JP6664203B2 - Backlight and display device - Google Patents

Description

  The present invention relates to a backlight and a display device including the backlight.

  In recent years, with the spread of information electronic devices, thin and lightweight display devices have been widely used as displays for mobile phones or personal computers, various devices used in industrial applications, in-vehicle display devices, handy terminals or advertisement display devices. Used in the field.

  Further, as the field in which the display device is used has expanded, for example, in amusement equipment, a plurality of small display devices other than the main display device are operated, and images are integrally displayed by connecting the small display devices. It is increasingly used for effects that give an impact to viewers. Further, in a display device mounted on a vehicle, switches are often arranged around the display device in consideration of designability, and it is required to reduce a frame of the display device.

  In order to narrow the frame of the display device, it is necessary to simplify the components of the display device by making them as thin as possible. However, it has been difficult to secure the vibration resistance and shock resistance of the display device in order to make the constituent members thinner and simpler.

  Conventionally, a technique has been disclosed in which a side surface of a liquid crystal panel and a side surface of a backlight unit are fixed by a fixing member including a plate (plate-shaped member) and an adhesive layer applied to one surface of the plate (for example, Patent Document 1).

JP 2014-126686 A

  Patent Literature 1 relates to a technology related to a display device mounted on a portable information terminal. The use environment does not assume severe conditions as compared with an industrial use, an in-vehicle use, or an amusement. Resistance and impact resistance are not so demanded. Therefore, a display device in which the side surface of the liquid crystal panel and the side surface of the backlight unit are fixed by a fixing member composed of a plate (plate-like member) and an adhesive layer applied to one surface of the plate can be used. is there.

  However, in Patent Literature 1, the components of the display device are fixed with a member having an adhesive or a double-sided tape, so that if the device is used under a severe temperature environment for a long time, the adhesive may deteriorate over time. As a result, the adhesive strength of the pressure-sensitive adhesive or the double-sided tape is remarkably reduced, and a problem that the components of the display device are decomposed occurs. Therefore, in a display device used in a severe use environment or a temperature environment, it is not sufficient to rely only on the adhesive strength of the adhesive.

  The present invention has been made in order to solve such a problem, and an object of the present invention is to provide a backlight and a display device that can stably fix a member and have a narrow frame.

In order to solve the above-described problems, a backlight according to the present invention includes a light source, a light guide plate that emits light from the light source in a predetermined direction, and an optical device that adjusts an intensity distribution of light emitted from the light guide plate. A sheet and a light source are arranged, the light source plate has a mounting surface on which the light guide plate and the optical sheet are mounted from the back side, and the outer periphery of the mounting surface is predetermined on at least one side other than the side on which the light source is arranged. A rear housing having a positioning portion, a light source, a light guide plate, and a front housing having an opening through which light emitted from the optical sheet passes, which is positioned by the positioning portion and accommodates the optical sheet. covering a portion of at least the front housing is positioned by the positioning unit, and a first fixing tape for fixing the back casing and the front casing, the positioning unit, Ru stepped portion der having a step.

According to the present invention, a backlight includes a light source, a light guide plate that emits light from the light source in a predetermined direction, an optical sheet that adjusts an intensity distribution of light emitted from the light guide plate, and a light source. A rear surface having a mounting surface on which the light guide plate and the optical sheet are mounted from the rear side, and having a predetermined positioning portion on at least one side of the outer periphery of the mounting surface other than the side on which the light source is arranged. A housing, a light source, a light guide plate, and a front housing having an opening through which light emitted from the optical sheet passes, and which is positioned by the positioning unit, and at least the front housing is positioned. covering a portion that is positioned in the section, and a first fixing tape for fixing the back casing and the front casing, the positioning unit, the stepped portion der because having a step, stably fixing the member And small amount Reduction is possible.

FIG. 1 is an exploded perspective view illustrating an example of a configuration of a display device according to a first embodiment of the present invention. FIG. 2 is a plan view illustrating an example of a configuration of the backlight according to the first embodiment of the present invention. FIG. 3 is a diagram illustrating an example of an AA cross section in FIG. 2. FIG. 4 is an enlarged view of a part a in FIG. 3. FIG. 4 is an enlarged view of a part b in FIG. 3. FIG. 3 is a diagram illustrating another example of the AA cross section in FIG. 2. FIG. 7 is an enlarged view of a part c in FIG. 6. FIG. 7 is an enlarged view of a part d in FIG. 6. It is a figure which shows an example of the shape of the front housing | casing and back housing | casing by Embodiment 2 of this invention. FIG. 13 is a cross-sectional view illustrating an example of a configuration of a display device according to a third embodiment of the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  In each of the drawings described below, components denoted by the same reference numerals indicate substantially the same components.

<First Embodiment>
FIG. 1 is an exploded perspective view showing an example of the configuration of the display device 1 according to the first embodiment of the present invention. Hereinafter, the description will be made assuming that the display device 1 is a liquid crystal display device.

  As shown in FIG. 1, the display device 1 includes a display element 2, a backlight 3 that irradiates the display element 2 from the back, and a housing 4 that has the opening therein and accommodates the display element 2 and the backlight 3. And a circuit board 5. Hereinafter, each component will be described in detail.

<Display element 2>
The display element 2 is composed of a transmissive or semi-transmissive liquid crystal display panel using the birefringence of liquid crystal, and includes a first substrate 6 and a second substrate 7. On the first substrate 6, a color filter, a light shielding layer, a counter electrode, and the like are formed on an insulating substrate such as glass. On the second substrate 7, a thin film transistor (hereinafter, referred to as TFT) serving as a switching element and a pixel electrode are formed on an insulating substrate such as glass.

  Further, the display element 2 includes a spacer (not shown) for maintaining a distance between the first substrate 6 and the second substrate 7 and a sealing material (FIG. 7) for bonding the first substrate 6 and the second substrate 7 together. A liquid crystal (not shown) sandwiched between the first substrate 6 and the second substrate 7, a sealing material (not shown) for sealing a liquid crystal injection port, An alignment film (not shown) for aligning the liquid crystal, and a polarizing plate (see FIG. 1) disposed on the surface of the first substrate 6 on the side of the housing 4 and on the surface of the second substrate 7 on the side of the backlight 3, respectively. (Not shown) and a driving IC (Integrated) disposed on the outer peripheral portion of the second substrate 7 or on a tape-shaped wiring material (TCP: Tape Carrier Package, COF: Chip On Film, etc.) connected to the outer peripheral portion. Circuit 8).

<Backlight 3>
The backlight 3 includes a light source 9 that emits light, a light guide plate 10 that has an emission surface that enters the light emitted from the light source 9 from the side surface and propagates to the front surface, and an anti-emission surface that is a surface facing the emission surface, An optical sheet 11 for controlling the intensity distribution and spread of the light emitted from the light guide plate 10; a reflection sheet 12 for returning the light exiting from the non-emission surface of the light guide plate 10 to the light guide plate 10; 9, a light guide plate 10, an optical sheet 11, and a reflective sheet 12).

  As the light source 9, a point light source of RGB (Red: Red, Green: Green, Blue: Blue), an LED (Light Emitting Diode) of a light emission color other than RGB, or a fluorescent tube lamp (not shown) is arranged. . When a point light source is used as the light source 9, a light source substrate on which the point light source is mounted may be made of a general glass epoxy resin or a flexible flat cable. A material based on a metal such as aluminum or a ceramic may be used for enhancing.

  The light guide plate 10 is made of a transparent acrylic resin, polycarbonate resin, glass, or the like, and emits light from the light source 9 from an emission surface. At least one of the emission surface and the anti-emission surface of the light guide plate 10 has a scattering dot pattern or prism shape for emitting light and adjusting the intensity distribution and emission direction of the light in the surface.

  The optical sheet 11 is arranged on the emission surface of the light guide plate 10 and adjusts the intensity distribution and the emission angle of the light emitted from the light guide plate 10. Although three optical sheets 11 are shown in the example of FIG. 1, a lens sheet for condensing light, a diffusion sheet for uniformizing light, or a visual field for adjusting luminance in a viewing angle direction. It is only necessary to arrange the required number of corner adjustment sheets according to the purpose.

  The front housing 13 has an opening through which light emitted from the optical sheet 11 passes, and the display element 2 is positioned and held on the outer peripheral portion on the upper surface side (the display element 2 side). In addition, as a material of the front housing 13, a metal such as aluminum, stainless steel, or iron, or a resin material such as PC (Polycarbonate: polycarbonate) and ABS (Acrylonitrile Butadiene Styrene: acrylonitrile butadiene styrene) can be used.

  The rear housing 14 has the mounting surface on which the light source 9 is positioned and held (arranged), and on which the light guide plate 10 and the optical sheet 11 are mounted from the rear side. In addition, as a material of the rear case 14, it is desirable to use a metal having high thermal conductivity in order to efficiently conduct heat emitted from the light source 9. In particular, if aluminum or an aluminum alloy having high thermal conductivity is used, the heat generated by the light source 9 can be efficiently radiated, and the inside of the backlight 3 can be prevented from being trapped.

  The front housing 13 and the rear housing 14 are generally fixed to each other by a hook structure or a screw, and hold other components of the backlight 3, the display element 2, the circuit board 5, and the like. However, the front housing 13 and the rear housing 14 may be integrated.

<Case 4>
The housing 4 is a frame-shaped member that holds the display element 2, the backlight 3, a touch panel (not shown), a protection member (not shown), and the like. The housing 4 is formed of a thin metal or resin molded product, and is fixed to the backlight 3 by a nail-shaped fixing structure or a screw. Note that the housing 4 may be formed integrally, or may be configured by combining a plurality of members. Further, a mounting portion (a screw, a mounting hole, or the like) for a final product may be provided on a side surface, a front surface, a back surface, a peripheral portion, or the like of the housing 4.

<Circuit board 5>
The circuit board 5 controls the display element 2 and the light source 9 by electric input / output signals. A copper pattern is usually formed on the circuit board 5 by glass epoxy or the like, and electronic components are mounted on the surface by soldering. The circuit board 5 is disposed and fixed mainly on the back surface side (the side from which light is not emitted) of the display device 1. However, the FPC (Flexible Flexible Circuit) in which wiring is formed on a film-like base material connected to the display element 2 is provided. It is also possible to adopt a configuration in which electronic components are mounted on a printed circuit. In order to protect the circuit board 5 from external pressure or static electricity, a protective cover (not shown) made of a metal such as aluminum, stainless steel, or galvanized steel sheet, or a thin film-like resin such as PET (Polyethylene Terephthalate). Zu) may be attached. When a metal protective cover is used, a resin such as PET is provided on the circuit board 5 side of the protective cover in order to avoid electrical contact with the circuit board 5 or electronic components arranged on the circuit board 5. It is desirable to take a countermeasure against the insulation by attaching a sheet made of a material.

<Touch panel>
The touch panel (not shown) converts the information on the position coordinates input from the outside (user) into an electric signal by a circuit provided with a transparent electrode formed on a transparent substrate, and is connected to an end. It is transmitted to the control circuit of the final product via the output wiring section. As the output wiring portion, an FPC is used because of its thinness and flexibility of connection due to flexibility, but different materials or structures may be used as long as they have the same function or characteristics. The touch panel is provided with a protective member (not shown) made of a transparent material such as glass or plastic on the front side in order to prevent damage, deformation, abrasion, or contamination due to pressure or contact from the input surface side. Is also good. Printing can be added to the periphery of the front surface or the back surface of the protective member for shading or design purposes.

  Next, a characteristic structure of the display device 1 will be described.

  FIG. 2 is a plan view illustrating an example of the configuration of the backlight 3.

  As shown in FIG. 2, at least one side of the backlight 3 is provided with a light source arrangement side 15. Note that the light source arrangement side 15 may be provided on a plurality of sides in order to achieve a desired luminance specification, and is not limited to one side.

  FIG. 3 is a diagram showing an example of the AA cross section of FIG. FIG. 4 is an enlarged view of a part a of FIG. 3, and FIG. 5 is an enlarged view of a part b of FIG.

  As shown in FIGS. 3 to 5, if a BM width 16 that is a width of a BM (Black Matrix) provided in the display element 2 is a narrow frame of, for example, 1 mm, a backlight is included in the BM width 16. It can be confirmed that the picture frame 19 is settled (the inside end of the picture frame of the backlight 3 is located outside the inside end of the BM). The light-shielding / backlight fixing tape 17 (first fixing tape) includes a front case 13, an optical sheet 11, a light guide plate 10, a reflection sheet 12, and a light source 9 (illustrated here) which are components of the backlight 3. ), The rear housing 14 and the double-sided tape 18 are held and fixed.

  As shown in FIG. 4, on the display element 2 side of the light-shielding / backlight fixing tape 17 fixing each component of the backlight 3, a double-sided tape for attaching and fixing the backlight 3 and the display element 2 is provided. 20 are provided. It is desirable that the double-sided tape 20 be made of a black material so that light from the backlight 3 is not transmitted or reflected. Similarly, the light-shielding / backlight fixing tape 17 is a tape having a function of shielding light from the backlight 3. It is necessary to arrange so as to overlap the end portion (extend to the inside of the opening of the front housing 13 so as to overlap a part of the optical sheet 11 in plan view).

  The front housing wall thickness 21 of the front housing 13 is equivalent to the thinnest thickness (for example, 0.5 mm) that can be molded in white with high reflection efficiency when a resin molded product is used to realize a narrow frame. A resin molded product is applicable. Note that the thickness that can be formed is not limited here because there is a possibility that the thickness will be further reduced due to future technological progress.

  As shown in FIG. 5, it can be confirmed that the front case 13 and the light guide plate 10 are fixed by the double-sided tape 18. The purpose of using the double-sided tape 18 is that light from the light source 9 propagates through the light guide plate 10 and is efficiently reflected on the front case 13, and that the front case 13 and the light guide plate 10 are attached and fixed. The purpose is to improve the rigidity of the backlight 3.

  The rear housing 14 is provided at one end with a rear housing step portion 22 (positioning portion) having a step, which is one of the features of the first embodiment. When fixing each constituent member of the backlight 3 with the light-shielding / backlight fixing tape 17, the front housing 13 is hooked (positioned) and fixed to the rear housing step 22 so that strong fixing is possible. Becomes That is, the front housing 13 is positioned by the rear housing step 22, and houses the light source 9, the light guide plate 10, and the optical sheet 11 from the front. The light-shielding / backlight fixing tape 17 covers the position where the front casing 13 is positioned at the rear casing step 22, and fixes the rear casing 14 and the front casing 13. In addition, as a processing method of the rear case step portion 22, a crushing process at the time of press working with a die, a shaving process by a machine, or the like can be given.

  Next, another example of the configuration of the backlight 3 will be described.

  FIG. 6 is a diagram illustrating another example of the AA cross section in FIG. 2. FIG. 7 is an enlarged view of a part c in FIG. 6, and FIG. 8 is an enlarged view of a part d in FIG. Hereinafter, portions different from the configuration of the backlight 3 illustrated in FIGS. 3 to 5 will be described, and description of the same portions will be omitted.

  As shown in FIGS. 6 to 8, the backlight 3 and the display element 2 are provided above the front housing frame 23 (projection) of the front housing 13 (on the display element 2 side of the front housing frame 23). And a front housing double-sided tape 26 for attaching and fixing the tape. The front housing frame 23 overlaps the outer periphery of the optical sheet 11 in plan view. It is desirable that the front case double-sided tape 26 be made of a black material so that light from the backlight 3 is not transmitted or reflected.

  It is desirable that the front case frame width 25 of the front case frame 23 is 1 mm or less so that the BM width of the display element 2 is 16 or less. The optical sheet 11 is accommodated inside the frame width 25 of the front housing.

  The backlight fixing tape 24 holds and fixes each component of the backlight 3 and is realized by using a tape or the like having a function of blocking light from the backlight 3.

  From the above, according to the first embodiment, it is possible to stably and firmly fix the members constituting the backlight 3 and narrow the frame even under a severe use environment or a temperature environment. Become.

  In the above description, the case where the light-shielding / backlight fixing tape 17 (see FIGS. 3 to 5) and the backlight fixing tape 24 (see FIGS. 6 to 8) use a tape having a light-shielding function has been described. It is not limited. For example, the rigidity of the backlight 3 can be further enhanced by sticking or applying an adhesive to a thin spring steel material or the like in addition to the tape and fixing the adhesive.

  In the above, the configuration of the side facing the light source arrangement side 15 (section AA in FIG. 2) has been described, but the same configuration applies to all sides where the light source 9 is not disposed. That is, the rear housing 14 has the rear housing step 22 on at least one side of the outer periphery of the mounting surface other than the side where the light source 9 is arranged.

<Embodiment 2>
In the first embodiment, the case where the front housing 13 is hooked on the rear housing step 22 of the rear housing 14 has been described, but the present invention is not limited to this. Embodiment 2 of the present invention is characterized in that, as shown in FIG. 9, a comb-shaped comb-shaped portion is formed at each end of the front case 13 and the rear case 14. The other configuration is the same as that of the first embodiment, and the description is omitted here.

  As shown in FIG. 9, the front housing projection 27 that forms the comb teeth (second comb teeth) of the front housing 13 is a comb tooth (first comb teeth) of the rear housing 14. Can be fitted into the rear housing recess 28.

  As described above, according to the second embodiment, it is possible to more securely fix the members constituting the backlight 3 than in the first embodiment.

<Embodiment 3>
In the first embodiment, the case has been described in which the front housing 13 and the light guide plate 10 are fixed to each other with the double-sided tape 18 attached thereto, but the present invention is not limited to this. In the third embodiment of the present invention, as shown in FIG. 10, the light guide plate 10 includes a light guide plate main body 30 and a light guide plate white molded part that is integrally formed with the light guide plate main body 30 and molded into white (two-color molding). 29. The other configuration is the same as that of the first embodiment, and the description is omitted here.

  As shown in FIG. 10, the light guide plate 10 accommodates the optical sheet 11 by forming a light guide plate white molding 29 (projection) at a portion corresponding to the outer periphery of the mounting surface of the rear housing 14. It has a recess. The light-shielding / backlight fixing tape 17 (second fixing tape) fixes the rear housing 14 and the light guide plate 10.

  From the above, according to the third embodiment, in addition to the effect of the first embodiment, the double-sided tape 18 used in the first embodiment is not required, so that the number of parts or the cost can be reduced. Becomes

  In the present invention, each embodiment can be freely combined, or each embodiment can be appropriately modified or omitted within the scope of the invention.

  REFERENCE SIGNS LIST 1 display device, 2 display element, 3 backlight, 4 housing, 5 circuit board, 6 first substrate, 7 second substrate, 8 driving IC, 9 light source, 10 light guide plate, 11 optical sheet, 12 reflection Sheet, 13 front housing, 14 rear housing, 15 light source arrangement side, 16 BM width, 17 light-shielding / backlight fixing tape, 18 double-sided tape, 19 backlight frame, 20 double-sided tape, 21 front housing wall thickness, 22 Rear housing recess, 23 Front housing frame, 24 Backlight fixing tape, 25 Front housing frame width, 26 Front housing double-sided tape, 27 Front housing protrusion, 28 Rear housing recess, 29 Light guide plate white molding , 30 light guide plate body.

Claims (8)

Light source,
A light guide plate that emits light from the light source in a predetermined direction,
An optical sheet for adjusting the intensity distribution of light emitted from the light guide plate,
The light source is arranged, and has a mounting surface for mounting the light guide plate and the optical sheet from the back side, and at least one side of the outer periphery of the mounting surface other than the side on which the light source is arranged in advance. A rear housing having a determined positioning portion,
Positioned by the positioning portion, the light source, the light guide plate, and the optical sheet is accommodated from the front side, a front housing having an opening through which light emitted from the optical sheet passes,
A first fixing tape that covers at least a position where the front housing is positioned by the positioning unit, and fixes the rear housing and the front housing;
Equipped with a,
The positioning unit, Ru stepped portion der having a step, the backlight. Light source,
  A light guide plate that emits light from the light source in a predetermined direction,
  An optical sheet for adjusting the intensity distribution of light emitted from the light guide plate,
  The light source is arranged, and has a mounting surface for mounting the light guide plate and the optical sheet from the back side, and at least one side of the outer periphery of the mounting surface other than the side on which the light source is arranged in advance. A rear housing having a determined positioning portion,
  Positioned by the positioning portion, the light source, the light guide plate, and the optical sheet is accommodated from the front side, and a front housing having an opening through which light emitted from the optical sheet passes,
  A first fixing tape that covers at least a position where the front housing is positioned by the positioning unit, and fixes the rear housing and the front housing;
With
  The positioning portion is a first comb tooth portion formed in a comb tooth shape,
  The backlight, wherein the front housing includes a second comb-shaped comb-shaped portion formed to fit with the first comb-shaped portion. Light source,
  A light guide plate that emits light from the light source in a predetermined direction,
  An optical sheet for adjusting the intensity distribution of light emitted from the light guide plate,
  The light source is arranged, and has a mounting surface for mounting the light guide plate and the optical sheet from the back side, and at least one side of the outer periphery of the mounting surface other than the side on which the light source is arranged in advance. A rear housing having a determined positioning portion,
  Positioned by the positioning portion, the light source, the light guide plate, and the optical sheet is accommodated from the front side, and a front housing having an opening through which light emitted from the optical sheet passes,
  A first fixing tape that covers at least a position where the front housing is positioned by the positioning unit, and fixes the rear housing and the front housing;
With
  The backlight, wherein the front housing has a protruding portion that overlaps with an outer periphery of the optical sheet in a plan view. The opening is opened so that the optical sheet is exposed,
The first fixed tape is characterized by extending to the inside of the opening so as to overlap with a part in plan view of the optical sheet, a backlight according to claim 1 or 2. The front housing, characterized in that it has a protruding portion that overlaps the outer circumference in plan view of the optical sheet, a backlight according to claim 1 or 2. The backlight according to claim 3 , wherein the positioning portion is a step portion having a step. The positioning portion is a first comb tooth portion formed in a comb tooth shape,
4. The backlight according to claim 3 , wherein the front housing includes a comb-shaped second comb-shaped portion formed so as to be fitted with the first comb-shaped portion. 5. A backlight according to any one of claims 1 to 7,
A display element disposed on the backlight;
A display device comprising:

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