JP6002261B2 - Light irradiation device - Google Patents

Description

  The present invention relates to a light irradiation apparatus used for a peripheral exposure apparatus or the like of a substrate (for example, a semiconductor substrate, a glass substrate for a liquid crystal display device, a glass substrate for a photomask) coated with a photosensitive resist, and in particular, on an irradiation object. The present invention relates to a light irradiation apparatus that uniformly irradiates a rectangular irradiation area.

  Conventionally, in the manufacturing process of a semiconductor (for example, IC (Integrated Circuit) or LSI (Large Scale Integrated circuit)), a photosensitive resist is applied to the surface of a semiconductor wafer, and this resist layer is exposed and developed through a mask. Thus, a circuit pattern is formed.

  As a method for applying a resist to the surface of a semiconductor wafer, generally, the wafer is placed on a turntable, the resist is dropped and rotated near the center of the surface of the wafer, and the resist is applied to the entire surface of the wafer by centrifugal force. A spin coat method is used in which is applied.

  In such a spin coating method, the resist is applied not only to the circuit pattern formation region at the center of the wafer but also to the edge portion of the wafer where the circuit pattern is not formed. However, the edge portion of the wafer is often gripped by a transfer device or the like in order to transfer the wafer. If the resist on the edge portion of the wafer is left untouched, a part of the wafer edge portion is transferred during transfer of the wafer. There are problems such as peeling and missing. If the resist at the edge of the wafer is missing and adheres to the circuit pattern formation region of the wafer, a desired circuit pattern is not formed, resulting in a problem that yield decreases. For this reason, in general, a resist is exposed using a peripheral exposure apparatus that irradiates the periphery including the edge of the wafer with ultraviolet light, and unnecessary resist applied to the edge of the wafer is removed. It has been broken. Such a light irradiation apparatus for a peripheral exposure apparatus is described in Patent Document 1, for example.

  A light irradiation apparatus for a peripheral exposure apparatus (edge exposure apparatus) described in Patent Document 1 includes a light source unit having a lamp therein, a first light guide that guides ultraviolet light emitted from the light source unit, and a first light guide. A light mixing optical element (quartz rod) that mixes ultraviolet light emitted from the light guide, a second light guide that guides light emitted from the light mixing optical element, and light from the second light guide on the substrate And an irradiation head that projects onto the edge portion, and is configured so that ultraviolet light emitted from the lamp is condensed on a rectangular irradiation area at the edge portion of the substrate.

  In recent years, ultraviolet LEDs (Light Emitting Diodes), which have a longer lifespan and lower power consumption than lamps, have been put into practical use, and peripheral exposure apparatuses using the same have also been proposed (for example, Patent Document 2). ).

  After exposure by such a peripheral exposure apparatus, unnecessary resist on the edge of the wafer is removed by etching or the like, but if the unnecessary resist is not completely removed and remains thin on the wafer (so-called gray zone) If a region is generated), this may cause a lack of resist in a later process. Therefore, the cross-sectional shape of the resist edge after the unnecessary resist is removed (that is, the cross-sectional shape of the resist edge remaining in the circuit pattern formation region) is steep between the circuit pattern formation region and the edge of the wafer. It is desirable to have a shape that stands up (that is, with less sagging).

  The occurrence of such a gray zone region is caused by the irradiation intensity distribution of the ultraviolet light projected from the peripheral exposure apparatus onto the edge of the substrate. In other words, if the irradiation intensity distribution of the ultraviolet light projected from the peripheral exposure device onto the edge of the substrate changes gently between the circuit pattern formation and the edge of the wafer, the circuit pattern formation region An insufficiently exposed area is formed between the wafer edge and the edge of the wafer, and the cross-sectional shape of the resist edge remaining in the circuit pattern formation area also becomes gentle (that is, a gray zone area is generated). ). For this reason, the irradiation intensity distribution of the ultraviolet light projected from the peripheral exposure apparatus onto the edge of the substrate rises sharply between the circuit pattern formation region and the edge of the wafer (that is, there is little sagging). desirable.

Japanese Patent No. 3947365 JP 2007-194583 A

  In the peripheral exposure apparatuses described in Patent Documents 1 and 2, a rectangular slit is formed in the irradiation head, and ultraviolet light mixed by the light mixing optical element is projected onto the substrate through the slit. Yes. For this reason, the ultraviolet light projected onto the substrate passes through the slit and becomes only a rectangular light beam whose spread angle is limited to some extent, and is relatively steep between the circuit pattern formation region and the edge of the wafer. The irradiation intensity distribution rises (that is, has little sagging).

  However, since the circuits formed on the wafer are more and more integrated and the circuit pattern is miniaturized recently, the circuit pattern is formed more steeply than before between the circuit pattern formation region and the edge of the wafer. There is a need for a light irradiation apparatus capable of projecting light of an irradiation intensity distribution (that is, less sagging).

  The present invention has been made in view of such circumstances, and an object of the present invention is to irradiate light having an irradiation intensity distribution that rises steeply to a rectangular irradiation area on an irradiation object. Is to provide a device.

  In order to achieve the above object, a light irradiation apparatus of the present invention is a light irradiation apparatus that irradiates light to a rectangular irradiation area on an irradiation object, and aligns the direction of the optical axis on the substrate. A plurality of light-emitting elements that are two-dimensionally arranged to emit light, a lens unit that is arranged on the optical axis of each light-emitting element, and that shapes the light emitted from the light-emitting elements into light having a predetermined spread angle; A cylindrical light guide member that has a mirror surface formed so as to surround the optical axis of the light emitting element in a rectangular shape on the inner surface, mixes and guides light emitted from the lens unit, and a light guide member An aperture stop having a rectangular opening centered on the optical axis, and an aperture stop disposed between the light guide member and the object to be irradiated, and the mirror surface spread toward the object to be irradiated, The lens is inclined at a predetermined angle smaller than the spread angle with respect to the optical axis of the light guide member. At least part of the light emitted from the unit is reflected by the mirror surface, it passes through the end face near the opening of the aperture stop, wherein the incident substantially perpendicularly to the irradiation area.

  According to such a configuration, since the region where the ultraviolet light does not overlap is minimized at the edge portion of the irradiation area, the irradiation intensity distribution in the irradiation area rises sharply. Therefore, for example, if the light irradiation apparatus of the present invention is applied to a semiconductor peripheral exposure apparatus, it is possible to irradiate ultraviolet light having an irradiation intensity distribution that rises sharply between the circuit pattern formation region and the edge of the wafer. In other words, the so-called gray zone region can be reduced.

  Further, at least part of the light emitted from the lens unit can be configured to be reflected only once by the mirror surface.

  Further, it is desirable that the spread angle is in the range of 5 to 20 °, and the predetermined angle is smaller than ½ of the spread angle.

  Further, it is desirable that the exit side opening formed by the mirror surface of the light guide member is configured to be larger than the aperture stop aperture.

  The light is preferably light in the ultraviolet wavelength region.

  As described above, according to the present invention, a light irradiation apparatus that can irradiate light of an irradiation intensity distribution that rises steeply on a rectangular irradiation area on an irradiation target is realized.

It is a schematic diagram which shows the structure of the light irradiation apparatus which concerns on embodiment of this invention. It is an optical path figure of the ultraviolet light radiate | emitted from each lens unit with which the light irradiation apparatus which concerns on embodiment of this invention was equipped. It is an optical path figure of the ultraviolet light radiate | emitted from the lens unit located in the center of FIG. FIG. 3 is an optical path diagram of ultraviolet light emitted from a lens unit located one position away from the center of FIG. 2. FIG. 3 is an optical path diagram of ultraviolet light emitted from a lens unit at two positions away from the center of FIG. 2 (that is, the outermost position). It is a figure explaining the light ray which injects into the edge part of the irradiation area irradiated with the light irradiation apparatus which concerns on embodiment of this invention. It is a schematic diagram which shows the structure and optical path diagram of the light irradiation apparatus which concern on the comparative example of this invention. It is a figure explaining the light ray which injects into the edge part of the irradiation area irradiated with the light irradiation apparatus which concerns on the comparative example of this invention. The graph which shows the irradiation intensity distribution on the irradiation area at the time of using the light irradiation apparatus which concerns on embodiment of this invention, and the irradiation intensity distribution on the irradiation area at the time of using the light irradiation apparatus which concerns on the comparative example of this invention It is. It is the graph which expanded the irradiation intensity distribution of the E section of FIG. 9 to the horizontal axis direction.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or an equivalent part in a figure, and the description is not repeated.

  FIG. 1 is a schematic diagram illustrating a configuration of a light irradiation apparatus 100 according to an embodiment of the present invention. FIG. 1A is a front view of the light irradiation device 100 when viewed from the exit side of the light irradiation device 100. FIG.1 (b) is sectional drawing by the AA line of Fig.1 (a). FIG.1 (c) is the B section enlarged view of Fig.1 (a). The light irradiation apparatus 100 of this embodiment is incorporated in a peripheral exposure apparatus or the like, and is substantially parallel light in the ultraviolet wavelength range with respect to a rectangular irradiation area P on an irradiation object W (for example, a resist on a glass substrate). It is an apparatus that irradiates. In FIG. 1A, for convenience of explanation, some components such as the aperture stop 150 are omitted.

  As shown in FIG. 1, the light irradiation device 100 includes 25 LED units 110, 25 lens units 120 arranged corresponding to the LED units 110, a light guide member 130, and an aperture stop 150. And a case (not shown) for housing these components. The LED unit 110, the lens unit 120, the light guide member 130, and the aperture stop 150 are arranged in order along the optical axis AX (the axis passing through the center of the light emitted from the light irradiation device 100) toward the irradiation object W. Is arranged. In the present embodiment, the working distance WD of the light irradiation device 100 (the distance from the emission opening 130f of the light guide member 130 to the irradiation object W) is set to about 10 mm, and the light irradiation device 100 emits light from the light irradiation device 100. The light in the ultraviolet wavelength region (hereinafter referred to as “ultraviolet light”) is condensed so as to have a uniform light amount distribution on the working distance WD (details will be described later). In the present specification, the traveling direction of ultraviolet light emitted from the light irradiation device 100 (that is, the direction parallel to the optical axis AX) is defined as the Z-axis direction, and is orthogonal to the Z-axis direction and 2 orthogonal to each other. Two directions are defined as an X-axis direction and a Y-axis direction.

  As shown in FIG. 1A, the 25 LED units 110 according to the present embodiment have 5 rows (Y-axis direction) × 5 (X-axis) on the XY plane with the optical axes aligned in the Z-axis direction. (Axial direction) is arranged in a square lattice. Each LED unit 110 includes a substantially square substrate 112 and an LED element 114 (light emitting element) arranged at the center of the substrate 112 with the optical axis aligned in the Z-axis direction (FIG. 1). (C)). Each LED element 114 of the present embodiment has a rectangular outer shape of, for example, 2.15 mm (length in the X-axis direction) × 2.15 mm (length in the Y-axis direction) (FIG. 1 (c)). The two sides are arranged so as to be parallel to the X-axis direction, and are electrically connected to the substrate 112. The board 112 is an electronic circuit board made of glass epoxy resin, ceramics, etc., and is connected to an LED drive circuit (not shown), and each LED element 114 receives a drive current from the LED drive circuit via the board 112. It comes to be supplied. When a drive current is supplied to each LED element 114, each LED element 114 emits light with a light amount corresponding to the drive current, and ultraviolet light with a predetermined light amount is emitted. In the present embodiment, each LED element 114 is configured to emit ultraviolet light having a wavelength of 395 nm upon receiving a drive current from the LED drive circuit.

  In addition, the drive current supplied to each LED element 114 is adjusted so that each LED element 114 of this embodiment may radiate | emit the ultraviolet light of a substantially uniform light quantity. Further, in the present embodiment, the centers C of the LED units 110 arranged in five rows (Y-axis direction) × 5 (X-axis direction) (that is, the center of the substrate 112 of the LED unit 110 located at the center). Are arranged so as to substantially coincide with the optical axis AX (FIG. 1A).

  As shown in FIG. 1B, each lens unit 120 of the present embodiment is a lens that molds ultraviolet light emitted from the LED element 114 into ultraviolet light having a predetermined spread angle (9 °). Each lens unit 120 includes a first lens 122, a second lens 124, and a third lens 126 having a common optical axis. In the present embodiment, the first lens 122, the second lens 124, and the third lens 126 are all plano-convex lenses. The first lens 122, the second lens 124, and the third lens 126 are supported by a lens barrel frame (not shown), their positions are adjusted so that their optical axes substantially coincide with the optical axis of the LED element 114, and a predetermined interval is obtained. Placed. The ultraviolet light that has passed through each lens unit 120 is emitted toward the light guide member 130 at the subsequent stage.

  The light guide member 130 is a rectangular cylindrical member having four mirror surfaces 130a, 130b, 130c, and 130d formed on the inner surface. As shown in FIG. 1 (a), the four mirror surfaces 130a, 130b, 130c, and 130d of the present embodiment have 25 LED units 110 and lens units 120 in a rectangular shape when viewed from the Z-axis direction. So that all the ultraviolet light emitted from the lens unit 120 is incident on the light guide member 130 (ie, arranged so as to surround the optical axis of the LED element 114 and the lens unit 120 in a rectangular shape). It is configured. As described above, since the ultraviolet light emitted from the lens unit 120 has a predetermined spread angle (9 °), the ultraviolet light of each angle component is reflected within the light guide member 130 (that is, The light guide member 130 emits ultraviolet light having a substantially uniform light amount distribution. Although details will be described later, the mirror surfaces 130a and 130b of the present embodiment are inclined in the Y-axis direction by a predetermined angle (1.6 °) with respect to the optical axis AX, and the mirror surfaces 130c and 130d are Inclined in the X-axis direction by a predetermined angle (1.6 °) with respect to the optical axis AX. In the light guide member 130, a rectangular incident opening 130e is formed on the lens unit 120 side, and a rectangular outgoing opening 130f larger than the incident opening 130e is formed on the irradiation object W side. As described above, the four mirror surfaces 130a, 130b, 130c, and 130d of the present embodiment are inclined so as to move away from the optical axis AX (that is, spread toward the irradiation object W) as they move away from the lens unit 120. ing. For this reason, the ultraviolet light incident on the mirror surfaces 130a, 130b, 130c, and 130d is reflected by the mirror surfaces 130a, 130b, 130c, and 130d, so that a predetermined angle (that is, an inclination angle (1.6 °) )) Twice the angle (that is, 3.2 °) (the details will be described later).

  The ultraviolet light that has passed through the light guide member 130 is emitted toward the subsequent aperture stop 150. The aperture stop 150 is a plate-like member having a rectangular opening at the center, and is disposed at a predetermined position between the emission opening 130 f and the irradiation object W. The aperture of the aperture stop 150 is set to be smaller than the output aperture 130f of the light guide member 130, and has a function of removing unnecessary light from the ultraviolet light output from the light guide member 130. And it is comprised so that the rectangular irradiation area P on the irradiation target W may be irradiated with the ultraviolet light from which the unnecessary light was removed by the aperture stop 150.

  Next, the optical path of ultraviolet light emitted from each lens unit 120 of the present embodiment will be described. FIG. 2 is an optical path diagram of ultraviolet light emitted from each lens unit 120 shown in FIG. FIG. 3 is an optical path diagram of ultraviolet light emitted from the lens unit 120 located at the center in FIG. FIG. 4 is an optical path diagram of ultraviolet light emitted from the lens unit 120 at a position one away from the center in FIG. FIG. 5 is an optical path diagram of ultraviolet light emitted from the lens unit 120 at a position two away from the center (ie, the outermost position) in FIG. 2 to 5, the optical path of the ultraviolet light is shown using broken lines.

  As shown in FIGS. 2 and 3, the ultraviolet light emitted from the lens unit 120 located at the center spreads at a predetermined spread angle (9 °), and each mirror surface 130 a, 130 b, 130 c of the light guide member 130, The light travels without being reflected by 130d and is irradiated into a rectangular irradiation area P (for example, about 70 mm × about 70 mm) on the irradiation object W.

  As shown in FIGS. 2 and 4, the ultraviolet light emitted from the lens unit 120 at a position one away from the center spreads at a predetermined spread angle (9 °), and a part thereof (for example, FIG. 6). The light beam indicated by “m1” in the middle is reflected by at least one of the mirror surfaces 130a, 130b, 130c, and 130d (the mirror surface 130a in FIGS. 2 and 4) of the light guide member 130, and on the irradiation object W. The rectangular irradiation area P is irradiated.

  Further, as shown in FIGS. 2 and 5, the ultraviolet light emitted from the lens unit 120 at a position two away from the center spreads at a predetermined spread angle (9 °) and a part thereof (for example, FIG. 5). , The light spreading toward the Y axis direction negative side) is reflected by at least one of the mirror surfaces 130a, 130b, 130c, 130d of the light guide member 130 (the mirror surface 130a in FIGS. 2 and 5). Irradiation is performed in a rectangular irradiation area P on the irradiation object W.

  As a result, in the central portion of the rectangular irradiation area P on the irradiation object W, ultraviolet light emitted from the central lens unit 120 and ultraviolet light emitted from the lens unit 120 at a position one distance away from the center. The light and the ultraviolet light emitted from the lens unit 120 at a position two away from the center overlap, and a substantially uniform irradiation intensity is obtained. Further, in the peripheral portion of the rectangular irradiation area P on the irradiation object W, the ultraviolet light emitted from the lens unit 120 at a position away from the center and the lens unit 120 at a position away from the center by two. The ultraviolet light emitted from the light overlaps, and a substantially uniform irradiation intensity is obtained. However, in the edge part (edge part of the peripheral part) of the rectangular irradiation area P on the irradiation object W, the unnecessary light is shielded by the aperture stop 150, so that the rectangular irradiation area on the irradiation object W is obtained. There arises a problem that an ultraviolet light does not overlap in the edge portion (end portion of the peripheral edge) of P. When the region where the ultraviolet light does not overlap increases in the edge portion of the irradiation area P, the irradiation intensity in the region is extremely reduced, and the irradiation intensity distribution in the region becomes a gentle curve. Therefore, in the present embodiment, the mirror surfaces 130a, 130b, 130c, and 130d are tilted so that the edge of the irradiation area P is inclined so that an irradiation intensity distribution that rises sharply is obtained at the edge of the irradiation area P. The configuration is such that substantially vertical light rays are incident, and the region where the ultraviolet light does not overlap is minimized.

  FIG. 6 is an enlarged view of a portion C in FIG. 2, and is a diagram illustrating light rays incident on an edge portion of a rectangular irradiation area P on the irradiation object W. “M1” and “m2” in FIG. 6 are both ultraviolet rays emitted from the lens unit 120 at a position away from the center and having the maximum angular component in the Y-axis direction (that is, the angular component of 9 °). The light beam. The light beam “m1” is a light beam that passes through the outermost side of the ultraviolet light beam having an angle component of 9 °, and the light beam “m2” is a light beam that passes through the vicinity of the end surface portion of the aperture stop 150 and reaches the irradiation object W. . As described above, the four mirror surfaces 130a, 130b, 130c, and 130d of the present embodiment are inclined at a predetermined inclination angle (1.6 °) so as to be away from the optical axis AX as they are away from the lens unit 120. Yes. Therefore, as shown in FIG. 6, when the ultraviolet light is incident on any one of the mirror surfaces 130a, 130b, 130c, and 130d (mirror surface 130a in FIG. 6), the angle component is an inclination angle (1.6 °). ) Is twice as small as. That is, the ultraviolet light ray “m1” having the maximum angle component of 9 ° is emitted from the light guide member 130 as the ultraviolet light having the angular component of 5.8 ° (that is, the light ray “n1”). As a result, a region where the ultraviolet light does not overlap is formed at the edge of the rectangular irradiation area P on the irradiation target W over a width of about 0.8 mm.

(Comparative example)
Here, in order to explain the effect of the configuration of the present embodiment, a comparative example is given. FIG. 7 is a schematic diagram illustrating a configuration and an optical path diagram of a light irradiation apparatus 100C according to a comparative example, which is compared with the configuration of the present embodiment. FIG. 8 is an enlarged view of a portion D in FIG. 7 and is a diagram for explaining light rays incident on an edge portion of a rectangular irradiation area P on the irradiation object W. In the light irradiation apparatus 100C of this comparative example, the mirror surfaces 130Ca, 130Cb, 130Cc (not shown in FIG. 7) and 130Cd (not shown in FIG. 7) of the light guide member 130C are parallel to the optical axis AX, and the inclination angle It differs from the light irradiation apparatus 100 of this embodiment by the point which does not have (1.6 degrees). Note that “m1” in FIG. 8 is a light beam emitted from the lens unit 120 at a position two away from the center, and has a maximum angular component in the Y-axis direction (that is, an angular component of 9 °) and an aperture. It is a light beam that passes through the vicinity of the end face of the diaphragm 150 and reaches the irradiation object W. Further, “m2” in FIG. 8 is a light beam emitted from the lens unit 120 at one position away from the center, and has a maximum angular component in the Y-axis direction (that is, an angular component of 9 °) and an aperture. It is a light beam that passes through the vicinity of the end face of the diaphragm 150 and reaches the irradiation object W.

  As shown in FIG. 8, in this comparative example, since each mirror surface 130Ca, 130Cb, 130Cc, 130Cd of the light guide member 130C is parallel to the optical axis AX, ultraviolet light is mirror surfaces 130Ca, 130Cb, 130Cc, 130Cd. The angle component is maintained even if it is incident on. That is, the ultraviolet ray “m1” having the maximum angle component of 9 ° is emitted from the light guide member 130C as the ultraviolet ray having the angle component of 9 ° (that is, the ray “n1”). As a result, a region where the ultraviolet light does not overlap is formed at the edge portion of the rectangular irradiation area P on the irradiation object W over a width of about 1.0 mm.

  9 shows an irradiation intensity distribution (solid line in FIG. 9) on the irradiation area P when the light irradiation device 100 according to the present embodiment is used, and an irradiation area when the light irradiation device 100C according to the comparative example is used. 10 is a graph showing an irradiation intensity distribution on P (broken line in FIG. 9). In FIG. 9, the vertical axis represents the relative intensity of ultraviolet light, and the horizontal axis represents the irradiation position (mm) where the position of the optical axis AX is 0 mm. FIG. 10 is a graph obtained by enlarging the irradiation intensity distribution in the E portion (that is, the edge portion of the irradiation area P) in FIG. 9 in the horizontal axis direction.

  As shown in FIG. 9, when using the light irradiation apparatus 100 according to the present embodiment and when using the light irradiation apparatus 100C according to the comparative example, the relative intensity 0.8 or more over the entire irradiation area P. The irradiation intensity distribution can be obtained.

  However, in FIG. 10, as can be seen by comparing the irradiation intensity distributions of the two, the irradiation intensity distribution of the light irradiation apparatus 100 according to the present embodiment rises sharply compared to the light irradiation apparatus 100C of the comparative example. ing. As described above, this is an influence of the region where the ultraviolet light does not overlap, which is formed at the edge portion of the irradiation area P, and the region where the ultraviolet light does not overlap is included in the light irradiation device 100 according to the present embodiment. This is because it is smaller.

  As described above, in the present embodiment, by tilting the mirror surfaces 130a, 130b, 130c, and 130d of the light guide member 130, an area where the ultraviolet light does not overlap at the edge portion of the irradiation area P is minimized. The irradiation intensity distribution that rises sharply is obtained. Therefore, when the light irradiation apparatus 100 according to the present embodiment is applied to a semiconductor peripheral exposure apparatus, it is possible to irradiate ultraviolet light having an irradiation intensity distribution that rises sharply between the circuit pattern formation region and the edge of the wafer. It is possible to reduce the so-called gray zone region.

  In the present embodiment, the angle component of the light beam “n1” is further reduced by increasing the inclination angle (1.6 °) of the mirror surfaces 130a, 130b, 130c, and 130d (that is, the irradiation area). It is also possible to approach a light beam perpendicular to P). However, when the tilt angle is increased, the amount of ultraviolet light that is blocked by the aperture stop 150 increases, and the amount of light as a whole decreases. Accordingly, the inclination angles of the mirror surfaces 130a, 130b, 130c, and 130d are appropriately set in consideration of the required light amount, the rising characteristics of the irradiation intensity distribution, and the like.

  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 present embodiment, each mirror surface 130a, 130b, 130c, 130d of the light guide member 130 is separated from the ultraviolet light emitted from the lens unit 120 at one position away from the center and two from the center. Although the configuration is such that the ultraviolet light emitted from the lens unit 120 at the position is reflected only once, it is not limited to such a configuration. For example, each mirror surface 130a, 130b, 130c, 130d of the light guide member 130 is elongated in the Z-axis direction, and ultraviolet light emitted from the lens unit 120 located at the center is also reflected by each mirror surface 130a, 130b, 130c, 130d. It can also be configured to reflect. In addition, each mirror surface 130a, 130b, 130c, 130d of the light guide member 130 may be configured to reflect the ultraviolet light emitted from each lens unit 120 a plurality of times. In this case, the irradiation intensity decreases each time the ultraviolet light is reflected due to the influence of the reflectivity of each mirror surface 130a, 130b, 130c, 130d.

  In the present embodiment, the 25 LED units 110 arranged in a square lattice are used. However, the LED units 110 do not necessarily need to be arranged in a square lattice. It can also be arranged in a lattice or concentric circle. Moreover, the number of the LED units 110 should just be at least 2 or more, and can be suitably changed according to the area and shape of the irradiation area P.

  In the present embodiment, the first lens 122, the second lens 124, and the third lens 126 have been described as being planoconvex lenses. However, the ultraviolet light emitted from the LED element 114 is converted into ultraviolet light having a predetermined spread angle. As long as it can be molded into light, lenses having other shapes (for example, meniscus lenses) can be applied to the first lens 122, the second lens 124, and the third lens 126. Further, the lens unit 120 of the present embodiment does not necessarily have a three-lens configuration.

  In addition, although the lens unit 120 of the present embodiment is a lens that molds ultraviolet light emitted from the LED element 114 into ultraviolet light having a divergence angle (9 °), the divergence angle is obtained in the irradiation area P. The irradiation intensity distribution can be changed as appropriate according to the uniformity of the irradiation intensity distribution (that is, the degree of overlap of ultraviolet light) and the rising characteristics. In addition, it is preferable that the divergence angle of the ultraviolet light radiate | emitted from the lens unit 120 is 5-20 degrees from a viewpoint of the utilization efficiency of ultraviolet light, and the standup characteristic of irradiation intensity distribution. When the divergence angle is smaller than 5 °, the utilization efficiency of the emitted ultraviolet light is lowered, and a desired irradiation intensity cannot be obtained in the irradiation area P. If the spread angle is larger than 20 °, the region where the ultraviolet light does not overlap increases at the edge portion of the irradiation area P, and the rising characteristic of the irradiation intensity distribution deteriorates. Further, the inclination angle of each mirror surface 130a, 130b, 130c, 130d is reflected by each mirror surface 130a, 130b, 130c, 130d, and the angle component of the ultraviolet light irradiated to the irradiation area P is smaller than the spread angle. It is desirable that the angle is set to be smaller than ½ of the divergence angle so as to be (that is, substantially parallel light).

  Moreover, although the LED unit 110 of this embodiment shall be provided with the one LED element 114, it is not limited to this structure, The LED unit 110 has multiple (for example, four) LED elements 114. Can be provided.

  The LED element 114 according to the present embodiment emits ultraviolet light having a wavelength of 395 nm, but is not limited to such a configuration, and other wavelengths (for example, a wavelength of 365 nm, a wavelength of 385 nm, and a wavelength of 405 nm). ) Or a combination of a plurality of types of LED elements having different wavelengths (that is, mixing a plurality of wavelengths).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

100, 100C Light irradiation device 110 LED unit 112 Substrate 114 LED element 120 Lens unit 122 First lens 124 Second lens 126 Third lens 130, 130C Light guide members 130a, 130b, 130c, 130d, 130Ca, 130Cb, 130Cc, 130Cd Mirror surface 150 Aperture stop

Claims (5)

A light irradiation device for irradiating light on a rectangular irradiation area on an irradiation object,
A plurality of light-emitting elements that are two-dimensionally arranged on the substrate with the direction of the optical axis aligned, and emit the light; and
A lens unit that is arranged on the optical axis of each light emitting element, and shapes the light emitted from the light emitting element into light having a predetermined spread angle;
A cylindrical light guide member which has a mirror surface formed on the inner surface so as to surround the optical axes of the plurality of light emitting elements in a rectangular shape, and mixes and guides light emitted from the lens unit;
An aperture stop having a rectangular opening centered on the optical axis of the light guide member, and disposed between the light guide member and the irradiated object;
With
The mirror surface is inclined at a predetermined angle smaller than the spread angle with respect to the optical axis of the light guide member so as to spread toward the irradiation object,
At least a part of the light emitted from the lens unit is reflected by the mirror surface, passes through the vicinity of the end surface portion of the aperture stop aperture, and is incident substantially perpendicular to the irradiation area. Light irradiation device.   The light irradiation apparatus according to claim 1, wherein at least part of the light emitted from the lens unit is reflected only once by the mirror surface.   The light irradiation apparatus according to claim 1 or 2, wherein the divergence angle is in a range of 5 to 20 °, and the predetermined angle is smaller than ½ of the divergence angle.   4. The light irradiation apparatus according to claim 1, wherein an emission side opening formed by the mirror surface of the light guide member is larger than an opening of the aperture stop. 5.   The light irradiation apparatus according to claim 1, wherein the light is light in an ultraviolet wavelength region.

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