JP7834239B2 - Electronic indicating instrument - Google Patents

Description

This disclosure relates to an electronic indicating instrument equipped with a display unit that uses a backlight for display.

In conventional side-edge type electronic indicators with backlighting, the display unit, consisting of a circuit board with light-emitting diodes (LEDs) and heat-generating components, a light guide plate, and a liquid crystal panel, was assembled in this order without any gaps. This structure made it easy for heat generated on the circuit board with the LEDs and heat-generating components to transfer to the liquid crystal panel. This led to a rise in the temperature of the liquid crystal panel, which accelerated the degradation of its components and easily resulted in a decrease in the performance of the electronic indicator.

As a technology to address the structural problems described above, Patent Document 1 discloses a surface light source device having a structure in which a heat sink plate is bonded and fixed to the lower surface of a light guide plate via a thermally conductive adhesive layer. The surface light source device described in Patent Document 1 suppresses the overheating of the light guide plate by efficiently transferring heat from the light guide plate to the heat sink plate via the thermally conductive adhesive layer and dissipating the heat.

Japanese Unexamined Patent Publication No. 10-199320

However, the surface light source device described in Patent Document 1 above had the problem that its structure became complex and assembly work complicated because it required the addition of components such as a thermally conductive adhesive layer and a heat sink.

This disclosure has been made in view of the above, and aims to provide an electronic indicator instrument that comprises a substrate on which a heat-generating component is mounted, a light guide plate, and a display unit in that order, and that can suppress the temperature rise of the display unit caused by heat transfer from the heat-generating component with a simple structure.

To solve the above-mentioned problems and achieve the objective, the electronic indicator instrument according to this disclosure comprises a liquid crystal display panel, a printed circuit board on which a backlight and heat-generating components are mounted and located on the back side of the liquid crystal display panel, and a light guide plate provided between the liquid crystal display panel and the printed circuit board, which takes in incident light from the backlight from the side and emits it toward the back of the liquid crystal display panel. The light guide plate is provided with ribs that protrude toward the front side at the ends of a pair of opposing side sides different from the side on which the incident light is incident, thereby separating the liquid crystal display panel and the front surface of the light guide plate. The printed circuit board has a lower region, which is the lower area in the in-plane direction of the printed circuit board, on which the backlight and heat-generating components are mounted, and a pattern antenna for short-range wireless communication is mounted in the upper region, which is the upper area in the in-plane direction of the printed circuit board.

The electronic indicator instrument according to this disclosure comprises a circuit board on which heat-generating components are mounted, a light guide plate, and a display unit in that order, and has the effect of being able to suppress the temperature rise of the display unit caused by heat transfer from the heat-generating components with a simple structure.

Perspective view showing an electronic indicator according to Embodiment 1 Exploded perspective view showing the component configuration of the front part of the electronic indicator instrument according to Embodiment 1. A perspective view showing the assembled front view of the electronic indicator according to Embodiment 1. Front view of the light guide plate of the electronic indicator instrument according to Embodiment 1, as seen from the front. A bottom view of the light guide plate of the electronic indicator instrument according to Embodiment 1, viewed from below. Front view of the circuit board of the electronic indicator instrument according to Embodiment 1, as seen from the front. Rear view of the circuit board of the electronic indicator instrument according to Embodiment 1, as seen from the rear side. This is a bottom view of the assembled state of the display device, light guide plate, and circuit board of the electronic indicator instrument according to Embodiment 1, as seen from below. Rear view of a first example of a circuit board included in the electronic indicator instrument according to Embodiment 2, viewed from the rear side. Rear view of a second example of a circuit board included in the electronic indicator instrument according to Embodiment 2, viewed from the rear side. Rear view of a third example of a circuit board included in the electronic indicator instrument according to Embodiment 2, viewed from the rear side.

The electronic indicator instrument according to the embodiment will be described in detail below with reference to the drawings.

Embodiment 1.
Figure 1 is a perspective view showing the electronic indicator 100 according to Embodiment 1. Figure 2 is an exploded perspective view showing the component configuration of the front part 1 of the electronic indicator 100 according to Embodiment 1. Figure 3 is a perspective view showing the assembled state of the front part 1 of the electronic indicator 100 according to Embodiment 1. Figure 4 is a front view of the light guide plate 5 of the electronic indicator 100 according to Embodiment 1, viewed from the front. Figure 5 is a bottom view of the light guide plate 5 of the electronic indicator 100 according to Embodiment 1, viewed from below. Figure 6 is a front view of the circuit board 6 of the electronic indicator 100 according to Embodiment 1, viewed from the front. Figure 7 is a rear view of the circuit board 6 of the electronic indicator 100 according to Embodiment 1, viewed from the rear. Figure 6 shows the front of the circuit board 6, which is the front of the circuit board 6. Figure 7 shows the back of the circuit board 6, which is the back of the circuit board 6, which is the back of the circuit board 6.

As shown in Figure 1, the electronic indicator 100 according to Embodiment 1 has a front section 1 located on the front side of the electronic indicator 100 that displays information such as measurement data, and a cylindrical section 2 located on the rear side of the front section 1 that houses components such as a power supply circuit and connection terminals. The electronic indicator 100 employs a side-edge backlight system.

In the electronic indicator 100, the width direction of the front section 1 is defined as the width direction of the electronic indicator 100. The width direction of the front section 1 and the width direction of the electronic indicator 100 are parallel to the X-axis direction in Figure 1 and correspond to the left-right direction in Figure 1. Furthermore, the depth direction of the front section 1 is defined as the depth direction of the electronic indicator 100. The depth direction of the front section 1 and the depth direction of the electronic indicator 100 are parallel to the Y-axis direction in Figure 1 and correspond to the direction connecting the lower left and upper right in Figure 1. In addition, in the depth direction of the front section 1 and the depth direction of the electronic indicator 100, the side on which the front section 1 is located is defined as the front side. That is, in the Y-axis direction shown in Figure 1, the side facing the lower left of the paper is defined as the front side. Furthermore, in the depth direction of the front section 1 and the depth direction of the electronic indicator 100, the side on which the cylindrical section 2 is located is defined as the back side. That is, in the Y-axis direction shown in Figure 1, the side facing the upper right of the paper is defined as the back side. Furthermore, the height direction of the front section 1 is the same as the height direction of the electronic indicator 100. The height direction of the front section 1 and the height direction of the electronic indicator 100 are parallel to the Z-axis direction in Figure 1 and correspond to the up and down direction in Figure 1.

As shown in Figure 2, the front section 1 is constructed by assembling the cover 3, the display device 4, the light guide plate 5, and the substrate 6 in that order. As shown in Figure 3, the assembled unit, with the cover 3, the display device 4, the light guide plate 5, and the substrate 6, is housed within the cover 3.

The cover 3 forms the outer casing of the front portion 1 of the electronic indicator meter 100 and is fitted and fixed to the cylindrical portion 2. The cover 3 houses the display device 4, the light guide plate 5, and the substrate 6 from the rear side. The cover 3 has a rectangular parallelepiped shape with two opposing surfaces, one on the front side and one on the rear side, that are open. The front side is the side into which the display device 4 is assembled. The rear side is the side facing the cylindrical portion 2 in the depth direction. Specifically, the front side has an opening 3a into which the display device 4 is fitted.

The display device 4 is a display unit that displays information. It is incorporated into the cover 3 from the rear side, and one side that serves as the display screen is exposed to the front side through an opening 3a provided on one side of the front of the cover 3. The display device 4 is composed of a display device such as a liquid crystal panel in which liquid crystal is sealed between opposing substrates.

The light guide plate 5 is incorporated into the cover 3 from the rear side and uniformly diffuses the light from the backlight, which is the light source, and guides it as planar light to the back side of the display device 4. In other words, the light guide plate 5 takes in the light emitted from the backlight as incident light from its lower side surface 5f, which is the lower side surface of the light guide plate 5, and uniformly diffuses the captured incident light, which is then emitted as output light from the front surface 5a of the light guide plate 5 toward the back side of the display device 4.

The back surface 5b of the light guide plate 5 is configured to reflect and diffuse incident light that enters from the lower surface 5f and emit it from the front surface 5a of the light guide plate. The back surface 5b of the light guide plate is provided with a structure that uniformly diffuses the light from the backlight and guides it to the back side of the display device 4, such as a diffusion structure with a roughened surface over the entire surface, or a total reflection structure that combines a flat surface and a prism-like uneven structure.

From the viewpoint of efficiently guiding the backlight to the back of the display device 4, the light guide plate 5 is preferably made of a material with high light transmittance, and from the viewpoint of thinning and weight reduction, it is preferable to use a resin such as acrylic or polycarbonate.

As shown in Figures 4 and 5, the light guide plate 5 has ribs 50 at both ends in the width direction to form a space S between the display device 4 and the light guide plate 5, which will be described later. That is, as shown in Figures 4 and 5, the light guide plate 5 has ribs 50 at both ends in the width direction to separate the display device 4 from the flat portion 5g, which is the main body of the light guide plate 5. The flat portion 5g, which is the main body of the light guide plate 5, is the main surface of the light guide plate 5. The in-plane direction of the flat portion 5g is parallel to the in-plane direction of the display device 4 and the in-plane direction of the substrate 6.

Specifically, as shown in Figures 4 and 5, the light guide plate 5 has ribs 50 at both ends in the width direction of the flat portion 5g, which is the main body of the light guide plate 5, for separating the display device 4 from the light guide plate 5. The light guide plate 5 has a first rib 51 which is a rib 50 provided in the width direction that protrudes toward the front from the left peripheral edge of the front surface 5a of the light guide plate 5, which is the front surface of the light guide plate 5. The light guide plate 5 also has a second rib 52 which is a rib 50 provided in the width direction that protrudes toward the front from the right peripheral edge of the front surface 5a of the light guide plate 5, which is the front surface of the light guide plate 5.

The front surface 5a of the light guide plate can be described as the front surface of the flat portion 5g, which is the main body of the light guide plate 5. Furthermore, the left peripheral edge of the front surface 5a of the light guide plate can be described as the left side adjacent region 5al, which is adjacent to the left side surface 5c, which is the left side of the light guide plate 5. Similarly, the right peripheral edge of the front surface 5a of the light guide plate can be described as the right side adjacent region 5ar, which is adjacent to the right side surface 5d, which is the right side of the light guide plate 5.

The lower side surface 5f of the light guide plate 5 is the side surface onto which light emitted from the backlight enters the light guide plate 5. The left side surface 5c and the right side surface 5d of the light guide plate 5 are a pair of opposing sides of the light guide plate 5 that are different from the lower side surface 5f, which takes in light emitted from the backlight as incident light. The left side adjacent region 5al and the right side adjacent region 5ar are adjacent side regions to the left side surface 5c and the right side surface 5d, which are a pair of opposing sides different from the lower side surface 5f into which the incident light enters. Therefore, the ribs 50 are provided in the left side adjacent region 5al and the right side adjacent region 5ar, which are adjacent side regions on the front surface 5a of the light guide plate 5 that are different from the left side surface 5c and the right side surface 5d, which are a pair of opposing sides different from the lower side surface 5f into which the incident light enters.

The first rib 51 has a U-shape in the in-plane direction of the front surface 5a of the light guide plate. That is, the first rib 51 has two parallel parts, a first parallel part 511 and a second parallel part 512, which are provided in the in-plane direction of the front surface 5a of the light guide plate and are parallel to the extending direction of the left side surface 5c, which is the left side surface of the light guide plate 5, and a connecting part 513 that connects the upper end of the first parallel part 511 and the upper end of the second parallel part 512.

The first parallel section 511 is positioned on the left side 5c of the front surface 5a of the light guide plate in the width direction. The second parallel section 512 is positioned to the right of the first parallel section 511 in the width direction, on the interior side of the front surface 5a of the light guide plate. The first rib 51 is connected at the connection point between the first parallel section 511 and the connecting section 513, and at the connection point between the second parallel section 512 and the connecting section 513, in a perpendicular manner in the in-plane direction of the front surface 5a of the light guide plate.

The second rib 52 has a U-shape in the in-plane direction of the front surface 5a of the light guide plate. That is, the second rib 52 has a first parallel section 521 and a second parallel section 522, which are two parallel sections provided in the in-plane direction of the front surface 5a of the light guide plate, parallel to the extending direction of the right side surface 5d, which is the right side surface of the light guide plate 5, and a connecting section 523 that connects the upper end of the first parallel section 521 and the upper end of the second parallel section 522.

The first parallel section 521 is positioned on the right side 5d of the front surface 5a of the light guide plate in the width direction. The second parallel section 522 is positioned to the left of the first parallel section 521 in the width direction, on the interior side of the front surface 5a of the light guide plate. The second rib 52 is connected at the connection point between the first parallel section 521 and the connecting section 523, and at the connection point between the second parallel section 522 and the connecting section 523, in a perpendicular manner in the in-plane direction of the front surface 5a of the light guide plate.

Furthermore, the ribs 50 are provided continuously across the entire width in the height direction on the front surface 5a of the light guide plate. That is, the first rib 51 and the second rib 52 are provided continuously across the entire area in the height direction on the front surface 5a of the light guide plate. Specifically, the first rib 51 and the second rib 52 are provided continuously across the entire width on the front surface 5a of the light guide plate, between the position of the lower surface 5f into which the incident light is incident and the position of the upper surface 5e facing the lower surface 5f. Therefore, it can be said that the ribs 50 are provided continuously from one end to the other in the height direction on the front surface 5a of the light guide plate.

Here, the height direction can be rephrased as the direction perpendicular to the longitudinal direction of the lower surface 5f on the front surface 5a of the light guide plate, through which incident light enters the light guide plate 5. Furthermore, the height direction can be rephrased as the direction parallel to the longitudinal direction of the left side surface 5c and the right side surface 5d of the light guide plate 5.

By providing the first rib 51 and the second rib 52 continuously from one end to the other in the height direction, compared to the case where the first rib 51 and the second rib 52 are provided discontinuously with a slit or other dividing section in the middle in the height direction, the light incident on the light guide plate 5 from the LED 61 can be diffused more uniformly in the space S between the display device 4 and the light guide plate 5 and transmitted to the front side.

The protruding length L of the rib 50, that is, the protruding lengths L of the first rib 51 and the second rib 52, is set to approximately 4.0 mm, for example. The protruding lengths L of the first rib 51 and the second rib 52 are the lengths that the first rib 51 and the second rib 52 protrude from the flat portion 5g of the light guide plate 5 toward the front in the depth direction of the light guide plate 5 and the electronic indicator 100, and the lengths that the first rib 51 and the second rib 52 protrude toward the front from the front surface 5a of the light guide plate. The protruding length L of the first rib 51 and the protruding length L of the second rib 52 are set to the same dimension. Note that the protruding length L of the rib 50 may be appropriately changed depending on various conditions such as the size of the electronic indicator 100 and the use of each component of the electronic indicator 100.

The first rib 51 and the second rib 52 are made of a material and dimensions that have sufficient strength to maintain a separated state between the display device 4 and the light guide plate 5. The first rib 51 and the second rib 52 may be formed integrally with the flat portion 5g, which is the main body portion of the light guide plate 5 other than the first rib 51 and the second rib 52, when the light guide plate 5 is formed, or they may be formed separately from the flat portion 5g and joined to the flat portion 5g. The first rib 51 and the second rib 52 may be made of the same material as the flat portion 5g of the light guide plate 5, or they may be made of a different material than the flat portion 5g.

The light guide plate 5, by having the ribs 50 having the above-described configuration, can separate the display device 4 and the light guide plate 5 in the depth direction, thereby forming a space S between the display device 4 and the light guide plate 5. More specifically, the light guide plate 5, by having the ribs 50 having the above-described configuration, can separate the flat portion 5g, which is the main body of the light guide plate 5, from the display device 4 in the depth direction, and can also separate the front surface 5a of the light guide plate 5 from the display device 4 in the depth direction.

As described above, the first rib 51 has two parallel sections: a first parallel section 511 and a second parallel section 512. This allows the electronic indicator 100 to reliably and stably separate the display device 4 and the light guide plate 5, forming a space S between the display device 4 and the light guide plate 5. Similarly, the second rib 52 has two parallel sections: a first parallel section 521 and a second parallel section 522. This allows the electronic indicator 100 to reliably and stably separate the display device 4 and the light guide plate 5, forming a space S between the display device 4 and the light guide plate 5.

Furthermore, if sufficient strength can be obtained to maintain the separated state between the display device 4 and the flat portion 5g, which is the main body of the light guide plate 5, it is also possible to configure the first rib 51 to have only the first parallel portion 511. In this case, the connecting portion 513 is unnecessary. The same applies to the second rib 52.

The circuit board 6 is a printed circuit board in which a light source and electronic components are mounted on an insulating substrate, with only conductive wiring laid on the substrate and inside, and no electronic components attached, so that it can function as an electronic circuit. The circuit board 6 is assembled into the cover 3 from the rear side, and the light source for the backlight and heat-generating components such as the CPU (Central Processing Unit) are mounted on it.

As shown in Figure 6, on the front surface 6a of the substrate 6, the LEDs 61, which are heat-generating components used as backlighting sources, are mounted below the center of the substrate 6 in the height direction. Multiple LEDs 61 are arranged at equal intervals in the width direction.

As shown in Figure 7, on the back surface 6b of the circuit board 6, heat-generating components such as the control microcomputer 62 and the measurement calculation microcomputer 63 used to control the electronic indicator 100 are mounted below the center position in the height direction of the circuit board 6.

Figure 8 is a bottom view of the assembled electronic indicator meter 100 according to Embodiment 1, showing the display device 4, light guide plate 5, and substrate 6. In Figure 8, the front side of the paper is the side that the front surface of the display device 4, the front 4a, faces. Also in Figure 8, the back side of the paper is the side that the back surface of the substrate 6, the back 6b, faces.

As shown in Figure 8, the first rib 51 and the second rib 52 of the light guide plate 5 are connected to the display device 4 in contact with the back surface 4b of the display device 4, and are fixed to the back surface 4b of the display device 4. The first rib 51 is connected to the display device 4 in contact with the left outer edge in the width direction of the display device 4 on the back surface 4b. The second rib 52 is connected to the display device 4 in contact with the right outer edge in the width direction of the display device 4 on the back surface 4b.

Furthermore, the front surface 5a of the light guide plate 5 and the back surface 4b of the display device 4 are not in contact, and a space S is formed between the front surface 5a of the light guide plate and the back surface 4b of the display device by the protruding length L of the first rib 51 and the second rib 52. In other words, in the electronic indicator instrument 100, the front surface 5a of the light guide plate and the back surface 4b of the display device are spaced apart in the depth direction of the light guide plate 5 and the electronic indicator instrument 100 by the protruding length L of the first rib 51 and the second rib 52.

The space S functions as an insulating air layer in heat transfer between the front surface 5a of the light guide plate and the back surface 4b of the display device. In other words, the space S functions as an insulating air layer in heat transfer from the substrate 6 to the display device 4 via the light guide plate 5. As a result, in the electronic indicator 100, heat transfer from the substrate 6 to the display device 4 via the light guide plate 5 is suppressed by the space S, and the temperature rise of the display device 4 caused by the heat generated on the substrate 6 is suppressed. As a result, in the electronic indicator 100, the deterioration of components of the display device 4 caused by the heat generated on the substrate 6 is suppressed, and the deterioration of the display performance of the electronic indicator 100 is suppressed.

In the depth direction of the electronic indicator 100, the width of the space S is approximately 4.0 mm, which is the protruding length L of the first rib 51 and the second rib 52. The width of the space S in the depth direction of the electronic indicator 100 can be changed to any dimension by changing the protruding length L of the first rib 51 and the second rib 52. The width of the space S in the depth direction of the electronic indicator 100 may be appropriately changed depending on various conditions such as the size of the electronic indicator 100 and the specifications of each component of the electronic indicator 100.

Next, the assembly method of the electronic indicator 100 will be described. In assembling the electronic indicator 100, as shown in Figure 2, the display device 4, the light guide plate 5, and the circuit board 6 on which heat-generating components such as the LED 61, control microcomputer 62, and measurement calculation microcomputer 63 are mounted are assembled into the interior of the cover 3 from the opening on the back side of the cover 3 in this order. Each component is fixed to the cover 3 and the circuit board 6 by fitting their respective fitting parts (not shown). However, the method of fixing each component is not limited.

As described above, the electronic indicator meter 100 according to Embodiment 1 has a structure in which a display device 4, a light guide plate 5 having a first rib 51 and a second rib 52, and a substrate 6 on which heat-generating components are mounted are arranged in this order. In the electronic indicator meter 100, the front surface 5a of the light guide plate and the back surface 4b of the display device are separated in the depth direction by the first rib 51 and the second rib 52, and a space S that functions as an air layer for heat insulation is formed between the front surface 5a of the light guide plate and the back surface 4b of the display device in the depth direction.

As a result, the electronic indicator 100 can insulate and suppress the transfer of heat generated on the substrate 6 to the display device 4 via the light guide plate 5 using the space S which functions as an insulating air layer. This suppresses the temperature rise of the display device 4 caused by the heat generated on the substrate 6, and thus suppresses the deterioration of the components of the display device 4 caused by the heat generated on the substrate 6.

In the electronic indicator 100, the light emitted from the LED 61 on the substrate 6 enters the light guide plate 5 from the lower side surface 5f, which is the lower side surface of the light guide plate 5. The ribs 50 are located at both ends in the width direction of the planar portion 5g of the light guide plate 5. Specifically, the first rib 51 is provided projecting forward from the left outer peripheral edge of the front surface 5a of the light guide plate 5 in the width direction. The second rib 52 is provided projecting forward from the right outer peripheral edge of the front surface 5a of the light guide plate 5 in the width direction. Therefore, the ribs 50 do not obstruct the incidence of light emitted from the LED 61 onto the light guide plate 5.

Furthermore, to form a space similar to the space S described above, ribs for securing space can be provided inside the cover 3. However, considering the simple assembly procedure shown in Figures 2 and 3, the ribs for securing space provided inside the cover 3 would need to hold down the light guide plate 5 and substrate 6 from both sides in the width direction of the display device 4, and the display size of the display device 4 would need to be reduced by the size of the ribs for securing space inside the cover 3. Reducing the display size of the display device 4 would lead to a decrease in the visibility of information for the user.

On the other hand, in the electronic indicator 100, by providing ribs 50, specifically the first rib 51 and the second rib 52, at both ends in the width direction of the light guide plate 5, it is unnecessary to reduce the size of the display device 4 due to the provision of the first rib 51 and the second rib 52, and the electronic indicator 100 can be assembled with easy work.

Furthermore, in the electronic indicator 100, as shown in Figure 8, the presence of a space S allows light to be diffused by this space S, thus eliminating the need for a diffusion sheet to uniformly diffuse the backlight light and illuminate the back surface 4b of the display device 4. However, even in the electronic indicator 100, providing a diffusion sheet would further uniformize the light illuminating the back surface 4b of the display device 4. Therefore, the electronic indicator 100 does not prevent the use of a diffusion sheet.

Furthermore, in the electronic indicator 100, heat-generating components such as the LED 61, the control microcomputer 62, and the measurement calculation microcomputer 63 are positioned relatively lower in the in-plane direction of the substrate 6. Therefore, in the electronic indicator 100, the heat generated by the LED 61 and the heat-generating components is diffused upward in the in-plane direction of the substrate 6 by natural convection inside the cover 3, thereby suppressing localized temperature increases in the in-plane direction of the substrate 6. As a result, when considering the front section 1 as a whole, localized temperature increases can be suppressed, and consequently, the overall temperature increase of the front section 1 can be suppressed.

Furthermore, since the electronic indicator 100 has ribs 50 on the light guide plate 5, it is unnecessary to add components such as the thermally conductive adhesive layer and heat sink used in the surface light source device described in Patent Document 1. As a result, the electronic indicator 100 has a simple structure, is easy to assemble, and does not incur increased manufacturing costs due to additional parts.

Therefore, according to the first embodiment of the electronic indicator 100, the front section 1 has a circuit board 6 on which an LED 61 and heat-generating components such as a control microcomputer 62 and a measurement calculation microcomputer 63 are mounted, a light guide plate 5, and a display device 4 which is a display unit. This provides the effect of suppressing the temperature rise of the display device 4 and the entire front section 1 caused by heat transfer from the heat-generating components with a simple structure. As a result, the electronic indicator 100 can suppress the deterioration of components of the display device 4 caused by heat generated on the circuit board 6, and can suppress a decrease in the display performance of the electronic indicator 100.

Embodiment 2.
Embodiment 2 describes a case where a pattern antenna 64 for near-field communication (NFC) is mounted on the circuit board 6. The electronic indicator 101 according to Embodiment 2 differs from the electronic indicator 100 according to Embodiment 1 in that the NFC pattern antenna 64 is mounted on the circuit board 6, which has heat-generating components such as an LED 61, a control microcomputer 62, and a measurement calculation microcomputer 63 mounted on it. In the following, components having the same functions as the electronic indicator 100 according to Embodiment 1 are denoted by the same reference numerals and their descriptions are omitted. The explanation will focus on the differences between the electronic indicator 101 according to Embodiment 2 and the electronic indicator 100 according to Embodiment 1.

Figure 9 is a rear view of a first example of the circuit board 6 of the electronic indicator meter 101 according to Embodiment 2, viewed from the rear side. Figure 10 is a rear view of a second example of the circuit board 6 of the electronic indicator meter 101 according to Embodiment 2, viewed from the rear side. Figure 11 is a rear view of a third example of the circuit board 6 of the electronic indicator meter 101 according to Embodiment 2, viewed from the rear side. Figures 9, 10, and 11 show the back surface 6b of the circuit board 6.

In the first example, the circuit board 6 has heat-generating components such as the LED 61, control microcomputer 62, and measurement/calculation microcomputer 63 mounted on it in the same way as the circuit board 6 of the electronic indicator 100 according to Embodiment 1. On the other hand, in the electronic indicator 101 according to Embodiment 2, a pattern antenna 64 for NFC is further mounted on the back surface 6b of the circuit board 6, as shown in Figure 9.

Here, we assume that the substrate 6 is virtually divided into four sections vertically and horizontally in the in-plane direction of the substrate 6, that is, that the back surface 6b of the substrate is virtually divided into four sections vertically and horizontally in the in-plane direction of the back surface 6b. The back surface 6b of the substrate is divided into the lower left region 6b1, which is the lower and left side of the back surface 6b in the in-plane direction of the back surface 6b; the lower right region 6b2, which is the lower and right side of the back surface 6b in the in-plane direction of the back surface 6b; the upper left region 6b3, which is the upper and left side of the back surface 6b in the in-plane direction of the back surface 6b; and the upper right region 6b4, which is the upper and right side of the back surface 6b in the in-plane direction of the back surface 6b.

In the electronic indicator meter 101 according to Embodiment 2, when the substrate 6 is virtually divided into four sections vertically and horizontally in the in-plane direction of the substrate 6, an NFC pattern antenna 64 is provided in either the left or right region of the upper region of the substrate 6, or in the central region of the upper region of the substrate 6.

As shown in Figure 9, the substrate 6 of the first example has heat-generating components such as a control microcomputer 62 and a measurement/calculation microcomputer 63 provided in the lower left region 6b1 and the lower right region 6b2, which are the two lower regions in the in-plane direction of the substrate 6b when the back surface 6b of the substrate 6b is virtually divided into four sections vertically and horizontally in the in-plane direction of the substrate 6b. Also, as shown in Figure 9, the substrate 6 of the first example has an NFC pattern antenna 64 provided in the upper right region 6b4, which is one of the upper regions in the in-plane direction of the substrate 6b when the back surface 6b of the substrate 6b is virtually divided into four sections vertically and horizontally in the in-plane direction of the substrate 6b.

In the second example, as shown in Figure 10, the substrate 6 has heat-generating components such as a control microcomputer 62 and a measurement/calculation microcomputer 63 in the lower left region 6b1 and the lower right region 6b2, which are the two lower regions in the in-plane direction of the substrate 6b when the back surface 6b of the substrate 6b is virtually divided into four sections vertically and horizontally in the in-plane direction of the substrate 6b. Also, as shown in Figure 10, the substrate 6 of the second example has an NFC pattern antenna 64 in the upper left region 6b3, which is one of the upper regions in the in-plane direction of the substrate 6b when the back surface 6b of the substrate 6b is virtually divided into four sections vertically and horizontally in the in-plane direction of the substrate 6b.

In the third example, as shown in Figure 11, the substrate 6 has heat-generating components such as a control microcomputer 62 and a measurement/calculation microcomputer 63 in the lower left region 6b1 and the lower right region 6b2, which are the two lower regions in the in-plane direction of the substrate back surface 6b when the substrate back surface 6b of the substrate 6b is virtually divided into four sections vertically and horizontally in the in-plane direction of the substrate back surface 6b. Furthermore, as shown in Figure 11, the substrate 6 of the third example has an NFC pattern antenna 64 in the upper central region 6b5, which is the upper central region in the in-plane direction of the substrate back surface 6b when the substrate back surface 6b of the substrate 6b is virtually divided into two sections vertically in the in-plane direction of the substrate back surface 6b. The upper central region 6b5 is the central region of the area formed by combining the upper left region 6b3 and the upper right region 6b4 described above.

In other words, in the electronic indicator 101, heat-generating components such as a control microcomputer 62 and a measurement/calculation microcomputer 63 are provided in the lower region, which is the lower area in the in-plane direction of the back surface 6b of the substrate 6. In addition, in the electronic indicator 101, an NFC pattern antenna 64 is provided in the upper region in the in-plane direction of the back surface 6b of the substrate 6. Furthermore, in the electronic indicator 101, an operating switch for operating the electronic indicator 101 may be mounted in the aforementioned lower region.

Furthermore, the pattern antenna 64 can reliably perform its function as a pattern antenna regardless of whether it is installed in the upper left region 6b3, the upper right region 6b4, or the upper central region 6b5.

As described above, in the electronic indicator 101, heat-generating components such as the control microcomputer 62 and the measurement calculation microcomputer 63 are mounted in the lower region of the back surface 6b of the substrate 6, while the NFC pattern antenna 64 is mounted in the upper region of the back surface 6b of the substrate 6. This allows the electronic indicator 101 to quickly dissipate the heat generated by the heat-generating components mounted in the lower region to the upper region through natural convection, thereby achieving temperature uniformity within the substrate 6.

In the electronic indicator meter 101, the arrangement of the NFC pattern antenna 64 as described above allows for a large area of the pattern antenna 64, which is also powered by the antenna of a mobile terminal, etc., to be secured in the in-plane direction of the substrate 6. By securing a large area of the pattern antenna 64 in the in-plane direction of the substrate 6, heat from heat-generating components can be quickly diffused to the upper region by convection, and the temperature inside the front section 1 can be made uniform.

In other words, in the electronic indicator 101, by not providing localized high-temperature areas on the substrate 6 in the in-plane direction, it is possible to prevent high heat from being applied to the front portion 1, thereby suppressing the deterioration of components within the front portion 1 caused by localized temperature rises within the front portion 1, and also suppressing the decrease in the display performance of the electronic indicator 100 caused by localized temperature rises within the front portion 1.

As described above, in the electronic indicator 101 according to Embodiment 2, heat-generating components such as the control microcomputer 62 and the measurement calculation microcomputer 63 are mounted in the lower region of the back surface 6b of the substrate 6, and the NFC pattern antenna 64 is mounted in the upper region of the back surface 6b of the substrate 6, thereby enabling uniform temperature distribution within the substrate 6. As a result, the electronic indicator 101 can prevent localized heat transfer to the display device 4, prevent deterioration of the components of the display device 4, and suppress a decrease in the display performance of the electronic indicator 100.

The configurations shown in the above embodiments are merely examples, and can be combined with other known technologies, or the embodiments themselves can be combined. Furthermore, parts of the configuration can be omitted or modified without departing from the spirit of the invention.

1 Front section, 2 Round section, 3 Cover, 3a Opening, 4 Display device, 4a Front of display device, 4b Rear of display device, 5 Light guide plate, 5a Front of light guide plate, 5al Left side adjacent area, 5ar Right side adjacent area, 5b Rear of light guide plate, 5c Left side, 5d Right side, 5e Top side, 5f Bottom side, 5g Flat section, 6 Substrate, 6a Front of substrate, 6b Rear of substrate, 6b1 Lower left area, 6b2 Lower right area, 6b3 Upper left area, 6b4 Upper right area, 6b5 Upper central area, 50 Rib, 51 First rib, 52 Second rib, 61 LED, 62 Control microcomputer, 63 Measurement and calculation microcomputer, 64 Pattern antenna, 100, 101 Electronic indicator, 511, 521 First parallel section, 512, 522 Second parallel section, 513, 523 connecting section, L protruding length, S space.

Claims (2)

LCD display panel,
A printed circuit board on which the backlight and heat-generating components are mounted and located on the back side of the liquid crystal display panel,
A light guide plate is provided between the liquid crystal display panel and the printed circuit board, which takes in incident light from the backlight from the side and emits it toward the back of the liquid crystal display panel,
Equipped with,
The light guide plate is provided with ribs that protrude toward the front at the ends of a pair of opposing side surfaces different from the side surface into which the incident light is incident, thereby separating the liquid crystal display panel from the front surface of the light guide plate .
The aforementioned printed circuit board is
The backlight and the heat-generating components are mounted in the lower region, which is the lower region in the in-plane direction of the printed circuit board.
A pattern antenna for short-range wireless communication is mounted in the upper region in the in-plane direction of the printed circuit board.
An electronic indicating instrument characterized by the following. The ribs are provided continuously from one end to the other end of the light guide plate in the height direction of the light guide plate.
The electronic indicating instrument according to claim 1, characterized by the following: