JP2014053328A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device, a backlight device, and a light guide device which provide even illuminance and are thin.SOLUTION: According to an embodiment, a display device includes a light source, light guide means receiving light emitted from the light source, a display panel, and reflection means which is provided between the light guide means and the display panel, allows penetration of a part of light emitted from the light guide means toward the display panel and reflects a part of the light.

Description

  Embodiments described herein relate generally to a display device.

  In recent years, a liquid crystal display (LCD) has been widely used. The LCD includes a liquid crystal panel configured by disposing a liquid crystal material between a pair of glass substrates, and a backlight device that irradiates the liquid crystal panel with light from the back surface of the liquid crystal panel.

  A direct-type backlight device in which light sources are arranged in an array directly below a liquid crystal panel irradiates the liquid crystal panel with light through a diffusion plate or the like provided facing the liquid crystal panel. According to this method, there is a problem that the backlight device must be made thick in order to make the illuminance of the liquid crystal panel uniform.

JP 2010-272245 A

  A thin display device is provided.

  According to the embodiment, the display device includes a display panel, a light source provided to face a part of the display panel, and a light guide unit provided between the display panel and the light source. The light guiding means is opposed to the light source, a first end on which light emitted from the light source is incident, a second end extending to substantially the same position as an end of the display panel, and the display An emission surface that faces the panel and emits light to the display panel, and a curved curved portion that is continuous from the first end and guides light from the first end to the emission surface.

1 is a schematic block diagram of an image display system including an image display device 110 according to a first embodiment. 1 is a schematic block diagram of a display module 200. FIG. FIG. 2 is a horizontal sectional view of the backlight device 6 and the liquid crystal panel 1 according to the first embodiment. FIG. 2 is a top view of the backlight device 6 and the liquid crystal panel 1 according to the first embodiment. The graph which shows typically the brightness | luminance of the horizontal direction of the liquid crystal panel 1 when not providing the reflection layer 14. FIG. FIG. 4 is a bottom view of the reflective layer 14 as viewed from the direction A in FIG. 3. The bottom view of the reflection layer 14 which is a modification of FIG. The bottom view of the reflection layer 14 which is another modification of FIG. FIG. 6 is a horizontal sectional view of a backlight device 6 ′ and a liquid crystal panel 1 according to a second embodiment. The graph which shows typically the brightness | luminance of the horizontal direction of the liquid crystal panel 1 when not providing reflective layer 14 '. FIG. 10 is a bottom view of the reflective layer 14 ′ viewed from the direction B in FIG. 9.

  Hereinafter, embodiments will be specifically described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic block diagram of an image display system including an image display device 110 according to the first embodiment.

  The image display device 110 includes a control unit 156 that controls the operation of each unit, an operation unit 116, and a light receiving unit 118. The control unit 156 includes a ROM (Read Only Memory) 157, a RAM (Random Access Memory) 158, a CPU (Central Processing Unit) 159, and a flash memory 160.

  The control unit 156 is a system control program and various processing programs stored in advance in the ROM 157 according to an operation signal input from the operation unit 116 or an operation signal transmitted from the remote controller 117 and input via the light receiving unit 118. Start up. The control unit 156 uses the RAM 158 as a work memory of the CPU 159, and controls the operation of each unit according to the activated program. The control unit 156 stores and uses information necessary for various settings in a flash memory 160 that is a nonvolatile memory such as a NAND flash memory.

  The image display apparatus 110 includes an input terminal 144, a tuner 145, a PSK (Phase Shift Keying) demodulator 146, a TS (Transport Stream) decoder 147a, and a signal processing unit 120.

  The input terminal 144 transmits the satellite digital television broadcast signal received by the BS / CS digital broadcast reception antenna 143 to the satellite digital broadcast tuner 145. The tuner 145 tunes the received digital broadcast signal and transmits the tuned digital broadcast signal to the PSK demodulator 146. The PSK demodulator 146 demodulates the TS from the digital broadcast signal and transmits the demodulated TS to the TS decoder 147a. The TS decoder 147a decodes the TS into a digital signal including a digital video signal, a digital audio signal, and a data signal, and transmits these to the signal processing unit 120.

  Here, the digital video signal is a digital signal related to video that can be output by the image display device 110, and the digital audio signal is a digital signal related to audio that can be output from the image display device 110. The data signal is a digital signal indicating various information about the demodulated service.

  The image display apparatus 110 also includes an input terminal 149, a tuner unit 150 having two tuners 150a and 150b, two OFDM (Orthogonal Frequency Division Multiplexing) demodulators 151, two TS decoders 147b, and an analog tuner. 168 and an analog demodulator 169.

  The input terminal 149 transmits the terrestrial digital television broadcast signal received by the terrestrial digital broadcast receiving antenna 148 to the terrestrial digital broadcast tuner unit 150. The tuners 150a and 150b of the tuner unit 150 each tune the received digital broadcast signal, and transmit the tuned digital broadcast signal to two OFDM demodulators 151. The OFDM demodulator 151 demodulates the TS from the digital broadcast and transmits the demodulated TS to the corresponding TS decoder 147b. The TS decoder 147b decodes the TS into a digital video signal, an audio signal, and the like, and transmits these to the signal processing unit 120. The terrestrial digital television broadcast acquired by each of the tuners 150a and 150b of the tuner unit 150 includes a digital video signal, a digital audio signal, and a data signal simultaneously by two OFDM demodulators 151 and TS decoders 147b, respectively. After being decoded as a digital signal, it can be transmitted to the signal processing unit 120.

  The antenna 148 can also receive a terrestrial analog television broadcast signal. The received terrestrial analog television broadcast signal is distributed by a distributor (not shown) and transmitted to the analog tuner 168. The analog tuner 168 tunes the received analog broadcast signal and transmits the tuned analog broadcast signal to the analog demodulator 169. The analog demodulator 169 demodulates the analog broadcast signal and transmits the demodulated analog broadcast signal to the signal processing unit 120. Further, as an example, the image display apparatus 110 can also watch CATV by connecting a CATV (Common Antenna Television) tuner to an input terminal 149 to which an antenna 148 is connected.

  In addition, the image display device 110 includes a line input terminal 137, an audio processing unit 153, a speaker 115, a graphic processing unit 152, an OSD (On Screen Display) signal generation unit 154, a video processing unit 155, A display module 200.

The signal processing unit 120 performs appropriate signal processing on the digital signal transmitted from the TS decoders 147a and 147b or the control unit 156. More specifically, the signal processing unit 120 separates the digital signal into a digital video signal, a digital audio signal, and a data signal. The separated digital video signal is transmitted to the graphic processing unit 152, and the audio signal is transmitted to the audio processing unit 153. The signal processing unit 120 converts the broadcast signal transmitted from the analog demodulator 169 into a video signal and an audio signal in a predetermined digital format. The video signal converted to digital is transmitted to the graphic processing unit 152, and the audio signal is transmitted to the audio processing unit 153.
The signal processing unit 120 also performs predetermined digital signal processing on the input signal from the line input terminal 137.

  The audio processing unit 153 converts the input audio signal into an analog audio signal in a format that can be reproduced by the speaker 115. The analog audio signal is transmitted to the speaker 115 and reproduced.

  The OSD signal generation unit 154 generates an OSD signal for displaying a UI (user interface) screen or the like under the control of the control unit 156. The data signal separated from the digital broadcast signal in the signal processing unit 120 is converted into an OSD signal of an appropriate format by the OSD signal generation unit 154 and transmitted to the graphic processing unit 152.

  The graphic processing unit 152 performs a decoding process on the digital video signal transmitted from the signal processing unit 120. The decoded video signal is combined with the OSD signal transmitted from the OSD signal generation unit 154 to be combined and transmitted to the video processing unit 155. The graphic processing unit 152 can also selectively transmit the decoded video signal or OSD signal to the video processing unit 155.

  The video processing unit 155 converts the signal transmitted from the graphic processing unit 152 into an analog video signal in a format that can be displayed on the display module 200. The analog video signal is transmitted to the display module 200 and displayed. Details of the display module 200 will be described later with reference to FIG.

Further, the image display apparatus 110 includes a LAN (Local Area Network) terminal 131, a LAN,
An I / F (Interface) 164, a USB (Universal Serial Bus) terminal 133, a USB I / F 165, and an HDD (Hard Disk Drive) 170 are provided.

  The LAN terminal 131 is connected to the control unit 156 via the LAN I / F 164. The LAN terminal 131 is used as a general LAN-compatible port using Ethernet (registered trademark). In the present embodiment, a LAN cable is connected to the LAN terminal 131 and can communicate with the Internet 130.

  The USB terminal 133 is connected to the control unit 156 via the USB I / F 165. The USB terminal 133 is used as a general USB compatible port. For example, a mobile phone, a digital camera, a card reader / writer for various memory cards, an HDD, a keyboard, and the like are connected to the USB terminal 133 via a hub. The control unit 156 can perform communication (transmission / reception) of information with a device connected via the USB terminal 133.

  The HDD 170 is a magnetic storage medium built in the image display device 110 and has a function of storing various types of information that the image display device 110 has.

  FIG. 2 is a schematic block diagram of the display module 200. The display module 200 includes a liquid crystal panel (display panel) 1, a timing controller 2, a gate driver 3, a source driver 4, a backlight controller 5, and a backlight device 6.

  The liquid crystal panel 1 has a structure in which a pair of glass substrates are disposed to face each other and a liquid crystal material is disposed between the glass substrates. The liquid crystal panel 1 includes a plurality of (for example, 1080) scanning lines, a plurality of (for example, 1920 * 3) signal lines, and liquid crystal pixels formed at each intersection of the scanning lines and the signal lines.

  The timing controller 2 supplies an input video signal input from the video processing unit in FIG. 1 to the source driver 4 and controls operation timings of the gate driver 3, the source driver 4, and the backlight controller 5.

  The gate driver 3 sequentially selects one of the scanning lines. The source driver 4 supplies the input video signal to the signal line of the liquid crystal panel 1. This input video signal is supplied to the liquid crystal pixel connected to the scanning line selected by the gate driver 3, and the orientation of the liquid crystal material in the liquid crystal pixel changes according to the voltage of the input video signal. The gate driver 3 and the source driver 4 constitute a panel controller.

  On the other hand, the backlight device 6 is provided on the back surface of the liquid crystal panel 1 and irradiates the liquid crystal panel 1 with light. Of the irradiated light, light having an intensity corresponding to the orientation of the liquid crystal material is transmitted through the liquid crystal material and displayed on the liquid crystal panel 1.

  FIG. 3 is a horizontal sectional view of the backlight device 6 and the liquid crystal panel 1 according to the first embodiment, and FIG. 4 is a top view thereof. In FIG. 4, only a part of the members is drawn for simplification. The backlight device 6 includes light sources 10a and 10b, waveguides 11a and 11b, light guide plates 12a and 12b, a reflection plate 13, and a reflection layer 14. The waveguides 11a and 11b and the light guide plates 12a and 12b constitute light guide means. Hereinafter, since each member is provided symmetrically, one member with the subscript “a” will be mainly described.

  The light sources 10a and 10b are point light sources such as LEDs. As shown in FIG. 4, a plurality of light sources 10 a and 10 b arranged in, for example, two rows in the vertical direction below the center in the horizontal direction of the liquid crystal panel 1 are provided. Light emitted from the light sources 10a and 10b is mainly incident on the waveguides 11a and 11b, respectively. However, a part of the light does not enter the waveguides 11a and 11b, and directly travels between them toward the reflective layer 14 and the liquid crystal panel 1. By providing the light sources 10a and 10b not on the side of the liquid crystal panel 1 but on the lower side, the bezel of the image display device 110 can be thinned.

  The waveguide 11a is a light pipe-shaped waveguide having an incident surface facing the light source 10a, an exit surface facing the light guide plate 12a, and a curved light guide that guides light from the entrance surface to the exit surface. . The waveguide 11 a is provided between the light source 10 a and the vicinity of the center of the liquid crystal panel 1. The light irradiated from the light source 10a and incident from the incident surface reaches the exit surface while diffusing in the waveguide 11a, and is emitted from the exit surface to the light guide plate 12a.

  The light guide plate 12a is made of, for example, acrylic having a thickness of about 2 mm, and is provided so as to face a region on the edge side from a region where the waveguide 11a of the liquid crystal panel 1 faces. The light guide plate 12a may be integrally formed using the same material as the waveguide 11a to reduce the number of parts. A diffusion member (not shown) such as silk printing is applied to at least a part of the lower surface of the light guide plate 12a. The light that has exited from the exit surface of the waveguide 11a and entered the light guide plate 12a is scattered by the diffusion member and is emitted toward the liquid crystal panel 1 that faces the light guide plate 12a. By controlling the density of the diffusing member, it is possible to suppress luminance unevenness of light that illuminates the liquid crystal panel 1.

  The reflection plate 13 includes a first reflection surface 131 that surrounds the side opposite to the light emission direction of the light sources 10a and 10b and a side, and a second reflection surface that faces the opposite side of the light guide plates 12a and 12b from the liquid crystal panel 1. 132a and 132b. The reflecting plate 13 emits light from the light guide plates 12a and 12b and travels in the direction opposite to the liquid crystal panel 1 or reflects light from the later-described reflecting layer 14 and travels in the direction opposite to the liquid crystal panel 1 on the liquid crystal panel 1 side. To improve the light utilization efficiency.

  The reflection layer 14 includes a transmission plate 141 that has high transparency and transmits light, and a reflection material (or scattering material) 142 that reflects (or scatters) light. The reflective layer 14 is provided between the liquid crystal panel 1 and the waveguides 11a and 11b and the light guide plates 12a and 12b.

  The transmission plate 141 is made of PMMA (polymethyl methacrylate), PET (polyethylene terephthalate), PC (polycarbonate), or the like. The transmission plate 141 may contain beads or the like, and may not only transmit light but also have a diffusion function to suppress uneven brightness of light that illuminates the liquid crystal panel 1. The reflective material 142 is obtained by printing a reflective material such as silk on the back surface (or surface) of the transmission plate 141, for example.

  The light emitted from the light guide plate 12a and directed to the liquid crystal panel 1 is reflected at a position where the reflective material 142 is provided, and is transmitted through the transmission plate 141 at a position where the reflective material 142 is not provided and reaches the liquid crystal panel 1. . That is, the position where the reflective material 142 is not provided is an opening that transmits light. The reflector 142 is provided so that the luminance of the liquid crystal panel 1 is uniform as follows.

  FIG. 5 is a graph schematically showing the luminance in the horizontal direction of the liquid crystal panel 1 when the reflective layer 14 is not provided. The horizontal axis is the horizontal position, and the vertical axis is the luminance. As indicated by a solid line in FIG. 8, a luminance peak 20 occurs only in the vicinity of the center of the liquid crystal panel 1 in the horizontal direction. This is because part of the light emitted from the light sources 10a and 10b does not enter the waveguides 11a and 11b, but leaks from these and reaches the liquid crystal panel 1 directly.

  Therefore, the reflection layer 14 is provided to make the luminance uniform. 6 is a bottom view of the reflective layer 14 as viewed from the direction A in FIG. As shown in the figure, in the vicinity of the center in the horizontal direction facing between the waveguides 11a and 11b, the area where the reflecting material 142 is printed is widened and the opening is narrowed. The shape of the opening is, for example, a circle or an ellipse, and its minimum diameter is, for example, 10 to 20 μm. Thereby, the transmittance in the region corresponding to the luminance peak 20 in FIG. 5 becomes lower than the predetermined value, and the occurrence of the peak can be suppressed.

  Furthermore, the diameter of the opening is increased as the distance from the position of the reflecting layer 14 facing the waveguides 11a and 11b approaches the edge. In other words, the area where the reflector 142 is printed is narrowed. Thereby, the transmittance of the reflective layer 14 increases as it approaches the edge, and the luminance peak 20 can be uniformly diffused throughout the liquid crystal panel 1.

  As a result, as shown by the dotted line in FIG. 5, the luminance unevenness of the liquid crystal panel 1 can be suppressed and made uniform.

  As shown in FIG. 4, since the light sources 10a and 10b are arranged in the vertical direction and the light diffused in the waveguides 11a and 11b reaches the liquid crystal panel 1, the luminance in the vertical direction of the liquid crystal panel 1 becomes almost uniform. In this case, it is not necessary to change the shape of the reflector 142 between the vicinity of the center in the vertical direction and the vicinity of the edge.

  In order to realize the same structure as that of FIG. 3 with a so-called direct-type backlight device in which the waveguides 11a and 11b and the light guide plates 12a and 12b are not provided, the opening of the reflective layer 14 is formed to be extremely small. I have to. However, it is difficult to accurately form such a small opening by printing. Therefore, in consideration of the limit of printing accuracy, it is necessary to ensure a sufficiently long distance between the light source and the reflective layer to diffuse light, and the backlight device becomes thick.

  On the other hand, in the present embodiment, the waveguides 11a and 11b sufficiently secure a so-called “running distance” for diffusing light. The luminance of the liquid crystal panel 1 can be made uniform without forming a very small opening.

  Thus, in the first embodiment, since the reflective layer 14 having different transmittances according to the position is provided, the liquid crystal panel 1 can be illuminated uniformly. Furthermore, by arranging the light sources 10a and 10b below the liquid crystal panel 1, a narrow bezel can be realized. Even when the light sources 10a and 10b are arranged as described above, the light is sufficiently diffused in the vertical direction of the liquid crystal panel 1 in the waveguides 11a and 11b. Thinner.

  Hereinafter, some modified examples of FIG. 6 will be described. The reflection layer 14 only needs to have higher transmittance as it approaches the edge from the vicinity of the center in the horizontal direction. For example, in FIG. 6, the reflective material 142 is formed so that the diameter of the opening becomes larger as it approaches the edge. However, for example, the density of the opening may be changed while keeping the diameter constant. Further, the opening does not necessarily have to be a circle or an ellipse, and may have any shape such as a triangle, a quadrangle, or a hexagon.

  Further, a linear opening may be provided as shown in FIG. In this case, the reflector 142 may be formed so that the width of the line becomes thicker as it approaches the edge, or in other words, so that the density of the linear openings becomes higher, in other words, the interval between the openings becomes narrower. Alternatively, the reflective material 142 may be formed.

  Furthermore, in the present embodiment, an example in which the reflective material 142 is formed on the transmission plate 141 is shown. However, a hole is formed in the reflective or diffusing material plate to form an opening, which corresponds to the horizontal position. A transmittance (or reflectance) may be realized.

  Further, when the backlight device 6 is further thinned and the waveguides 11 a and 11 b are shortened, there is a possibility that luminance unevenness occurs in the vertical direction of the liquid crystal panel 1. In this case, as shown in FIG. 8, the transmittance of the reflective layer 14 may be controlled in accordance with the position in the vertical direction. For example, the opening may be reduced at the position where the light sources 10a and 10b are provided (arrow P), and the opening may be increased at the position where the light sources 10a and 10b are not provided (arrow Q).

(Second Embodiment)
In the first embodiment described above, light emitted from the light sources 10a and 10b is guided to the light guide plates 12a and 12b by the light pipe-shaped waveguides 11a and 11b, respectively. On the other hand, the second embodiment described below uses a triangular prism-shaped waveguide.

  FIG. 9 is a horizontal sectional view of the backlight device 6 ′ and the liquid crystal panel 1 according to the second embodiment. Parts similar to those in FIG. 3 are denoted by the same reference numerals, and different points will be mainly described below.

  The backlight device 6 'of FIG. 9 includes triangular prism-shaped waveguides 11a' and 11b 'instead of the light pipe-shaped waveguides 11a and 11b. The waveguide 11a 'has an incident surface facing the light source 10a, and a reflecting surface that is inclined by about 45 degrees with respect to the light incident direction and refracts light toward the light guide plate 12a.

  FIG. 10 is a graph schematically showing the luminance in the horizontal direction of the liquid crystal panel 1 when the reflective layer 14 ′ is not provided. The horizontal axis is the horizontal position, and the vertical axis is the luminance. As shown by the solid line in the figure, three luminance peaks 21, 22a, and 22b occur. The luminance peak 21 occurs because a part of the light emitted from the light sources 10a and 10b does not enter the waveguides 11a 'and 11b', but leaks between them and reaches the liquid crystal panel 1 directly. The luminance peaks 22a and 22b occur because light leaks at the connection portions between the waveguides 11a 'and 11b' and the light guide plates 12a and 12b and reaches the liquid crystal panel 1.

  Therefore, the brightness is made uniform by providing the reflective layer 14 '. FIG. 11 is a bottom view of the reflective layer 14 ′ viewed from the direction B in FIG. 9.

  As shown in the figure, in order to suppress the peak 21, the diameter of the opening of the reflecting material 142 is reduced at a position (arrow S) facing between the waveguide 11a 'and the waveguide 11b'. Similarly, in order to suppress the peaks 22a and 22b, an opening is also formed at a position (arrow T) facing the connecting portion between the waveguide 11a ′ and the light guide plate 12a and the connecting portion between the waveguide 11b ′ and the light guide plate 12b. Reduce the diameter. On the other hand, at the position (arrow U) facing the waveguides 11a 'and 11b', the diameter of the opening is relatively increased. Accordingly, the transmittance in the region corresponding to the peaks 21, 22a, and 22b in FIG. 10 is lower than the predetermined value, and the transmission in the region corresponding to between the peaks 21 and 22a and between the peaks 21 and 22b. It can suppress that a rate becomes higher than predetermined value and a peak arises.

  Furthermore, outside the region (arrow T) facing the connecting portion between the waveguide 11a ′ and the light guide plate 12a and the connecting portion between the waveguide 11b ′ and the light guide plate 12b, the diameter of the opening becomes closer to the edge. Increase As a result, the transmittance of the reflective layer 14 increases as it approaches the edge, and the luminance peaks 20, 21 a, 21 b can be uniformly diffused throughout the liquid crystal panel 1.

  As a result, as shown by the dotted line in FIG. 10, the luminance unevenness of the liquid crystal panel 1 can be suppressed and made uniform.

  Thus, also in the second embodiment, the liquid crystal panel 1 can be illuminated uniformly because the reflective layer 14 ′ having a different transmittance depending on the position is provided.

  Of course, also in the second embodiment, as shown in FIGS. 7 and 8, a reflective material 142 having a shape different from that of FIG. 10 may be formed to adjust the transmittance of the reflective layer 14 ′.

  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 embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

6 Backlight device 10a, 10b Light source 11a, 11b, 11a ′, 11b ′ Waveguide 12a, 12b Light guide plate 13 Reflecting plate 14 Reflecting layer 141 Transmitting plate 142 Reflecting material 110 Image display device

Claims (11)

A display panel;
A light source provided facing a part of the display panel;
Comprising light guide means provided between the display panel and the light source;
The light guiding means includes
A first end facing the light source and receiving light emitted from the light source;
A second end extending to substantially the same position as the end of the display panel;
An emission surface facing the display panel and emitting light to the display panel;
And a curved curved portion that is continuous from the first end and guides light from the first end to the exit surface.   The display device according to claim 1, wherein the light source is provided to face a substantially center of the display panel.   The display device according to claim 2, wherein the light source is not provided except for a position facing a substantially center of the display panel. The light guiding means includes
First light guiding means having the second end extending to substantially the same position as the first end of the display panel;
The 2nd light guide means which has the 2nd end part extended to the position substantially the same as the 2nd end part on the opposite side to the 1st end part of the display panel of Claim 2 or 3 is included. Display device. The light source is
A first light source for irradiating light to the first end of the first light guide;
The display device according to claim 4, further comprising: a second light source that irradiates light to the first end portion of the second light guide unit.   The display device according to claim 1, wherein a diffusion member that scatters light is provided on at least a part of the light source side surface of the light guide unit.   8. A reflection unit provided between the display panel and the light guide unit, the reflection unit configured to transmit a part of light emitted from the light guide unit to the display panel and reflect a part thereof. The display apparatus in any one of.   The display device according to claim 7, wherein an end portion of the reflecting means extends to a position substantially the same as an end portion of the display panel.   The display device according to claim 7 or 8, wherein the reflecting means is provided with a reflective material by printing.   The display device according to claim 9, wherein the light that is irradiated from the light source and leaks from the light guiding unit and reaches the display panel is controlled by adjusting a density of the reflecting material.   The display device according to claim 1, wherein the light source is an LED.