JP2019197093A - Display device and illumination device - Google Patents

Abstract

To provide a display device having followability of a back light to a display image.SOLUTION: A display device 1 comprises a display panel 10 for displaying an image and a plurality of light sources 22, which are arranged so that intervals between adjacent light sources 22 are equal, for backlighting the display panel 10. Each of the light sources 22 is disposed in each lighting area 40 obtained by dividing the display panel into honeycomb-shaped sections, at a center of the lighting area 40. The display device 1 further comprises partitions 31 for dividing the lighting areas 40.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a display device and a lighting device.

  Conventionally, as a control of a liquid crystal display panel for displaying an image and a backlight having a plurality of light sources for illuminating the liquid crystal display panel from the back, the display surface of the liquid crystal display panel is divided into a plurality of display areas. A technique (local dimming control) for detecting the maximum value (peak luminance value) of the luminance value of each pixel and controlling the brightness of the backlight for each display area according to the peak luminance value is known (Patent Literature). 1).

JP 2007-279395 A

  Conventional display devices including Patent Document 1 divide a display area into a grid, and a light source illuminates with a required luminance for each display area.

  Here, the display device as a vehicle instrument displays a large number of curvilinear display images such as a speedometer and an engine speed meter. When such a display device tries to draw a curved display image by controlling the light source for each display area divided in a grid pattern, the luminance of the light source can be controlled only at the linear boundary of the display area. . For this reason, the display device makes the boundary between the light source with high brightness and the light source with low brightness stand out.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a display device and an illumination device having a backlight follow-up property with respect to a display image.

  In order to solve the above-described problems, a display device according to the present invention includes a display panel that displays an image and a plurality of light sources that illuminate the display panel from the back, so that the distances between adjacent light sources are equal. And a light source disposed.

  In the display device and the illumination device according to the present invention, the backlight can follow the display image.

The front view which shows embodiment of the display apparatus which concerns on this invention. Schematic explanatory drawing of the light source substrate which has a display panel and a backlight unit. The figure which shows the shape of the partition 31 in the peripheral edge 32 of case 30. FIG.

  Embodiments of a display device according to the present invention will be described with reference to the accompanying drawings. The display device according to the present invention can be applied to all display devices including a display panel having a backlight. For example, the display device is mounted on a vehicle such as an automobile or a motorcycle, a ship, an agricultural machine, or a construction machine. In this embodiment, the display device according to the present invention will be described using an example in which the display device is a display device mounted on an automobile and having a liquid crystal display panel.

  FIG. 1 is a front view showing a display device 1 which is an embodiment of a display device according to the present invention.

  FIG. 2 is a schematic explanatory view of the light source substrate 21 having the display panel 10 and the backlight unit 20. 2A is a front view, and FIG. 2B is a cross-sectional view taken along the line BB in FIG. 2A.

  In the following description, the “front side” means the near side in FIG. 1 and the upper side (display panel 10 side) in FIG. 2B and the side that is visible to the viewer (driver). “Back side” means the back side in FIG. 1 and the lower side (light source substrate 21 side) in FIG.

  The display device 1 mainly includes a display panel 10, a backlight unit 20, a circuit board (not shown), and a case 30.

  The display panel 10 is a TFT (Thin Film Transistor) liquid crystal display panel. The display panel 10 has a pair of surface glass substrates that enclose a liquid crystal layer. Transparent electrodes are formed on the pair of glass substrates with ITO (Indium Tin Oxide) or the like. The display panel 10 has a pair of surface polarizing plates (polarizing filters) arranged so as to sandwich the pair of surface glass substrates. The display panel 10 is connected to a circuit board via FPC (Flexible Printed Circuits). The display panel 10 is controlled by a control unit of the circuit board, so that a driving voltage is applied to the liquid crystal layer through the transparent electrode. Thereby, the orientation of the liquid crystal molecules in the liquid crystal layer is controlled, and the transmittance of each pixel 11 of the display panel 10 changes. By such a combination of the pixels 11, the display panel 10 displays a substantially circular curved image such as the speedometer 10a and the engine speed meter 10b, and images such as various vehicle information and navigation information.

  The backlight unit 20 as an illumination device is provided on the back side of the display panel 10. The backlight unit 20 includes a light source substrate 21 and a light guide (not shown), and illuminates the display panel 10 from the back side. The light source substrate 21 is mounted with a plurality of LEDs (Light Emitting Diodes) 22 which are an example of a light source. The light source substrate 21 is connected to the circuit board through a flexible substrate such as an FPC. The LED 22 emits light toward the display panel 10 (light guide) when a drive current is supplied. The light guide guides the light emitted from the LED 22 toward the display panel 10. The light guide is a transparent resin such as polymethyl methacrylate resin (PMMA) formed in a flat plate shape.

  As shown in FIG. 2A, each LED 22 illuminates the display panel 10 divided into a plurality of lighting areas 40 from the back for each lighting area 40. Each lighting region 40 includes a plurality of pixels 11 (for example, four in the direction along the line BB in FIG. 2B). For this reason, one LED 22 illuminates the plurality of pixels 11 included in the lighting region 40. In other words, the lighting region 40 is an illumination range of one LED 22, and the illumination range includes a plurality of pixels 11.

  The lighting region 40 is partitioned into a honeycomb shape by being partitioned by the partition 31 of the case 30. And LED22 is arrange | positioned so that it may be located in the center in this lighting area | region 40 (hexagon). Thereby, it arrange | positions so that the distance between adjacent LED22 may become equal. For example, the LEDs adjacent to the LED 22a in FIG. 2A are the LEDs 22b to 22f, and the LEDs 22b to 22f are all arranged so that the distance from the LED 22a is equal.

  In FIG. 2, an example in which one LED 22 is arranged in each lighting area 40 is shown, but a plurality of LEDs may be arranged in one lighting area 40. Even in such a case, a pair of LEDs included in one lighting area 40 is positioned at the center of the lighting area 40, and the distance between a pair of LEDs between adjacent lighting areas is equal. ing.

  The circuit board mainly has a control unit for controlling the display panel 10 and the backlight unit 20. The control unit includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, and executes predetermined arithmetic processing according to a program written in the ROM, for example. For example, the control unit acquires vehicle speed, engine speed, various vehicle information, navigation information, and the like from an ECU (Electronic Control Unit) of the vehicle via various sensors. Based on the acquired information, the control unit forms a speedometer 10a, an engine speed meter 10b, and the like on the display panel 10, and displays the information.

  The control unit functions as a so-called GDC (Graphics Display Controller), generates a necessary image, and displays the image on the display panel 10. Further, the control unit controls the transmittance of each pixel 11 by controlling the driving voltage of the liquid crystal layer. Furthermore, a control part controls the brightness | luminance of each LED22 according to the image to display.

  The case 30 accommodates the display panel 10, the backlight unit 20, and the circuit board in the internal space. The case 30 constitutes the appearance of the display device 1. Further, the case 30 has a partition 31 for separating the irradiation range between the LEDs 22 and forming the lighting region 40 as a separate part from the case 30. The partition 31 is a standing wall that divides the light source substrate 21 (the back surface of the display panel 10) into a honeycomb shape, the front surface has a predetermined gap with the display panel 10, and the back surface is in contact with the light source substrate 21.

  Since the partition 31 forms a hexagon, the hexagon cannot follow the periphery of the display panel 10 that is a quadrangle. Here, FIG. 3 is a diagram showing the shape of the partition 31 at the peripheral edge 32 of the case 30.

  In the peripheral edge 32 of the case 30, the partition 31 forms a deformed square, pentagon, or hexagon, and forms a closed lighting region 40 together with the peripheral edge 32. At this time, a side that forms a quadrangle in which the variation in the area of the lighting region 40 increases is formed on the short side of the display panel 10. Further, the side forming the pentagon having a small (or no) area variation is formed on the long side of the display panel 10. For this purpose, the honeycomb shape is formed so that one diagonal line of the hexagon coincides with the direction of the short side. Thereby, the display device 1 can minimize the variation in the area of the unintended lighting region 40 at the peripheral edge 32.

  Here, in the case where the display panel 10 divided into the plurality of lighting regions 40 includes a plurality of LEDs 22 that illuminate from the back for each lighting region 40 as in the display device 1 in the present embodiment, the local dimming control is performed. Used. The local dimming control is used for a television or the like, and controls the luminance for each lighting area 40 corresponding to each LED 22.

  The display device 1 is mounted on an automobile and displays a number of substantially circular curved display images such as a speedometer 10a and an engine speed meter 10b. The display device 1 in the present embodiment can improve the followability of the backlight with respect to the display image, particularly when displaying a curved display image.

  That is, the display apparatus 1 arrange | positions LED22 so that the distance between adjacent LED22 may become equal, and made the boundary of the lighting area | region 40 between adjacent LED22 approach the curve. Specifically, the display device 1 is divided into a honeycomb shape that is a hexagonal shape that is closest to a circle among shapes such as a triangle, a quadrangle, and a hexagon that can be planarly filled on the light source substrate 21. A lighting region 40 having a shape was formed, and each LED 22 was arranged at the center of the lighting region 40. Compared with the case where the lighting region 40 is formed in a lattice shape, the followability of the backlight to the display image can be improved when the display panel 10 draws a curved display image. That is, the display device 1 can form the boundary of the lighting region 40 having different luminance when drawing a curved display image as curved as possible, and the light leakage at the boundary can be made inconspicuous.

  Further, in the display device 1, the case 30 has a honeycomb-shaped partition 31. The honeycomb shape generally has a high structural strength per unit area. Thereby, compared with the case where a grid | lattice-like partition is provided, the intensity | strength of case 30 can be improved and the load to the display panel 10 can also be eased by extension. Moreover, as a result of improving the strength, the case 30 can be made thinner and lighter.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  For example, the lighting area 40 has been described as being partitioned by the partition 31 of the case 30, but the case 30 does not have the partition 31 as long as the distance between the adjacent LEDs 22 is equal. Also good. Further, when there is no partition 31, for example, the lighting region 40 is formed in a honeycomb shape with a light guide or the like, and the transmittance of the pixels 11 of the display panel 10 may be controlled according to the lighting region 40.

  The display panel 10 is not limited to a liquid crystal display panel, and may be a display panel having another backlight.

DESCRIPTION OF SYMBOLS 1 Display apparatus 10 Display panel 10a Speedometer 10b Engine speed meter 11 Pixel 20 Backlight unit 21 Light source board 22 LED
30 Case 31 Partition 32 Perimeter 40 Lighting area

Claims (4)

A display panel for displaying images,
A display device comprising: a plurality of light sources that illuminate the display panel from the back, and the light sources arranged so that the distances between adjacent light sources are equal.   The display device according to claim 1, wherein each of the light sources is arranged at a center of the lighting region in each lighting region partitioned into a honeycomb shape.   The display device according to claim 2, further comprising a partition that divides the lighting region. An illumination device having a plurality of light sources for illuminating a display panel for displaying an image from the back side,
The lighting device, wherein the plurality of light sources are arranged such that distances between adjacent light sources are equal.

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