WO2022019282A1

WO2022019282A1 - Light irradiation device

Info

Publication number: WO2022019282A1
Application number: PCT/JP2021/027040
Authority: WO
Inventors: 幹彦五十木
Original assignee: Hoya株式会社
Priority date: 2020-07-23
Filing date: 2021-07-19
Publication date: 2022-01-27
Also published as: TW202210171A; EP4186700A1; CN115884879A; JP2022021973A

Abstract

A light irradiation device for irradiating, with light, an irradiation object that is capable of moving relative thereto, the light irradiation device comprising: a substrate; a plurality of light-emitting elements which are arranged on the substrate in an array of n-units (n is an integer of 2 or more) by m-rows (m is an integer of 2 or more); a cover glass which allows light from the respective light-emitting elements to pass therethrough; a support part which has an opening for light to pass therethrough and which supports the cover glass; and a pair of first reflective mirrors which are disposed between the substrate and the cover glass and which is for guiding light, wherein the formulae (1) and (2) are satisfied, where a represents the distance from a light-emitting element in the first row positioned on the most upstream side to a light-emitting element in the m-th row positioned on the most downstream side, b represents the interval between the pair of first reflective mirrors, h represents the height of the pair of first reflective mirrors, d represents the distance from the substrate to the support part, and w represents the width of the opening in a first direction.　(1): h≤(a+b)/2√3, (2): w≥d•2√3-a

Description

Light irradiation device

The present invention relates to a light irradiation device that irradiates light on an irradiation target object conveyed in one direction.

Conventionally, a printing device that prints using UV ink that is cured by irradiation with ultraviolet light is known. In such a printing apparatus, after ink is ejected from the nozzle of the head to the medium, the dots formed on the medium are irradiated with ultraviolet light. By irradiating with ultraviolet light, the dots are cured and fixed on the medium, so that good printing can be performed even on a medium that does not easily absorb liquid.

In recent years, in the ultraviolet light irradiation device used for such printing devices, LED (Light Emitting Diode) elements have been replaced with conventional discharge lamps in order to reduce power consumption, extend the service life, and reduce the size of the device. Is put into practical use as a light source (for example, Patent Document 1).

Japanese Patent No. 5482537

The ultraviolet light irradiation device described in Patent Document 1 is between a light source unit having a plurality of ultraviolet light sources (ultraviolet LEDs) arranged along a direction orthogonal to the transport direction of the object to be irradiated, and between the light source unit and the object to be irradiated. The light source unit is provided with a pair of reflecting members arranged so as to sandwich the light source unit from the upstream side and the downstream side in the transport direction, and the ultraviolet light from the ultraviolet light source is guided and emitted by the pair of reflecting plates. By doing so, we have adopted a structure that gives directional light to ultraviolet light.

However, when the configuration as in Patent Document 1 is adopted, since the reflective member has a predetermined reflectance, the amount (intensity) of the ultraviolet light decreases each time the ultraviolet light is reflected by the reflective member, and the irradiation is performed. In order to obtain a predetermined amount of light (that is, the amount of light for reliably curing the UV ink) on the object, it is necessary to increase the number of ultraviolet light LEDs in order to compensate for the decrease in the amount of light. As a result, there arises a problem that the cost of the device is increased, the size is increased, and the power consumption is increased. Therefore, there is a demand for a light irradiation device capable of efficient irradiation without increasing the number of LEDs.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light irradiation device capable of efficient irradiation while giving directivity to emitted light.

In order to achieve the above object, the light irradiation device of the present invention is a light irradiation device that irradiates light to an irradiation object that can move relatively along a first direction, and is a first direction and a first light irradiation device. A substrate defined by a second direction orthogonal to the direction, n on the substrate along the second direction (n is an integer of 2 or more), and m columns along the first direction (m is an integer of 2 or more). A plurality of light emitting elements arranged in the same direction in the third direction orthogonal to the first direction and the second direction, and a cover glass through which light emitted from the plurality of light emitting elements is transmitted. It has an opening through which light transmitted through the cover glass passes, and is arranged between the substrate and the cover glass so as to sandwich the light path of the plurality of light emitting elements in the first direction and the support portion that supports the cover glass. It is provided with a pair of first reflection mirrors for guiding light, and is located on the downstream side in the first direction from the light emitting element in the first row located on the upstream side in the first direction when viewed from the second direction. The distance to the light emitting element in the mth row is a, the distance between the pair of first reflection mirrors is b, the height of the pair of first reflection mirrors in the third direction is h, and the distance from the substrate to the support portion. Is d, and when the width of the opening in the first direction is w, the following equations (1) and (2) are satisfied.

h ≦ (a + b) / 2√3 ・・・ (1)
w ≧ d ・ 2√3-a ・・・ (2)

According to such a configuration, a light ray (ultraviolet light) having a strong spreading angle of 60 ° or less is reflected once on the first reflecting

surfaces

108a and 109a, or is not reflected and is not reflected, and the irradiated object P. Since it reaches the top, the influence of reflection by the first reflecting

surfaces

108a and 109a (that is, a decrease in the amount of light) hardly occurs. Therefore, the first reflecting

surfaces

108a and 109a enable efficient irradiation while giving directivity to the emitted light.

Further, it extends from the tip of the first reflection mirror located on the upstream side in the first direction to the upstream side in the first direction so as to face the cover glass, and reflects the light reflected by the irradiation target toward the irradiation target. A second reflection mirror can be provided. Further, in this case, it is desirable that the second reflection mirror is integrally formed with the first reflection mirror located on the upstream side in the first direction.

Further, it extends from the tip of the first reflection mirror located on the downstream side in the first direction to the downstream side in the first direction so as to face the cover glass, and reflects the light reflected by the irradiation target toward the irradiation target. A third reflection mirror can be provided. Further, in this case, it is desirable that the third reflection mirror is integrally formed with the first reflection mirror located on the downstream side in the first direction.

Further, it is desirable that the housing has a substrate, a plurality of light emitting elements, and a pair of first reflection mirrors, and the support portion and the cover glass form a part of the housing.

Further, it is desirable that the light is light in the ultraviolet wavelength range. Further, in this case, the irradiation target has a sheet-like shape, and the light in the ultraviolet wavelength range can be configured to cure the ink applied on the surface of the irradiation target.

As described above, according to the present invention, a light irradiation device capable of efficient irradiation while giving directivity to the emitted light is realized.

FIG. 1 is an external view illustrating the configuration of the light irradiation device according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 (b). FIG. 3 is a diagram illustrating a configuration of a light source unit provided in the light irradiation device according to the first embodiment of the present invention. FIG. 4 is a schematic diagram illustrating the configuration of the light irradiation device according to the first embodiment of the present invention. FIG. 5 is a simulation result for explaining the operation and effect of the light irradiation device according to the first embodiment of the present invention. FIG. 6 is a schematic diagram illustrating the configuration of the light irradiation device according to the first embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

(First Embodiment)
1 and 2 are views showing the configuration of the light irradiation device 1 according to the first embodiment of the present invention, FIG. 1 (a) is a perspective view, and FIG. 1 (b) is a front view. .. Further, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1 (b). As shown in FIGS. 1 and 2, the light irradiation device 1 of the present embodiment is a light source device incorporated in a printing device or the like to cure an ultraviolet curable ink or an ultraviolet curable resin, and is conveyed in one direction. It is arranged above the irradiation target object P (for example, a sheet-shaped recording medium or the like), and emits line-shaped ultraviolet light to the irradiation target object P. Note that FIG. 1A shows only the light irradiation device 1 for convenience of explanation, but in an actual printing device or the like, a plurality of recording heads that each apply ink of different colors irradiate the light irradiation device 1. The light irradiation device 1 is arranged in a narrow space on the downstream side of each recording head so as to be arranged in the transport direction of the object P. Further, in the present specification, the transport direction of the irradiation target P is the X-axis direction (first direction), the arrangement direction of the LED (Light Emitting Diode) element 217 described later is the Y-axis direction (second direction), and the LED element. The direction in which the 217 emits ultraviolet light is defined as the Z-axis direction (third direction) and will be described. Further, in general, the ultraviolet light means light having a wavelength of 400 nm or less, but in the present specification, the ultraviolet light cures the ultraviolet curable ink applied on the irradiation target P. It is intended to mean light having a possible wavelength (eg, wavelength 250-420 nm).

As shown in FIGS. 1 and 2, the light irradiation device 1 of the present embodiment includes a light source unit 200, a cooling fan 300, a housing 100 for accommodating the light source unit 200 and the cooling fan 300, and the like.

The housing 100 is a box-shaped case that is long in the Y-axis direction, and is provided with a glass cover glass 105 that emits ultraviolet light on the front surface (the surface on the plus side in the Z-axis direction). Further, a pair of

mirror units

108 and 109 are arranged between the light source unit 200 and the cover glass 105 so as to be separated from each other in the X-axis direction (FIG. 2), and the front surface of the cover glass 105 has an edge portion of the cover glass 105. A support plate 107 (support portion) for supporting the glass from the plus side in the Z-axis direction is arranged (FIGS. 1 (b) and 2). The support plate 107 has a rectangular opening 107a (opening) in the central portion, so that ultraviolet light that has passed through the cover glass 105 is irradiated onto the irradiation target P through the opening 107a. It has become. As described above, in the present embodiment, the cover glass 105 and the support plate 107 are arranged so as to cover the front surface of the housing 100, and the cover glass 105 and the support plate 107 form a part of the housing 100. There is.

Further, an exhaust port 101 for exhausting air in the housing 100 is formed on the left side surface (the surface on the minus side in the X-axis direction) of the housing 100, and is formed on the back surface (the surface on the minus side in the Z-axis direction) of the housing 100. In the housing 100, four intake ports 103 for supplying air are formed, and a cooling fan 300 is arranged corresponding to each intake port 103 (FIGS. 1A and 2). The light irradiation device 1 is electrically connected to a power supply device (not shown), and power from the power supply device is supplied to an internal light source unit 200, a cooling fan 300, and the like.

3A and 3B are views for explaining the configuration of the light source unit 200 of the present embodiment, FIG. 3A is a front view (a view seen from the plus side in the Z-axis direction), and FIG. 3B is a view. It is a side view (the view seen from the minus side in the X-axis direction). As shown in FIG. 3, the light source unit 200 includes four LED modules 210 arranged side by side in the Y-axis direction and a heat sink 220, and the ultraviolet light emitted from the LED module 210 is a pair of mirror units. The light is guided by 108 and 109, and is irradiated onto the irradiation target P through the cover glass 105 and the opening 107a on the front surface of the housing 100 (see the broken line arrow in FIG. 2).

The LED module 210 includes a rectangular plate-shaped substrate 215 defined in the X-axis direction and the Y-axis direction, and a plurality of LED elements 217 having the same characteristics, and has an end surface (Z-axis direction) of the base plate 222 of the heat sink 220. It is fixed on the end face on the plus side).

The substrate 215 of each LED module 210 is a rectangular wiring board made of a material having high thermal conductivity (for example, aluminum nitride), and as shown in FIG. 3A, there are five rows (for example) on the surface thereof. COB (Chip On Board) LED elements 217 of (X-axis direction) x 20 (Y-axis direction) are mounted. Further, in the present embodiment, the LED element 217 is located in the LED mounting area S (the area surrounded by the broken line in FIG. 3A) at the substantially central portion in the X-axis direction of the substrate 215 in the X-axis direction and the Y-axis direction. They are arranged at regular intervals (for example, 2 mm). As shown in FIG. 3B, in the present specification, for convenience of explanation, the LED elements 217 arranged in each row are sequentially arranged along the X-axis direction as

LED elements

217a, 217b, and 217c. It is called 217d and 217e.

An anode pattern (not shown) and a cathode pattern (not shown) for supplying electric power to each LED element 217 are formed on the substrate 215, and each LED element 217 is soldered to the anode pattern and the cathode pattern, respectively. Attached and electrically connected. Further, the substrate 215 is electrically connected to a driver circuit (not shown) by a wiring cable (not shown), and a drive current is supplied to each LED element 217 from the driver circuit via an anode pattern and a cathode pattern. It has become so. When a drive current is supplied to each LED element 217, ultraviolet light (for example, a wavelength of 385 nm) having an amount of light corresponding to the drive current is emitted from each LED element 217, and a line parallel to the Y-axis direction is emitted from the LED module 210. Ultraviolet light is emitted. As shown in FIG. 3A, in the present embodiment, four LED modules 210 are arranged in the Y-axis direction, and linear ultraviolet light from each LED module 210 is continuous in the Y-axis direction. It is configured as follows. The drive current supplied to each LED element 217 is adjusted so that each LED element 217 of the present embodiment emits ultraviolet light having a substantially uniform amount of light, and is emitted from the four LED modules 210. The line-shaped ultraviolet light has a substantially uniform light amount distribution in the X-axis direction and the Y-axis direction.

The heat sink 220 is a so-called air-cooled heat sink that is arranged so as to be in close contact with the back surface of the substrate 215 of the LED module 210 and dissipates heat generated by each LED module 210. The heat sink 220 is made of a material having good thermal conductivity such as aluminum or copper, and has a thin plate-shaped base plate 222 extending in the Y-axis direction and a plurality of heat dissipation formed on a surface opposite to the surface on which the substrate 215 abuts. It has fins 225 and. Each radiating fin 225 has a thin plate-like shape parallel to the XZ plane, and is provided at a predetermined interval in the Y-axis direction. In this embodiment, the plurality of heat radiation fins 225 are uniformly cooled by the cooling air generated by the cooling fan 300.

When a drive current flows through each LED element 217 and ultraviolet light is emitted from each LED element 217, the temperature rises due to the self-heating of the LED element 217, but the heat generated by each LED element 217 is the substrate 215 and the base plate. It is rapidly conducted to the heat radiating fins 225 via the 222, and is radiated from each heat radiating fin 225 into the surrounding air. Then, the air heated by the radiating fins 225 is quickly exhausted through the exhaust port 101 by the cooling air generated by the cooling fan 300. As described above, in the present embodiment, since each LED module 210 is uniformly cooled by the heat sink 220 and the cooling fan 300, the decrease in luminous efficiency caused by the temperature rise of the LED element 217 is suppressed.

As described above, in the present embodiment, the pair of

mirror units

108 and 109 are arranged between the light source unit 200 and the cover glass 105 so as to be separated from each other in the X-axis direction (FIG. 2), and the cover glass 105. A support plate 107 (support portion) that supports the edge portion of the cover glass 105 from the plus side in the Z-axis direction is arranged on the front surface (FIGS. 1 (b) and 2).

As shown in FIG. 2, the pair of

mirror units

108 and 109 are metal plate-shaped members extending in the Y-axis direction so as to sandwich the optical path of each ultraviolet light emitted from the LED element 217 from the X-axis direction. The

mirror units

108 and 109 extend in the Z-axis direction so as to stand substantially vertically from the cover glass 105 when viewed from the Y-axis direction, and are symmetrical with respect to the optical path of each ultraviolet light emitted from the LED element 217. Is located in. Further, the

mirror units

108 and 109 are provided with first reflecting

surfaces

108a and 109a facing each other so as to sandwich an optical path of each ultraviolet light emitted from the LED element 217.

It is known that the ultraviolet light emitted from the LED element 217 is generally radiated at a predetermined spread angle, and the intensity of the ultraviolet light having a larger angle component becomes weaker. However, in the present embodiment, the ultraviolet light is emitted from the LED element 217. Since the first reflecting

surfaces

108a and 109a are arranged so as to sandwich the optical path of each emitted ultraviolet light, the light is guided by the first reflecting

surfaces

108a and 109a including the ultraviolet light having a weak intensity and a large angle component. , Is emitted through the cover glass 105.
However, when such a configuration (that is, a configuration in which light is guided by the first reflecting

surfaces

108a and 109a) is adopted, since the first reflecting

surfaces

108a and 109a have a predetermined reflectance (for example, 90%), ultraviolet light is emitted. However, each time the light is reflected by the first reflecting

surfaces

108a and 109a, the amount of light decreases, and as a result, the amount of light on the irradiated object P decreases.
Therefore, in the present embodiment, among the ultraviolet light rays emitted from the LED element 217, the light rays having a small angle component (in order to solve such a problem and efficiently extract the ultraviolet light emitted from the LED element 217 (). For example, a light ray having a spread angle ≤ 60 °) is reflected once on the first reflecting

surfaces

108a and 109a, or is emitted without being reflected, and has a large angular component (for example, a light ray having a spread angle> 60 °). Is configured to be reflected by the first reflecting

surfaces

108a and 109a one or more times and then emitted (details will be described later).

Hereinafter, the functions of the first reflecting

surfaces

108a and 109a of the pair of

mirror units

108 and 109 will be described in detail.
FIG. 4 is a schematic diagram illustrating the relationship between the arrangement of the LED module 210, the

mirror units

108 and 109, the cover glass 105, and the support plate 107 and the light rays emitted from each LED element 217. FIG. 4A is a diagram showing the relationship with ultraviolet light having a small spread angle (for example, spread angle ≤ 60 °), and FIG. 4B is a diagram showing a relationship with a light beam having a large spread angle (for example, spread angle>. 60 °) It is a figure which shows the relationship with the ray of ultraviolet light. In FIG. 4A, L60a is a light ray having a spreading angle of 60 ° emitted from the LED element 217a, L60c is a light ray having a spreading angle of 60 ° emitted from the LED element 217c, and L60e is a light beam having a spreading angle of 60 °. It is a light ray having a spread angle of 60 ° emitted from 217e, and L0a is a light ray having a spread angle of 0 ° emitted from the LED element 217a. Further, in FIG. 4B, L65a is a light ray having a spread angle of 65 ° emitted from the LED element 217a, and L80e is a light ray having a spread angle of 80 ° emitted from the LED element 217e. In FIGS. 4 (a) and 4 (b), the ultraviolet light rays emitted from the

LED elements

217b and 217d are omitted for convenience of explanation, but in reality, the

LED elements

217b and 217d are also LED elements. Light rays similar to those of 217a, 217c, and 217e are emitted. Further, in FIGS. 4A and 4B, the shape of each LED element 217 is shown in a rectangular shape for convenience of explanation, but in reality, each LED element 217 is sufficiently thin in the Z-axis direction, and each LED element 217 is formed in a rectangular shape. The light emitting point of the LED element 217 is substantially located on the surface of the substrate 215.

As shown in FIG. 4A, in the present embodiment, when viewed from the Y-axis direction, the width of the LED mounting area S in the X-axis direction (that is, the most upstream side in the X-axis direction (minus side in the X-axis direction)). The distance from the LED element 217a in the first row located in) to the LED element 217e in the fifth row located on the most downstream side in the X-axis direction (plus side in the X-axis direction) is a, and the first reflecting surface 108a. , 109a is b, the height of the first reflecting

surfaces

108a and 109a in the Z-axis direction is h, the distance from the substrate 215 to the support plate 107 is d, and the distance between the support plates 107 in the X-axis direction (that is, , The width of the opening 107a in the X-axis direction) is set to w, and is configured to satisfy the following equations (1) and (2).

h ≦ (a + b) / 2√3 ・・・ (1)
w ≧ d ・ 2√3-a ・・・ (2)

Specifically, among the ultraviolet light rays emitted from the LED element 217a, the light rays L60a having a spreading angle of 60 ° are reflected once by the first reflecting surface 108a and emitted through the cover glass 105, and are also emitted. The light is emitted through the cover glass 105 without being incident on the first reflecting surface 109a (that is, passing through the tip of the first reflecting surface 109a) (FIG. 4A).
Further, among the ultraviolet light rays emitted from the LED element 217c, the light rays L60c having a spreading angle of 60 ° are reflected once by the first reflecting

surfaces

108a and 109a and are emitted through the cover glass 105. ing.
Further, among the ultraviolet light rays emitted from the LED element 217e, the light rays L60e having a spreading angle of 60 ° are reflected once by the first reflecting surface 109a, are emitted through the cover glass 105, and are first reflected. It is designed to be emitted through the cover glass 105 without incident on the surface 108a (that is, through the tip of the first reflecting surface 108a).
Therefore, among the ultraviolet light rays emitted from each LED element 217, the light rays having a spread angle of less than 60 ° are similarly reflected once by the first reflecting

surfaces

108a and 109a, or are not reflected. Is emitted through the cover glass 105. The light rays (light rays L60a, L60c, L60e, L0a) having a spreading angle of 60 ° or less pass through the opening 107a after passing through the cover glass 105 (that is, without being eclipsed by the support plate 107) on the irradiation target P. To reach.

On the other hand, among the ultraviolet light rays emitted from the LED element 217, the light rays having a spread angle of more than 60 ° (that is, the light rays L65a having a spread angle of 65 ° and the light rays L80e having a spread angle of 80 °) are the first reflecting surface. It is reflected by 108a and 109a at least once and emitted through the cover glass 105 (FIG. 4 (b)). A part of the light rays having a spreading angle of more than 60 ° (for example, the light rays L65a) pass through the opening 107a after passing through the cover glass 105 (that is, without being eclipsed by the support plate 107). Although reaching above, other light rays (eg, light rays L80e) do not pass through the opening 107a (that is, are vignetted by the support plate 107) and are randomly reflected by a component such as the support plate 107 before being irradiated. Reach on P.

Here, when the positional relationship between the LED element 217, the first reflecting

surface

108a, 109a, and the support plate 107 is examined, the distance in the X-axis direction from the central axis (light emitting point) of the LED element 217a to the first reflecting surface 109a is determined. It can be expressed as √3h from the relationship with the light ray L60a, and the distance in the X-axis direction from the central axis (light emitting point) of the LED element 217e to the first reflection surface 108a is expressed as √3h from the relationship with the light ray L60e. Therefore, the distance b between the first reflecting

surfaces

108a and 109a is set.
b ≧ √3h ＋ √3h－a
Can be expressed as, and the above equation (1) can be obtained by modifying this.
Further, the distance in the X-axis direction from the central axis (light emitting point) of the LED element 217a to one end (the end on the plus side in the X-axis direction) of the support plate 107 can be expressed as √3d in relation to the light beam L60a. Similarly, the distance in the X-axis direction from the central axis (light emitting point) of the LED element 217e to the other end (end on the minus side in the X-axis direction) of the support plate 107 is √3d in relation to the light beam L60e. Since it can be represented, the distance w in the X-axis direction of the support plate 107 is
w ≧ √3d + √3d-a
Can be expressed as, and the above equation (2) can be obtained by modifying this.

As described above, in the present embodiment, a light ray (ultraviolet light) having a strong intensity and a spread angle of 60 ° or less is reflected once on the first reflecting

surfaces

108a and 109a, or is not reflected and is irradiated. Since it reaches the object P, the influence of reflection by the first reflecting

surfaces

108a and 109a (that is, a decrease in the amount of light) is suppressed. A light ray having a spread angle of more than 60 ° (ultraviolet light) is reflected by the first reflecting

surfaces

108a and 109a at least once, but a light ray having a spread angle larger than 60 ° (ultraviolet light) is reflected at least once. Since the intensity is weak, the effect on the total amount of light emitted onto the object P to be irradiated is slight (that is, the effect of the decrease in the amount of light is small).

FIG. 5 is a simulation result for explaining the operation and effect of the light irradiation device 1 of the present embodiment, and the horizontal axis is the distance between the support plates 107 in the X-axis direction (that is, the width of the opening 107a in the X-axis direction) w (mm). ). The vertical axis is the integrated light amount of the ultraviolet light emitted from the light irradiation device 1, and is a relative value with the integrated light amount when w is 100 (mm) as 1.
As a simulation condition, the width of the LED mounting area S in the X-axis direction (that is, the most downstream side in the X-axis direction from the LED element 217a in the first row located on the upstream side in the X-axis direction (minus side in the X-axis direction) (that is, the negative side in the X-axis direction). The distance) a to the LED element 217e in the fifth row located on the plus side in the X-axis direction) is 10 (mm), the distance b between the first reflecting

surfaces

108a and 109a is 15 (mm), and the first reflecting surface. The height h of 108a and 109a in the Z-axis direction was 5 (mm), the distance d from the substrate 215 to the support plate 107 was 8 (mm), and w (mm) was changed to obtain the integrated light amount.
As a result, when w is about 17 (mm), the integrated light amount is about 0.9, and when w is 30 (mm) or more, the integrated light amount does not decrease (that is, the ultraviolet light emitted from the light irradiation device 1). Reaches on the irradiated object P without being eclipsed by the support plate 107).

Here, when the above simulation conditions are substituted into the above equation (1), the following results are obtained, and the equation (1) is satisfied.
h ≦ (a + b) / 2√3 ・・・ (1)
5 (mm) ≤ (10 (mm) +15 (mm)) / 2√3
5 (mm) ≤ 7.2 (mm)

Further, when the simulation condition is substituted into the above equation (2), the result is as follows.
w ≧ d ・ 2√3-a ・・・ (2)
w ≧ 8 (mm) × 2√3-10 (mm)
w ≧ 17.8 (mm)

That is, the conditions of the above equations (1) and (2) and the above simulation result are substantially the same, and when the above equations (1) and (2) are satisfied, the integrated amount of ultraviolet light emitted from the light irradiation device 1 is achieved. It can be seen that there is almost no decrease (that is, the integrated light amount is 0.9 or more).

The above is the description of the present embodiment, but the present invention is not limited to the above configuration, and various modifications can be made within the scope of the technical idea of the present invention.

For example, in the LED module 210 of the present embodiment, the LED elements 217 are arranged in a manner of 5 rows (X-axis direction) × 20 (Y-axis direction), but the configuration is limited to such a configuration. The LED elements 217 may be arranged in n (n is an integer of 2 or more) along the Y-axis direction and in m columns (m is an integer of 2 or more) along the X-axis direction.

Further, the first reflecting

surfaces

108a and 109a of the present embodiment extend in the Z-axis direction so as to stand up substantially vertically from the cover glass 105, and are arranged symmetrically with respect to the optical path of each ultraviolet light emitted from the LED element 217. However, the first reflecting

surfaces

108a and 109a do not necessarily have to be parallel to the Z-axis direction. For example, the first reflecting

surfaces

108a and 109a spread in a C shape with respect to the Z-axis direction. It can also be arranged as follows.

Further, in the present embodiment, the positional relationship between the LED element 217, the first reflecting

surfaces

108a and 109a, and the support plate 107 has been described as satisfying the equations (1) and (2), but the configuration is not necessarily limited to such a configuration. For example, it can be configured to satisfy the following equations (3) and (4).

h ≦ (a + b) / 2√2 ・・・ (3)
w ≧ d ・ 2√2-a ・・・ (4)

(Second embodiment)
FIG. 6 is a diagram illustrating a configuration of a light irradiation device 1A according to a second embodiment of the present invention. As shown in FIG. 6, in the light irradiation device 1A of the present embodiment, the XZ cross section of the pair of

mirror units

108 and 109 is L-shaped, and the tip portion of the first reflection surface 108a of the mirror unit 108 is formed. The second reflective mirror 108b extending in the negative side in the X-axis direction so as to face the cover glass 105, and the positive side in the X-axis direction so as to face the cover glass 105 from the tip of the first reflective surface 109a of the mirror unit 109. It differs from the light irradiation device 1 of the first embodiment in that it includes a third reflection mirror 109b that extends.

As shown in FIG. 6, the second reflection mirror 108b and the third reflection mirror 109b emit ultraviolet light emitted from the LED element 217 (LED element 217c in FIG. 6) and are reflected by the irradiation object P to be irradiated. It is configured to reflect again toward P (see the dashed arrow in FIG. 6).
Therefore, according to the configuration of the present embodiment, the ultraviolet light that did not contribute to the curing of the ultraviolet curable ink on the irradiation target P (that is, the ultraviolet light reflected by the irradiation target P) is again the irradiation target P. It becomes possible to further improve the utilization efficiency of ultraviolet light.

Note that, in FIG. 6, a light ray that is reflected only once by the second reflection mirror 108b and the third reflection mirror 109b is illustrated, but it is reflected multiple times depending on the angle component of the ultraviolet light. Further, the width of the second reflection mirror 108b and the third reflection mirror 109b in the X-axis direction is preferably as wide as possible so that the reflection can be performed a plurality of times. In this case, the width of the cover glass 105 in the X-axis direction is wide. The distance between the support plates 107 in the X-axis direction (that is, the width of the opening 107a in the X-axis direction) may be widened.

Further, it is not always necessary to provide both the second reflection mirror 108b and the third reflection mirror 109b, and one of them may be provided.

Further, the

mirror units

108 and 109 of the present embodiment have an L-shaped XZ cross section, and the first reflecting surface 108a and the second reflecting mirror 108b are integrally formed with the first reflecting surface 109a. Although it is assumed that the third reflection mirror 109b is integrally formed, the present invention is not necessarily limited to such a configuration. The first reflecting surface 108a and the second reflecting mirror 108b, and the first reflecting surface 109a and the third reflecting mirror 109b may be formed separately from each other.

It should be noted that the embodiment disclosed this time is an example in all respects and should be considered not to be restrictive. The scope of the present invention is shown by the scope of claims, not the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

1: Light irradiation device 1A: Light irradiation device 100: Housing 101: Exhaust port 103: Intake port 105: Cover glass 107: Support plate 107a: Opening 108: Mirror unit 108a: First reflection surface 108b: Second reflection mirror 109 : Mirror unit 109a: First reflective surface 109b: Third reflective mirror 200: Light source unit 210: LED module 215: Board 217: LED element 220: Heat sink 222: Base plate 225: Heat dissipation fin 300: Cooling fan

Claims

An irradiation device that irradiates light on an irradiation object that can move relatively along the first direction.
A substrate defined by the first direction and a second direction orthogonal to the first direction,
N pieces (n is an integer of 2 or more) are arranged on the substrate along the second direction, and m columns (m is an integer of 2 or more) are arranged along the first direction, and the first direction and the second direction are arranged. A plurality of light emitting elements arranged so that the directions of the optical axes are aligned in the third direction orthogonal to the direction, and
A cover glass through which the light emitted from the plurality of light emitting elements is transmitted, and
A support portion having an opening through which the light transmitted through the cover glass passes and supporting the cover glass, and a support portion.
A pair of first reflection mirrors arranged between the substrate and the cover glass so as to sandwich the optical paths of the plurality of light emitting elements in the first direction, and to guide the light.
Equipped with
When viewed from the second direction, the distance from the light emitting element in the first row located on the upstream side of the first direction to the light emitting element in the mth row located on the downstream side of the first direction is a. The distance between the pair of first reflection mirrors is b, the height of the pair of first reflection mirrors in the third direction is h, the distance from the substrate to the support is d, and the opening is The light irradiation device is characterized by satisfying the following equations (1) and (2), where w is the width of the first direction.

h ≦ (a + b) / 2√3 ・・・ (1)
w ≧ d ・ 2√3-a ・・・ (2)
The light extending from the tip of the first reflection mirror located on the upstream side in the first direction to the upstream side in the first direction so as to face the cover glass, and the light reflected by the irradiation target is the irradiation target. The light irradiation device according to claim 1, further comprising a second reflection mirror that reflects toward.
The light irradiation device according to claim 2, wherein the second reflection mirror is integrally formed with the first reflection mirror located on the upstream side in the first direction.
The light extending from the tip of the first reflection mirror located on the downstream side in the first direction to the downstream side in the first direction so as to face the cover glass, and the light reflected by the irradiation target is the irradiation target. The light irradiation device according to any one of claims 1 to 3, further comprising a third reflection mirror that reflects toward.
The light irradiation device according to claim 4, wherein the third reflection mirror is integrally formed with the first reflection mirror located on the downstream side in the first direction.
It has a housing that houses the substrate, the plurality of light emitting elements, and the pair of first reflection mirrors, and the support portion and the cover glass form a part of the housing. The light irradiation device according to any one of claims 1 to 5.
The light irradiation device according to any one of claims 1 to 6, wherein the light is light in the ultraviolet wavelength range.
The light irradiation device according to claim 7, wherein the irradiation target has a sheet-like shape, and light in the ultraviolet wavelength range cures the ink applied on the surface of the irradiation target.