JP7590273B2 - Light-emitting unit, lighting device, reading device and recording system - Google Patents

Description

The present invention relates to a light-emitting unit, a lighting device, a reading device, and a recording system.

In light-emitting units used in line sensors and the like, the amount of heat generated by the light source increases as the brightness of the light source increases, raising concerns about effects on optical characteristics such as deformation of the ends of the light guide and deterioration of the light source. Patent Document 1 shows that, in order to deal with heat generated by the light-emitting element used in the light source unit, a heat dissipation member with fins is attached to the side of the circuit board on which the light-emitting element is arranged, opposite the light-emitting element.

JP 2012-160309 A

In the configuration of Patent Document 1, a reflector is disposed between the light emitter and the light guide. The light guide may be sensitive to heat, and if the temperature of the reflector rises due to heat generated by the light emitter, the light guide, which is pressed against the reflector, may be deformed. In addition, to control the shape of the light emitted from the light emitter, a light distribution control member that covers part of the light emitter may be disposed between the light emitter and the light guide. If part of the light emitter is covered by the light distribution control member, further heat may be trapped between the light emitter and the light guide, which may cause deformation of the end of the light guide or deterioration of the light source.

The present invention aims to provide a technology that is advantageous for dissipating heat emitted from a light source in a light-emitting unit.

In view of the above problems, an light-emitting unit according to an embodiment of the present invention is a light-emitting unit including a substrate, a light-emitting element arranged on a first surface of the substrate, a front panel covering the first surface, and a back panel arranged on a second surface side of the substrate opposite the first surface, wherein the front panel is provided with an opening for extracting light emitted by the light-emitting element, and in an orthogonal projection onto the first surface, the opening is arranged to overlap with a portion of the light emission surface of the light-emitting element, the back panel has a higher thermal conductivity than the front panel and is provided with a protrusion protruding toward the first surface, the protrusion being in contact with at least one of the first surface, the light-emitting element, and the front panel, and the protrusion includes a fitting portion that fits with the front panel .

The above means provide a technology that is advantageous for dissipating heat emitted from a light source in a light-emitting unit.

FIG. 2 is a perspective view showing an example of the configuration of a light-emitting unit according to the embodiment. FIG. 2 is an exploded perspective view showing a configuration example of the light emitting unit of FIG. 1 . 2 is a cross-sectional view showing a configuration example of a light-emitting element used in the light-emitting unit of FIG. 1 . 2A to 2C are diagrams showing examples of the configuration of a protrusion of the light-emitting unit of FIG. 1 FIG. 2 is a cross-sectional view showing a configuration example of the light-emitting unit of FIG. 1 . FIG. 2 is a perspective view showing a configuration example of the light-emitting unit of FIG. 1 . 2A to 2C are diagrams showing examples of arrangement of flexible members of the light-emitting unit of FIG. 1 . FIG. 2 is a diagram showing an example of the configuration of a lighting device in which the light-emitting unit of FIG. 1 is incorporated. 10A and 10B are diagrams showing modified examples of the front panel of the light emitting unit of FIG. FIG. 2 is a diagram showing an example of the configuration of a recording system including the light emitting unit of FIG. 1 . FIG. 2 is a perspective view showing a modified example of the light emitting unit in FIG. 1 . FIG. 11 is an exploded perspective view showing a configuration example of the light emitting unit of FIG. 10 . 11A and 11B are diagrams showing an example of the configuration of a protruding portion of the light-emitting unit of FIG. 10 . 11A and 11B are diagrams showing examples of the configuration of an illumination device in which the light-emitting unit of FIG. 10 is incorporated, and a recording system including the light-emitting unit of FIG. 10 . 11A and 11B are diagrams showing examples of characteristics of the front panel and the back panel of the light-emitting unit of FIG.

The following embodiments are described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims, and not all combinations of features described in the embodiments are necessarily essential to the invention. Two or more of the features described in the embodiments may be combined in any desired manner. In addition, the same reference numbers are used for the same or similar configurations, and duplicate descriptions are omitted.

A light-emitting unit according to an embodiment of the present disclosure will be described with reference to Figs. 1(a) to 15(b). Figs. 1(a) and 1(b) are perspective views showing an example of the configuration of the light-emitting unit 100 of this embodiment, and Figs. 2(a) and 2(b) are exploded perspective views showing an example of the configuration of the light-emitting unit 100.

The light-emitting unit 100 includes a substrate 130, a light-emitting element 140 arranged on a surface 131 of the substrate 130, a front panel 120 arranged to cover the surface 131, and a back panel 160 arranged on the surface 132 side of the substrate 130 opposite the surface 131. The front panel 120 is provided with an opening 121 for extracting light emitted by the light-emitting element 140. In an orthogonal projection onto the surface 131 of the substrate 130, the opening 121 is arranged to overlap a part of the light-emitting surface 141 of the light-emitting element 140. In other words, the front panel 120 covers a part of the light-emitting surface 141 of the light-emitting element 140. In a lighting device incorporating the light-emitting unit 100 described later, the opening 121 allows the light emitted from the light-emitting element 140 to be efficiently incident on the light guide, thereby suppressing stray light and the like. The shape of the opening 121 of the front panel 120 may be circular, rectangular, polygonal, or the like, as shown in Figs. 1(a) to 2(b). Here, the light exit surface 141 may refer to the entire surface of the light emitting element 140 that emits light, or may refer to the portion of the surface of the light emitting element 140 from which light is actually emitted. Here, it is desirable that the front panel 120 contacts both the substrate 130 (surface 131) on which the light emitting element 140 is arranged and the light incidence surface of the light guide of the lighting device in which the light emitting unit 100 described later is incorporated (or the light guide cover member in contact with the light incidence surface). By contacting both the substrate 130 and the light incidence surface of the light guide of the lighting device, the front panel 120 prevents the light emitting element 140 (light exit surface 141 or light emitting surface) arranged on the substrate 130 from contacting the light incidence surface of the light guide. In other words, the front panel 120 functions as a spacer to create an air layer between the light emitting element 140 and the light guide, making it difficult for heat generated by the light emitting element 140 to be conducted to the light guide.

In this embodiment, the opening 121 is arranged so as to overlap a portion of the light exit surface 141 of the light-emitting element 140, but the arrangement of the opening 121 is not limited to this. For example, the opening 121 may be arranged so as to overlap the entire light exit surface 141 of the light-emitting element 140. In other words, the front panel 120 does not have to cover the light exit surface 141 of the light-emitting element 140. The shape and size of the opening 121 of the front panel 120 may be adjusted as appropriate depending on the configuration of the lighting device in which the light-emitting unit 100 is incorporated.

The front panel 120 may be made of a resin material with excellent thermal properties. Here, excellent thermal properties may mean properties such as excellent heat resistance and a low coefficient of thermal expansion. For example, resins such as polycarbonate, polyether ether ketone, and ABS may be used for the front panel 120.

The substrate 130 may be a so-called printed circuit board containing epoxy resin, polyimide resin, or the like. A ceramic substrate may also be used as the substrate 130. A wiring pattern (conductor, not shown) for supplying power to the light-emitting element 140 may be formed on surfaces 131 and 132 of the substrate 130. The wiring pattern may be arranged only on surface 131, or may be arranged on both surfaces 131 and 132. The substrate 130 may also be a multilayer wiring substrate. The wiring pattern may be formed as appropriate according to the conditions required for the light-emitting unit 100.

3(a) to 3(c) are cross-sectional views showing an example of the configuration of the light-emitting element 140. As shown in FIG. 3(a), the light-emitting element 140 has a configuration in which a light-emitting diode (LED) chip 143 arranged in a case 142 is sealed with a resin 144. The light-emitting element 140 may be configured to emit white light. In this case, an LED that emits blue light and an LED that emits yellow light may be arranged as the LED chip 143. Also, for example, an LED that emits blue-white light may be arranged as the LED chip 143, and a phosphor that is excited by blue light and emits yellow light may be dispersed in the resin 144. The light-emitting element 140 may be a surface-mount type element mounted on the surface 131 of the substrate 130. Also, the light-emitting element 140 may be a so-called top-emitting type element in which the light-emitting surface 141 is arranged on the surface opposite to the surface facing the surface 131 of the substrate 130.

The shape of the light emitting surface 141 may be flat, as shown in FIG. 3(a). The shape of the light emitting surface 141 may also have a convex shape that bulges outward from the case 142 toward the side from which light is emitted, as shown in FIG. 3(b). For example, the light emitting element 140 may be configured such that the side of the resin 144 is not covered by the case 142, and light is emitted to a surface other than the substrate 130 side, as shown in FIG. 3(c).

The back panel 160 is a member having a higher thermal conductivity than the front panel 120. The back panel 160 may be made of a metal material such as aluminum, copper, or an alloy thereof. As shown in FIGS. 1(a) to 2(b), the back panel 160 has a protrusion 161 that protrudes from the surface 131 of the substrate 130. This protrusion 161 is in contact with at least one of the surface 131 of the substrate 130, the light-emitting element 140, and the front panel 120. In the configuration shown in FIGS. 1(a) to 2(b), the protrusion 161 is in contact with the front panel 120.

In the light-emitting unit 100, the amount of heat generated by the light-emitting element 140 increases, and the LEDs arranged in the light-emitting element 140 may deteriorate. In addition, optical components such as a light guide of a lighting device incorporating the light-emitting unit 100 may be deformed by the heat. For this reason, it is necessary to dissipate the heat generated by the light-emitting element 140 arranged on the surface 131 of the substrate 130 to the surface 132 side of the substrate 130. However, a substrate 130 made of a material with low thermal conductivity as described above does not easily allow the heat generated by the light-emitting element 140 arranged on the surface 131 side to pass to the surface 132 side.

Therefore, in this embodiment, the protrusion 161 of the back panel 160, which has a higher thermal conductivity than the front panel 120, protrudes from the surface 132 side of the substrate 130 to the surface 131 side, and contacts the front panel 120. This allows the heat generated by the light-emitting element 140 arranged on the surface 131 of the substrate 130 to be efficiently transferred to the surface 132 side of the substrate 130 and dissipated from the back panel 160. When the protrusion 161 is in contact with the surface 131 of the substrate 130, or even when it is in direct contact with the light-emitting element 140, the heat can be similarly transferred from the surface 131 of the substrate 130 to the surface 132 side, and dissipated from the back panel 160. The back panel 160 may be larger than the front panel 120, as shown in Figures 1(a) to 2(b). By increasing the area of the back panel 160, the heat dissipation effect can be improved.

The back panel 160 may protrude from outside the outer edge of the substrate 130 toward the surface 131 of the substrate 130, as shown in Figs. 1(a) to 2(b). In this case, as shown in Figs. 1(a) to 2(b), the protruding portion 161 may function as a fitting portion that fits with the front panel 120. This may facilitate the assembly of the substrate 130 on which the light-emitting element 140 is arranged, the front panel 120, and the back panel 160, as well as the positioning during assembly.

Also, for example, as shown in FIG. 1(a) to FIG. 2(b), consider the case where two protrusions 161 functioning as a joint are arranged. In this case, in the orthogonal projection onto the surface 131 of the substrate 130, a virtual line 410 connecting the two protrusions 161 functioning as a joint may be arranged to pass through the light emitting element 140 as shown in FIG. 4(a). In this case, the virtual line 410 may include a virtual line 410a that is parallel to a line connecting two opposing sides of the outer edge of the substrate 130 at the shortest distance. By arranging the two protrusions 161 functioning as a joint in this way, the protrusion 161 of the back panel 160 can be arranged near the light emitting element 140. By arranging the protrusion 161 of the back panel 160 with high thermal conductivity near the heat-generating light emitting element 140, heat is easily transferred to the surface 132 side of the substrate 130.

Also, consider the case where the front panel 120 is in close contact with the light emitting element 140. In this case, by arranging the virtual line 410 connecting the two protrusions 161 that function as a joint so as to pass through the light emitting element 140, the front panel 120 can be more evenly forced toward the light emitting element 140. By bringing the front panel 120 into more reliable contact with the light emitting element 140, it becomes possible to transfer heat from the light emitting element 140 to the front panel 120. This allows the heat generated by the light emitting element 140 to be transferred to the back panel 160 via the front panel 120, more than when air is present between the front panel 120 and the light emitting element 140.

As shown in Figs. 1(a) to 2(b) and 4(b), the direction in which the protrusion 161 of the back panel 160 and the light emitting element 140 functioning as two mating parts are arranged is the Y direction, and the direction intersecting the Y direction is the Z direction. The Y direction and the Z direction are directions along the faces 131 and 132 of the substrate 130. The direction intersecting the Y direction and the Z direction and heading from the face 132 to the face 131 of the substrate 130 is the X direction. The X direction, the Y direction, and the Z direction may be mutually orthogonal. In this case, as shown in Fig. 4(b), the length 420 of the protrusion 161 functioning as a mating part along the Z direction may be 1/3 or more of the length 430 of the light emitting element 140 along the Z direction. By increasing the length in the Z direction of the protrusion 161 of the back panel 160 that fits with the front panel 120, the path for transferring heat from the front panel 120 to the back panel 160 is widened. In other words, heat can be more effectively transferred from the surface 131 of the substrate 130 on which the light emitting element 140 is disposed to the surface 132. Although FIGS. 1(a) to 2(b), 4(a), and 4(b) show a case in which two protrusions 161 functioning as a joint are disposed, three or more protrusions 161 functioning as a joint may be disposed.

The protrusion 161 of the back panel 160 is not limited to protruding from the outer side of the outer edge of the substrate 130 to the surface 131 of the substrate 130. FIG. 5 is a cross-sectional view passing through the opening 121 of the front panel 120 of the light-emitting unit 100. For example, as shown in FIG. 5, the back panel 160 may have a protrusion 162 that penetrates the substrate 130 and protrudes to the surface 131 of the substrate 130. In this case, the protrusion 162 is in contact with at least one of the surface 131 of the substrate 130, the light-emitting element 140, and the front panel 120, similar to the protrusion 161 described above. This makes it possible to transfer heat to the surface 132 of the substrate 130 from a position closer to the light-emitting element 140, compared to transferring heat to the surface 132 of the substrate 130 from the outer edge side of the substrate 130. The protrusion 162 may function as a joint portion as described above. In addition, the protrusion 162 of the back panel 160 may be used for positioning when assembling the substrate 130 on which the light-emitting element 140 is arranged, the front panel 120, and the back panel 160. By using the protrusion 162 for positioning when assembling the substrate 130 on which the light-emitting element 140 is arranged, the front panel 120, and the back panel 160, assembling the light-emitting unit 100 can be made easier.

As shown in Figs. 5 and 6, in an orthogonal projection onto the surface 132 of the substrate 130, the back panel 160 may have an opening 163 that exposes the surface 132 of the substrate 130 on the inside of the outer edge of the back panel 160. As shown in Figs. 1(b) and 6, in an orthogonal projection onto the surface 132 of the substrate 130, the outer edge of the back panel 160 may have a recess 164 that is disposed on the inside of the outer edge of the substrate 130. By providing the opening 163 or recess 164 in the back panel 160, the surface 132 of the substrate 130 is exposed. By exposing the surface 132 of the substrate 130, it becomes possible to dissipate heat directly from the surface 132 into the atmosphere.

Furthermore, as shown in Figs. 1(a) to 2(b), 5, and 6, the front panel 120 may have a protrusion 122 that penetrates the substrate 130 and protrudes toward the surface 132 of the substrate 130. In this case, the protrusion 122 may be in contact with the back panel 160. This makes it easier to transfer heat from the surface 131 of the substrate 130 to the surface 132. As shown in Figs. 1(a) to 2(b), 5, and 6, the protrusion 122 may further penetrate the back panel 160 and protrude from the back panel 160. This makes it possible to dissipate heat directly from the protrusion 122 into the atmosphere. As shown in Fig. 2(b), the protrusion 122 of the front panel 120 may be used for positioning when assembling the substrate 130 on which the light-emitting element 140 is arranged, the front panel 120, and the back panel 160. The protrusions 122 are used for positioning when assembling the substrate 130 on which the light emitting elements 140 are arranged, the front panel 120, and the back panel 160, making it easier to assemble the light emitting unit 100.

2(a) and 2(b), a flexible member 150 having a higher thermal conductivity than the front panel 120 may be disposed between the back panel 160 and the surface 132 of the substrate 130. The flexible member 150 may be a double-sided tape containing a resin or the like. For example, the flexible member 150 may be made of silicone rubber or the like that is elastic and has high thermal conductivity. As shown in FIG. 2(a) and 2(b), the flexible member 150 may be disposed at a position that overlaps with the light-emitting element 140 in an orthogonal projection onto the surface 131 of the substrate 130. This allows heat to be more efficiently transferred from the surface 132 of the substrate 130 to the back panel 160 and dissipated from the back panel 160.

7, the flexible member 150 may have an extension 151 extending from the surface 132 of the substrate 130 to the surface 131 side, passing through the outer edge of the substrate 130. This extension 151 may be in contact with at least one of the surface 131 of the substrate 130, the light-emitting element 140, and the front panel 120. As shown in FIG. 7, the extension 151 may be in direct contact with the light-emitting element 140. By contacting the light-emitting element 140 with the flexible member 150, which has a higher thermal conductivity than the front panel 120, the heat generated by the light-emitting element 140 can be more efficiently transferred to the surface 132 side of the substrate 130.

Figure 8 is a diagram showing an example of the configuration of an illumination device 800 incorporating the light-emitting unit 100 of this embodiment. Figure 8 is a cross-sectional view of the illumination device 800, taken along a line passing through an opening 121 in a front panel 120 of the light-emitting unit 100. The illumination device 800 includes the light-emitting unit 100, a light guide 810 that guides the light emitted from the light-emitting unit 100, and a frame 820 that houses the light-emitting unit 100 and the light guide 810.

As shown in FIG. 8, the light guide 810 is close to the light emitting unit 100. The light guide 810 can be arranged so as to be in contact with the front panel 120 of the light emitting unit 100. The light guide 810 can be made of a resin such as acrylic. Acrylic can soften and deform at temperatures below 100° C., so it is necessary to make it difficult for heat generated by the light emitting element 140 to be transmitted. For this reason, as described above, the light emitting unit 100 of this embodiment is configured so that heat is efficiently transmitted from the surface 131 on the side of the substrate 130 on which the light emitting element 140 is arranged to the surface 132 side of the substrate 130. This makes it possible to suppress defects caused by heat generated by the light emitting unit 100 in the lighting device 800.

As shown in FIG. 8, the protrusion 122 of the front panel 120 described above may be fitted into the frame 820. Fitting the protrusion 122 into the frame 820 can facilitate positioning when assembling the light-emitting unit 100 to the frame 820. The frame 820 can be made of a metal such as aluminum or an alloy thereof. Fitting the protrusion 122 of the front panel 120 into the frame 820, which has a higher thermal conductivity than the front panel 120, can facilitate dissipation of heat generated by the light-emitting element 140 from the protrusion 122 of the front panel 120 through the frame 820.

As described above, the light guide 810 is disposed close to the light-emitting unit 100. This may result in heat being trapped between the light-emitting element 140 and the light guide 810. As described above, if the front panel 120 is configured to cover part of the light-emitting surface 141 of the light-emitting element 140, the space between the light-emitting element 140 and the light guide 810 may become narrower, further increasing the possibility of heat being trapped.

9(a), the inner wall of the front panel 120, including the side wall 123 of the opening 121, may have a ventilation section 910 formed by a groove extending from the inner wall to the outer edge (outer wall) 124 of the front panel 120. This groove may be provided on the surface of the front panel 120 facing the light guide 810, or may be provided on the surface of the front panel 120 facing the light emitting element 140 or the surface 131 of the substrate 130, as shown in FIG. 9(a). For example, if it is not desired to transmit heat to the light guide 810 (the material constituting the light guide 810 is a material with low heat resistance), it is desirable to provide a groove on the surface of the front panel 120 facing the light emitting element 140. Here, when two ventilation sections 910 are provided, one may be a groove provided on the surface of the front panel 120 facing the light guide 810, and the other may be a groove provided on the surface of the front panel 120 facing the light emitting element 140. From the viewpoint of brightness, as shown in FIG. 9(a), a groove constituting the ventilation section 910 may be arranged in a portion of the front panel 120 facing the surface 131 of the substrate 130. Also, for example, as shown in FIG. 9(b), the inner wall of the front panel 120 including the side wall 123 of the opening 121 may be provided with a ventilation section 910 constituted by a through hole reaching the outer edge 124 of the front panel 120 from the inner wall. This allows the heat between the light emitting element 140 and the light guide 810 to be efficiently released to the outside, and makes it possible to suppress the influence of the heat generated by the light emitting element 140 on the light guide 810. The ventilation section 910 may be arranged in two or more places, preferably four or more places, taking into account the flow of air (convection).

Here, when the ventilation section 910 is provided in two places, it is desirable to provide one on the upper surface of the inner wall of the front panel 120 and one on the lower surface in consideration of facilitating convection, but this is not limited to this. For example, if two ventilation sections 910 are provided on the upper surface of the inner wall of the front panel 120, the air (gas) with an increased temperature will escape from the two ventilation sections 910, and air will enter the space from the gap between the front panel 120 and the substrate 130, or the gap between the front panel 120 and the light guide 810. Also, for example, if one ventilation section 910 is provided on the upper surface of the inner wall of the front panel 120 and one on a surface that is neither upper nor lower, air will be taken into the space from the latter ventilation section 910 and exhausted from the upper ventilation section 910. Furthermore, in the case where there are two ventilation sections 910, when the orientation of the center of the hole (groove) on the inner wall side of one ventilation section 910 with respect to the center of the light emitting element 140 is set to 0 degrees in the orthogonal projection onto the surface 131 of the substrate 130, it is desirable that the center of the hole on the inner wall side of the front panel 120 of the other ventilation section 910 is within the range of 150 to 210 degrees. Note that the center here may be the geometric center of gravity or the center of the circumscribed circle when the hole on the inner wall side of the front panel 120 is viewed in a plan view. Furthermore, in the case where four ventilation sections 910 are provided, it is desirable that the orientation of the center of the second, third, and fourth ventilation sections 910 is within the range of 60 to 120 degrees, 150 to 210 degrees, and 240 to 300 degrees when the orientation of the center of one ventilation section 910 is set to 0 degrees. With such a configuration, it is easy to generate an air flow by appropriate convection, regardless of the orientation in which the light emitting unit 100 of this embodiment is installed. However, if four ventilation sections 910 are provided, one may be missing as long as three of the four ventilation sections 910 satisfy the above conditions.

The inner wall of the front panel 120 here includes the side wall 123 of the opening 121 of the front panel 120, and forms a space (a space including the light-emitting element 140) together with the substrate 130 and the light guide 810. In other words, this inner wall may be composed only of the side wall 123 of the opening 121 of the front panel 120, or may include members other than the front panel 120, such as the substrate 130 and the outer member of the front panel 120, and a light guide holder (e.g., the frame 820) that holds the light guide 810. This space may be sealed, but as described above, a gap may be generated between the front panel 120 and the light guide 810 or between the front panel 120 and the substrate 130. However, it is desirable that this gap be 20% or less (preferably 7% or less, more preferably 3% or less) of the distance between the substrate 130 (light emission surface 141 of the light-emitting element 140) and the light guide 810. Alternatively, it is desirable for this gap to be 30% or less of the diagonal length of the light emitting surface 141 of the light emitting element 140 (preferably 3% or less of the diagonal length, and more preferably 1% or less).

The sidewall 123 of the opening 121 of the front panel 120 may be configured to have a high light reflectance, such as white, in order to allow the light emitted by the light emitting element 140 to enter the light guide 810 more efficiently. For example, the front panel 120 including the sidewall 123 of the opening 121 may be formed of a white resin. Also, for example, at least the sidewall 123 of the opening 121 of the front panel 120 may be painted white, or a metal such as aluminum may be formed on the sidewall 123 of the opening 121. For example, the sidewall 123 of the opening 121 may have a higher light reflectance than the surface 131 of the substrate 130. Here, the light reflectance of the surface 131 of the substrate 130 does not include the above-mentioned wiring pattern and may be the light reflectance of an insulating resist.

If the sidewall 123 of the opening 121 of the front panel 120 is configured to easily reflect light, such as white, the above-mentioned ventilation portion 910 may be a portion that does not easily reflect light. Therefore, if the proportion of the ventilation portion 910 occupies in the inner wall of the front panel 120 increases, the light emitted by the light emitting element 140 may not efficiently enter the light guide 810. In addition, if the light emitted from the light emitting element 140 passes through the ventilation portion 910, it may become stray light. Therefore, the area of the ventilation portion 910 arranged in the opening 121 may be 20% or less of the area of the sidewall 123 of the opening 121 of the front panel 120. Furthermore, in order to reflect light more on the sidewall 123 of the opening 121 and suppress stray light, the area of the ventilation portion 910 arranged in the opening 121 may be 10% or less of the area of the sidewall 123 of the opening 121 of the front panel 120. Here, the area of the ventilation section 910 refers to the area of the hole on the side wall 123 side of the opening 121 when a hole is provided in the front panel 120. Also, when a groove is provided in the front panel 120, the area refers to the area of the opening 121 on the side wall 123 side that is surrounded by the straight line and the groove when linearly interpolating between the portions of the side wall 123 where no groove is provided.

On the other hand, as described above, the ventilation section 910 needs to release the air between the light emitting element 140 and the light guide 810 to the outside and allow the outside air to flow in. The inventors conducted an experiment and found that the effect of providing the ventilation section 910 can be obtained when the area of the ventilation section 910 arranged on the side wall 123 of the opening 121 of the front panel 120 is 1% or more of the area of the side wall 123 of the opening 121 of the front panel 120. Furthermore, it was found that a higher effect can be obtained when the area of the ventilation section 910 arranged on the side wall 123 of the opening 121 of the front panel 120 is 2% or more of the area of the side wall 123 of the opening 121 of the front panel 120. From the above, the area of the ventilation section 910 arranged on the side wall 123 of the opening 121 of the front panel 120 may be 1% or more and 20% or less, or may be 2% or more and 10% or less of the area of the side wall 123 of the opening 121 of the front panel 120.

As described above, when light emitted from the light emitting element 140 enters the ventilation portion 910, it may become stray light. Therefore, in the example shown in FIG. 9(a), the groove is straight (linear), but as shown in FIG. 9(c), the ventilation portion 910 may be bent in an orthogonal projection onto the surface 131 of the substrate 130. By bending the ventilation portion 910, the possibility that light that enters the ventilation portion 910 passes through the ventilation portion 910 is reduced. Furthermore, as shown in the cross-sectional view of FIG. 9(d), when a groove is formed as the ventilation portion 910 in a portion facing the surface 131 of the substrate 130 of the front panel 120, the ventilation portion 910 may be bent according to the step of the light emitting element 140. FIG. 9(c) shows a structure that is bent once or twice at a right angle as the bending structure of the ventilation portion 910, but is not limited to these shapes and may have various shapes. When bending the ventilation section 910, the grooves shown in Figures 9(a) and 9(d) may reduce the number of steps and improve ease of formation when fabricating the front panel 120, compared to the through holes shown in Figure 9(b).

In addition, for example, regardless of whether the ventilation section 910 is bent or not, the inner wall of the ventilation section 910 may be a color with low light reflectance, such as black. This makes it possible to suppress stray light passing through the ventilation section 910 provided in the front panel 120.

In addition, the sidewall 123 of the opening 121 of the front panel 120 does not have to be a color with high reflectance such as white. The sidewall 123 of the opening 121 of the front panel 120 may be a color with low reflectance such as black. For example, the sidewall 123 of the opening 121 may have a lower light reflectance than the surface 131 of the substrate 130. Here, the light reflectance of the surface 131 of the substrate 130 may be the light reflectance of an insulating resist without including the above-mentioned wiring pattern. When the ventilation section 910 is arranged on the sidewall 123 of the opening 121 of the front panel 120, it may be easier to design the front panel 120 against the above-mentioned stray light, etc., if the reflectance of the sidewall 123 of the opening 121 of the front panel 120 is low. In addition, even if the ventilation section 910 is not provided, the sidewall 123 of the opening 121 of the front panel 120 may be a color with low reflectance.

Also, as shown in FIG. 8, a light-transmitting member 830 may be disposed in the opening 121 of the front panel 120. The light-transmitting member 830 may have, for example, the function of an optical filter. That is, the light-transmitting member 830 may function so that appropriate light emitted by the LED chip 143 or the light-emitting element 140 (the combination of the LED chip 143 and the resin 144) enters the light guide 810, as in the relationship between the LED chip 143 and the resin 144 described above. For example, an appropriate phosphor may be dispersed in the light-transmitting member 830. Also, for example, the light-transmitting member 830 may have the function of a lens. Also, the light-transmitting member 830 may have the function of suppressing the transmission of heat, like heat-cutting glass. Two or more of these functions of the light-transmitting member 830 may be combined.

The lighting device 800 incorporating the light-emitting unit 100 of this embodiment shown in FIG. 8 can further be incorporated into a reading device. FIG. 10 is a schematic diagram of a recording system 1000 including a reading device 1100 incorporating the above-mentioned lighting device 800. The recording system 1000 includes a copier, a printer, and a data recording device that records data on a hard disk or memory. FIG. 10 shows an example of the recording system 1000 in which a copier, a printer, or the like records data on paper media.

The recording system 1000 shown in FIG. 10 includes a reading device 1100 incorporating an illumination device 800 for reading a medium, a recording device 1200 for recording on the recording medium based on image information acquired by the reading device 1100, and a transport device 1300 for transporting the recording medium. Here, the reading device 1100 includes an illumination device 800 incorporating a light-emitting unit 100, and an image sensor 1101 for acquiring image information of an object illuminated by the illumination device 800.

The recording device 1200 can record images including characters on the recording medium 1400 (e.g., paper) by any method such as an inkjet method or an electrophotographic method. The conveying device 1300 can be a conveying roller that conveys the recording medium from upstream to downstream. In one embodiment, the recording system 1000 can perform a copy process, and in this case, the recording device 1200 records the image information read by the reading device 1100 as an image on the recording medium. In one embodiment, the recording system 1000 can perform feedback control. For example, the reading device 1100 can read image information on the recording medium after recording by the recording device 1200 and transmit it to the recording device 1200 as read data. Based on this read data, the recording device 1200 can check the recording state on the recording medium and control the recording parameters for the next recording.

The recording system 1000 to which the reading device 1100 including the illumination device 800 incorporating the light-emitting unit 100 of this embodiment is applied is not limited to a device that records on a recording medium 1400 such as paper, as described above. The recording device 1200 may record image information read by the reading device 1100 as electronic data on a recording medium such as a hard disk or memory. In this case, the recording device 1200 may include a recording medium such as a hard disk or memory. In this case, the recording system 1000 may not include the above-mentioned conveying device 1300.

Here, modified examples of the back panel 160 will be described. FIGS. 11(a) and 11(b) are perspective views showing an example of the configuration of a light-emitting unit 100 equipped with a modified back panel 160, corresponding to the above-mentioned FIGS. 1(a) and 1(b). Similarly, FIGS. 12(a) and 12(b) are exploded perspective views showing an example of the configuration of a light-emitting unit 100 equipped with a modified back panel 160, corresponding to the above-mentioned FIGS. 2(a) and 2(b).

11(a) to 12(b), the back panel 160 may further include a protruding portion 165 that protrudes outward beyond the outer edge of the substrate 130 in orthogonal projection onto the surface 131 of the substrate 130. The protruding portion 165 may protrude outward beyond the outer edge of the front panel 120 in orthogonal projection onto the surface 131 of the substrate 130. By providing the back panel 160 with the protruding portion 165, not only is the area of the back panel 160 increased, but heat dissipation is also possible from a portion of the surface of the back panel 160 that faces the surface 132 of the substrate 130. In other words, it is possible to further improve the effect of heat dissipation from the back panel 160 to the atmosphere. The protruding portion 165 may be flat, or may include a portion 165a that protrudes in a direction along the surface 132 of the substrate 130 and a portion 165b that is bent from the portion 165a toward the surface 131 of the substrate 130, as shown in FIG. 13(a). For example, the portion 165b of the protruding portion 165 may be arranged to cover the outer wall of the front panel 120, as shown in FIG. 13(a).

As shown in Figures 11(a) to 12(b), the protruding portion 165 does not have to be in contact with the surface 131 of the substrate 130, the light-emitting element 140, and the front panel 120. As described above, by providing the protruding portion 161 and the like, the back panel 160 can efficiently transfer heat generated by the light-emitting element 140 arranged on the surface 131 of the substrate 130 to the surface 132 of the substrate 130, and dissipate the heat from the back panel 160. In addition, the protruding portion 165 may be in contact with at least one of the surface 131 of the substrate 130, the light-emitting element 140, and the front panel 120.

14(a) is a diagram showing an example of the configuration of a lighting device 800 incorporating a light-emitting unit 100 including a back panel 160 with a protruding portion 165. The substrate 130 may be a flexible substrate as shown in FIG. 14(a). As shown in FIG. 11(a) to FIG. 12(b) and FIG. 14(a), the substrate 130 has a shape having a longitudinal direction (Z direction) and a lateral direction (Y direction) intersecting the longitudinal direction. In this case, the front panel 120 and the back panel 160 may be arranged at one end of the substrate 130 in the longitudinal direction. In addition, as shown in FIG. 11(a) to FIG. 12(b), a plurality of electrodes 133a to 133c are arranged at the other end of the substrate 130 in the longitudinal direction. The plurality of electrodes 133a to 133c are connected to a power supply unit 840 provided on a frame 820 of the lighting device 800 as shown in FIG. 14(a).

In this case, as shown in Figs. 11(a) to 12(b) and 14(a), the protruding portion 165 protrudes in the longitudinal direction from an end edge along the short side of one end of the longitudinal direction of the substrate 130. At this time, the back panel 160 may be electrically connected to one electrode 133a among the multiple electrodes 133a to 133c. In the configuration shown in Figs. 11(b) and 12(b), the connection terminal 166 provided on the back panel 160 contacts the pad 135 provided at the end of the wiring pattern 134, and the back panel 160 is electrically connected to the electrode 133a. As shown in Figs. 11(b) and 12(b), the wiring pattern 134 may be arranged on the surface 132 or the surface 131 of the substrate 130, or, if the substrate 130 has a laminated structure, may be arranged on any layer between the surface 131 and the surface 132. As described above, the substrate 130 has a wiring pattern (conductor, not shown) for supplying power from the power supply unit 840 to the light-emitting element 140. The wiring pattern for supplying power to the light-emitting element 140 can be connected to electrodes 133b and 133c other than the electrode 133a electrically connected to the back panel 160. In the configuration shown in FIGS. 11(a) to 12(b), three electrodes 133a to 133c are arranged, but this is not limited thereto, and the substrate 130 may have four or more electrodes arranged thereon.

The position of the protrusion 165 and the electrical connection to the electrode 133a as described above effectively suppresses damage to the light emitting element 140 and/or the drive circuit (power supply unit 840 in the configuration shown in FIG. 14(a)) that controls the amount of power supplied to the light emitting element 140 due to static electricity, in addition to heat dissipation, in the reading device 1100 equipped with the lighting device 800 in which the light emitting unit 100 is incorporated. Specifically, as shown in FIG. 14(b), in the reading device 1100 used in the recording system 1000 using paper, film, etc. as the recording medium 1400, the recording medium 1400 may be disposed in contact with or close to the reading device 1100. At this time, for example, the recording medium 1400 may be moved by the conveying device 1300, similar to the recording system 1000 shown in FIG. 10. Also, for example, a user of the recording system 1000 may place the recording medium 1400 on the reading device 1100 and remove the recording medium 1400 after use. When the recording medium 1400 moves in this manner, static electricity may be generated in the reading device 1100.

As shown in FIG. 14(b), the reading device 1100 may include an illumination device 800, an image sensor 1101, and a housing 1102 that houses the illumination device 800 and the image sensor 1101. At this time, the illumination device 800 illuminates the recording medium 1400, which is the object to be illuminated, through a window 1103 provided in the housing 1102. The window 1103 provided in the housing 1102 is often made of a dielectric material such as glass or transparent resin, and static electricity may be generated by the movement of the recording medium 1400. This static electricity may damage the light-emitting element 140 of the light-emitting unit 100 of the illumination device 800 and/or the drive circuit (power supply unit 840) that controls the amount of power supplied to the light-emitting element 140.

Therefore, as shown in FIG. 14(b), the protruding portion 165 of the back panel 160 of the light-emitting unit 100 is arranged so as to protrude from the outer edge of the substrate 130 toward the window 1103 of the reading device 1100. The back panel 160 is also connected to the electrode 133a as described above. At this time, the electrode 133a to which the back panel 160 is electrically connected is connected to the ground terminal (ground terminal) of the power supply unit 840. In other words, the back panel 160 is grounded. This allows the protruding portion 165 to function as a lightning rod, and the static electricity generated at the window 1103 can be transmitted from the back panel 160 to the substrate 130 without passing through the light-emitting element 140. In this case, as described above, the electrode 133a may be electrically connected to the back panel 160 and not electrically connected to the light-emitting element 140. In other words, the supply of power to the light-emitting element 140 may be performed using the electrode 133b and the electrode 133c. This makes it possible to separate the path through which static electricity passes via the back panel 160 from the path through which power is supplied to the light-emitting element 140, and prevents static electricity generated at the window 1103 from passing through the light-emitting element 140. As a result, the protruding portion 165 of the back panel 160 not only effectively dissipates heat, but can also be used to prevent damage caused by static electricity to the light-emitting element 140 and/or the drive circuit (power supply unit 840) that controls the amount of power supplied to the light-emitting element. In other words, it is possible to improve the reliability of the light-emitting unit 100, the lighting device 800 incorporating the light-emitting unit 100, the reading device 1100 incorporating the lighting device 800, and the recording system 1000 including the reading device 1100.

The positions of the connection terminals 166 and pads 135 that electrically connect the back panel 160 and the substrate 130 may be closer to the end of the substrate 130 where the electrodes 133 are arranged than the light-emitting element 140, as shown in FIG. 12(a). However, this is not limited to this, and the back panel 160 and the substrate 130 may be electrically connected at any suitable position. For example, the connection terminals 166 and pads 135 may be arranged in a position that overlaps with the light-emitting element 140 in an orthogonal projection onto the surface 131 of the substrate 130.

Also, as shown in FIG. 13(b), the overhanging portion 165 may be arranged so that a virtual line 440 in the longitudinal direction (Z direction) passing through the light-emitting element 140 passes through the overhanging portion 165 in an orthogonal projection onto the surface 131 of the substrate 130. By arranging the overhanging portion 165 between the window 1103 of the reading device 1100 and the light-emitting element 140, the effect of static electricity on the light-emitting element 140 and/or the drive circuit (power supply unit 840) that controls the amount of power supplied to the light-emitting element 140 can be suppressed. Also, the number of overhanging portions 165 is not limited to one. As shown in FIG. 13(c), two or more overhanging portions 165 may be arranged. In this case, the overhanging portion 165 may be arranged so that a virtual line 440 in the longitudinal direction (Z direction) passing through the light-emitting element 140 passes through one or more overhanging portions 165.

As described above, the protruding portion 165 may include a portion 165a that protrudes in a direction along the surface 132 of the substrate 130, and a portion 165b that is bent from the portion 165a toward the surface 131 of the substrate 130. In this case, as shown in FIG. 14(a), the tip of the portion 165b may be arranged so as not to protrude beyond the light emitting element 140 and the front panel 120. However, it may be designed appropriately depending on conditions such as the arrangement and shape of the light guide 810, the direction of light emission from the light guide 810, and the shape of the housing 1102 of the reading device 1100. Also, as shown in FIG. 13(c), the protruding portion 165 may not have the portion 165b that bends toward the surface 131 of the substrate 130, and may only have the portion 165a that protrudes in a direction along the surface 132 of the substrate 130.

15A shows an example of the numerical value of the electrical resistance of the back panel 160 using a metal material as described above, and an example of the numerical value of the electrical resistance of the front panel 120 using a resin material as described above. In order to prevent static electricity transmitted to the back panel 160 from being transmitted to the light-emitting element 140 via the front panel 120, an R ratio obtained by dividing the resistance value of the front panel 120 by the resistance value of the back panel 160 may satisfy the following formula (1).
1.0×10 ³ <R ratio<1.0×10 ³⁰ ... (1)
15A each satisfy the formula (1). Furthermore, the R ratio may satisfy the following formula (1a).
1.0×10 ¹⁵ <R ratio<1.0×10 ²⁵ ... (1a)
Numerical examples 1 and 4 in FIG. 15A satisfy formula (1a).

15B shows an example of the thermal conductivity of the back panel 160 using a metal material as described above, and an example of the thermal conductivity of the front panel 120 using a resin material as described above. It is necessary to efficiently transfer the heat generated by the light emitting element 140 arranged on the surface 131 of the substrate 130 to the surface 132 of the substrate 130 and dissipate the heat from the back panel 160. In other words, it is necessary to make it difficult for the heat generated by the light emitting element 140 to be transferred from the front panel 120 to the light guide 810, etc. In order to more efficiently transfer heat from the front panel 120 to the back panel 160, the C ratio obtained by dividing the thermal conductivity of the front panel 120 by the thermal conductivity of the back panel 160 may satisfy the following formula (2).
1.0×10 ^-7 <C ratio <1.0... (2)
15B, the combinations of numerical examples 1 to 4 each satisfy formula (2). Furthermore, the C ratio may satisfy the following formula (2a).
1.0×10 ^-4 <C ratio<1.0×10 ^-1 ... (2a)
Numerical examples 1 to 3 in FIG. 15B satisfy formula (2a).

As described above, the light-emitting unit 100 of this embodiment can efficiently transfer heat generated from the light-emitting element 140, which is a light source, to the surface 132 of the substrate 130 opposite the surface 131 on which the light-emitting element 140 is arranged, and dissipate the heat. This makes it possible to improve the reliability of the light-emitting unit 100 of this embodiment, the illumination device 800 incorporating the light-emitting unit 100, the reading device 1100 incorporating the illumination device 800, and the recording system 1000 including the reading device 1100.

The invention is not limited to the above-described embodiment, and various modifications and variations are possible within the scope of the invention.

100: Light emitting unit, 120: Front panel, 121: Opening, 130: Substrate, 131, 132: Surface, 140: Light emitting element, 141: Light emitting surface, 160: Back panel, 161: Protrusion

Claims (37)

A light-emitting unit including a substrate, a light-emitting element disposed on a first surface of the substrate, a front panel covering the first surface, and a back panel disposed on a second surface side of the substrate opposite to the first surface,
the front panel is provided with an opening for extracting light emitted by the light-emitting element,
the opening is arranged to overlap a portion of a light emission surface of the light emitting element in an orthogonal projection onto the first surface,
The back panel comprises:
It has a higher thermal conductivity than the front panel,
A protrusion protruding toward the first surface side is provided,
the protrusion is in contact with at least one of the first surface, the light-emitting element, and the front panel;
The light emitting unit according to claim 1, wherein the protrusion includes a fitting portion that fits with the front panel . an inner wall of the front panel including a side wall of the opening is provided with a ventilation portion including at least one of a groove and a through hole extending from the inner wall to an outer edge of the front panel;
2 . The light-emitting unit according to claim 1 , wherein an area of the ventilation portion disposed on the side wall of the opening is 1% or more and 20% or less of an area of the side wall of the opening. A light-emitting unit including a substrate, a light-emitting element disposed on a first surface of the substrate, a front panel covering the first surface, and a back panel disposed on a second surface side of the substrate opposite to the first surface,
the back panel has a higher thermal conductivity than the front panel;
the front panel is provided with an opening for extracting light emitted by the light-emitting element,
an inner wall of the front panel including a side wall of the opening is provided with a ventilation portion including at least one of a groove and a through hole extending from the inner wall to an outer edge of the front panel;
an area of the ventilation portion disposed on the side wall of the opening is 1% or more and 20% or less of an area of the side wall of the opening,
the back panel includes a protruding portion protruding beyond the first surface from the second surface side,
the protrusion is in contact with at least one of the first surface, the light-emitting element, and the front panel;
The light emitting unit according to claim 1, wherein the protrusion includes a fitting portion that fits with the front panel . The light-emitting unit according to claim 3, characterized in that, in orthogonal projection onto the first surface, the opening is arranged to overlap a portion of the light-emitting surface of the light-emitting element. the ventilation portion is a groove that extends from the inner wall to an outer edge of the front panel,
5. The light-emitting unit according to claim 2, wherein the groove is disposed in a portion of the front panel facing the first surface. 6. The light-emitting unit according to claim 2 , wherein the ventilation portion is bent. 4. The light-emitting unit according to claim 1, wherein the protrusion protrudes toward the first surface from outside an outer edge of the substrate. the ventilation portion is a groove that extends from the inner wall to an outer edge of the front panel,
the groove is disposed in a portion of the front panel facing the first surface,
4. The light-emitting unit according to claim 2 , wherein the protrusion protrudes toward the first surface from outside an outer edge of the substrate. The ventilation portion is bent,
4. The light-emitting unit according to claim 2 , wherein the protrusion protrudes toward the first surface from outside an outer edge of the substrate. The protruding portion is a first protruding portion,
The back panel further includes a second protruding portion that penetrates the substrate and protrudes toward the first surface,
10. The light-emitting unit according to claim 7 , wherein the second protrusion is in contact with at least one of the first surface, the light-emitting element, and the front panel. 4. The light-emitting unit according to claim 1, wherein the protrusion penetrates the substrate and protrudes toward the first surface side. the ventilation portion is a groove that extends from the inner wall to an outer edge of the front panel,
the groove is disposed in a portion of the front panel facing the first surface,
4. The light-emitting unit according to claim 2 , wherein the protrusion penetrates the substrate and protrudes toward the first surface side. 13. The light-emitting unit according to claim 8, wherein the ventilation portion is bent. The ventilation portion is bent,
4. The light-emitting unit according to claim 2 , wherein the protrusion penetrates the substrate and protrudes toward the first surface side. The protrusion includes two of the engagement portions,
The light-emitting unit according to claim 1 , wherein, in an orthogonal projection onto the first surface, a virtual line connecting the two joint portions passes through the light-emitting element. 16. The light-emitting unit according to claim 15 , wherein the imaginary lines include imaginary lines parallel to a line connecting two opposing outer edges of the substrate at the shortest distance. When a direction in which the two joint portions and the light emitting element are arranged is defined as a first direction, and a direction intersecting the first direction is defined as a second direction,
17. The light-emitting unit according to claim 15 , wherein the length of the engagement portion along the second direction is equal to or greater than one-third of the length of the light-emitting element along the second direction. 18. The light-emitting unit according to claim 1, wherein the front panel has a protrusion penetrating the substrate and protruding toward the second surface side. 20. The light-emitting unit according to claim 18 , wherein the protrusion penetrates the back panel and protrudes from the back panel. 20. The light-emitting unit according to claim 1, wherein a light-transmitting member is disposed in the opening of the front panel. 21. The light-emitting unit according to claim 1, further comprising a flexible member between the back panel and the second surface, the flexible member having a higher thermal conductivity than the front panel. the flexible member includes an extension portion extending from the second surface to a side of the first surface through an outer edge of the substrate,
The light-emitting unit according to claim 21 , wherein the extension portion is in contact with at least one of the first surface, the light-emitting element, and the front panel. The light-emitting unit according to claim 1 , wherein, in an orthogonal projection onto the second surface, the back panel has an opening through which the substrate is exposed on an inner side than an outer edge of the back panel. 24. The light-emitting unit according to claim 1, wherein an outer edge of the back panel has a recess disposed inwardly of an outer edge of the substrate in an orthogonal projection onto the second surface. 25. The light-emitting unit according to claim 1, wherein a side wall of the opening has a higher light reflectance than the first surface. 25. The light-emitting unit according to claim 1, wherein a side wall of the opening has a lower light reflectance than the first surface. 27. The light-emitting unit according to claim 1, wherein the back panel further includes a protruding portion that protrudes outward beyond an outer edge of the substrate in an orthogonal projection onto the first surface. 28. The light-emitting unit according to claim 27 , wherein the protruding portion is not in contact with the first surface, the light-emitting element, or the front panel. the substrate has a shape having a longitudinal direction and a lateral direction intersecting the longitudinal direction,
the front panel and the back panel are disposed at one end of the substrate in the longitudinal direction,
29. The light-emitting unit according to claim 27 , wherein the protruding portion protrudes in the longitudinal direction from an end side along the short direction of one end of the longitudinal direction of the substrate. A plurality of electrodes are disposed on the other end of the substrate in the longitudinal direction,
30. The light-emitting unit according to claim 29 , wherein the back panel and one of the plurality of electrodes are electrically connected to each other. The light-emitting unit described in claim 29 or 30, characterized in that the protrusion portion includes a first portion protruding in a direction along the second surface and a second portion bent from the first portion toward the first surface . 32. The light-emitting unit according to claim 29, wherein, in an orthogonal projection onto the first surface, the imaginary line in the longitudinal direction passing through the light-emitting element passes through the protruding portion. A light-emitting unit according to any one of claims 1 to 32 ;
A light guide that guides light emitted from the light emitting unit;
a frame that accommodates the light emitting unit and the light guide;
A lighting device comprising: A lighting device according to claim 33 ;
an image sensor for acquiring image information of an object illuminated by the illumination device;
A reading device comprising: A lighting device including the light-emitting unit according to any one of claims 27 to 32 , a light guide that guides light emitted from the light-emitting unit, and a frame that accommodates the light-emitting unit and the light guide;
an image sensor for acquiring image information of an object illuminated by the illumination device;
a housing that houses the illumination device and the image sensor;
A reading device comprising:
the lighting device illuminates an object to be illuminated through a window provided in the housing;
A reading device, characterized in that the protruding portion protrudes from an outer edge of the substrate toward the window side. 36. A reading device according to claim 34 or 35 , characterized in that the back panel is grounded. A reading device according to any one of claims 34 to 36 ,
a recording device that records the image information acquired by the reading device on a recording medium;
A recording system comprising:

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