Backlight substrate and display device

Abstract

In a backlight substrate of a display device, only one surface is formed as a mounting surface on which conductive pattern wiring is formed, a light-emitting element is mounted on the mounting surface, and a ground contact is attached, the ground contact being produced using a conductive material provided with a contact part which is electrically connected to a ground pattern on the mounting surface and is biased and brought into contact with a chassis arranged on the opposite-surface side of the mounting surface.

Description

Backlight substrates, display devices

[0001] The present technology relates to a display device and a backlight substrate mounted on the display device.

[0002] In some cases, a ground pattern on an electronic circuit board is electrically connected to a metal member inside an electronic device. Patent Document 1 listed below discloses a technique for interposing a conductive terminal between the board and the opposing metal member.

[0003] JP 2018-88342 A

[0004] Consider a display device such as a television receiver or monitor, particularly one equipped with a backlight, such as a liquid crystal display. In the case of a transmissive liquid crystal display, the backlight is disposed behind the liquid crystal panel that constitutes the display screen. For example, a backlight substrate is disposed on which a large number of light-emitting diodes (LEDs) that emit light as the backlight are disposed.

[0005] In this case, it may be necessary to further connect the ground of the circuit formed on the backlight board to a metal member on the back side, specifically the chassis, to ensure sufficient ground current capacity. To achieve this, for example, screws are used to secure the board and the chassis, creating electrical continuity. However, when screws are used, loosening of the screws can change the current path, resulting in voltage drops and ripples. Furthermore, dimensional tolerances and expansion and contraction of the board due to temperature can prevent proper contact between the screws and the board's ground, preventing the chassis from functioning as a ground.

[0006] There is also a method of sandwiching the conductive terminal between the mounting surface of the board and the chassis as in Patent Document 1, but this cannot be used for backlight boards where the chassis is on the opposite side of the mounting surface.

[0007] Therefore, the present disclosure proposes a technique that allows a backlight substrate of a display device to be appropriately grounded to a chassis.

[0008] The backlight substrate according to the present technology has only one surface as a mounting surface on which conductive pattern wiring is formed, light-emitting elements are mounted on the mounting surface, and a ground contact made of a conductive material is attached, the ground contact having an abutment portion that is electrically connected to the ground pattern on the mounting surface and is biased to contact a chassis of a display device arranged on the opposite side of the mounting surface.The backlight substrate is a single-layer substrate on which conductive pattern wiring is formed only on one side as a backlight substrate to be attached to the back side of the display surface of a display device.This single-layer substrate is provided with a ground contact that electrically connects the mounting surface on which the conductive pattern wiring is formed and the chassis arranged on the opposite side.The ground contact has spring properties so that it is biased to contact the chassis.

[0009] 1 is an explanatory diagram of a display device according to an embodiment of the present technology; FIG. 2 is an explanatory diagram of a backlight substrate mounted on a display device according to an embodiment; FIG. 3 is an explanatory diagram of conductive pattern wiring of a backlight substrate according to an embodiment; FIG. 4 is an explanatory diagram of a single-layer substrate; FIG. 5 is an explanatory diagram of an aluminum single-layer substrate; FIG. 6 is a perspective view of a ground contact according to an embodiment; FIG. 7 is an explanatory diagram of a backlight substrate and a ground contact according to an embodiment; FIG. 8 is an explanatory diagram of a state in which a ground contact according to an embodiment is attached; FIG. 9 is an explanatory diagram of a case in which a ground contact is not provided; FIG. 10 is an explanatory diagram of a case in which a ground contact according to an embodiment is attached; FIG. 11 is a plan view, a perspective view, and a side view of another ground contact according to an embodiment; FIG. 12 is an explanatory diagram of solder strength, spring repulsion force, and tape peel strength according to an embodiment; FIG. 13 is a plan view, a front view, and a right side view of a first type connector according to an embodiment; FIG. 14 is a plan view, a front view, and a right side view of a second type connector according to an embodiment; FIG. 15 is a plan view, a front view, and a right side view of a third type connector according to an embodiment; FIG. 16 is an explanatory diagram of an arrangement state of a third type connector according to an embodiment; FIG. 17 is an explanatory diagram of a connection example of a third type connector according to an embodiment; FIG. 18 is an explanatory diagram of a connection example of a third type connector according to an embodiment; 10A and 10B are explanatory diagrams of pattern examples when a first type connector of the embodiment is used, and an explanatory diagram of pattern examples when a third type connector of the embodiment is used.

[0010] The embodiments will be described below in the following order: <1. Display device and backlight substrate> <2. Ground contact> <3. Connector> <4. Summary and modifications>

[0011] 1, the front side of the display device 1 is defined as the front, and the rear side is defined as the rear, and the up, down, left, and right directions are defined when viewing the display device 1 from the front side. However, the up, down, left, and right directions of a single component shall follow the directions shown in the figure.

[0012] 1 shows a display device 1 according to an embodiment, the front side of which is a display surface 2. This display device 1 is configured using, for example, a transmissive liquid crystal panel, and therefore a backlight is disposed behind the display surface 2.

[0013] The backlight is constructed by arranging the required number of backlight boards 3 on the back side of the liquid crystal panel that constitutes the display surface 2. As shown in Fig. 2, each backlight board 3 is equipped with a large number of LEDs, indicated by small dots, arranged in the vertical and horizontal directions, and the light emitted by these large number of LEDs provides the backlight. Note that Fig. 2 is merely a schematic diagram, and the number of dots does not accurately represent the number of LEDs.

[0014] FIG. 3 schematically shows a portion of the pattern wiring formed on the mounting surface 3a of one backlight substrate 3. The backlight substrate 3 of this embodiment has a ground pattern 4, power supply patterns 9a and 9b, an LED wiring pattern 8, and a driver wiring pattern 7 formed as conductive pattern wiring. To distinguish between the wiring patterns, the ground pattern 4 is shown in gray, the power supply patterns 9a and 9b are shown with dotted lines of different roughness, and the LED wiring pattern 8 and the driver wiring pattern 7 are shown in black. The white areas indicate areas where the insulating material is exposed. Furthermore, while the example of FIG. 3 shows the power supply patterns 9a and 9b formed because the circuit uses two different power supply voltages, a circuit using only one power supply voltage may also be used. Hereinafter, the power supply patterns 9a and 9b will be collectively referred to as the "power supply pattern 9."

[0015] The electronic components mounted on the board include LEDs 5 and LED drivers 6. The LEDs 5 are chip components and are arranged in a row on an LED wiring pattern 8. The LED drivers 6 are also chip components, and a plurality of them are arranged on a driver wiring pattern 7. Although not shown in Fig. 3, a connector, which will be described later, is mounted in a connector hole 17.

[0016] As shown in the figure, LEDs 5 are arranged at approximately equal intervals on the backlight substrate 3, vertically and horizontally, and LED wiring patterns 8 are formed for the LEDs 5. Although each LED 5 is shown as a square in the figure, this may represent, for example, a full-color LED chip of R (red), G (green), and B (blue), three monochromatic LED chips each of R, G, and B, or multiple monochromatic LED chips that are not a combination of R, G, and B. Therefore, although not distinguished in the figure, each LED wiring pattern 8 is actually formed by three signal lines for R, G, and B or signal lines for multiple monochromatic LEDs. The LED wiring pattern 8 connects one of the anodes or cathodes of each LED 5 to the power supply voltage and the other to the LED driver. In this example, multiple LEDs 5 are connected in series between the power supply pattern 9 and the light-emitting current terminal of the LED driver 6, so the anode of each LED 5 is connected to the power supply pattern 9 or to the cathode of the LED 5 on the power supply pattern 9 side. The cathode of each LED 5 is connected to the LED driver 6 or to the anode of the LED 5 on the LED driver 6 side.

[0017] A required number of LED drivers 6 are arranged on the backlight board 3, and a driver wiring pattern 7 is formed for each of the LED drivers 6. The driver wiring pattern 7 is wiring that supplies serial data as a light-emission control signal to the LED drivers 6 via a connector (not shown). Multiple LED drivers 6 are connected in series to one serial data system, and each LED driver 6 receives a light-emission control signal based on its assigned slave address. Each LED driver 6 then supplies a light-emission current to its assigned LED 5 in accordance with the received light-emission control signal, causing the LED 5 to emit light. Note that while the driver wiring pattern 7 is shown as a single line, it may actually be composed of a pattern of multiple lines, such as a transmission line for serial data as a light-emission control signal and a transmission line for a clock, or it may be composed of a single line in a so-called asynchronous system.

[0018] Power supply patterns 9a and 9b are formed so that a power supply voltage serving as an operating power source is applied to the LEDs 5 and the LED drivers 6. A ground pattern 4 is also formed, and the ground terminal of each LED driver 6 is connected to the ground pattern 4.

[0019] In order to ensure current capacity, the power supply patterns 9a and 9b are made to be relatively wide conductive pattern wiring, and the ground pattern 4 is made to be a planar conductive pattern wiring having a relatively wide area, so-called a solid ground.

[0020] Although it is not clearly shown in the figure due to its small size, an insulating region is naturally provided between adjacent conductive patterns. Furthermore, the conductive pattern wiring shown in the figure is merely an example for explanation purposes and does not faithfully represent the circuit for LED light emission.

[0021] A single-layer substrate with one mounting surface is used as the backlight substrate 3. For example, it is a single-layer substrate made of a normal base material as shown in FIG. 4 or an aluminum single-layer substrate as shown in FIG.

[0022] The single-layer substrate of the normal base material shown in Fig. 4 has a conductor layer 10 formed on an insulating layer 11. The conductor layer 10 is made into a conductive pattern wiring as shown in Fig. 3. The mounting surface 3a is formed by the conductor layer 10. Note that no conductive pattern wiring is formed on the opposite surface 3b, which is the back side of the mounting surface 3a.

[0023] 5, both sides of an aluminum conductor layer 13 are covered with insulating layers 12 and 14, and a conductor layer 10 is formed on the insulating layer 12 side. The conductor layer 10 (conductive pattern wiring) forms a mounting surface 3a. No conductive pattern wiring is formed on the opposite surface 3b.

[0024] The reason for using a single-sided, single-layer substrate with only one mounting surface 3a on which a conductor layer 10 serving as conductive pattern wiring is that it is advantageous in terms of substrate cost as the backlight substrate 3. In particular, as the screen size of the display device 1 increases, the area required for the backlight substrate increases, and multiple substrates with large areas become necessary. For this reason, low-cost single-layer substrates are suitable for the backlight substrate 3.

[0025] In this disclosure, the term "single-layer substrate" does not mean a substrate having one layer, but rather a substrate having one mounting surface (single layer) on which the conductor layer 10 serving as the conductive pattern wiring is formed.

[0026] 6 and 11 are attached to the backlight substrate 3, which is a single-sided, single-layer substrate as described above, to electrically connect the ground pattern 4 to the chassis. The ground contact 20 will be described in detail below.

[0027] First, the backlight board 3 of this embodiment is assumed to be an ultra-multi-division model in which the number of light-emitting elements is significantly increased compared to normal. In other words, the number of LEDs 5 is increased and the pitch between the LEDs 5 is narrowed. In this case, by optimizing the configuration, it is desirable to mount the LED driver 6 on the backlight board 3, and the LED driver 6 is also mounted as shown in Figure 3. For this reason, it is necessary to provide a ground pattern 4 on the backlight board 3.

[0028] In the case of conventional backlight boards with a relatively small number of LEDs and a relatively small pitch, the LED driver was provided outside the backlight board, and the LEDs and connectors were mounted on the backlight board. In this case, the backlight board only needed to have a pattern that allowed light-emitting drive current to flow from the power supply voltage to the LEDs, and no ground was required. In contrast, in this embodiment, the LED driver 6 is mounted on the backlight board 3, which means that not only the power supply voltage but also a ground is required for the operation of the LED driver 6. In other words, as described above, not only the power supply pattern 9 and the LED wiring pattern 8 but also the driver wiring pattern 7 and the ground pattern 4 are required.

[0029] Here, a relatively large current capacity is required for the ground as well, since a relatively large current will flow through the many LEDs 5. On the other hand, as the number of LEDs 5 increases and a corresponding number of LED drivers 6 are installed, the wiring patterns also increase, making it difficult to secure a large area for the ground pattern 4 on the mounting surface 3 a, and there will be locations where the wiring patterns will necessitate dividing the ground pattern 4 into island-like sections.

[0030] The ground island-like division caused by the LED wiring pattern 8, driver wiring pattern 7, etc., results in locally high ground resistance. Therefore, a large current for LED light emission passes through the wiring pattern with locally high resistance, resulting in a voltage drop. This modulates the overall reference potential of the light emission control signal (including control signals for LED light emission intensity adjustment, light emission timing, drive data, temperature compensation, and brightness compensation) in the amplitude direction, resulting in large fluctuations in the potential of the digital signal. To keep the undershoot and overshoot of the digital signal within specifications (within -0.3 V on the ground side), the high resistance within the ground pattern 4 must be eliminated. For example, if the total current of the LEDs 5 is 10 A, the resistance near the power supply where the current is concentrated must be 0.03 Ω (30 milliohms) or less, and the resistance of the ground pattern 4 must be less than this.

[0031] Furthermore, for example, the contact resistance of a connector contact is on the order of 10 mΩ per pin, and multiple contacts are connected in parallel to use multi-polar contacts to reduce resistance and prevent voltage drop, so high resistance within the ground pattern 4 must be avoided.

[0032] In view of these circumstances, when a single-layer substrate is used from the above-mentioned cost viewpoint, it is necessary to eliminate high resistance portions within the ground pattern 4 and ensure sufficient grounding capability.

[0033] Therefore, in the backlight board 3 of this embodiment, which is a single-sided, single-layer printed circuit board, a ground contact 20, which is a metal fitting that electrically connects the chassis on which the backlight board 3 is attached to the ground pattern 4 on the board, is newly provided to achieve stable conductivity.

[0034] Although there is a method of using screws to attach the backlight board 3 to the chassis to establish electrical continuity between the ground and the chassis, screws have the disadvantage of reducing the stability of the current path if the screws come loose. In response to this, the ground contact 20 also ensures the stability of the current path, allowing a large current of, for example, several amperes, to flow stably.

[0035] It is also possible to use the aluminum base (aluminum conductor layer 13) of the aluminum single-layer substrate shown in Figure 5, but because of the insulating layer 14, DC conduction is not achieved simply by contacting the chassis. For this reason, the aluminum conductor layer 13 cannot be used as is. If the aluminum conductor layer 13 were to be used, some kind of configuration would need to be added to establish electrical continuity between the aluminum conductor layer 13 and the mounting surface 3a, and between the aluminum conductor layer 13 and the chassis, which would increase costs and eliminate the cost-effectiveness of the single-layer substrate, making this unrealistic.

[0036] 6, the ground contact 20 employed in this embodiment is made of a conductive metal, with a solder joint 21 at the periphery and a spring portion 22 in the center. For example, a notch is made on three sides of the center portion of a flat metal plate, and the center portion is bent downward to form the spring portion 22. The spring portion 22 is then bent back toward the solder joint 21. The apex of this bent portion becomes the abutment portion 23 with the chassis.

[0037] 7A and 7B schematically show the backlight substrate 3 and chassis 15 before the ground contacts 20 are attached. Fig. 7A is a cross-sectional view, and Fig. 7B is a plan view. Note that the backlight substrate 3 is an example in which an aluminum single-layer substrate is used. Of the conductor layers 10 in each figure, the conductor layer 10 shown in the center is the conductor layer 10 that forms the ground pattern 4. When attaching the ground contacts 20 to this conductor layer 10 (ground is indicated as "GND"), first a contact hole 16 is formed that penetrates from the mounting surface 3a to the opposite surface 3b.

[0038] Fig. 7C is a side view of the ground contact 20 in Fig. 6, and Fig. 7D is a plan view. The ground contact 20 in Fig. 7D is placed on the conductor layer 10 (GND) in Fig. 7B, and the solder joint portion 21 is soldered to the conductor layer 10 (GND). At this time, the spring portion 22 passes through the contact hole 16.

[0039] 8 shows a state in which the conductor layer 10 (GND) is electrically connected to the chassis 15 by the ground contact 20. The backlight substrate 3 is fixed to the chassis 15 by mechanical screws, double-sided tape, adhesive, or the like in an area other than the area where the mounted components are located.

[0040] The ground contact 20, which is solder-bonded to the conductor layer 10 (GND), which is the ground pattern 4, has its central spring portion 22 fitted into the contact hole 16 and penetrates so as to protrude toward the opposite surface 3b. However, when the backlight board 3 is attached to the chassis 15, the abutting portion 23 abuts against the chassis 15 as shown in FIG. 8. At this time, the abutting portion 23 is pressed against the chassis 15 by the bias of the spring portion 22. By attaching the ground contact 20 in this manner, the ground pattern 4 is electrically connected to the chassis 15, which is at a common reference potential, in a stable electrical manner, independent of the fixing mechanism for the backlight board 3 and chassis 15.

[0041] Fig. 9 is a schematic diagram of the board mounting surface when no ground contact 20 is provided, and Fig. 10 is a schematic diagram of the board mounting surface when the ground contact 20 is provided. Fig. 9 shows a state in which the ground patterns 4a, 4b, and 4c are divided into islands by the LED 5, LED driver 6, LED wiring pattern 8, and power supply pattern 9.

[0042] 10, ground contacts 20 are arranged for these ground patterns 4a, 4b, and 4c to connect them to a common reference potential, thereby enhancing the ground function even in a single-layer board.

[0043] There are various possible shapes for the ground contact 20. Figure 11 shows another shape of the ground contact 20. Figure 11A is a plan view, Figure 11B is a perspective view, Figure 11C is a side view, and Figure 11D is a side view showing the state in which the abutting portion 23 is pressed against the chassis 15.

[0044] The ground contact 20 in this example is formed so that four pieces protrude from a flat base portion 24, and each piece serves as a solder joint portion 21. One end of the base portion 24 is bent to form a spring portion 22. The spring portion 22 is further bent, and the apex of the bent portion serves as a contact portion 23.

[0045] In this ground contact 20, the four solder joint portions 21 are solder-joined to the conductor layer 10 (GND) with the spring portions 22 fitted into the contact holes 16. Then, in the state shown in Fig. 11C, the abutting portions 23 protrude from the contact holes 16. When the backlight board 3 on which the ground contacts 20 are arranged in this manner is attached to the chassis 15, the abutting portions 23 are pressed by the chassis 15, and the ground contact 20 is deformed into the state shown in Fig. 11D. In other words, the abutting portions 23 are pressed against the chassis 15.

[0046] FIG. 3 shows a state in which ground contacts 20 as shown in FIG. 11 are attached to required locations on the ground pattern 4.

[0047] 6 and 11 are attached to the backlight board 3 by soldering. The spring portion 22 provides an appropriate biasing force, which allows the abutment portion 23 to make good contact with the chassis 15 and stabilize the current path. Therefore, the shape and thickness of the spring portion 22 must be designed appropriately to ensure an appropriate spring repulsive force.

[0048] Specifically, the parameters of the shape, thickness, and material of the ground contact 20 may be adjusted so that the following relationship holds: solder strength>tape peel strength>spring repulsion force>contact pressure for stable conduction.

[0049] The tape peel strength is the peel strength of the double-sided tape 19 when it is assumed that the backlight substrate 3 and the chassis 15 are fixed with double-sided tape, as shown in Fig. 12. In Fig. 12, the arrows indicate the spring repulsion force DA, the tape peel strength DB, and the solder strength DC.

[0050] A contact pressure that stabilizes conductivity is set, and the parameters of the ground contact 20 are set so that a spring repulsion force exceeding this is obtained. The double-sided tape 19 is selected so that its tape peel strength exceeds the spring repulsion force. Furthermore, these strengths must not exceed the solder strength at the solder joint 21. This prevents the backlight board 3 from peeling off from the chassis 15 due to the spring repulsion force, and also prevents the ground contact 20 from coming off the mounting surface 3a.

[0051] <3. Connector> Next, the connector mounted on the backlight board 3 will be described. The backlight board 3 is provided with a connector hole 17, and the connector housing is disposed so as to drop into this connector hole 17. First, examples of such drop-in type connectors that can be used with the backlight board 3 are shown in Figures 13, 14, and 15. Each figure shows a plan view, a front view, and a right side view.

[0052] 13 has a plurality of terminals 41 arranged on the upper surface of a housing 43. Each of these terminals 41 is solder-joined to the conductive pattern wiring of the backlight board 3. In the case of this connector 40, the terminals 41 are arranged in the longitudinal direction (direction d1) of the housing 43 and protrude to one side relative to the longitudinal direction (downward in a plan view). Furthermore, terminals 42 to which electric wires are connected are arranged on the lower side of the housing 43. The electric wires referred to here include, for example, flexible flat cables (FFCs) and flexible printed circuits (FPCs).

[0053] 3, which has been explained above, shows the wiring pattern when such a connector 40 is mounted, and the various conductive pattern wirings connected to the terminals 41 of the connector 40 are concentrated on the right side of the connector hole 17 in Fig. 3. This allows each terminal 41 and each conductive pattern wiring to be soldered together.

[0054] 14 also has a plurality of terminals 41 arranged on the upper surface of a housing 53, and terminals 52 to which electric wires are connected arranged on the lower surface. In this case, the terminals 51 to be solder-joined to the conductive pattern wiring of the backlight board 3 protrude in a staggered pattern on the left and right sides of the longitudinal direction (direction d1).

[0055] For example, in the embodiment, the connectors 40 and 50 described above can be used, but the backlight board 3 has the following circumstances:

[0056] The backlight board 3 requires power supply to the LED drivers 6 and data communication between the LED drivers 6, so measures to prevent unwanted radiation are necessary. In the case of a multi-layer board, a shielding effect can be achieved by sandwiching the mounting surface with pattern wiring between ground layers, making it possible to prevent radiation, but this method cannot be used with a single-layer board. Therefore, it is desirable to keep the routing distance of the data bus and clock supply pattern as short as possible to prevent them from acting as an antenna.

[0057] Especially with long wiring, resonance points often exist in the 300 MHz to 1 GHz band, and unexpected peaks must be avoided. This requires the use of low-pass filters that significantly reduce harmonics, which dulls the rise and fall of logic waveforms so much that signals cannot be sent using high-speed digital clocks. Lowering the clock signal frequency reduces performance.

[0058] For these reasons, it is important to shorten and efficiently use wiring, and for this purpose, it is preferable to newly design, manufacture and use a connector 30 as shown in FIG.

[0059] 15 has a plurality of terminals 31 arranged on the upper surface of the housing 33. Each of these terminals 31 is solder-joined to the conductive pattern wiring of the backlight board 3. In the case of this connector 30, the terminals 31 are arranged in the longitudinal direction (direction d1) of the housing 43 and are linear terminals that protrude on both sides of the longitudinal direction (upward and downward in a plan view). In other words, the terminals 31 are not arranged in a staggered pattern as in FIG. 14, and the protruding portions on both sides of the terminal 31 are in the same positions.

[0060] As can be seen from the front view, the lower side of the housing 33 is formed with an electric wire joint portion 35 in which terminals 32 to which electric wires such as FFCs and FPCs are connected are arranged.

[0061] 16 shows the state in which the connector 30 is attached to the backlight board 3. The connector 40 is arranged so that its housing 33 passes through the connector hole 17. Then, on the mounting surface 3a, each terminal 31 is solder-joined to the corresponding conductive pattern wiring (conductor layer 10).

[0062] On the opposite surface 3b, the electric wire joint portion 35 protrudes from the connector hole 17. For example, an FFC 18 is inserted into this electric wire joint portion 35 in a direction parallel to the backlight board 3 and connected to the terminal 32.

[0063] Use of such a connector 30 enables more efficient wiring. Figures 17, 18, 19, and 20 show schematic diagrams of the connector 30. Each terminal 31 protrudes to the left and right of the longitudinal direction of the connector 30 (up and down in the figures).

[0064] Focusing on one terminal 31X, it can be connected to the conductive pattern wiring P1 as shown in Fig. 17, or to the pattern P2 as shown in Fig. 18. In other words, the wiring pattern for each terminal 31 can be led to the connector 30 from either direction.

[0065] 19, the terminal 31X can be connected to both the conductive pattern wirings P3 and P4, which means that the terminal 31X can function as a jumper wiring between the conductive pattern wiring P3 and the conductive pattern wiring P4.

[0066] 20, the terminal 31Y can be connected to both the conductive pattern wirings P5 and P6. This means that the terminal 31Y can form wiring that allows the conductive pattern wirings P5 and P6 to share current. For example, by using the conductive pattern wirings P5 and P6 for the amount of current supplied to the terminal 31Y, it becomes possible to form each of the conductive pattern wirings P5 and P6 with a narrow width, which increases the degree of freedom in wiring design around connectors where conductive pattern wirings tend to be densely packed.

[0067] The wiring is compared in Figures 21 and 22. Figure 21 is an enlarged view of the periphery of the connector hole 17 on the mounting surface 3a when using the connector 40. In other words, it is an enlarged view of a portion of Figure 3. On the other hand, Figure 22 shows an example of a possible pattern when using the connector 30 in the same area. Note that each figure is a schematic diagram showing the terminals 41, 31 of the connectors 30, 40 and the pad portions to which the terminals 41, 31 are soldered, integrated together. Although the connectors 30, 40 themselves are not shown, it should be assumed that the connectors 30, 40 exist.

[0068] In the case of Fig. 21, the driver wiring pattern 7 shown as the attention point NA1 in the figure is extended from the pad PD on the right side of the connector 40, around the connector 40, and to the left. In other words, the need to wrap the driver wiring pattern 7 around makes the wiring length longer. In contrast, in the case of Fig. 22, by using the connector 30, the driver wiring pattern 7 in the attention point NA1a can be connected to the pad on the left side of the connector 30, eliminating the need to wrap the wiring around. This makes it possible to shorten the wiring length.

[0069] 21, the power supply patterns 9a and 9b are each formed so as to extend as wide patterns from the connector 30 to the region on the right side, but in the region on the left side of the connector 30, as shown by the attention point NA2, the power supply patterns 9a and 9b are pulled in from other regions and connected to the LEDs 5. In contrast, in FIG. 22, as shown by the attention point NA2a, the terminals 31 are used instead of jumpers, allowing wide power supply patterns 9a and 9b to be formed on both the left and right sides of the connector 30. Therefore, power supply voltage can be supplied to the LEDs 5 in the region on the left side with short wiring. As in the above example, using the connector 30 can improve wiring efficiency.

[0070] 4. Summary and Modifications The backlight substrate 3 according to the above embodiment provides the following effects.

[0071] In the backlight substrate 3 of the embodiment, only one surface is a mounting surface 3a on which conductive pattern wiring is formed, LEDs 5, which are light-emitting elements, are mounted on the mounting surface 3a, and ground contacts 20 made of a conductive material are attached, the ground contacts 20 being electrically connected to the ground pattern 4 on the mounting surface 3a and having abutting portions 23 that are biased to contact the chassis 15 of the display device 1, which is arranged on the opposite surface 3b. This allows the ground pattern 4 formed on the mounting surface, even in a single-layer substrate with only one mounting surface 3a on which conductive pattern wiring is formed, to be appropriately connected to the chassis 15, which has a common ground potential. Therefore, even if the mounting surface 3a cannot be widely provided with ground or the ground pattern 4 is divided due to wiring of the LEDs 5 or the like, each ground pattern 4 can be appropriately connected to a common ground potential, ensuring sufficient current capacity and providing appropriate grounding functionality.

[0072] In the embodiment, the backlight substrate 3 has contact holes 16 formed through the mounting surface 3a to the opposite surface 3b. The ground contacts 20 are attached so that their abutment portions 23 pass through the contact holes 16 and are exposed to the opposite surface 3b. The contact holes 16 are provided on the substrate, and the ground contacts 20 are arranged in the contact holes 16. This structure allows the ground contacts 20 to be arranged at appropriate locations on the substrate, increasing the degree of freedom in arrangement. In particular, the chassis 15 to which the ground contacts 20 are connected is not entirely flat, but has a shape required for the internal structure of the display device 1, so not every location is suitable for contact with the ground contacts 20. In response to this situation, the contact holes 16 can be selected to match positions on the chassis 15 that are suitable for contact, and the ground contacts 20 can be arranged there. Furthermore, for the backlight substrate 3, it is desirable to arrange the ground contacts 20 in locations where the ground pattern 4 is isolated like an island due to the wiring pattern. Simply provide the contact holes 16 in such locations. In other words, by providing and arranging the contact holes 16, the ground contacts 20 can be arranged at locations that take into account the current capacity of the ground pattern 4.

[0073] It is also possible to arrange the ground contacts 20 without providing the contact holes 16. For example, a structure is conceivable in which a part of the ground contacts 20 is fixed on the mounting surface at the edge of the backlight substrate 3 or in a cutout portion near the edge, and the part that wraps around to the opposite surface has a springy shape so that it is biased by the chassis to come into contact.

[0074] In the backlight substrate 3 of the embodiment, the ground contacts 20 are fixed to the ground pattern 4 on the mounting surface 3a by soldering. By fixing the ground contacts 20 on the mounting surface 3a by soldering, the ground contacts 20 can be mounted in the same process as the mounting of components such as the LEDs 5, thereby improving the efficiency of the manufacturing process.

[0075] The backlight board 3 of the embodiment has a structure in which the opposite surface 3b is adhered to the chassis 15 with double-sided tape 19, and the spring repulsive force of the ground contacts 20 for biasing the abutment portions 23 is set to be weaker than the peel strength of the double-sided tape 19. This prevents the spring repulsive force of the ground contacts 20 from destabilizing the bond between the backlight board 3 and the chassis 15. Furthermore, the shape, thickness, material, etc. of the ground contacts 20 are designed so that the spring repulsive force is stronger than the contact pressure of the abutment portions 23 at which conductivity is stable, thereby stabilizing the conduction function of the ground contacts 20.

[0076] In the backlight substrate 3 of the embodiment, the solder strength between the ground contact 20 and the ground pattern 4 is set to be stronger than the peel strength of the double-sided tape 19. By setting the solder strength of the soldering on the mounting surface 3 a to be stronger than the peel strength of the double-sided tape 19, the ground contact 20 is stably fixed and positioned.

[0077] In the backlight substrate 3 of the embodiment, the ground contact 20 has a solder joint 21 that is joined to the ground pattern 4, a spring portion 22 that is formed by bending the surface that is continuous with the solder joint 21, and a contact portion 23 that is formed by bending the spring portion 22. For example, as described with reference to Figures 6 and 11, the ground contact 20 is provided with the solder joint 21, and the solder joint 21 is joined to the ground pattern 4. The surface that is continuous with the solder joint 21 is then bent to form the spring portion 22. The spring portion 22 is further bent to form the contact portion 23. This allows the ground contact 20, in which the contact portion 23 is biased, to be realized as a component with an extremely simple structure.

[0078] The backlight board 3 of the embodiment is equipped with an LED driver 6 as a light-emitting driver that drives light-emitting elements to emit light based on control signals. The backlight board 3 is an ultra-multi-division type, with an increased number of LEDs 5 and a small pitch between the LEDs. In a backlight board 3 in which an extremely large number of LEDs 5 are arranged at such high density, the configuration can be optimized by providing an LED driver 6. However, the inclusion of the LED driver 6 requires a ground. For such a board requiring a ground, using a ground contact 20 as in the embodiment is extremely effective.

[0079] The backlight board 3 of the embodiment is provided with an example in which a connector 30 is attached, in which each of a plurality of terminals solder-joined to the conductive pattern wiring on the mounting surface 3a protrudes on both sides of the housing 33 in the longitudinal direction (see FIGS. 15 and 22). By using the connector 30 as shown in FIG. 15, the conductive pattern wiring can be led to each terminal 31 on the backlight board 3 from either the left or right side of the connector 30 in the longitudinal direction. This simplifies the design of the wiring pattern of the board and eliminates the need for wiring that wraps around the connector 30. This improves wiring efficiency and shortens the wiring distance, and is advantageous for reducing unwanted radiation and improving noise resistance.

[0080] The backlight board 3 of this embodiment has a connector hole 17 that penetrates from the mounting surface 3a to the opposite surface 3b, and the connector 30 has a plurality of terminals 31 soldered to the mounting surface 3a with the housing 33 penetrating the connector hole 17. As shown in Figure 16, the connector 30 is a so-called drop-in type, and is attached to the backlight board 3 with the housing 33 penetrating the connector hole 17. This prevents the housing 33 of the connector 30 from protruding from the mounting surface on which the LEDs 5 are mounted, allowing the LEDs 5 to be positioned closer to the liquid crystal panel. This improves backlight efficiency and provides a configuration suitable for making the display device 1 thinner.

[0081] In the embodiment, the connector 30 has the electric wire joint 35 at a position on the opposite surface 3b of the housing 33 where the electric wire joint 35 passes through the connector hole 17. As shown in Fig. 16, the electric wire joint 35 is formed on a portion of the housing 33 that protrudes toward the opposite surface 3b, and the FFC 18 is connected to the electric wire joint 35. This prevents the FFC 18 from being positioned in the light-emitting direction of the LED 5.

[0082] In the embodiment, the plurality of terminals 31 to be soldered in the connector 30 are formed in a straight line. In the connector 30, all of the terminals 31 are formed in a straight line without any bends, with both ends protruding to the left and right of the housing 33. This makes it easy to understand the correspondence between the ends of the terminals 31.

[0083] In the embodiment, an example has been given in which some of the terminals of the connector 30 are used as jumpers that electrically connect patterns provided on both sides in the longitudinal direction of the connector 30. As shown in Fig. 19, the terminal 31 can be used as a jumper that electrically connects the conductive pattern wirings P3 and P4 provided on both sides in the direction d1, which is the longitudinal direction of the connector 30, thereby making it possible to improve the efficiency of pattern design on the board.

[0084] In the embodiment, an example has been given in which the power supply patterns 9 (9a, 9b) are formed so as to be electrically continuous on both sides of the connector 30 in the longitudinal direction via the terminals of the connector 30. As shown in FIG. 22 , the power supply pattern 9a is formed so as to be electrically continuous on both sides of the connector 30 in the longitudinal direction via the connector 30. The same is true for the power supply pattern 9b. In other words, the terminals 31 of the connector 30 are used instead of jumpers to make the power supply patterns 9a, 9b continuous in the left-right direction of the connector 30. This makes it possible to efficiently layout the power supply patterns 9a, 9b that provide a power supply voltage for flowing current to each LED 5, and to simplify the overall pattern wiring on the board.

[0085] The backlight substrate 3 of the embodiment is a single-layer substrate in which a conductive pattern wiring (conductor layer 10) is formed on one side of an insulating layer 11, or a single-layer substrate in which a conductive pattern wiring (conductor layer 10) is formed on one insulating layer 12 of an aluminum conductor layer 13 covered on both sides with insulating layers 12, 14. For example, the single-layer substrate is shown in Fig. 4 or the aluminum single-layer substrate is shown in Fig. 5. By using these single-layer substrates, the backlight substrate 3 can be constructed at low cost.

[0086] The display device 1 of the embodiment includes the backlight substrate 3 having the above-described configuration. This makes it possible to realize a display device with stable image quality due to a backlight with stable performance, and is also advantageous in terms of manufacturing costs.

[0087] The effects described in this specification are merely examples and are not limiting, and other effects may also be present.

[0088] The present technology can also be configured as follows. (1) A backlight substrate for a display device, only one of whose surfaces is a mounting surface on which conductive pattern wiring is formed, on which light-emitting elements are mounted, and on which ground contacts made of a conductive material are attached, the ground contacts having abutting portions that are electrically connected to a ground pattern on the mounting surface and that are biased to make contact with a chassis of the display device arranged on the side opposite the mounting surface. (2) The backlight substrate according to (1) above, in which contact holes are formed penetrating from the mounting surface to the opposite surface, and the ground contacts are attached such that the abutting portions pass through the contact holes and are exposed on the opposite surface. (3) The backlight substrate according to (1) or (2) above, in which the ground contacts are fixed to the ground pattern on the mounting surface by soldering. (4) The backlight substrate according to (3) above, in which the opposite surface is structured to be adhered to the chassis with double-sided tape, and the spring repulsion force for biasing the abutting portions of the ground contacts is weaker than the peel strength of the double-sided tape. (5) The backlight substrate according to (4) above, wherein the solder strength between the ground contact and the ground pattern is stronger than the peel strength of the double-sided tape. (6) The backlight substrate according to any one of (1) to (5) above, wherein the ground contact has: a joint portion joined to the ground pattern, a spring portion formed by bending a surface continuous with the joint portion, and the abutment portion formed by bending the spring portion. (7) The backlight substrate according to any one of (1) to (6) above, wherein a light-emitting driver is mounted on the backlight substrate that drives the light-emitting elements to emit light based on a control signal. (8) The backlight substrate according to any one of (1) to (7) above, wherein each of a plurality of terminals solder-joined to the conductive pattern wiring on the mounting surface is fitted with a connector structured to protrude in both directions relative to the longitudinal direction of the housing.(9) The backlight substrate according to (8) above, wherein a connector hole is formed penetrating from the mounting surface to the opposite surface, and the connector has a plurality of terminals solder-bonded on the mounting surface with the housing penetrating the connector hole. (10) The backlight substrate according to (9) above, wherein an electric wire attachment portion is provided at a position on the opposite surface of the housing where the wire attachment portion penetrates the connector hole. (11) The backlight substrate according to any of (8) to (10) above, wherein the plurality of solder-bonded terminals are formed in a straight line. (12) The backlight substrate according to any of (8) to (11) above, wherein some of the terminals of the connector are used as jumpers that electrically connect patterns provided on both sides in the longitudinal direction of the connector. (13) The backlight substrate according to any of (8) to (12) above, wherein a power supply pattern is formed so as to be electrically continuous on both sides in the longitudinal direction of the connector via the terminals of the connector. (14) The backlight substrate according to any one of (1) to (13) above, which is a single-layer substrate having a conductive pattern wiring formed on one side of an insulating layer, or a single-layer substrate having a conductor layer covered on both sides with insulating layers and having a conductive pattern wiring formed on one of the insulating layers. (15) A display device in which a backlight substrate is disposed behind a display surface, the backlight substrate having only one side serving as a mounting surface on which the conductive pattern wiring is formed, light-emitting elements mounted on the mounting surface, and ground contacts made of a conductive material are attached, the ground contacts being electrically connected to the ground pattern on the mounting surface and having a contact portion that is biased to come into contact with a chassis of the display device disposed on the side opposite the mounting surface. (16) The display device according to claim 15, wherein the backlight substrate is fitted with a connector in which each of a plurality of terminals solder-bonded to the conductive pattern wiring on the mounting surface protrudes on both sides in the longitudinal direction of the housing. The display device according to (15).

[0089] Also in this disclosure, the connector 30 shown in Figure 15 has the following configuration (100): (100) A connector in which a plurality of terminals to be solder-joined on a board are formed and arranged so as to protrude in both directions relative to the longitudinal direction of the housing, and a wire attachment portion is formed in the housing so as to be located on the opposite side of the board from the plurality of solder-joined terminals when the housing is attached to the board in a state in which the wire attachment portion passes through holes formed in the board.

[0090] REFERENCE SIGNS LIST 1 display device 3 backlight substrate 3a mounting surface 3b opposite surface 4 ground pattern 5 LED 6 LED driver 7 driver wiring pattern 8 LED wiring pattern 9a, 9b power supply pattern 15 chassis 16 contact hole 17 connector hole 20 ground contact 21 solder joint portion 22 spring portion 23 abutting portion 24 base portion 30 connector 31 terminal 32 terminal 33 housing

Claims

1. A backlight substrate for a display device, only one of whose surfaces is a mounting surface on which conductive pattern wiring is formed, on which light-emitting elements are mounted, and on which ground contacts made of a conductive material are attached, the ground contacts being electrically connected to the ground pattern on the mounting surface and having abutments that are biased to make contact with the chassis of the display device located on the opposite side of the mounting surface.

2. A backlight substrate as described in claim 1, wherein a contact hole is formed that penetrates from the mounting surface to the opposite surface, and the ground contact is attached in a state where the abutment portion passes through the contact hole and is exposed on the opposite surface.

3. The backlight substrate according to claim 1, wherein the ground contact is fixed to the ground pattern on the mounting surface by soldering.

4. A backlight substrate as described in claim 3, wherein the opposite surface is structured to be adhered to the chassis with double-sided tape, and the spring repulsion force for biasing the abutment portion of the ground contact is weaker than the peel strength of the double-sided tape.

5. The backlight substrate according to claim 4, wherein the solder strength between the ground contact and the ground pattern is stronger than the peel strength of the double-sided tape.

6. The backlight substrate according to claim 1, wherein the ground contact has: a joint portion that is joined to the ground pattern; a spring portion that is formed by bending a surface that is continuous with the joint portion; and the abutment portion that is formed by bending the spring portion.

7. The backlight board according to claim 1, further comprising a light emitting driver for driving the light emitting elements to emit light based on a control signal.

8. A backlight substrate as described in claim 1, wherein a connector is attached in which each of a plurality of terminals solder-joined to the conductive pattern wiring on the mounting surface is structured to protrude in both directions relative to the longitudinal direction of the housing.

9. A backlight substrate as described in claim 8, wherein a connector hole is formed that penetrates from the mounting surface to the opposite surface, and the connector is such that a plurality of the terminals are soldered on the mounting surface with the housing passing through the connector hole.

10. The backlight substrate according to claim 9, wherein an electric wire attachment portion is provided at a position on the opposite surface of the housing that passes through the connector hole.

11. The backlight substrate according to claim 8, wherein the plurality of terminals to be soldered are formed in a straight line.

12. The backlight substrate according to claim 8, wherein some of the terminals of the connector are used as jumpers for electrically connecting patterns provided on both sides of the connector in the longitudinal direction.

13. The backlight substrate according to claim 8, wherein the power supply pattern is formed so as to be electrically continuous on both sides of the longitudinal direction of the connector via the terminals of the connector.

14. A backlight substrate as described in claim 1, which is a single-layer substrate having a conductive pattern wiring formed on one side of an insulating layer, or a single-layer substrate having a conductor layer covered on both sides with insulating layers and having a conductive pattern wiring formed on one of the insulating layers.

15. A display device in which a backlight substrate is arranged on the back of a display surface, only one side of the backlight substrate is a mounting surface on which conductive pattern wiring is formed, light-emitting elements are mounted on the mounting surface, and ground contacts made of a conductive material are attached which are electrically connected to the ground pattern on the mounting surface and have a contact portion that is urged into contact with a chassis of the display device arranged on the side opposite the mounting surface.

16. A display device as described in claim 15, wherein the backlight substrate is fitted with a connector in which each of a plurality of terminals solder-joined to the conductive pattern wiring on the mounting surface is structured to protrude on both sides of the longitudinal direction of the housing.

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