JP7281363B2 - Light irradiation device - Google Patents

Description

The present invention relates to a light irradiation device having a light emitting element such as an LED (Light Emitting Diode) as a light source, and more particularly to a light irradiation device having a reflecting mirror for guiding light from the light emitting element.

2. Description of the Related Art Conventionally, ultraviolet curable inks that are cured by irradiation with ultraviolet light have been used as inks for sheet-fed offset printing. Ultraviolet curable resins are used as sealants for FPDs (Flat Panel Displays) such as liquid crystal panels and organic EL (Electro Luminescence) panels. A light irradiation device that irradiates ultraviolet light is generally used for curing such ultraviolet curable inks and ultraviolet curable resins (for example, Patent Document 1).

The light irradiation device described in Patent Document 1 includes a light-emitting element module having a plurality of light-emitting elements, and a reflecting cylinder (reflecting mirror) arranged to surround the plurality of light-emitting element modules. The ultraviolet light emitted from the front panel (cover glass) is mixed by the reflecting cylinder and emitted from the front panel (cover glass).

JP 2013-215661 A

According to the configuration of Patent Document 1, the ultraviolet light emitted from each light emitting element is mixed and emitted by the reflecting tube portion (reflecting mirror), so a uniform light intensity distribution can be obtained on the irradiation target. However, in the configuration of Patent Document 1, since ultraviolet light is emitted through the front panel (cover glass), if part of the ultraviolet light is reflected on the front and back surfaces of the cover glass, There is a problem that unintended stray light (return light) is generated. In addition, if the stray light generated in the light passage area is emitted in an unintended direction, a light image (so-called ghost) is formed in an area on the irradiation target that is not originally intended to be irradiated with light. Problems also arise.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and an object thereof is to provide a light irradiation device in which generation of stray light is reduced even in a configuration having a cover glass. .

As a result of intensive studies, the present inventors have found that stray light is generated by reflection on the front and back surfaces of the cover glass. It is reflected light of light with a relatively large incident angle (for example, 6° or more). It was found that the generation of such stray light can be suppressed to a low level by arranging the stray light. The present invention is based on such findings.

That is, the light irradiation device of the present invention includes a light source unit having a substrate and a plurality of light emitting elements arranged on the surface of the substrate, and a cover glass arranged substantially perpendicular to the optical axis of the plurality of light emitting elements. and a pair of partition plates arranged between the plurality of light emitting elements and the cover glass so as to define a light passage area through which light from the plurality of light emitting elements passes, and the light source unit, the cover glass, and the partition plate. and a case where the pair of partition plates are inclined at a predetermined angle with respect to the optical axes of the plurality of light emitting elements so as to spread toward the cover glass, and the surfaces of the pair of partition plates facing each other has a mirror surface for guiding light from the plurality of light emitting elements on the side of the light emitting element, has a light absorbing portion for absorbing stray light generated in the light passing area on the side of the cover glass, and has a plurality of light emitting elements to the cover glass is L1, the distance from the optical axis of the plurality of light emitting elements to the intersection of the cover glass and each partition plate is L2, the length of the light absorbing portion is L3, and the predetermined angle is θ. In addition, the following conditional expression (1) is satisfied .

According to such a configuration, the stray light generated in the light passage area is absorbed by the light absorbing portion, so that the occurrence of ghost is suppressed and a uniform light intensity distribution is obtained.

ケースの内面に、ケース内で発生する迷光を吸収する光吸収部を有することを特徴とする。 From another point of view, the light irradiation device of the present invention comprises a light source unit having a substrate and a plurality of light emitting elements arranged on the surface of the substrate, and a light emitting device substantially perpendicular to the optical axis of the plurality of light emitting elements. a pair of partition plates each formed with a mirror surface for guiding light from a plurality of light emitting elements; and a case accommodating the light source unit, the cover glass, and the partition plate, The partition plate is inclined at a predetermined angle with respect to the optical axis of the plurality of light emitting elements so as to spread toward the cover glass. When the distance from the optical axis to the intersection of the cover glass and the extension line of each partition plate is L2, the distance from the cover glass to the edge of each partition plate is L3, and the predetermined angle is θ, the following conditions are satisfied: satisfies the formula (1),

The inner surface of the case has a light absorbing portion that absorbs stray light generated in the case.

Also, a plurality of sealing lenses that seal each of the plurality of light emitting elements can be further provided. Further, in this case, each sealing lens can have a convex portion formed so as to protrude in the optical axis direction of the sealing lens at the center of the exit surface of the sealing lens. Further, in this case, a plurality of light source units are provided, and each of the plurality of light source units has a light emitting element having a different emission wavelength. should be different depending on

Moreover, it is desirable that the light emitted from the plurality of light emitting elements is light in the ultraviolet wavelength range.

As described above, according to the present invention, it is possible to realize a light irradiation device in which the generation of stray light is reduced even though it has a structure including a cover glass.

FIG. 1 is a diagram showing the configuration of a light irradiation device according to a first embodiment of the present invention. FIG. 2 is a ray diagram showing the configuration of the light irradiation device according to the first embodiment of the present invention. FIG. 3 is a diagram for explaining how ultraviolet light is emitted from the light irradiation device according to the first embodiment of the present invention. FIG. 4 is a ray diagram showing the configuration of a light irradiation device according to Comparative Example 1 of the present invention. FIG. 5 is a diagram for explaining how ultraviolet light is emitted from a light irradiation device according to Comparative Example 1 of the present invention. FIG. 6 is a diagram showing the configuration of a light irradiation device according to a second embodiment of the present invention. FIG. 7 is a diagram showing the configuration of a light irradiation device according to a third embodiment of the present invention. FIG. 8 is a diagram explaining the details of the Q section in FIG.

BEST MODE FOR CARRYING OUT THE 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 denoted by the same reference numerals, and the description thereof will not be repeated.

(First embodiment)
1A and 1B are diagrams showing the configuration of a light irradiation device 100 according to the first embodiment of the present invention, FIG. 1A is a front view, and FIG. It is a sectional view taken along line AA. For example, the light irradiation device 100 of the present embodiment is incorporated in a peripheral exposure device or the like, and for a rectangular irradiation area P (not shown in FIG. 1) on an irradiation target W (not shown in FIG. 1), It is a device that irradiates light in the ultraviolet wavelength range (hereinafter referred to as "ultraviolet light"). Hereinafter, in this specification, the longitudinal direction of the ultraviolet light emitted from the light irradiation device 100 (the direction in which the LED elements 114 are arranged) is the X-axis direction, and the lateral direction (that is, the vertical direction in FIG. 1) is the Y direction. A direction orthogonal to the axial direction, the X-axis and the Y-axis is defined as the Z-axis direction and explained.

As shown in FIG. 1, the light irradiation device 100 includes an LED unit 110 (light source unit), a partition plate 120, a cover glass 130, an aperture 140, and a case 150 for housing or fixing these parts. ing.

The LED unit 110 of this embodiment includes a rectangular substrate 112 having two sides parallel to the X-axis and two sides parallel to the Y-axis. a plurality of LED elements 114 (light emitting elements) arranged in a row, a sealing lens 116 arranged to seal each LED element 114, and a cooling device 118.

Although any shape can be used for each LED element 114, in this embodiment, it has a rectangular outer shape of 2 mm (length in the X-axis direction) x 2 mm (length in the Y-axis direction). are using. Each LED element 114 is mounted on the substrate 112 and electrically connected to the substrate 112 . The substrate 112 is an electronic circuit board made of glass epoxy resin, ceramics, or the like, and is connected to an LED drive circuit (not shown). supplied. When a drive current is supplied to each LED element 114, each LED element 114 emits light with an amount of light corresponding to the drive current, and a predetermined amount of ultraviolet light is emitted. In this embodiment, each LED element 114 is configured to receive drive current from the LED drive circuit and emit ultraviolet light with a wavelength of 395 nm.

The sealing lens 116 is a hemispherical or bullet-shaped lens that seals each LED element 114 and molds the ultraviolet light emitted from each LED element 114 into ultraviolet light with a predetermined spread angle. It is made of silicone-based resin that can transmit light.

The cooling device 118 is a so-called air-cooling heat sink that is arranged in close contact with the back surface of the substrate 112 and dissipates heat generated by each LED element 114 . The cooling device 118 includes a plurality of heat radiation fins (not shown) made of a material with good thermal conductivity such as aluminum or copper, and a cooling fan (not shown). The radiator fins are uniformly cooled. When power is supplied to the LED unit 110 and ultraviolet light is emitted from each of the LED elements 114, the self-heating of the LED elements 114 raises the temperature, resulting in a significant drop in luminous efficiency. , the LED elements 114 are uniformly cooled by the cooling device 118, thereby suppressing the occurrence of such a problem.

The partition plate 120 is a pair of plate-like members that guide the ultraviolet light from each LED element 114 and define a region (light passage region) through which the ultraviolet light passes within the case 150 . The pair of partition plates 120 of the present embodiment sandwich the optical axis AX from the Y-axis direction so as to be symmetrical with respect to the optical axis AX of the LED element 114, and extend forward (positive direction of the Z-axis). are arranged so as to spread at a predetermined inclination angle .theta. A mirror surface 121 is formed on the inner surface (opposing surface) of each partition plate 120 on the LED element 114 side, and a light absorbing portion 123 ( 1) are formed.

The mirror surface 121 is a member that guides the ultraviolet light from each LED element 114 toward the cover glass 130 . The light absorbing portion 123 is a member that absorbs return light (hereinafter referred to as “stray light”) reflected by the front surface or the back surface of the cover glass 130 . It is formed by applying black electroless nickel plating or chromium plating to a part of the side. In this embodiment, unnecessary stray light in the case 150 is absorbed by the light absorbing portion 123, thereby suppressing the occurrence of ghosts (unintended emitted light) caused by the stray light. More specifically, the distance from the LED element 114 to the cover glass 130 is L1, the distance from the optical axis AX to the edge of the partition plate 120 (that is, to the intersection of the cover glass 130 and the partition plate 120) is L2, Assuming that the length of the light absorbing portion 123 when viewed from the X-axis direction is L3, and the inclination angle of the mirror surface 121 with respect to the optical axis AX (that is, the inclination angle of the partition plate 120) is θ, the following conditional expression: (1) is satisfied, and stray light that is 1.3 times or more of the tilt angle θ of the mirror surface 121 is prevented from entering the mirror surface 121 . That is, stray light that is 1.3 times or more the tilt angle θ of the mirror surface 121 is absorbed by the light absorbing portion 123 .

The cover glass 130 is a plate-like member made of glass that is arranged on the tip side (Z-axis direction side) of the case 150 and functions as an emission window.

The apertures 140 are arranged outside (Z-axis direction side) of the cover glass 130 so as to sandwich the optical axis AX from the Y-axis direction, and are made of a pair of metal plates that regulate ultraviolet light emitted from the cover glass 130. It is a member. By adjusting the spacing of the apertures 140 in the Y-axis direction, the irradiation range in the Y-axis direction can be adjusted.

Hereinafter, the specific configuration of the light irradiation device 100 of the present embodiment will be described in further detail with reference to an example (Example 1) and a comparative example (Comparative Example 1).

The light irradiation device 100 of Example 1 has the configuration shown in FIG. 1 and satisfies the above conditional expression (1). FIG. 2 is a ray diagram showing a specific configuration of this embodiment, FIG. 2(a) is a ray incident on the cover glass 130 at an incident angle of 2° A ray incident on the glass 130 at an incident angle of 5.25°, and FIG. 2C shows a ray incident on the cover glass 130 at an incident angle of 8°. In this embodiment, the distance from the LED element 114 to the cover glass 130 is L1: 106 mm, the distance from the optical axis AX to the edge of the partition plate 120 is L2: 36.377 mm, and when viewed from the X-axis direction The length of the light absorbing portion 123 is L3: 67 mm, and the inclination angle of the mirror surface 121 with respect to the optical axis AX (that is, the inclination angle of the partition plate 120) is θ: 18°. In FIG. 2, for convenience of explanation, the cooling device 118, the case 150, etc. are omitted, the mirror surface 121 is indicated by a solid line, and the light absorbing portion 123 is indicated by a broken line.

As shown in FIG. 2(a), in the case of light rays incident on the cover glass 130 at an incident angle of 2°, most of the rays pass through the cover glass 130, and the rectangular irradiation area on the irradiation object W incident on P. Further, even if part of the light beam incident on the cover glass 130 at an incident angle of 2° is reflected by the surface of the cover glass 130 and stray light is generated, the stray light has a sufficiently low light intensity and , the light is reflected by the mirror surface 121 and again enters the cover glass 130 at an incident angle of 2°, and enters the rectangular irradiation area P on the object W to be irradiated, so that it does not become a so-called ghost.

As shown in FIG. 2(b), most of the light rays incident on the cover glass 130 at an incident angle of 5.25° pass through the cover glass 130 and form a rectangular shape on the object W to be irradiated. Incident on the irradiation area P. Further, even if a portion of the light beam incident on the cover glass 130 at an incident angle of 5.25° is reflected by the surface of the cover glass 130 and stray light is generated, the light intensity of the stray light is sufficiently small. Since it is reflected by the mirror surface 121 and enters the light absorbing portion 123 , the light is absorbed by the light absorbing portion 123 . Therefore, such stray light does not become a so-called ghost.

As shown in FIG. 2(c), in the case of a light beam incident on the cover glass 130 at an incident angle of 8°, part of the light beam passes through the cover glass 130 to form a rectangular irradiation on the object W to be irradiated. The light is incident on the area P, but another part is reflected by the surface of the cover glass 130 to generate stray light. However, since such stray light enters the light absorbing portion 123 and is absorbed, it does not become a so-called ghost.

As described above, in the present embodiment, the light absorbing portion 123 absorbs stray light that satisfies the above conditional expression (1) and that is 1.3 times or more the tilt angle θ of the mirror surface 121 and cannot be ignored in terms of intensity. , thereby suppressing the occurrence of ghosts. FIG. 3 is a diagram for explaining the state of ultraviolet light emitted from the light irradiation device 100 of the present embodiment. A parallel screen is arranged to project the ultraviolet light emitted from the light irradiation device 100 . As shown in FIG. 3, the ultraviolet light emitted from the cover glass 130 of the light irradiation device 100 spreads as it separates in the Z-axis direction (upward direction in FIG. 3), and a substantially trapezoidal image of the ultraviolet light appears on the screen. is observed with approximately uniform brightness.

Comparative example 1

FIG. 4 is a ray diagram showing the configuration of a light irradiation device 100Z of a comparative example. As shown in FIG. 4, the light irradiation device 100Z of the present comparative example does not include the light absorbing portion 123, and the mirror surface 121 is formed on the entire inner surface (opposing surface) of each partition plate 120. It is different from the light irradiation device 100 of Example 1. FIG. It should be noted that FIG. 4 shows rays incident on the cover glass 130 at an incident angle of 8°, as in FIG. 2(c). Further, as in Example 1, also in this modification, the distance from the LED element 114 to the cover glass 130 is L1: 106 mm, and the inclination angle of the mirror surface 121 with respect to the optical axis AX (that is, the inclination angle of the partition plate 120) is θ: 18°.

As shown in FIG. 4, in the case of a light beam incident on the cover glass 130 at an incident angle of 8°, part of the light beam passes through the cover glass 130 and enters a rectangular irradiation area P on the object W to be irradiated. The light is incident, but another part is reflected by the surface of the cover glass 130 to generate stray light. Then, the stray light is reflected by the mirror surface 121 and re-enters the cover glass 130 at an incident angle of 28°, and illuminates the outside of the irradiation area P on the object W to be irradiated. That is, a ghost (unintended emitted light) is generated on the object W to be irradiated. FIG. 5 is a diagram for explaining the state of ultraviolet light emitted from the light irradiation device 100Z of this comparative example. A parallel screen is arranged to project the ultraviolet light emitted from the light irradiation device 100Z. As shown in FIG. 5, the ultraviolet light emitted from the cover glass 130 of the light irradiation device 100Z spreads as it separates in the Z-axis direction (upward direction in FIG. 5), and an approximately trapezoidal shape is formed at approximately the center of the screen. Although the ultraviolet light image is observed with substantially uniform brightness, triangular ghosts are observed on the left and right sides of the ultraviolet light image. As is clear from a comparison of FIGS. 5 and 3, it can be seen that almost no ghost occurs in the light irradiation device 100 of Example 1. FIG.

As described above, in the present embodiment, the light absorbing portion 123 absorbs stray light that satisfies the above conditional expression (1) and that is 1.3 times or more the tilt angle θ of the mirror surface 121 and cannot be ignored in terms of intensity. , thereby suppressing the occurrence of ghosts. Therefore, in the irradiation area P, the intended light amount distribution (that is, the designed value) can be obtained.

Although the present embodiment has been described above, the present invention is not limited to the above configuration, and various modifications are possible within the scope of the technical idea of the present invention.

For example, the light irradiation device 100 of the present embodiment has been described as a device that emits ultraviolet light, but it is not necessarily limited to such a configuration, and the present invention can be applied to general light such as white light. It is also possible to apply it to a lighting device.

In the present embodiment, the above conditional expression (1) is satisfied, and stray light that is 1.3 times or more the tilt angle θ of the mirror surface 121 is absorbed by the light absorbing portion 123, but this is not necessarily the case. It is not limited to such a configuration. Since stray light is reduced by forming the light absorbing portion 123 on the cover glass 130 side of the inner surface of each partition plate 120 , conditional expression (1) does not necessarily need to be satisfied depending on the application of the light irradiation device 100 .

(Second embodiment)
FIG. 6 is a cross-sectional view showing the configuration of a light irradiation device 200 according to the second embodiment of the invention. In the light irradiation device 200 of this embodiment, the length of the partition plate 220 is short, only the mirror surface 221 is formed on the inner surface (facing surface) of each partition plate 120, and the light absorbing material 223 is provided on the inner wall surface of the case 150. It differs from the light irradiation device 100 of the first embodiment in that it is attached. In this embodiment, the distance from the LED element 114 to the cover glass 130 is L1, the distance from the optical axis AX to the intersection of the cover glass 130 and the partition plate 120 is L2, and the distance is L2 when viewed from the X-axis direction. Assuming that the distance from the cover glass 130 to the end of the partition plate 120 at this time is L3, and the inclination angle of the mirror surface 121 with respect to the optical axis AX (that is, the inclination angle of the partition plate 120) is θ, the above conditional expression (1) is configured to meet

In other words, according to the configuration of the present embodiment, stray light whose intensity is not negligible and which is 1.3 times or more the tilt angle θ of the mirror surface 221 reaches the light absorbing material 223 without striking the mirror surface 221. It is absorbed by the light absorbing material 223 . Therefore, like the light irradiation device 100 of the first embodiment, the occurrence of ghosts is suppressed.

(Third Embodiment)
7A and 7B are diagrams showing the configuration of a light irradiation device 300 according to a third embodiment of the present invention, FIG. 7A is a front view, and FIG. It is a sectional view taken along line AA. 8 is an enlarged view for explaining the details of the Q portion of FIG. 7, FIG. 8(a) is an enlarged plan view, and FIG. 8(b) is a line BB of FIG. It is a cross-sectional view. As shown in FIGS. 7 and 8, the light irradiation device 300 of this embodiment differs from the light irradiation device 100 of the first embodiment in that it includes three LED units 110, 110A, and 110B.

The three LED units 110, 110A, and 110B respectively have LED elements 114, 114A, and 114B with different emission wavelengths, and in this embodiment, the LED elements 114 emit ultraviolet light with a wavelength of 365 nm, Ultraviolet light with a wavelength of 385 nm is emitted from the LED element 114A, and ultraviolet light with a wavelength of 405 nm is emitted from the LED element 114B.

Further, as shown in FIG. 8, in the present embodiment, the LED elements 114, 114A, and 114B are sealed, and the ultraviolet light emitted from each LED element 114, 114A, and 114B is provided with directivity. Stop lenses 116, 116A, 116B are provided. The sealing lenses 116, 116A, and 116B of the present embodiment have semispherical shapes with substantially circular cross sections in the direction perpendicular to the optical axes 116x, 116Ax, and 116Bx, respectively. The ultraviolet light emitted from is passed through sealing lenses 116, 116A, and 116B. Convex portions 116a, 116Aa, and 116Ba projecting in the Z-axis direction (optical axis direction) are formed at approximately the center portions (that is, vertex portions) of the exit surfaces of the sealing lenses 116, 116A, and 116B. there is The convex portions 116a, 116Aa, and 116Ba are portions that function as identification marks for identifying the respective 114, 114A, and 114B, respectively. 116a projects in the shape of a quadrangular prism, the projection 116Aa projects in the shape of a triangular prism, and the projection 116Ba projects in the shape of a cylinder.

Thus, in this embodiment, since the sealing lenses 116, 116A, and 116B have the projections 116a, 116Aa, and 116Ba functioning as identification marks, the sealing lenses 116, 116A, and 116B are attached. Even after the projections 116a, 116Aa, and 116Ba, the type (that is, the wavelength) of the LED positioned directly below can be specified from the shape of the projections 116a, 116Aa, and 116Ba. In addition, since the light irradiation device 300 of this embodiment has three types of LED elements 114, 114A, and 114B with different wavelengths in the Y-axis direction, it is asymmetrical in the Y-axis direction and has directivity. The directionality of the light irradiation device 300 can be recognized from the difference in the shape of the convex portions 116a, 116Aa, and 116Ba. Therefore, in the mounting process of the light irradiation device 300, the mounting posture (that is, direction) of the light irradiation device 300 is not mistaken.

As shown in FIG. 7B, also in this embodiment, as in the first embodiment, a pair of partition plates 120 sandwich the optical paths of the LED units 110, 110A, and 110B from the Y-axis direction and forward ( It is arranged so as to widen at a predetermined inclination angle θ toward the positive side of the Z axis). A mirror surface 121 is formed on the inner surface (facing surface) of each partition plate 120, and a light absorbing portion 123 (the gray portion in FIG. 7) is formed on the inner surface (facing surface) of each partition plate 120 on the cover glass 130 side. ) is formed. Further, as shown in FIG. 7B, in the present embodiment, the distance from the outermost LED element 114 (or 114B) to the cover glass 130 in the Y-axis direction is L1, and the distance from the LED element 114 (or 114B) is L1. ) from the optical axis AX to the edge of the partition plate 120 (that is, to the intersection of the cover glass 130 and the partition plate 120) is L2, and the above conditional expression (1) is satisfied.

In this embodiment, a configuration including three LED units 110, 110A, and 110B with different emission wavelengths was described, but the configuration is not necessarily limited to such a configuration. is appropriately set according to the specifications of the light irradiation device 300 .

Also, although the three LED units 110, 110A, and 110B of the present embodiment have LED elements 114, 114A, and 114B with different emission wavelengths, respectively, the configuration is not necessarily limited to this. Instead, the same LED elements can be mounted on all the LED units 110, 110A, and 110B (that is, they can be configured with one kind of emission wavelength).

In addition, the plurality of LED elements 114, 114A, and 114B of the present embodiment are aligned at equal intervals along the X-axis direction, and are arranged in a square lattice as a whole. Instead, they may be arranged in a zigzag pattern as a whole, or may be arranged randomly.

It should be noted that the embodiments disclosed this time are illustrative in all respects and should not be considered restrictive. The scope of the present invention is indicated by the scope of the claims rather than the above description, and is intended to include all modifications within the scope and meaning of equivalents of the scope of the claims.

100, 200, 300: light irradiation device 100Z: light irradiation devices 110, 110A, 110B: LED unit 112: substrates 114, 114A, 114B: LED elements 116, 116A, 116B: sealing lenses 116a, 116Aa, 116Ba: convex portions 116x, 116Ax, 116Bx: optical axis 118: cooling devices 120, 220: partition plates 121, 221: mirror surfaces 123, 223: light absorbing portion 130: cover glass 140: aperture 150: case

Claims (6)

a light source unit having a substrate and a plurality of light emitting elements arranged on the surface of the substrate;
a cover glass arranged substantially perpendicular to the optical axes of the plurality of light emitting elements;
a pair of partition plates arranged between the plurality of light emitting elements and the cover glass so as to define a light passing region through which light from the plurality of light emitting elements passes;
a case that houses the light source unit, the cover glass, and the partition plate;
with
the pair of partition plates are inclined at a predetermined angle with respect to the optical axes of the plurality of light emitting elements so as to spread toward the cover glass;
A mirror surface for guiding the light from the plurality of light emitting elements is provided on the side of the plurality of light emitting elements on the surfaces facing each other of the pair of partition plates, and the light is generated in the light passing area on the side of the cover glass. has a light absorbing portion that absorbs stray light that
The distance from the plurality of light emitting elements to the cover glass is L1, the distance from the optical axis of the plurality of light emitting elements to the intersection of the cover glass and each partition plate is L2, and the length of the light absorbing portion is L3. and a light irradiation device that satisfies the following conditional expression (1), where θ is the predetermined angle .

a light source unit having a substrate and a plurality of light emitting elements arranged on the surface of the substrate;
a cover glass arranged substantially perpendicular to the optical axes of the plurality of light emitting elements;
a pair of partition plates each formed with a mirror surface for guiding light from the plurality of light emitting elements;
a case that houses the light source unit, the cover glass, and the partition plate;
with
The pair of partition plates are inclined at a predetermined angle with respect to the optical axes of the plurality of light emitting elements so as to spread toward the cover glass,
L1 is the distance from the plurality of light emitting elements to the cover glass, L2 is the distance from the optical axis of the plurality of light emitting elements to the intersection of the cover glass and the extension lines of the partition plates, and L2 is the distance from the cover glass to the respective partition plates. When the distance to the edge of the partition plate is L3 and the predetermined angle is θ, the following conditional expression (1) is satisfied,

A light irradiation device , wherein the inner surface of the case has a light absorbing portion that absorbs stray light generated within the case . 3. The light irradiation device according to claim 1 , further comprising a plurality of sealing lenses for sealing each of said plurality of light emitting elements. 4. The sealing lens according to claim 3 , wherein each sealing lens has a convex portion formed so as to protrude in the optical axis direction of the sealing lens at the center of the exit surface of the sealing lens. Light irradiation device. Having a plurality of the light source units,
each of the plurality of light source units has the light emitting element having a different emission wavelength,
5. The light irradiation device according to claim 4 , wherein the shape of the convex portion differs according to the emission wavelength of the light emitting element when viewed from the optical axis direction. 6. The light irradiation device according to any one of claims 1 to 5 , wherein the light emitted from the plurality of light emitting elements is light in an ultraviolet wavelength range.

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