JP2015213001A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device which includes a back light which has desired luminance distribution and in which a problem of heat radiation hardly occurs.SOLUTION: A display device includes: a rectangular screen 160; long substrates 211, 212; and LEDs 220 which are a plurality of light emitting elements arrayed in the longitudinal direction of the substrates 211, 212 respectively. When viewed from a direction vertical to the screen 160, a first end 211a of the substrate 211 and a first end 212a of the substrate 212 are located between a central line 163 of two opposing sides 161, 162 and the side 161 of the screen 160, a second end 211b of the substrate 211 and a second end 212b of the substrate 212 are located between the central line 163 and the side 162. A distance A from the first end 211a of the substrate 211 to the side 161 is shorter than a distance B from the second end 211b of the substrate 211 to the side 162. A distance A from the second end 212b of the second substrate 212 to the second side 162 is shorter than a distance B from the first end 212a of the second substrate 212 to the first side 161.

Description

  The present invention relates to a display device.

  A liquid crystal display as an example of a display device generally includes a liquid crystal panel, a light source (backlight), a control circuit that controls each component of the liquid crystal panel, a power supply circuit that supplies power to the liquid crystal panel and the control circuit, and the like. Configured.

  The light source is composed of, for example, a plurality of LEDs (Light Emitting Diodes). The plurality of LEDs are, for example, arranged in a line in the longitudinal direction on an LED substrate (or simply referred to as a substrate) formed of a long plate-like member, and fixed to a support (for example, Patent Document 1). Hereinafter, a module in which the plurality of LEDs are arranged on the substrate is referred to as an LED bar.

JP 2011-34956 A JP 2011-49149 A

  In the liquid crystal display, it is required to reduce the component cost while ensuring the desirable illumination characteristics and heat dissipation of the backlight. These requirements are interrelated. For example, if the material of the LED substrate is changed from aluminum to resin in order to reduce the component cost, the heat dissipation is reduced.

  As a desirable illumination characteristic of the backlight, a luminance distribution in which the luminance at the center of the screen is higher than the luminance at the periphery may be required. In order to obtain such a luminance distribution, for example, in the display device of Patent Document 1, it is conceivable to arrange a larger number of LEDs by narrowing the arrangement interval of LEDs near the center of one LED bar. However, there is a possibility that the heat radiation may be hindered by narrowing the arrangement interval of the LEDs. The problem of heat dissipation is particularly likely to occur when an inexpensive resin material is used for the LED substrate.

  The present invention has been made to solve the above-described problems, and provides a display device including a backlight having a luminance distribution in which the luminance at the center of the screen is higher than the luminance at the periphery and is less likely to cause heat dissipation. The purpose is to do.

  In order to achieve the above object, a liquid crystal display device according to one embodiment of the present invention includes a rectangular screen, elongated first and second substrates, the first substrate, and the second substrate. A plurality of light emitting elements arranged in the respective longitudinal directions, and when viewed from a direction perpendicular to the screen, the first end of the first substrate and the first end of the second substrate are The second end of the first substrate and the second end of the second substrate are located between the center line of the two opposing sides and the first side which is one of the two sides. And the second side which is the other of the two sides, and the distance from the first end of the first substrate to the first side is from the second end of the first substrate to the second side. The distance from the second end of the second substrate to the second side is shorter than the distance from two sides to the first end of the second substrate. Shorter than the distance of up to.

  According to such a configuration, the first substrate and the second substrate overlap in the direction parallel to the two sides near the center of the screen. Therefore, the first substrate and the second substrate are offset in the direction in the vicinity of the center of the screen and arranged with an interval in the direction. As a result, it is possible to provide a display device including a backlight that has a luminance distribution in which the luminance at the center of the screen is higher than the luminance at the periphery and is less likely to cause heat dissipation.

  Further, the longitudinal directions of the first substrate and the second substrate may be inclined from a direction orthogonal to the two sides.

  Further, the first end of the first substrate and the second end of the second substrate may be located on one straight line orthogonal to the two sides.

  According to such a configuration, the above-described effects can be obtained by arranging the first substrate and the second substrate so as to be offset on both sides of a straight line orthogonal to the two sides.

  Moreover, you may provide the some board | substrate pair which each consists of a said 1st board | substrate and a said 2nd board | substrate.

  According to such a configuration, for example, when the screen is large, the same effect as described above can be obtained using the plurality of substrate pairs.

  The first substrate and the second substrate may be arranged in a point-symmetric shape with a point of intersection of diagonal lines of the screen as a symmetric point.

  With such a configuration, a good luminance distribution with high symmetry within the screen can be obtained.

  The plurality of light emitting elements are arranged on the first substrate and the second substrate at regular intervals, and any light emitting element on the first substrate and any light emitting element on the second substrate The interval between them may be equal to or larger than the regular interval.

  According to such a structure, since the space | interval of the light emitting element on a different board | substrate becomes equal to or larger than the space | interval of the light emitting element arranged on each board | substrate, favorable heat dissipation can be obtained more reliably.

  According to the display device of one embodiment of the present invention, a display device including a backlight having a luminance distribution in which the luminance at the center of the screen is higher than the luminance at the periphery and the problem of heat dissipation is unlikely to occur.

2 is an exploded perspective view showing an example of a configuration of a liquid crystal display according to Embodiment 1. FIG. 6 is a front view showing an example of an arrangement of LED bars according to a comparative example of Embodiment 1. FIG. 6 is a diagram illustrating an example of a luminance distribution according to a comparative example of Embodiment 1. FIG. 6 is a graph showing an example of a relationship between an LED arrangement interval and a rear frame temperature according to the first embodiment. 5 is a graph showing an example of a relationship between an LED arrangement interval and a substrate temperature according to Embodiment 1; 3 is a front view showing an example of an arrangement of LED bars according to Embodiment 1. FIG. 3 is a front view showing an example of an arrangement of LED bars according to Embodiment 1. FIG. 6 is a diagram showing an example of a luminance distribution according to Embodiment 1. FIG. 10 is a front view showing an example of an arrangement of LED bars according to a comparative example of Embodiment 2. FIG. 6 is a front view showing an example of an arrangement of LED bars according to Embodiment 2. FIG. 10 is a front view showing an example of an arrangement of LED bars according to a comparative example of Embodiment 2. FIG. 6 is a front view showing an example of an arrangement of LED bars according to Embodiment 2. FIG. 10 is a front view showing an example of an arrangement of LED bars according to a comparative example of Embodiment 3. FIG. 12 is a front view showing an example of an arrangement of LED bars according to Embodiment 3. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that each of the embodiments described below shows a specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement of constituent elements, connection forms, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims are described as arbitrary constituent elements.

(Embodiment 1)
The display device according to the first embodiment will be described with an example of a liquid crystal display based on FIGS.

  FIG. 1 is an exploded perspective view showing an example of the configuration of the liquid crystal display 10.

  As shown in FIG. 1, the liquid crystal display 10 includes a front cabinet 11, a bezel 12, an open cell 13, a cell guide 14, an optical member 15, a reflecting member 16, a rear frame 17, and a light source 20.

  The front cabinet 11 and the rear frame 17 are housings of the liquid crystal display 10 in the present embodiment. For example, the front cabinet 11 and the rear frame 17 may be made of resin.

  The bezel 12 is a member that supports the open cell 13.

  The open cell 13 includes a liquid crystal panel, a COF (Chip on Film, Chip on Flexible), and a PCB (Printed Circuit Board, printed circuit board). The COF is a flexible cable equipped with an IC (Integrated Circuit) that drives a liquid crystal panel. The IC generates a drive signal for driving the liquid crystal panel based on a signal from a control circuit (not shown) input via the PCB.

  The cell guide 14 is a member for preventing displacement of the open cell 13.

  The optical member 15 is a member for adjusting the luminance or the like of light from the light source 20, and is composed of an optical sheet and a diffusion plate.

  The reflection member 16 is a sheet-like member that reflects light from the light source 20.

  The light source 20 is an LED bar in which a plurality of light emitting elements 22 are arranged in a longitudinal direction on a long rectangular substrate 21 and constitutes a backlight of the liquid crystal display 10. The light emitting element 22 is composed of, for example, an LED. The light source 20 is attached to the reflecting member 16 via, for example, a heat dissipation tape (not shown). The dotted line in FIG. 1 is a straight line indicating the arrangement position of one conventional LED bar. Hereinafter, such an arrangement position of the conventional LED bar is referred to as an axis. In the present embodiment, two LED bars are arranged on both sides of the shaft instead of the conventional one LED bar.

  Below, the arrangement | positioning of the LED bar which concerns on this Embodiment is demonstrated in detail based on the comparison with the conventional arrangement | positioning, and the effect acquired by such arrangement | positioning is demonstrated.

  FIG. 2 is a front view showing an example of the arrangement of the LED bar 200 according to the comparative example as seen from the direction perpendicular to the screen 160. The arrangement of the LED bar 200 is projected onto the screen 160 of the liquid crystal display 10 by vertical projection. Represents. As shown in FIG. 2, the screen 160 is a horizontally long rectangle as an example. Specifically, the screen 160 may be a display surface of a liquid crystal panel constituting the open cell 13 shown in FIG. 1.

  In the comparative example of FIG. 2, one LED bar 200 is arranged on an axis substantially parallel to the upper side and the lower side of the screen 160. The LED bar 200 is configured by arranging a plurality of LEDs 220 on a long substrate 210. The LEDs 220 located outside the center are arranged at a constant interval L0, and the central LEDs 220 are arranged at an interval L1 that is narrower than the interval L0.

  FIG. 3 is a diagram showing an example of the luminance distribution in the screen obtained by the LED bar 200 arranged as shown in FIG. According to the LED bar 200 of the comparative example, a desired luminance distribution in which the luminance at the center of the screen is higher than the luminance at the periphery can be obtained.

  However, as pointed out in the problem column, in order to obtain such a luminance distribution, there is a concern that reducing the arrangement interval of the LEDs near the center of the LED bar causes a problem of heat dissipation. Therefore, the present inventor confirmed by simulation what kind of temperature rise each of the rear frame 17 and the substrate 210 shows according to the arrangement interval of the LEDs.

  FIG. 4 is a graph showing the temperature rise of the rear frame 17 with respect to the LED arrangement interval for a plurality of LED drive currents.

  FIG. 5 is a graph showing the temperature rise of the substrate 210 with respect to the LED arrangement interval for a plurality of LED drive currents.

  4 and 5, both the rear frame 17 and the substrate 210 have a larger temperature rise as the LED arrangement interval is narrower. From this result, in order to make the problem of heat dissipation difficult to occur, it is considered effective to widen the arrangement interval of the LEDs.

  Therefore, in the embodiment, instead of the single LED bar of the comparative example, two LED bars are arranged offset above and below the position where the comparative example LED bar is arranged.

  FIG. 6 is a front view showing an example of the arrangement of the LED bars 201 and 202 according to the embodiment when viewed from the direction perpendicular to the screen 160, and the arrangement of the LED bars 201 and 202 is the same as the notation in FIG. Is represented by vertical projection onto the screen 160 of the liquid crystal display 10.

  In the embodiment of FIG. 6, the LED bar 201 is configured by arranging a plurality of LEDs 221 at a constant interval L0 on a long substrate 211. The LED bar 202 is configured by arranging a plurality of LEDs 222 on a long substrate 212 at a constant interval L0.

  Here, the LED bars 201 and 202 correspond to the light source 20, the substrates 211 and 212 correspond to the substrate 21, and the LEDs 221 and 222 correspond to the light emitting element 22.

  LED bar 201,202 is arrange | positioned so that the following conditions may be satisfy | filled.

  The substrate 211 and the substrate 212 have substantially the same length.

  The first end 211a in the longitudinal direction of the substrate 211 and the first end 212a in the longitudinal direction of the substrate 212 are the center line 163 of the first side 161 and the second side 162 facing each other on the screen 160, and the first side 161. Is located between. Here, the center line 163 is a straight line that is at the same distance from both the first side 161 and the second side 162.

  The second end 211 b in the longitudinal direction of the substrate 211 and the second end 212 b in the longitudinal direction of the substrate 212 are located between the center line 163 and the second side 162.

  Further, the distance A from the first end 211 a of the substrate 211 to the first side 161 is shorter than the distance B from the second end 211 b of the substrate 211 to the second side 162.

  Further, the distance A from the second end 212 b of the substrate 212 to the second side 162 is shorter than the distance B from the first end 212 a of the substrate 212 to the first side 161.

  When the LED bars 201 and 202 are arranged in this way, the LED bars 201 and 202 overlap in the direction parallel to the first side 161 and the second side 162 near the center of the screen 160, as shown in FIG. . That is, they overlap in the vertical direction of the drawing. Therefore, the LED bars 201 and 202 are arranged so as to be offset above and below the axis on which the LED bar 200 of the comparative example is located, so that the same number of LEDs as the LEDs arranged by the conventional LED bar 200 are arranged in the center of the screen 160. A space L2 is provided above and below in the vicinity. Here, the interval L2 is equal to or larger than the interval L0.

  As a result, it is possible to provide the liquid crystal display 10 including a backlight having a luminance distribution in which the central luminance of the screen 160 is higher than that of the peripheral luminance and hardly causing heat dissipation.

  FIG. 7 is a front view showing an example of the arrangement of the LED bars 201 and 202 according to another embodiment. Similar to the notation in FIG. 2, the arrangement of the LED bars 201 and 202 is changed to the screen 160 of the liquid crystal display 10. Represented by vertical projection to

  The embodiment of FIG. 7 differs from the embodiment of FIG. 6 in that the longitudinal directions of the substrates 211 and 212 are inclined by an angle θ from the direction perpendicular to the first side 161 and the second side 162. The first end 211 a of the substrate 211 and the second end 212 b of the substrate 212 may be located on one straight line orthogonal to the first side 161 and the second side 162.

  FIG. 8 is a diagram showing an example of the luminance distribution in the screen obtained by the LED bars 201 and 202 having the arrangement shown in FIG. According to the LED bars 201 and 202 of the example, similarly to the LED bar 200 of the comparative example, a desired luminance distribution in which the luminance at the center of the screen is higher than the luminance at the periphery can be obtained.

(Embodiment 2)
A display device according to Embodiment 2 will be described with reference to FIGS.

  The display device according to the second embodiment is to be compared with a comparative example including a plurality of LED bars, and the pair of LED bars 201 and 202 described in the first embodiment is replaced with the plurality of LED bars of the comparative example. It is provided corresponding to each of.

  FIG. 9 is a front view showing an example of the arrangement of the two LED bars 200 according to the comparative example viewed from the direction perpendicular to the screen 160. The arrangement of the LED bars 200 is arranged on the screen 160 of the liquid crystal display 10. Represented by vertical projection.

  FIG. 10 is a front view illustrating an example of the arrangement of the LED bars 201 and 202 according to the embodiment when viewed from the direction perpendicular to the screen 160. The arrangement of the LED bars 201 and 202 is directed to the screen 160 of the liquid crystal display 10. This is represented by vertical projection.

  In the example of FIG. 10, a pair of LED bars 201 and 202 is arranged corresponding to the position of each LED bar 200 of the comparative example. The LED bars 201 and 202 are arranged so as to satisfy the same conditions as those described with reference to FIG.

  FIG. 11 is a front view showing an example of the arrangement of the three LED bars 200 according to the comparative example as seen from the direction perpendicular to the screen 160. The arrangement of the LED bars 200 on the screen 160 of the liquid crystal display 10 is shown. Represented by vertical projection.

  FIG. 12 is a front view illustrating an example of the arrangement of the LED bars 201 and 202 according to the embodiment when viewed from the direction perpendicular to the screen 160. The arrangement of the LED bars 201 and 202 is directed to the screen 160 of the liquid crystal display 10. This is represented by vertical projection.

  In the example of FIG. 12, a pair of LED bars 201 and 202 is arranged corresponding to the position of each LED bar 200 of the comparative example. The LED bars 201 and 202 are arranged so as to satisfy the same conditions as those described with reference to FIG.

  When the LED bars 201 and 202 are arranged in this way, the LED bars 201 and 202 are parallel to the first side 161 and the second side 162 in the vicinity of the center of the screen 160 as seen in FIGS. Overlap. That is, they overlap in the vertical direction of the drawing. Therefore, by arranging the LED bars 201 and 202 so as to be offset above and below the axis on which the LED bar 200 of the comparative example is located, the same number of LEDs as the LEDs arranged on the LED bar 200 are arranged near the center of the screen 160. It arrange | positions by providing the space | interval L2 up and down. Here, the interval L2 is equal to or larger than the interval L0.

  As a result, it is possible to provide the liquid crystal display 10 including a backlight having a luminance distribution in which the central luminance of the screen 160 is higher than that of the peripheral luminance and hardly causing heat dissipation.

(Embodiment 3)
A display device according to Embodiment 3 will be described with reference to FIGS.

  The display device according to the third embodiment is to be compared with a comparative example including a plurality of LED bars, and the pair of LED bars 201 and 202 described in the first embodiment is replaced with the plurality of LED bars of the comparative example. It is provided corresponding to each of.

  FIG. 13 is a front view showing an example of the arrangement of the two LED bars 200 according to the comparative example as viewed from the direction perpendicular to the screen 160. The arrangement of the LED bars 200 on the screen 160 of the liquid crystal display 10 is shown. Represented by vertical projection.

  In the comparative example of FIG. 13, unlike the comparative example of FIG. 11, the LED bar 200 is arranged on an axis substantially parallel to the left and right sides of the screen 160.

  FIG. 14 is a front view illustrating an example of the arrangement of the LED bars 201 and 202 according to the embodiment when viewed from the direction perpendicular to the screen 160. The arrangement of the LED bars 201 and 202 is directed to the screen 160 of the liquid crystal display 10. This is represented by vertical projection.

  In the example of FIG. 14, a pair of LED bars 201 and 202 is arranged corresponding to the position of each LED bar 200 of the comparative example. The LED bars 201 and 202 are arranged so as to satisfy the same conditions as those described with reference to FIG.

  However, in the example of FIG. 14, the upper side and the lower side of the screen 160 correspond to the first side 161 and the second side 162.

  When the LED bars 201 and 202 are arranged in this way, the LED bars 201 and 202 overlap in the direction parallel to the first side 161 and the second side 162 near the center of the screen 160 as shown in FIG. . That is, they overlap in the left-right direction of the drawing. Therefore, by arranging the LED bars 201 and 202 so as to be offset to the left and right of the axis where the LED bar 200 of the comparative example is located, the same number of LEDs as the LEDs arranged on the LED bar 200 are arranged near the center of the screen 160. It arrange | positions by providing the space | interval L2 on right and left. Here, the interval L2 is equal to or larger than the interval L0.

  As a result, it is possible to provide the liquid crystal display 10 including a backlight that has a luminance distribution in which the central luminance of the screen 160 is higher than the peripheral luminance and is less likely to cause heat dissipation.

  The display device according to the embodiment of the present invention has been described above, but the present invention is not limited to this embodiment. Unless it deviates from the meaning of this invention, the form which gave various deformation | transformation which those skilled in the art can think to this Embodiment can be contained in the scope of the present invention.

  INDUSTRIAL APPLICABILITY The present invention is useful for a display device including a backlight having a luminance distribution in which the luminance at the center of the screen is higher than the luminance at the periphery and is less likely to cause heat dissipation.

DESCRIPTION OF SYMBOLS 10 Liquid crystal display 11 Front cabinet 12 Bezel 13 Open cell 14 Cell guide 15 Optical member 16 Reflective member 17 Rear frame 20 Light source 21 Substrate 22 Light emitting element 160 Screen 161 1st edge 162 2nd edge 163 Centerline 200, 201, 202 LED bar 210, 211, 212 Substrate 220, 221, 222 LED

Claims (6)

A rectangular screen;
A long first substrate and a second substrate;
A plurality of light emitting elements arranged in the longitudinal direction on each of the first substrate and the second substrate,
Seen from the direction perpendicular to the screen,
The first end of the first substrate and the first end of the second substrate are located between a center line of two opposite sides of the screen and a first side which is one of the two sides,
The second end of the first substrate and the second end of the second substrate are located between the center line and a second side that is the other of the two sides,
The distance from the first end of the first substrate to the first side is shorter than the distance from the second end of the first substrate to the second side,
A distance from the second end of the second substrate to the second side is shorter than a distance from the first end of the second substrate to the first side;
Display device. Each longitudinal direction of the first substrate and the second substrate is inclined from a direction orthogonal to the two sides,
The display device according to claim 1. The first end of the first substrate and the second end of the second substrate are located on one straight line orthogonal to the two sides,
The display device according to claim 2. Each comprising a plurality of substrate pairs comprising the first substrate and the second substrate;
The display device according to claim 1. The display device according to claim 1, wherein the first substrate and the second substrate are arranged in a point-symmetric shape with a point of intersection of a diagonal line of the screen as a symmetric point. The plurality of light emitting elements are arranged on the first substrate and the second substrate at regular intervals,
The interval between any light emitting element on the first substrate and any light emitting element on the second substrate is equal to or greater than the constant interval,
The display apparatus of any one of Claims 1-5.