-plate type arranged in the longitudinal direction of the straight tube lamp 12, similarly to the wavelength selection filter 33. For this reason, the wavelength selection filter 33 and the absorption filter 35 that are elongated in the longitudinal direction of the straight tube lamp 12 can be manufactured easily and at a lower cost compared to the case where the wavelength selection filter 33 and the absorption filter 35 are manufactured as a single component.

  With the above configuration, the light emitted from the straight tube lamp 12 is reflected directly or by the reflecting mirror unit 13 and enters the wavelength selection filter 33 at various incident angles as shown in FIG. According to the optical characteristics of the wavelength selection filter 33 (see reference numeral f1 in FIG. 4), the vertically incident light transmits light in a wavelength range (390 to 500 nm) set with a high transmittance, and light of other wavelengths. Hardly penetrates. Since the light transmitted through the wavelength selection filter 33 is in a wavelength range where the transmittance of the absorption filter 35 is high, the light passes through the absorption filter 35 and is irradiated onto the workpiece W.

On the other hand, a part of the light incident on the wavelength selection filter 33 obliquely passes through the wavelength selection filter 33 in accordance with the incident angle dependency of the wavelength selection filter 33. The transmitted light is incident on the absorption filter 35, and light in a wavelength range (from 390 nm) with a high transmittance is transmitted and transmitted according to the optical characteristics of the absorption filter 35 (see symbol f 2 in FIG. 4). Light in the wavelength range (less than 390 nm) set at a low rate is absorbed by the absorption filter 35.
Thus, the two-stage filter configuration of the wavelength selection filter 33 and the absorption filter 35 irradiates the work W with light in a wavelength range (390 to 500 nm) necessary for the work W, and an unnecessary wavelength range (particularly less than 390 nm) for the work W. ) Can be cut off with high accuracy.

  Further, in the above-described two-stage filter configuration, only the light that has passed through the wavelength selection filter 33 is incident on the absorption filter 35. Therefore, it is possible to suppress the deterioration of the light absorption material of the absorption filter 35 and to suppress the performance deterioration of the absorption filter 35.

  As described above, the present embodiment includes the wavelength selection filter 33 that transmits light including the necessary wavelength in the irradiation region, and the absorption filter 35 that absorbs light outside the necessary wavelength range. Since the light that has passed through the wavelength selection filter 33 and the absorption filter 35 is irradiated onto the work W that is the irradiation region, the configuration using the wavelength selection filter 33 having the incident angle dependency is unnecessary in the irradiation region. Therefore, it becomes possible to block light of a proper wavelength with high accuracy and to irradiate light of a necessary wavelength with high accuracy.

  Further, since the absorption filter 35 is disposed so that light transmitted through the wavelength selection filter 33 is incident, the amount of light incident on the absorption filter 35 can be suppressed. Thereby, the performance deterioration of the absorption filter 35 can be suppressed and the life of the absorption filter 35 can be extended. As described above, in this configuration, by using a multi-stage filter configuration in which the wavelength selection filter 33 is arranged in the first stage and the absorption filter 35 is arranged in the second stage, light with an unnecessary wavelength in the irradiation region is blocked with high accuracy. The life of the absorption filter 35 can be extended.

  However, the absorption filter 35 may be disposed closer to the straight tube lamp 12 than the wavelength selection filter 33 as long as the lifetime of the absorption filter 35 can be sufficiently secured. According to this configuration, only light in the wavelength range that has passed through the absorption filter 35 is incident on the wavelength selection filter 33, so that light in the wavelength range that is absorbed by the absorption filter 35 is not irradiated onto the workpiece W.

  Moreover, since the reflecting mirror unit 13 that reflects the light of the straight tube lamp 12 so as to be incident on the wavelength selection filter 33 in an angle range including an oblique incident angle is provided, the use efficiency of the light is improved by using the reflecting mirror unit 13. While increasing, it is possible to avoid an adverse effect due to an increase in unnecessary light components that are obliquely incident on and transmitted through the wavelength selection filter 33 because the reflecting mirror unit 13 is used.

Further, the straight tube lamp 12 and the wavelength selection filter 33 which are light sources are accommodated in a box constituting the exterior body 2, and the opening 2K including the irradiation opening provided in the box includes the wavelength selection filter 33, and Since it is blocked by the cover unit 31 including the absorption filter 35, the wavelength selection filter 33 and the absorption filter 35 can be easily united and detached. Therefore, maintenance such as attachment / detachment and inspection of the wavelength selection filter 33 and the absorption filter 35 can be easily performed.
Moreover, since the exterior body 2 can be partitioned from the surroundings by the cover unit 31, it becomes possible to form an independent cooling space in the exterior body 2 while suppressing the influence of the surroundings, and to cool the exterior body 2. It can be done efficiently.

  Further, the cover unit 31 is incident between the wavelength selection filter 33 and the absorption filter 35 and the other filter (absorption filter 35) without passing through one filter (wavelength selection filter 33) disposed on the light source side. Since the packing 34 for shielding the light to be inserted is inserted, unnecessary light is irradiated to the irradiation region that has passed through the filter (wavelength selection filter 33) on the light source side, and the performance of the absorption filter 35 is deteriorated. Can be suppressed. In addition, since the packing 34 is inserted, the wavelength selection filter 33 and the absorption filter 35 can be disposed with a certain gap therebetween, and contact between the filters 33 and 35 can be suppressed.

The above-described embodiments are merely illustrative of one embodiment of the present invention, and can be arbitrarily modified and applied without departing from the spirit of the present invention.
For example, the case where the wavelength selection filter 33 and the absorption filter 35 are configured integrally with the cover unit 31 has been described. However, the present invention is not limited to this, and one or both of the filters 33 and 35 is the cover unit 31. You may make it arrange | position in another position. In short, the filters 33 and 35 may be arranged so as to irradiate the irradiation region with the light transmitted through the wavelength selection filter 33 and the absorption filter 35.
Further, an antireflection film may be provided on the surface of the absorption filter 35 to suppress the light component reflected by the absorption filter 35.

In addition, the case where the wavelength selection filter 33 and the absorption filter 35 are configured as a two-stage filter has been described. However, another optical filter is disposed on the light source side or the opposite side of the light source to form a three-stage or more filter configuration. May be. However, the two-stage filter configuration is most advantageous from the viewpoint of ensuring light transmittance.
Further, as the light source of the light irradiation device 1, it is also possible to use a configuration in which two or more straight tube lamps are arranged so that their respective tube axes are coaxially arranged in series. A light source in which light emitting elements such as LEDs are arranged can also be used.

1 Light irradiation device 2 Exterior body (box body)
2K opening (irradiation opening)
11 Irradiation unit 12 Straight tube lamp (light source)
13 Reflector unit 21 Cooling unit 31 Cover unit 33 Wavelength selection filter 34 Packing 35 Absorption filter W Workpiece (irradiation area)

Claims (5)

A light source that emits light including a wavelength necessary for the irradiation region; and a wavelength selection filter that transmits light including the necessary wavelength, and irradiates the irradiation region with light transmitted through the wavelength selection filter from the light source. In the light irradiation device,
A light irradiation apparatus comprising an absorption filter that absorbs light outside the range of the necessary wavelength, and irradiating the irradiation region with light transmitted through the wavelength selection filter and the absorption filter.   The light irradiation apparatus according to claim 1, wherein the absorption filter is arranged so that light transmitted through the wavelength selection filter is incident thereon.   The light irradiation apparatus according to claim 1, further comprising a reflecting mirror that reflects the light from the light source so that the light is incident on the wavelength selection filter in an angle range including an oblique incident angle. Housing the light source and the wavelength selection filter in a box;
The light irradiation apparatus according to claim 1, wherein the irradiation opening provided in the box is closed by a cover unit including the wavelength selection filter and the absorption filter.   Between the wavelength selection filter and the absorption filter, the cover unit is incident on the other filter without passing through the wavelength selection filter and the filter disposed on the light source side of the absorption filter. The light irradiation apparatus according to claim 4, wherein a packing for shielding light is inserted.

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