Outdoor unit

Abstract

To improve the degree of freedom in designing a substrate on which an LED is provided.SOLUTION: An outdoor unit of an air conditioner (1) includes: a casing (30) in which an opening (35) for maintenance is formed; and a substrate (42) which is arranged in the casing (30) and has a first surface (42a) on which an electric component (41) is arranged and a second surface (42b) facing the opening (35). The substrate (42) includes: a light-transmitting region (60) through which light is transmitted from the first surface (42a) to the second surface (42b) when the second surface (42b) is viewed from the front; and a first light source (46) provided on the first surface (42a). The first light source (46) is a surface-mounted LED which emits light toward the light-transmitting region (60).SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] This disclosure relates to an outdoor unit.

Background Art

[0002] The outdoor unit of the air conditioner described in Patent Document 1 includes a substrate having an LED for failure diagnosis provided on the mounting surface and a reflecting portion that reflects the light of the LED. The reflecting portion is provided so as to reflect the light of the LED toward the inspection port.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, as a method of visually recognizing the light of the LED on the substrate, there is a method of transmitting the light of the LED in the thickness direction of the substrate toward the solder surface, which is the back surface of the mounting surface on which the lead-type LED is mounted. In this method, grooves may be provided on the mounting surface so that a part of the substrate becomes thin. By emitting light toward this groove, it becomes easier to visually recognize the light of the LED that passes through the substrate.

[0005] However, for example, in order to mount a lead-type LED, it is necessary to perform soldering on the solder surface. Furthermore, when grooves are provided on the mounting surface where the substrate becomes thin, that portion cannot be effectively utilized. Thus, when an LED is provided on the substrate, the design freedom of the substrate cannot be said to be sufficient.

[0006] An object of this disclosure is to improve the design freedom of the substrate on which the LED is provided.

Means for Solving the Problems

[0007] The first aspect is An outdoor unit of an air conditioning system (1), A casing (30) having a maintenance opening (35) formed therein, The substrate (42) is disposed within the casing (30) and has a first surface (42a) on which predetermined electrical components (41) are arranged, and a second surface (42b) facing the opening (35), The aforementioned substrate (42) is When the second surface (42b) is viewed from the front, there is a light-transmitting region (60) through which light is transmitted from the first surface (42a) toward the second surface (42b), The first surface (42a) is provided with a first light source (46), The first light source (46) is an outdoor unit which is a surface-mount LED that emits light toward the light-transmitting region (60).

[0008] In the first embodiment, by using a surface-mount LED as the first light source (46), soldering on the second surface (42b) becomes unnecessary, and the need to provide a thin-walled portion, as is required when mounting a lead-type LED, is eliminated. As a result, the substrate (42) can be used effectively.

[0009] A second aspect is, in the first aspect, The light-transmitting region (60) is a region between the first surface (42a) and the second surface (42b) where no light-transmitting suppressing material (50a, 50b) is provided to suppress light transmission.

[0010] In the second embodiment, the areas where the light-transmitting inhibitors (50a, 50b) are not provided can be made into light-transmitting areas. As a result, the light from the first light source (46) emitted toward the areas where the light-transmitting inhibitors (50a, 50b) are not provided passes through the substrate (42), so that the light from the first light source (46) can be seen when the second surface (42b) is viewed from the front.

[0011] A third aspect is a manifestation of the first or second aspect, The first light source (46) is A light-emitting section (46a) having an LED element, The device comprises a light-emitting substrate (46b) provided on the first surface (42a) and controlling the light emission of the light-emitting section (46a), The light-emitting portion (46a) is arranged adjacent to the light-emitting substrate (46b) in a direction along the first surface (42a).

[0012] In the third embodiment, a chip LED side-emitting type can be used as the first light source (46).

[0013] A fourth aspect is a modification of the first or second aspect, The first light source (46) is A light-emitting section (46a) having an LED element, The system includes a light-emitting substrate (46b) that controls the light emission of the light-emitting section (46a), The light-emitting portion (46a) is positioned between the first surface (42a) and the light-emitting substrate (46b).

[0014] In the fourth embodiment, a chip LED back-emitting type can be used as the first light source (46).

[0015] The fifth aspect is one of the first to fourth aspects, A second light source (47) is positioned on the first surface (42a) at a predetermined distance from the first light source (46) and emits light toward the first surface (42a), The device further comprises a light-transmitting suppressing material that suppresses light transmission between the first surface (42a) and the second surface (42b), The light-transmitting materials (50a, 50b) suppress light transmission between the first surface (42a) and the second surface (42b) due to the light emitted from the second light source (47).

[0016] In the fifth embodiment, even if the first light source (46) and the second light source (47) are mounted on the first surface (42a), the light from the second light source (47) does not pass through the substrate (42) due to the light transmission suppression material (50a, 50b), so that only the light from the first light source (46) is visible when the second surface (42b) is viewed from the front. This prevents, for example, a service technician from mistaking the first light source (46) for the second light source (47).

Brief Description of the Drawings

[0017] [Figure 1] FIG. 1 is a piping system diagram of the air conditioner according to the present embodiment. [Figure 2] FIG. 2 is a plan sectional view showing the configuration of the outdoor unit. [Figure 3] FIG. 3 is a front sectional view showing the configuration of the outdoor unit. [Figure 4] FIG. 4 is a longitudinal sectional view showing the configuration of the electrical component unit. [Figure 5] FIG. 5 is a partially enlarged view of the substrate seen from the pattern surface. [Figure 6] FIG. 6 is a view of the surface-mounted LED mounted on the substrate seen from the side. [Figure 7] FIG. 7 is a view of two surface-mounted LEDs mounted on the substrate according to the modified example seen from the side. [Figure 8] FIG. 8 is a view showing the state where the surface-mounted LED of other embodiments is mounted on the substrate.

Modes for Carrying Out the Invention

[0018] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following embodiments are essentially preferred examples and are not intended to limit the scope of the present invention, its applications, or its uses. Also, the respective configurations of the following embodiments, modified examples, other examples, etc. can be combined or partially replaced within the scope where the present invention can be implemented. In the following drawings, the directions of up and down, front and back, left and right are indicated by arrows. Unless otherwise specified, the directions of up and down, etc. will be described according to the directions indicated by these arrows.

[0019] (1) Configuration of the Air Conditioner As shown in Figure 1, the air conditioning system (1) has a refrigerant circuit (5) that performs a refrigeration cycle by circulating a refrigerant. The air conditioning system (1) has an indoor unit (10) and an outdoor unit (20). The indoor unit (10) is installed indoors. The outdoor unit (20) is installed outdoors. The indoor unit (10) and the outdoor unit (20) are connected to each other by gas piping (6) and liquid piping (7). A gas shut-off valve (8) is connected to the gas piping (6). A liquid shut-off valve (9) is connected to the liquid piping (7).

[0020] (2) Indoor unit The indoor unit (10) includes an indoor heat exchanger (11) and an indoor fan (12). The indoor heat exchanger (11) is composed of, for example, a cross-fin type fin-and-tube heat exchanger. In the indoor heat exchanger (11), heat is exchanged between the refrigerant flowing inside its heat transfer tubes and the air blown by the indoor fan (12).

[0021] (3) Outdoor unit As shown in Figures 1 to 3, the outdoor unit (20) includes an outdoor heat exchanger (21), an outdoor fan (22), an outdoor expansion valve (23), a compressor (24), a four-way switching valve (25), and an electrical components unit (40). The outdoor heat exchanger (21), outdoor expansion valve (23), compressor (24), and four-way switching valve (25) are connected by refrigerant piping (26).

[0022] The outdoor heat exchanger (21) is composed of, for example, a cross-fin type fin-and-tube heat exchanger. The outdoor heat exchanger (21) has a plurality of fins (21a) and heat transfer tubes (21b). The plurality of fins (21a) are spaced apart in a direction perpendicular to the airflow direction. The heat transfer tubes (21b) extend through the fins (21a) in the thickness direction. The heat transfer tubes (21b) are arranged in multiple stages in the vertical direction.

[0023] In the outdoor heat exchanger (21), heat is exchanged between the refrigerant flowing inside the heat transfer tubes (21b) and the air blown by the outdoor fan (22). The outdoor expansion valve (23) is composed of, for example, an electronic expansion valve.

[0024] The compressor (24) is composed of a rotary compressor, such as a scroll compressor. The four-way switching valve (25) is a switching valve that switches between cooling operation and heating operation. During cooling operation, the first port (P1) and the second port (P2) of the four-way switching valve (25) are in communication, and the third port (P3) and the fourth port (P4) are in communication (shown by the solid line in Figure 1). During heating operation, the first port (P1) and the third port (P3) of the four-way switching valve (25) are in communication, and the second port (P2) and the fourth port (P4) are in communication (shown by the dashed line in Figure 1).

[0025] The outdoor unit (20) has a casing (30). The casing (30) has a main casing (30a) and a top plate (30b). The main casing (30a) is formed in the shape of a box with an open top. In other words, the top surface of the main casing (30a) has an opening (35). The top plate (30b) is attached to the main casing (30a) so as to close the opening (35) of the main casing (30a). The top plate (30b) is detachable from the main casing (30a). The opening (35) of the main casing (30a) is an example of an opening (35) for maintenance of the outdoor unit (20).

[0026] A partition member (31) extending in the front-to-back and up-to-down directions is arranged inside the main casing (30a). The partition member (31) divides the inside of the main casing (30a) into a machine room (32) and a blower room (33).

[0027] The machine room (32) is the space to the right of the partition member (31) inside the main casing (30a). The machine room (32) houses the compressor (24), the four-way switching valve (25), the refrigerant piping (26), and the electrical equipment unit (40).

[0028] The blower room (33) is the space to the left of the partition member (31) inside the main casing (30a). The outdoor fan (22) and the outdoor heat exchanger (21) are located in the blower room (33).

[0029] Intake ports (30c) communicating with the blower chamber (33) are formed on the rear and left side walls of the main casing (30a). When the outdoor fan (22) is driven, outside air is drawn into the blower chamber (33) from the intake ports (30c). An outlet port (30d) communicating with the blower chamber (33) is formed on the front wall of the main casing (30a). When the outdoor fan (22) is driven, the air inside the blower chamber (33) is blown out to the outside from the outlet port (30d).

[0030] (4) Electrical components unit The electrical component unit (40) constitutes a power conversion device for supplying power to the motor of the compressor (24). As shown in Figures 2 to 4, the electrical component unit (40) has a circuit board casing (43), predetermined electrical components (41), a circuit board (42), and a surface-mount LED (46). The electrical component unit (40) is located near the top plate (30b) on the machine room (32) side.

[0031] The circuit board casing (43) is a box-shaped member having an opening at the top. The circuit board casing (43) houses various electrical components (41), including a circuit board (42). In this embodiment, there is one circuit board (42) placed in the circuit board casing (43). The opening at the top of the circuit board casing (43) faces the bottom surface of the top plate (30b).

[0032] The electrical components (41) are mounted on the circuit board (42). The electrical components (41) include power transistors and control circuit components such as a microcomputer chip for controlling the device and memory for storing control programs.

[0033] A heat sink (not shown) is provided to suppress the temperature rise of electrical components (41) that generate relatively large amounts of heat, such as power transistors. The heat sink is made of a metal material.

[0034] (4-1) Circuit board As shown in Figure 4, the substrate (42) has a mounting surface (42a) and a pattern surface (42b). The mounting surface (42a) is an example of a first surface (42a). The pattern surface (42b) is an example of a second surface (42b). The substrate (42) is positioned so that the pattern surface (42b) faces the opening (35) of the main casing (30a). In other words, the substrate (42) is positioned so that the pattern surface (42b) faces upward and the mounting surface (42a) faces downward. The substrate (42) in this embodiment is single-layer.

[0035] Electrical components (41) and surface-mount LEDs (46) are arranged on the mounting surface (42a). Details of the surface-mount LEDs (46) will be described later. Various connectors (44) are also mounted on the mounting surface (42a). The connectors (44) are used, for example, to connect the output (AC power) of an inverter circuit (not shown) to a load (motor).

[0036] Multiple through-holes (hereinafter referred to as through-holes (42c)) are formed in the circuit board (42). The through-holes (42c) are formed for purposes such as providing electrical conductivity between the mounting surface (42a) and the pattern surface (42b). The terminals of the electrical components (41) are soldered to the wiring patterns on the circuit board (42).

[0037] As shown in Figure 5, a wiring pattern (50a) is formed on the pattern surface (42b). A predetermined circuit is formed when various electrical components (41) are electrically connected to the wiring pattern (50a). Silk (50b) is applied to the pattern surface (42b). Silk (50b) is a paint used to label predetermined information on the pattern surface (42b), such as component numbers, manufacturer logos, and manufacturing dates. The wiring pattern (50a) and silk (50b) are examples of light-transmitting materials (50a, 50b). Light-transmitting materials (50a, 50b) suppress the transmission of light between the mounting surface (42a) and the pattern surface (42b).

[0038] As shown in Figures 5 and 6, the substrate (42) has a light-transmitting region (60). The light-transmitting region (60) is the region through which light is transmitted from the mounting surface (42a) towards the pattern surface (42b) when viewed from the front with the pattern surface (42b) facing forward. In other words, the light-transmitting region (60) is the region where pattern wiring or silk screen, which are light-transmitting inhibitors (50a, 50b), are not provided.

[0039] (4-2) Surface-mount LEDs The surface-mount LED (46) is a light source that notifies service personnel of the microcontroller operation, communication status, or abnormal condition of the circuit board (42). The surface-mount LED (46) is a chip LED provided on the mounting surface (42a). In this embodiment, the surface-mount LED (46) blinks when the air conditioning system (1) is operating normally. The surface-mount LED (46) is an example of the first light source (46).

[0040] As shown in Figure 6, the surface-mount LED (46) of this embodiment is a chip LED with side-emitting emission. Specifically, the surface-mount LED (46) has a light-emitting section (46a) and a light-emitting substrate (46b).

[0041] The light-emitting part (46a) is a component from which an LED emits light. Specifically, the light-emitting part (46a) has an LED element and a sealing resin. The LED element is encapsulated in the sealing resin. The sealing resin is a transparent or translucent resin (such as silicone or epoxy resin). The sealing resin is generally formed into a rectangular parallelepiped. The light-emitting substrate (46b) controls the light emission of the LED element of the light-emitting part (46a). The light-emitting substrate (46b) is attached to the mounting surface (42a).

[0042] The light-emitting part (46a) is positioned adjacent to the light-emitting substrate (46b) in a direction along the mounting surface (42a). As a result, the light-emitting part (46a) emits light toward the mounting surface (42a) and also in a direction along the mounting surface (42a), as indicated by the arrow in Figure 6.

[0043] The light-emitting part (46a) is positioned so as not to overlap with the wiring pattern (50a) or silkscreen (50b) when viewed from the front of the pattern surface (42b). In other words, the surface-mount LED (46) emits light toward the light-transmitting area (60). As a result, some of the light emitted from the LED from the light-emitting part (46a) is transmitted from the mounting surface (42a) toward the pattern surface (42b), and the light from the surface-mount LED can be seen from the pattern surface.

[0044] (5) Characteristics (5-1) Feature 1 In the outdoor unit (20) of this embodiment, the substrate (42) has a light-transmitting region (60) through which light is transmitted from the mounting surface (42a) (first surface) toward the pattern surface (42b) (second surface) when viewed from the front with the pattern surface (42b) (second surface), and a surface-mount type LED (46) provided on the mounting surface (42a) that emits light toward the light-transmitting region (60).

[0045] According to this embodiment, by using a surface-mount LED as the light source mounted on the mounting surface (42a), the design flexibility of the substrate (42) can be increased compared to when a leaded LED is mounted. Specifically, with a leaded LED, it is necessary to solder the two leads connected to the LED to the pattern surface (42b) via a through-hole (42c). To facilitate the transmission of light from the LED, a slit (recess) is formed on the mounting surface (42a) at a position facing the LED (specifically, between the two leads), thereby locally thinning the substrate (42). Thus, when a leaded LED is used as the light source, the usable area of ​​the mounting surface (42a) and the pattern surface (42b) is narrowed, reducing the design flexibility. However, by using a surface-mount LED (46), soldering on the pattern surface (42b) is unnecessary, and there is no need to provide a slit, so the substrate (42) can be used more effectively.

[0046] In addition, the light emitted from the surface-mount LED (46) into the light-transmitting area (60) passes through the substrate (42) in the thickness direction, allowing the light from the surface-mount LED (46) to be visible from the pattern surface (42b). Therefore, the state of the light from the surface-mount LED (46) can be checked simply by opening the top panel (30b) of the outdoor unit (20). As a result, service technicians can easily check the operation of the microcontroller on the substrate (42), the communication status, or any abnormal conditions.

[0047] (5-2) Feature 2 In the outdoor unit (20) of this embodiment, the light-transmitting region (60) is the region where the wiring pattern (50a) and silk (50b) (light-transmitting suppressing material) that suppress light transmission between the mounting surface (42a) and the pattern surface (42b) are not provided.

[0048] According to this embodiment, since the light-transmitting region (60) does not have a wiring pattern (50a) or silkscreen, the light from the surface-mount LED (46) is emitted into this region, making the light visible from the pattern surface (42b).

[0049] (5-3) Feature 3 In the outdoor unit (20) of this embodiment, the surface-mount LED (46) is a chip LED with side emission. The light emitted from the light-emitting part (46a) of the side-emitting LED toward the mounting surface (42a) can be transmitted through the substrate (42) in the thickness direction. In addition, since the LEDs used in the outdoor unit (20) can be standardized to chip LEDs with side emission, there is no need to use a different type of LED only for the LEDs provided on the substrate (42), which reduces manufacturing costs and the complexity of parts management.

[0050] (6) Variant Modifications of the outdoor unit (20) of this disclosure will be described below. A configuration different from the above embodiment will be described below.

[0051] As shown in Figure 7, two surface-mount LEDs (46, 47) are mounted on the mounting surface (42a) of the substrate (42) in this example. One surface-mount LED is designated as the first surface-mount LED (46), and the other surface-mount LED is designated as the second surface-mount LED (47). The first surface-mount LED (46) and the second surface-mount LED (47) are arranged at a predetermined distance from each other. The first surface-mount LED (46) is an example of the first light source (46). The second surface-mount LED (47) is an example of the second light source (47). The first surface-mount LED (46) and the second surface-mount LED (47) have the same configuration as the side-emitting LED in the above embodiment. The second surface-mount LED (47) has a light-emitting part (47a) and a light-emitting substrate (47b).

[0052] The first surface-mount LED (46) is a light source that notifies service personnel of the microcontroller operation, communication status, or abnormal condition of the circuit board (42). The second surface-mount LED (47) is a light source that, for example, allows the manufacturer to check the quality of the circuit board (42) during the manufacturing process. In other words, the second surface-mount LED (47) is a light source that does not need to be checked by service personnel.

[0053] In this example, the substrate (42) is provided with light-transmitting suppressing materials (50a, 50b) that suppress the transmission of light toward the mounting surface (42a) of the second surface-mount LED (47). Specifically, the light-transmitting suppressing material is silk (50b) applied to the pattern surface (42b). The silk (50b) is applied to the pattern surface (42b) at a position corresponding to the area where the second surface-mount LED (47) is placed.

[0054] Thus, even when the second surface-mount LED (47) emits light, the light directed toward the mounting surface (42a) is suppressed from passing through the substrate (42) by the silk screen (50b) (see arrow in Figure 7). As a result, service technicians can see only the first surface-mount LED (46), preventing them from mistaking the light from the first surface-mount LED (46) for the light from the second surface-mount LED (47).

[0055] (7) Other embodiments The above embodiments and their modified forms may also be configured as follows.

[0056] As shown in Figure 8, the surface-mount LED (46) may be a back-emitting chip LED. In a back-emitting LED, the light-emitting part (46a) is positioned between the light-emitting substrate (46b) and the mounting surface (42a). The light-emitting substrate (46b) is connected to the substrate (42) to conduct electricity. Light is emitted from the light-emitting part (46a) in a direction toward the mounting surface (42a) and in a direction along the mounting surface (42a) (see arrows in Figure 8). A portion of the light toward the mounting surface (42a) passes through the light-transmitting region. That is, even with a back-emitting chip LED, the light transmitted through the substrate (42) can be seen from the pattern surface (42b).

[0057] The substrate (42) may be a stack of multiple substrates (42). In this case, the light-transmitting region (60) is a region through which light passes between each layer. In other words, the light-transmitting region (60) is a region between each layer where no wiring pattern (50a) or silkscreen (50b) is provided. Therefore, even with a multilayer substrate (42), by placing a surface-mount LED (46) on the mounting surface (42a) at a position corresponding to the light-transmitting region (60), the light from the LED can be seen from the back surface (pattern surface (42b)) of the mounting surface (42a).

[0058] In the above modified example, the light-transmitting suppressing material (50a, 50b) may be a wiring pattern (50a). Specifically, the second surface-mount LED (47) may be placed on the back side (mounting side (42a)) of the wiring pattern (50a). As a result, the light traveling from the second surface-mount LED (47) to the substrate (42) is suppressed by the wiring pattern (50a) to pass through the substrate (42).

[0059] While embodiments and modifications have been described above, it will be understood that a variety of changes in form and details are possible without departing from the spirit and scope of the claims. Furthermore, these embodiments and modifications may be combined or substituted as appropriate, as long as they do not impair the functions of the subject matter of this disclosure. The terms “First,” “Second,” etc., used above are used to distinguish the phrases to which these terms are attached, and do not limit the number or order of such phrases. [Industrial applicability]

[0060] As explained above, this disclosure is useful for outdoor units. [Explanation of Symbols]

[0061] 1. Air conditioning system 20 Outdoor Units 30 Casing 35 Aperture 41 Electrical components 42 circuit boards 42a Implementation side (first side) 42b Pattern surface (2nd surface) 46 Surface-mount LED, First surface-mount LED (First light source) 46a Light-emitting part 46b Light-emitting substrate 47 2nd surface-mounted LED (2nd light source) 50a,50b Translucent suppression material 60 Translucent area

Claims

1. An outdoor unit of an air conditioning system (1), A casing (30) having a maintenance opening (35) and a removable top plate (30b) that closes the opening (35), The casing (30) has a first surface (42a) on which electrical components (41) are arranged, The present invention comprises a substrate (42) having a wiring pattern forming a predetermined circuit and a second surface (42b) facing the opening (35), The aforementioned substrate (42) is When the second surface (42b) is viewed from the front, there is a light-transmitting region (60) through which light is transmitted from the first surface (42a) toward the second surface (42b), A first light source (46) is provided on the first surface (42a), The system includes a first light source (46) and a second light source (47) provided on the first surface (42a) at a predetermined distance from the first light source (46), The first light source (46) is a surface-mount LED that emits light toward the light-transmitting region (60), The light from the first light source (46) is visible from the side where the top plate (30b) is placed. An outdoor unit characterized by the following features.

2. The light-transmitting region (60) is a region between the first surface (42a) and the second surface (42b) where no light-transmitting suppressing material (50a, 50b) is provided to suppress light transmission. The outdoor unit according to feature 1.

3. The first light source (46) is A light-emitting section (46a) having an LED element, The device comprises a light-emitting substrate (46b) provided on the first surface (42a) and controlling the light emission of the LED element, The light-emitting portion (46a) is arranged adjacent to the light-emitting substrate (46b) in a direction along the first surface (42a). The outdoor unit according to claim 1 or 2, characterized by the features described above.

4. The first light source (46) is A light-emitting section (46a) having an LED element, The device comprises a light-emitting substrate (46b) provided on the first surface (42a) and controlling the light emission of the LED element, The light-emitting portion (46a) is positioned between the first surface (42a) and the light-emitting substrate (46b). The outdoor unit according to claim 1 or 2, characterized by the features described above.

5. An outdoor unit of an air conditioning system (1), A casing (30) having a maintenance opening (35) formed therein, The casing (30) has a first surface (42a) on which electrical components (41) are arranged, The substrate (42) has a second surface (42b) facing the opening (35), The aforementioned substrate (42) is When the second surface (42b) is viewed from the front, there is a light-transmitting region (60) through which light is transmitted from the first surface (42a) toward the second surface (42b), The first surface (42a) is provided with a first light source (46), The first light source (46) is a surface-mount LED that emits light toward the light-transmitting region (60), A second light source (47) is positioned on the first surface (42a) at a predetermined distance from the first light source (46) and emits light toward the first surface (42a), The present invention further comprises light-transmitting materials (50a, 50b) that suppress light transmission between the first surface (42a) and the second surface (42b), The outdoor unit is characterized in that the light-transmitting suppressing material (50a, 50b) suppresses light transmission between the first surface (42a) and the second surface (42b) due to the light emitted from the second light source (47).

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