JP4151670B2 - Display device and electronic device using the same - Google Patents

Description

  The present invention relates to a display device and an electronic apparatus using the display device.

  In general, a liquid crystal panel, which is one of display panels, is formed with a drive circuit and the like arranged around a display region. For example, a drive circuit may be arranged by forming a circuit using polysilicon or mounting an IC chip as COG (chip on glass) around a display region on a substrate forming a liquid crystal panel. is there. In general, a liquid crystal panel is provided with an input terminal for inputting a signal, and a wiring board is connected to the input terminal.

And a liquid crystal panel is often used with the surface light source unit arrange | positioned in the back surface or the front surface. The surface light source unit is generally formed by arranging a light emitting portion such as a fluorescent tube along one end surface of a light guide plate.
If the light-emitting part of such a surface light source unit is located outside the light guide plate, the area other than the light-emitting surface area becomes large due to the presence of the light-emitting part, and the display area is not displayed. There is a problem of becoming a device.

The display device according to the present invention includes a light guide plate including a recess opening along one end surface and a light-shielding portion formed along the one end surface, so as to fit inside the light guide plate from the one end surface. A surface light source unit having a light emitting portion disposed in the concave portion, a filling portion filling a space between the concave portion and the light emitting portion, a display region, and a circuit region formed around the display region And a liquid crystal panel that is disposed above the light guide plate so as to face the display region. The input terminal is a predetermined one of the four sides of the liquid crystal panel. The circuit area is provided along the predetermined one side and two sides intersecting the predetermined one side, and the light-emitting portion is provided along one side facing the predetermined one side. cage, said circuit region, the display region Formed in the same process as the thin film transistor made of polysilicon, the light shielding portion is formed so as to cover the entire concave portion from above the one end surface, and the surface of the light guide plate facing the liquid crystal panel, and the concave portion It is characterized by being formed so as to fill the gap between the two .

  In the present invention, the light emitting part is disposed in a recess provided in the light guide plate. Accordingly, the light source is not located outside the light guide plate, and the region other than the light emitting surface region is not enlarged due to the presence of the light source. Can do.

  In the display device according to the present invention, the light emitting unit is a fluorescent tube.

  In the present invention, since a fluorescent tube with high energy efficiency is used as the light emitting portion, a brighter display device can be obtained with a predetermined power consumption. In addition, this display device is not easily affected by noise as described above, even though the light emitting unit used in the surface light source unit is a fluorescent tube that easily generates noise.

  The display device according to the present invention is characterized in that the light emitting unit is an LED.

  In the present invention, since an LED, that is, a light emitting diode is used as the light emitting portion, a bright display device can be obtained with a predetermined power consumption. In addition, since the LED does not require a high-frequency power source that easily becomes a noise source, this display device has less noise problems.

  The display device according to the present invention further includes a filling portion that is disposed in the concave portion and substantially fills a space between the concave portion and the light emitting portion.

  In the present invention, since the filling portion that substantially fills the space between the concave portion and the light emitting portion is provided, the light source is securely fixed to the light guide plate by the filling portion.

  In the present invention, by appropriately arranging a light-shielding portion that weakens light emission in at least some directions, radiation in a partial direction of light from the light-emitting portion is limited, and a portion near the light-emitting portion is The amount of light emitted from the light guide plate can be reduced. Therefore, the amount of light from the light emitting surface of the surface light source unit is substantially uniform within the surface, and display without unevenness in brightness can be performed.

  The display device according to the present invention is characterized in that the light shielding portion is a reflecting member that reflects at least a part of light from the light emitting portion.

  In the present invention, the amount of light emitted from the portion close to the light emitting portion is reduced by reflecting light in an appropriate direction by the light shielding portion, so that the amount of light from the light emitting surface is substantially uniform within the surface. In addition, the light can be emitted from the other front region of the light guide plate. Therefore, a surface light source unit with high energy efficiency can be formed, and a brighter display device can be obtained with a predetermined power consumption.

  The display device according to the present invention is characterized in that the light-shielding portion is formed by dispersing light-absorbing or light-reflecting ink in the form of dots on the surface of the concave portion.

In the present invention, the light quantity at the front side of the light guide plate is made uniform by decreasing the light transmittance by increasing the amount of light-absorbing or light-reflecting ink at a higher density closer to the light source. The display device according to the present invention is characterized in that the light shielding part is at least a part of the light guide plate in the vicinity of the light emitting part.

  In the present invention, since the light shielding portion is formed as at least a part of the light guide plate in the vicinity of the light emitting portion, the light amount can be reduced without affecting the outer shape of the surface light source unit and without increasing the number of members. It can be made uniform.

  The display device according to the present invention is characterized in that the filling portion has optical characteristics similar to those of the light guide plate.

  According to the present invention, various optical characteristics of the filling portion, that is, various optical characteristics such as light reflectance, transmittance, dielectric constant, and the like are similar to those of the light guide plate. Therefore, the display device including the surface light source unit with high energy efficiency is provided. can get.

  The display device according to the present invention is characterized in that the filling portion contains light absorbing or light reflecting ink.

  According to the present invention, since the filling portion contains light-absorbing or light-reflecting ink, the amount of light can be controlled by adding light and shade to the filling portion.

  An electronic apparatus according to the present invention includes any one of the display devices as a display unit.

  According to the present invention, it is possible to obtain an electronic apparatus having the above-described effects on the display device.

  Hereinafter, preferred embodiments of the present invention will be described more specifically with reference to the drawings.

1. <Reference embodiment>
1.1 Display Device FIG. 1 is an exploded perspective view schematically showing a liquid crystal display device 10 as a display device of the present embodiment. As shown in this figure, the liquid crystal display device 10 of this embodiment includes a liquid crystal panel 14 as a display panel, a protective frame 12 disposed on the front surface of the liquid crystal panel 14, and a fixed member disposed on the back surface of the liquid crystal panel 14. The frame 28 includes a backlight 40 as a surface light source unit disposed on the back surface of the fixed frame 28, and a shield case 58 disposed on the back surface of the backlight 40.

  The protective frame 12 includes a display window 13 having a size corresponding to the display area of the liquid crystal panel 14 and physically protects the liquid crystal panel 14.

  The liquid crystal panel 14 is formed by sealing a liquid crystal between a pair of opposing substrates 16 and 16 and attaching a polarizing plate 18 to the outer surface side of the substrate 16. Further, the liquid crystal panel 14 includes a sealing portion 22 on one end surface 20 for sealing the liquid crystal after the liquid crystal is injected. The sealing portion 22 is formed as a protruding portion having a shape raised from the end face 20 in order to realize highly reliable sealing. The liquid crystal panel 14 is connected to an input terminal 24 of a wiring board 26, for example, an FPC (flexible wiring board).

  FIG. 2 is a block diagram schematically showing the electrical configuration of the liquid crystal panel 14. As shown in this figure, the liquid crystal panel 14 is provided with a display area 30 and a circuit area 70.

  The display area 30 includes a data line 31 and a scanning line 32, a pixel switching thin film transistor (hereinafter referred to as TFT) 34 connected to the data line 31 and the scanning line 32, and the data line 31 via the TFT 34. There is a liquid crystal cell 35 to which an image signal is input. Each pixel formed including the TFT 34 and the liquid crystal cell 35 includes a capacitive element 36 between the capacitive line 33, and the capacitive element 36 functions to improve the charge retention characteristics of the liquid crystal cell 35. Yes.

  The circuit area 70 includes a scanning line driving circuit 70 and a data line driving circuit 74. The scanning line driving circuit 71 is connected to the scanning line 32 and includes a shift register 72 and a level shifter 73. The data line driving circuit 74 is connected to the data line 31 and includes a shift register 75, a level shifter 76, a video line 77, and a switch 78. The TFTs 34 and the TFTs constituting the driving circuit such as the scanning line driving circuit 70 and the data line driving circuit 74 are formed together in the same process.

  The backlight 40 serving as a surface light source unit is disposed on the front side of the light guide plate 44, a fluorescent tube 50 serving as a light emitting unit, a light guide plate 44 for guiding light from the fluorescent tube 50 toward the entire front side. The lens sheet 42 for improving the light utilization efficiency and the back reflecting portion 54 that is disposed opposite to the back surface of the light guide plate 44 and reflects the light leaked from the light guide plate 44 to the back side to the front side are formed. Yes. An inverter is connected to the fluorescent tube 50 via a power cable 48. As the fluorescent tube 50, for example, a cold cathode tube is used. Since the backlight 40 uses the fluorescent tube 50 with high energy efficiency as a light emitting unit, the liquid crystal display device 10 can perform brighter display with predetermined power consumption.

  FIG. 3 is a schematic exploded perspective view showing a positional relationship between the liquid crystal panel 14 and the light guide plate 44 and the fluorescent tube 50 of the backlight 40. As shown in this figure, the liquid crystal panel 14 includes a display region 30, a circuit region 70 formed around the display region, and an input terminal 24. At least one of a drive circuit that drives each pixel of the liquid crystal panel 14 and a signal circuit that generates image information to be displayed on the liquid crystal panel 14 is formed in the circuit region 70. In the liquid crystal panel 14, the circuit region 70 and the input terminal 24 are formed in regions along the three sides of the display region 30, and the circuit region 70 and the input terminal are disposed in the region along the remaining one side of the display region 30. None of the terminals 24 are arranged.

  Further, as shown in FIG. 3, the light guide plate 44 is disposed in a positional relationship corresponding to the entire display region 30 of the liquid crystal panel 14. The fluorescent tube 50 is disposed along one end face 45 of the light guide plate 44. The end face 45 corresponds to one side of the display area 30, that is, an area along the side where neither the circuit area 70 nor the input terminal 24 is arranged.

  As described above, in the liquid crystal display device 10, neither the circuit region 70 nor the input terminal 24 is arranged in a region along the predetermined side of the display region 30 in the display panel 14, and the liquid crystal display device 10 corresponds to the predetermined one side. A fluorescent tube 50 is arranged along the end face 45 of the light guide plate 44 to be operated. Therefore, the fluorescent tube 50 that is likely to be a noise source is disposed at a position away from the circuit region 70 and the input terminal 24 where noise is easily picked up. Therefore, the possibility that the circuit region 70 and the input terminal 24 pick up noise is reduced, and the liquid crystal display device 10 is less susceptible to noise generated by the fluorescent tube 50 used in the backlight 40. Furthermore, the possibility of leakage current occurring in the circuit region 70 due to light and heat generated from the fluorescent tube 50 as a light source is also reduced. In particular, the TFT constituting the circuit region 70 is often made of a polycrystalline silicon TFT. In that case, the TFT is liable to malfunction due to the light from the fluorescent tube 50. However, since the circuit region is arranged at a position away from the fluorescent tube 50 as in the present embodiment, the occurrence of leakage current of the TFT constituting the circuit region 70 can be suppressed, and malfunction can be prevented.

  The back reflecting unit 54 is made of a material obtained by performing a high reflection process on the surface facing the light guide plate with a metal material or a sheet material. Thereby, the light leaking from the back side of the light guide plate 44 is reflected and returned to the light guide plate 44.

  As shown in FIG. 1, the fixed frame 28 is disposed between the backlight 40 and the liquid crystal panel 14, that is, on the back side of the liquid crystal panel 14 on the front side of the backlight 40. Thus, since the fixed frame 28 is disposed between the liquid crystal panel 14 and the backlight 40, a predetermined gap is formed between the liquid crystal panel 14, the lens sheet 42, and the light guide plate 44, and interference fringes are formed. And moire are prevented.

  The shield case 58 houses an inverter (not shown) that is a power source for generating a predetermined voltage supplied to the fluorescent tube 50 and the backlight 40.

1.2 Electronic Device Provided with Display Device FIGS. 4A, 4B, and 4C show examples of electronic devices that use the liquid crystal display device 10 that is the display device of this embodiment as a display unit. It is an external view. FIG. 4A shows a mobile phone 88, which includes the liquid crystal display device 10 above the front surface thereof. FIG. 4B shows a wristwatch 92 in which a display unit using the liquid crystal display device 10 is provided in the center of the front surface of the main body. FIG. 4C illustrates a portable information device 96 that includes a display unit including the liquid crystal display device 10 and an input unit 98. In addition to the liquid crystal display device 10, these electronic devices include various circuits such as a display information output source, a display information processing circuit, a clock generation circuit, and a power supply circuit that supplies power to these circuits, although not shown. The display signal generation unit is configured. In the case of a portable information device, for example, in the case of a portable information device, a display image is formed by supplying a display signal generated by a display signal generation unit based on information input from the input unit 98 or the like.

  Note that the electronic device in which the liquid crystal display device 10 of this embodiment is incorporated is not limited to a mobile phone, a wristwatch, and a portable information device, but a notebook personal computer, an electronic notebook, a pager, a calculator, a POS terminal, an IC card, and a mini disk. Various electronic devices such as players can be considered.

2. <Embodiment>
In the embodiment, the light guide plate of the backlight is provided with a recess that opens along one end surface, and the fluorescent tube as the light emitting unit is disposed in the recess, and the space between the recess and the light emitting unit is substantially reduced. The point which is provided with the filling part to fill and the point which is provided with the light-shielding part which restrict | limits the radiation | emission to the direction of at least one part of the light from a fluorescent tube differs from reference embodiment. Since other points are the same as those in the reference embodiment, the description thereof is omitted. In the drawings, the same reference numerals as those in the reference embodiment are assigned to the same parts as those in the reference embodiment.

2.1 Surface Light Source Unit The backlight 62 as the surface light source unit of the present embodiment is shown as a schematic cross-sectional view in FIG. 5 and as a schematic exploded perspective view in FIG. In FIGS. 5 and 6 and other similar drawings, the lens sheet 42 and the back reflecting portion 54 which are part of the backlight are omitted. As shown in FIG. 5 and FIG. 6, a recess 65 opening along one end surface 45 of the light guide plate 64 is provided, and a fluorescent tube 50 as a light emitting unit is disposed in the recess 65. The concave portion 65 is filled with a resin 66 as a filling portion having optical characteristics similar to those of the light guide plate 64 and hardened to fix the fluorescent tube 50 integrally to the light guide plate 64. Therefore, the fluorescent tube 50 is securely fixed to the light guide plate 64 by the resin 66 that substantially fills the space between the recess 65 and the fluorescent tube 50.

  As such a resin 66, those having various optical characteristics such as light reflectance, transmittance, refractive index, dielectric constant and the like similar to those of the light guide plate 64 are used. For example, when a general acrylic resin is used as the material of the light guide plate, a UV curable acrylic resin or the like is used as the resin 66. Thus, various optical characteristics of the resin 66 as the filling portion, that is, various optical characteristics such as light reflectance, transmittance, dielectric constant and the like are similar to those of the light guide plate 64, so that a highly energy-efficient backlight 62 is obtained. It is done.

  Thereafter, the reflector 52 is attached along the length direction of the fluorescent tube 50 to the end face 45 of the light guide plate 64 in which the recess 65 is filled with the resin 66. The reflector 52 is formed of, for example, a metal material or a sheet material, and the surface facing the fluorescent tube 50 is subjected to high reflection processing. Thereby, the reflector 52 reflects the light leaking from the fluorescent tube 50 or the light guide plate 64 and efficiently enters the light guide plate 64.

  As described above, in the backlight 62, the fluorescent tube 50 as the light emitting unit is disposed in the recess 65 provided in the light guide plate 64, so that the region other than the light emitting surface region may be increased due to the presence of the fluorescent tube 50. Absent. Further, by using such a backlight 62 arranged on the back side of the liquid crystal panel 14, it is possible to form a liquid crystal display device in which an area where no display is performed, a so-called frame area is small.

  Further, the backlight 62 has a light blocking portion 67 that restricts the emission of light from the fluorescent tube 50 in at least a part of the light guide plate on the concave surface 65a of the light guide plate shown in FIG. Along with. For example, the light shielding unit 67 absorbs light directly traveling from the fluorescent tube 50 toward the front side of the light guide plate 64, that is, light traveling directly toward the side close to the liquid crystal panel 14, and the amount of light emitted from the light guide plate 64 near the fluorescent tube 50. Is limiting.

  Therefore, by appropriately arranging the light shielding portion 67, it is possible to limit the emission of light from the fluorescent tube 50 in a part of the direction and reduce the amount of light emitted from the light guide plate 64 in a portion close to the fluorescent tube 50. it can. Thereby, it is possible to form the backlight 62 in which the amount of light from the light emitting surface is substantially uniform within the surface, and a liquid crystal display device capable of performing display without unevenness in brightness is obtained.

  The light shielding unit 67 makes the light amount on the front side of the light guide plate 64 uniform by lowering the light transmittance closer to the fluorescent tube 50 in correspondence with the amount of direct light reaching from the fluorescent tube 50. be able to. For example, as the light-shielding portion 67, a light-absorbing or light-reflecting ink that is dispersed and coated on the concave surface 65a in a dot shape is used. In this case, the amount of light on the front side of the light guide plate 64 can be made uniform by covering the light-absorbing or light-reflecting ink with a higher density at a position closer to the fluorescent tube 50 to lower the light transmittance. it can. That is, the light emitted from the light guide plate surface can be controlled by dispersing light absorbing or light reflective ink in a dot shape and using a sparse / dense distribution. It becomes possible to make uniform in the plane.

  Alternatively, a light-absorbing or light-reflecting ink coated on the upper surface of the light guide plate 64 in a dotted manner may be used. It is also possible to control the brightness in the surface of the light guide plate 64 by putting light-absorbing or reflecting ink into the resin 66 as the filling portion and adding light and shade to the inserted ink.

2.2 Modification of Embodiment 2.2.1 The light-shielding portion may be formed so as to absorb light as described above, but a highly reflective ink layer, a silver sputter layer or a vapor deposition layer, or a high It may be formed of a reflection sheet or the like so that the light directly going from the fluorescent tube 50 toward the front surface side of the light guide plate 64 is reflected in another direction.

  By reflecting light in an appropriate direction by such a light shielding portion, the amount of light emitted from a portion close to the fluorescent tube 50 can be reduced, and the amount of light from the light emitting surface can be made substantially uniform within the surface. The light can be emitted from the other front region of the light guide plate 64, and a backlight with high energy efficiency can be formed.

  2.2.2 For example, as shown in FIG. 7 which is a cross-sectional view corresponding to FIG. 5, a backlight 80 including a light shielding portion 81 may be formed as at least a part of the light guide plate 64 in the vicinity of the light emitting portion. it can. Thus, by forming the light shielding portion 81 as at least a part of the light guide plate 64, it is possible to make the light quantity uniform without affecting the outer shape of the backlight and without increasing the number of members.

  2.2.3 In the above, the example in which the light shielding portion is provided on the concave surface 65a of the light guide plate 64 is shown. However, for example, as shown in FIG. 8, which is a cross-sectional view corresponding to FIG. 5, the backlight 82 may include a light shielding portion 83 disposed on at least a part of the outer surface of the light guide plate 64. In this manner, by forming the light shielding portion 83 on the outer surface of the light guide plate 64, the light shielding portion 83 can be easily arranged to manufacture the backlight 82.

  2.2.4 In the above description, the light emitting unit, for example, the fluorescent tube 50 is fixed to the light guide plate 64 by the resin 66 filled in the recess 65 of the light guide plate 64. However, as long as the light emitting portion is positioned in the concave portion 65 and can be fixed to the light guide plate 64 sufficiently firmly, it may be fixed by other methods. For example, the fluorescent tube 50 is fixed to the reflector 52 attached to the end face 45 of the light guide plate 64 via a resin member or a metal member, and the fluorescent tube 50 is fixed to the light guide plate 64 via the reflector 52. It may be.

3. <Other variations>
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications may be made within the scope of the gist of the present invention or the equivalent scope of the claims. Is possible.

  3.1 In the above, an example in which the fluorescent tube 50 is used as the light emitting unit has been described, but the light emitting unit may be formed of an LED or the like. For example, a light emitting unit formed by connecting a plurality of LEDs in parallel or in series may be used.

  Thus, a bright display device can be obtained with a predetermined power consumption by using an LED, that is, a light emitting diode, as the light emitting portion. In addition, since a high-frequency power source that is likely to be a noise source is not required for driving the LED, a display device with less noise problems can be formed.

  3.2 In the above, an example of the display device 10 using the liquid crystal panel 14 as a display panel has been described. However, the display panel is not limited to the liquid crystal panel 14 and performs display by controlling transmission of light from a surface light source. Any other type of display panel may be used.

  3.3 In the above, the example of the backlight 40 disposed on the back side of the liquid crystal panel 14 is shown as the surface light source unit. However, the surface light source unit is a front light disposed on the front side of the liquid crystal panel 14. May be.

It is a typical disassembled perspective view which shows the liquid crystal display device of reference embodiment. It is a block diagram which shows typically the electric constitution of the liquid crystal panel of reference embodiment. It is a typical disassembled perspective view which shows the positional relationship between a liquid crystal panel, the light-guide plate of a backlight, and a fluorescent tube. BRIEF DESCRIPTION OF THE DRAWINGS It is an external view which shows the electronic device using the liquid crystal display device of embodiment, (A) is a mobile telephone, (B) is a wristwatch, (C) is a portable information device. It is typical sectional drawing which shows the backlight of embodiment. It is a typical disassembled perspective view which shows the backlight of embodiment. It is typical sectional drawing which shows the backlight of the modification of embodiment which formed the light-guide plate near the light emission part as a light-shielding part. It is typical sectional drawing which shows the backlight of the modification which has arrange | positioned the light-shielding part on the outer surface of a light-guide plate.

Explanation of symbols

10 Liquid crystal display device (display device)
14 Liquid crystal panel (display panel)
24 Input terminal 30 Display area 40, 60, 80, 82 Backlight (surface light source unit)
44, 64 Light guide plate 45 End face 50 Fluorescent tube (light emitting part)
65 Concave portion 66 Resin (filling portion)
67, 81, 83 Shading part 70 Circuit area 88 Mobile phone (electronic equipment)
92 Watch (electronic equipment)
96 Portable information devices (electronic devices)

Claims (6)

A light guide plate comprising a recess opening along one end surface , and a light shielding portion formed along the one end surface ;
A surface light source unit having a light emitting part arranged in the recess so as to be inside the light guide plate from the one end surface, and a filling part filling a space between the recess and the light emitting part;
A liquid crystal panel having a display area, a circuit area and an input terminal formed around the display area, and arranged to face the display area above the light guide plate;
In a display device comprising:
The input terminal is provided along a predetermined side of the four sides of the liquid crystal panel, the circuit region is provided along the predetermined side and two sides intersecting the predetermined side, and the light emitting unit is , Provided along one side opposite to the predetermined one side,
The circuit region is formed in the same process as a thin film transistor made of polysilicon in the display region,
The light shielding portion is formed so as to cover the entire concave portion from above the one end surface, and is formed so as to fill a space between the surface of the light guide plate facing the liquid crystal panel and the concave portion. Characteristic display device. The display device according to claim 1 , wherein the light shielding unit is a reflecting member that reflects at least part of light from the light emitting unit. The display device according to claim 1 , wherein the light-shielding portion is formed by dispersing light-absorbing or light-reflecting ink in the form of dots on the surface of the concave portion. The display device according to claim 1 , wherein the light emitting unit is a fluorescent tube. The display device according to claim 1 , wherein the light emitting unit is an LED. An electronic apparatus comprising the display device according to claim 1 as a display unit.

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