JP7261589B2 - backlight and display - Google Patents

Description

The present invention relates to backlights and display devices with backlights.

With the spread of information electronic equipment, thin and lightweight display devices are used in various fields such as displays for mobile phones and personal computers, various devices used in industrial applications, in-vehicle displays, handy terminals, and advertising displays. used in In recent years, as small display devices such as smartphones and tablets have narrower frames, there is a demand for narrower frames in large size display devices as well.

In a display device equipped with a backlight, the backlight may be made up of a metal housing, and a heat dissipation member made of a material with good thermal conductivity may be added to dissipate heat from the light source (see, for example, Patent Document 1). ).

Japanese Patent No. 4618310

However, in a display device with a backlight, the sides of the backlight are covered with a metal housing, and even if the optical sheets and the light guide plate placed inside expand or contract due to temperature changes, the coefficient of thermal expansion does not change. The low metal housing has little expansion or contraction. As a result, for example, when the optical sheet expands, it comes into contact with the metal housing, causing the optical sheet to wrinkle.

Therefore, it is necessary to provide a clearance between the optical sheet and the light guide plate and the metal housing for the expansion and contraction of the optical sheet and the light guide plate when the temperature changes, which causes a problem of widening the frame.

A method of narrowing the frame by eliminating the difference in thermal expansion coefficient between the optical sheet and the light guide plate and the housing by adopting a resin housing instead of the metal housing is also conceivable. However, in this case, since the backlight is made of a material having a low thermal conductivity, there is a problem that heat cannot be dissipated and the inside of the backlight becomes hot.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a backlight and a display device equipped with the backlight that can achieve both a narrow frame and a necessary heat dissipation property.

A backlight according to the present invention includes a light source substrate on which a light source is mounted, a metal rear housing having side portions for holding the light source substrate, a resin front housing for holding the rear housing, and an optical member made of resin that is housed in a housing formed by the front housing and the rear housing, wherein the rear housing includes a bottom surface facing the front housing and a bottom surface portion of the bottom housing. and the side surface projecting from one side toward the front housing, and the front housing includes a frame and a side of the frame other than the side corresponding to the side of the rear housing. Side wall portions protruding toward the rear housing, and grooves formed in the side walls and engageable with bottom end portions of the bottom surface portion of the rear housing on sides other than the sides where the side portions are provided. wherein the front housing and the rear housing are connected to the housing in a state in which the end of the bottom surface of the bottom surface of the rear housing is engaged with the groove of the side wall of the front housing. The rear housing includes a convex portion projecting from the bottom end of the bottom portion to the side opposite to the front housing, and the frame of the front housing formed on the side portion. The front housing further has a recess formed in the groove and capable of accommodating the protrusion.

ADVANTAGE OF THE INVENTION According to this invention, the display apparatus provided with the backlight and backlight which can make a narrow frame and ensure required heat dissipation simultaneously can be implement|achieved.

1 is an exploded perspective view of a display device according to Embodiment 1; FIG. 1 is a front view of a display device according to Embodiment 1; FIG. 2 is a rear perspective view of the display device according to Embodiment 1. FIG. FIG. 3 is a cross-sectional view taken along line AA of FIG. 2; FIG. 3 is a cross-sectional view taken along line BB of FIG. 2; FIG. 3 is a cross-sectional view taken along line CC of FIG. 2; FIG. 4 is a perspective view of the backlight before the front housing and the rear housing are engaged; It is a front view for demonstrating the effect|action of a backlight. FIG. 5 is a view corresponding to FIG. 4 of Embodiment 2; FIG. 6 is a view corresponding to FIG. 6 of Embodiment 2; FIG. 9 is an enlarged view of area D of FIG. 8; FIG. 11 is a rear perspective view of a display device according to Embodiment 3; FIG. 11 is an exploded perspective view of a display device according to Embodiment 4;

<Embodiment 1>
Embodiment 1 of the present invention will be described below with reference to the drawings. FIG. 1 is an exploded perspective view of a display device 100 according to Embodiment 1. FIG.

<Overall Configuration of Display Device>
As shown in FIG. 1, the display device 100 includes a display element 1 and a backlight 2. As shown in FIG. The display element 1 is a transmissive or semi-transmissive display panel for displaying an image, specifically a liquid crystal display panel or the like. In addition, in Embodiment 1, the display element 1 is a liquid crystal display panel.

The display element 1 is arranged on the upper surface of the backlight 2 . That is, the backlight 2 is arranged on the side opposite to the display surface 1a of the display element 1, and illuminates the display element 1 from the side opposite to the display surface. The backlight 2 includes a front housing 3, an optical sheet 2b, a light guide plate 2c, a reflection sheet 2d, a light source 2e, a light source substrate 2f, a rear housing 4, and a display element fixing member 2h.

The light source 2e is mounted on the light source substrate 2f. The light guide plate 2c includes an emission surface for receiving the light emitted from the light source 2e from the side surface and propagating the light forward, and a reflection emission surface provided on the opposite side of the emission surface. The optical sheet 2b is arranged on the exit surface of the light guide plate 2c in order to control the distribution or spread of the light emitted from the light guide plate 2c. The reflective sheet 2d is arranged on the reflective emission surface of the light guide plate 2c in order to direct the light emitted from the reflective emission surface of the light guide plate 2c toward the light guide plate 2c. The rear housing 4 is arranged behind the reflection sheet 2d and holds the light source substrate 2f, the optical sheet 2b, the light guide plate 2c, and the reflection sheet 2d.

As the light source 2e, a point light source of RGB (Red: red, Green: green, Blue: three primary colors of light), an LED with emission colors other than RGB, or a fluorescent tube lamp is arranged. When a point light source is used, the light source substrate 2f on which the point light source is mounted may be based on a general glass epoxy resin or a flexible flat cable. Moreover, in order to improve heat dissipation, a metal such as aluminum or a ceramic base may be used.

The light guide plate 2c is made of transparent acrylic resin, polycarbonate resin, glass, or the like. A scattering dot pattern or a prism shape is formed on the reflective emission surface and the emission surface of the light guide plate 2c to emit light and to adjust the intensity distribution and emission direction of the light within the plane. Note that the scattering dot pattern or prism shape may be formed only on one of the reflective emission surface and the emission surface of the light guide plate 2c.

Furthermore, an optical sheet 2b is arranged on the light guide plate 2c in order to adjust the intensity distribution or the emission angle of the emitted light. As the optical sheet 2b, a lens sheet for condensing light, a diffusion sheet for uniforming light, a viewing angle adjustment sheet for adjusting brightness in the viewing angle direction, or the like is arranged according to the purpose. be.

The front housing 3 has an opening 3a for emitting light from the light emitting surface of the light guide plate 2c, and holds the display element 1 on the upper surface via a display element fixing member 2h. Furthermore, the front housing 3 also holds the rear housing 4 . By combining the front housing 3 and the rear housing 4, a housing is formed in which a resin optical member is accommodated. Here, the optical members are the optical sheet 2b and the light guide plate 2c.

Resin materials such as PC (Polycarbonate) and ABS (Acrylonitrile Butadiene Styrene) can be used for the front housing 2a.

A light source substrate 2f on which a light source 2e is mounted is positioned and held on the rear housing 2g. In order to conduct the heat emitted from the light source 2e, it is desirable to use metal with high thermal conductivity for the rear housing 2g. By using aluminum or an aluminum alloy with particularly high thermal conductivity, it is possible to efficiently radiate heat from the light source 2e and prevent the backlight 2 from being filled with heat.

<Configuration of front housing and rear housing>
Next, characteristic configurations of the front housing 3 and the rear housing 4 will be described. FIG. 2 is a front view of the display device 100. FIG. FIG. 3 is a rear perspective view of the display device 100. FIG. 4 is a cross-sectional view taken along line AA of FIG. 2. FIG. 5 is a cross-sectional view taken along line BB of FIG. 2. FIG. FIG. 6 is a cross-sectional view taken along line CC of FIG. FIG. 7 is a perspective view of the backlight 2 before the front housing 3 and the rear housing 4 are engaged.

As shown in FIGS. 2 to 4 and 7, the rear housing 4 includes a bottom surface portion 4a facing the front housing 3, and one of the four sides of the bottom surface portion 4a facing the front housing 3. and a side surface portion 4b protruding into. The side surface portion 4b is provided substantially perpendicularly to the bottom surface portion 4a, and the rear housing 4 is L-shaped in cross section. A light source substrate 2f on which a light source 2e is mounted is held on the inner surface of the side surface portion 4b.

Further, as shown in FIGS. 1, 2, 5 and 6, the front housing 3 has a frame portion 3b and a side of the frame portion 3b other than the side corresponding to the side portion 4b of the rear housing 4. It has three side wall portions 3c each protruding toward the housing 4 side, and a groove portion 3d. Here, the sides of the frame portion 3b corresponding to the side portions 4b of the rear housing 4 are the sides located on the side portions 4b of the rear housing 4 when the front housing 3 and the rear housing 4 are combined. be.

The groove portion 3d is formed across the entire lateral direction of the lower end portion of the side wall portion 3c on the side facing the side portion 4b of the rear housing 4, and the entire lateral direction of the lower end portions of the two side wall portions 3c adjacent to the side wall portion 3c. formed over the The groove portion 3d can be engaged with a bottom portion end portion 4c existing on a side of the bottom portion 4a of the rear housing 4 other than the side on which the side portion 4b is provided. The rear housing 4 is held by the front housing 3 by engaging the bottom end 4c with the groove 3d.

The front housing 3 and the rear housing 4 form a housing in a state in which the groove 3d of the side wall 3c of the front housing 3 and the bottom end 4c of the bottom 4a of the rear housing 4 are engaged. An optical sheet 2b, a light guide plate 2c, and a reflection sheet 2d are accommodated inside the housing, and these are fixed on the light source 2e side. The optical sheet 2b is made of resin, and the front casing 3 uses a resin material with a thermal expansion coefficient equivalent to that of the optical sheet 2b. It is necessary to set the clearance according to the physical properties.

<Action>
Next, the action of the backlight 2 will be described with reference to FIG. FIG. 8 is a front view for explaining the action of the backlight 2. FIG.

As shown in FIG. 8, in the backlight 2, the side surface portion 4b of the rear housing 4 forms a side surface corresponding to the side of the housing on which the light source 2e is arranged, and the three side wall portions 3c of the front housing 3 form the other three sides. As a result, the side surface of the backlight 2 on the side where the light source 2e is arranged is made of metal, and the other three side surfaces are made of resin.

When the optical sheet 2b expands in the direction indicated by L1 in FIG. 8 (in the opposite direction in the case of contraction) due to a change in temperature, the front housing 3 similarly expands in the direction indicated by L2 (in the case of contraction in the opposite direction). Therefore, the front housing 3, the optical sheet 2b, and the light guide plate 2c, which are all formed with the same coefficient of thermal expansion, expand or contract in the same way when the temperature changes. 2b and the light guide plate 2c can be prevented from coming into contact with each other.

That is, it is possible to suppress wrinkling of the optical sheet 2b and breakage of the light guide plate 2c when the temperature changes. As a result, the clearance between the optical sheet 2b and the light guide plate 2c and the front housing 3, which takes into consideration the amount of expansion of the conventional optical sheet 2b and the light guide plate 2c, can be made as small as possible. The frame can be narrowed on three side surfaces corresponding to sides other than the side on which the light source 2e is arranged. By positioning the optical sheet 2b and the light guide plate 2c with respect to the side surface portion 4b of the rear housing 4 without clearance, the extension direction of the optical sheet 2b and the light guide plate 2c due to the expansion is set to the side surface of the rear housing 4. This is because it can be guided in a direction other than the portion 4b.

In addition, since the light source substrate 2f is arranged on the side surface portion 4b of the rear housing 4 made of metal, the backlight 2 and the display device 100 having excellent heat dissipation properties can be realized.

Further, the backlight 2 is configured such that the bottom end portion 4c of the rear housing 4 is slidably engaged with the groove 3d of the front housing 3. As shown in FIG. Hereinafter, this structure is also referred to as a slide structure. This is because the rear housing 4 made of metal and the front housing 3 made of resin individually expand or contract due to changes in environmental temperature. And even the rear housing 4 can withstand changes in environmental temperature without applying stress.

The groove portion 3d is formed with a length such that the end portion 4c of the bottom surface portion of the rear housing 4 does not come off when the front housing 3 expands. Further, the groove 3d is formed over the entire lateral direction of the three side walls 3c of the front housing 3, but it is sufficient if it can engage with a part of the bottom end 4c of the rear housing 4, so it is omitted as appropriate. be able to.

Further, as described above, by making the bottom edge 4c of the rear housing 4 and the groove 3d of the front housing 3 slide, the housing can be easily formed. It is sufficient that the portion 4c and the groove portion 3d of the front housing 3 are engaged with each other, and a structure other than the slide structure may be used.

<effect>
As described above, display device 100 according to Embodiment 1 includes backlight 2 and display element 1 arranged on backlight 2 . Further, in the backlight 2, the rear housing 4 has a bottom surface portion 4a facing the front housing 3, and a side surface portion 4b projecting from one side of the bottom surface portion 4a toward the front housing 3. The housing 3 is formed of a frame portion 3b, side wall portions 3c projecting toward the rear housing 4 from sides of the frame portion 3b other than the side corresponding to the side surface portion 4b of the rear housing 4, and the side wall portions 3c. and a groove 3d that can be engaged with a bottom end 4c existing on a side of the bottom surface 4a of the rear housing 4 other than the side on which the side surface 4b is provided, and the front housing 3 and the rear housing 4 are The housing is formed in a state in which the bottom end portion 4c of the bottom surface portion 4a of the rear housing 4 is engaged with the groove portion 3d of the side wall portion 3c of the front housing 3. As shown in FIG.

Therefore, it is possible to realize the backlight 2 and the display device 100 capable of achieving both a narrow frame and ensuring necessary heat dissipation.

Since a narrow frame can be realized in this way, the size of the backlight 2 and the display device 100 can be reduced.

<Embodiment 2>
Next, a display device 100A according to Embodiment 2 will be described. FIG. 9 is a view corresponding to FIG. 4 of the second embodiment. FIG. 10 is a view corresponding to FIG. 6 of the second embodiment. FIG. 11 is an enlarged view of area D in FIG. In the second embodiment, the same components as those described in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

In the first embodiment, the end portion 4c of the bottom surface portion of the rear housing 4 is slid into the groove portion 3d of the front housing 3 and engaged therewith.

On the other hand, in the second embodiment, as shown in FIGS. 9 to 11, the display device 100A includes a backlight 2A instead of the backlight 2, and the backlight 2A is different from the display device 100. Compared with the light 2, it has a front housing 3A instead of the front housing 3 and a rear housing 4A instead of the rear housing 4. - 特許庁

Compared to the rear housing 4, the rear housing 4A has a protrusion 4d projecting from the bottom end 4c of the bottom surface 4a to the opposite side of the front housing 3, It further includes a projecting portion 4e that supports the frame portion 3b of the body 3A. The front housing 3A further includes a recess 3e formed in the groove 3d of the front housing 3 and capable of accommodating the projection 4d.

The convex portion 4d protrudes downward from the back surface of the bottom surface portion edge portion 4c present on the side opposite to the side on which the side surface portion 4b of the bottom surface portion 4a is provided, among the bottom surface portion edge portions 4c present on the three sides. In addition, it is formed continuously on the whole or part of the width direction of the end portion 4c of the bottom portion. The concave portion 3e is formed at a position corresponding to the convex portion 4d on the bottom surface of the groove portion 3d. Note that the convex portions 4d do not have to be formed continuously, and a plurality of convex portions 4d may be formed at intervals in the width direction of the portion.

The protruding portion 4e is formed to protrude inward from the upper end portion of the side portion 4b over the entire lateral direction, and supports a portion of the frame portion 3b of the front housing 3A.

Since the protrusion 4d is accommodated in the recess 3e and the protrusion 4e supports the frame 3b of the front housing 3A, the rear housing 4 is separated from the front housing 3 even if the display device 100A receives an impact. become difficult.

The convex portion 4d may be formed also at the bottom end portion 4c on the other side, and the concave portion 3e may be formed at a position corresponding to the convex portion 4d on the bottom surface of the groove portion 3d.

Further, by adopting the structure of Embodiment 2, only the groove 3d formed in the side wall 3c on the side facing the side surface 4b of the rear housing 4 can be left, and the other grooves 3d can be omitted. It becomes possible.

As described above, in the backlight 2A according to the second embodiment, the rear housing 4 includes the protrusion 4d projecting from the bottom end 4c of the bottom surface 4a to the side opposite to the front housing 3, and the side surface. 4b and supports the frame 3b of the front housing 3A, and the front housing 3 further has a recess 3e formed in the groove 3d and capable of accommodating the projection 4d.

Therefore, it is possible to realize the backlight 2A and the display device 100A having excellent resistance to vibration and impact.

<Embodiment 3>
Next, a display device 100B and a backlight 2B according to Embodiment 3 will be described. FIG. 12 is a rear perspective view of the display device 100B according to Embodiment 3. FIG. In addition, in Embodiment 3, the same components as those described in Embodiments 1 and 2 are denoted by the same reference numerals, and descriptions thereof are omitted.

In the first embodiment, as shown in FIG. 3, the bottom surface portion 4a of the rear housing 4 is exposed. On the other hand, in Embodiment 3, as shown in FIG. For comparison, a front housing 3B is provided instead of the front housing 3. FIG.

The front housing 3B further has a rear portion 3f that covers the rear side of the bottom portion 4a of the rear housing 4 and is provided on the opposite side of the side wall portion 3c to the frame portion 3b compared to the front housing 3. . The rear surface portion 3f is connected to the lower ends of the three side walls so as to face the rear surface of the bottom surface portion 4a of the rear housing 4. As shown in FIG. An opening 3g is formed in a portion of the front housing 3B corresponding to the side surface portion 4b of the rear housing 4, so that the bottom surface portion 4a of the rear housing 4 can be accommodated in the front housing 3B. Note that the side surface portion 4b is omitted in FIG. 12 in order to make the drawing easier to see.

As described above, in the backlight 2B according to Embodiment 3, the front housing 3B is provided on the side opposite to the frame portion 3b in the side wall portion 3c, and the back side of the bottom surface portion 4a of the rear housing 4 is Since the back surface portion 3f is further included, the backlight 2B and the display device 100B having excellent resistance to vibration and impact can be realized.

<Embodiment 4>
Next, a display device 100C and a backlight 2C according to Embodiment 4 will be described. FIG. 13 is an exploded perspective view of the display device 100C according to the fourth embodiment. In Embodiment 4, the same components as those described in Embodiments 1 to 3 are denoted by the same reference numerals, and descriptions thereof are omitted.

In the fourth embodiment, as shown in FIG. 13, the display device 100C includes a backlight 2C instead of the backlight 2B, and the backlight 2C is different from the display device 100B according to the third embodiment. Compared to 2B, it has a side housing 5 made of metal instead of the rear housing 4 .

The side housing 5 holds the light source substrate 2 f, and the front housing 3 B holds the side housing 5 . Then, the front housing 3B and the side housing 5 form a housing. Specifically, the side housing 5 forms one of the four side surfaces of the housing, and the front housing 3B forms the other three side surfaces and the rear surface of the housing. The front housing 3B and the side housing 5 are joined with an adhesive, for example. Note that the front housing 3B of Embodiment 4 has the same configuration as the front housing 3B of Embodiment 3 except that it does not have the groove portion 3d, so the description thereof will be omitted.

As described above, the backlight 2C according to the fourth embodiment includes the light source board 2f on which the light source 2e is mounted, the metal side housing 5 that holds the light source board 2f, and the resin housing 5 that holds the side housing 5. and a resin optical member housed in a housing formed by the front housing 3B and the side housing 5, and the side housing 5 includes a plurality of side surfaces of the housing. The front housing 3B protrudes toward the optical member from the frame portion 3b and the sides of the frame portion 3b other than the side corresponding to the side housing 5, and the other side surface of the housing. and a rear surface portion 3f provided on the opposite side of the sidewall portion 3c from the frame portion 3b and forming the rear surface of the housing. Therefore, it is possible to realize the backlight 2C and the display device 100C having excellent resistance to vibration and impact.

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

1 display element, 2, 2A, 2B, 2C backlight, 2b optical sheet, 2c light guide plate, 2e light source, 2f light source substrate, 3, 3A, 3B front housing, 3b frame portion, 3c side wall portion, 3d groove portion, 3e Concave portion 3f Rear portion 4, 4A Rear housing 4a Bottom portion 4b Side portion 4c Bottom portion end portion 4d Protrusion 4e Protrusion 5 Side housing 100, 100A, 100B, 100C Display device.

Claims (3)

a light source substrate on which a light source is mounted;
a metal rear housing having a side portion for holding the light source substrate;
a front housing made of resin that holds the rear housing;
a resin optical member housed in a housing formed by the front housing and the rear housing;
The rear housing has a bottom surface portion facing the front housing, and the side surface portion protruding from one side of the bottom surface portion toward the front housing,
The front housing includes a frame, side walls protruding toward the rear housing from sides of the frame other than sides corresponding to the side surfaces of the rear housing, and a groove that can be engaged with an edge of the bottom surface portion of the rear housing that is present on a side other than the side on which the side surface portion is provided;
the front housing and the rear housing form the housing in a state in which the bottom end of the bottom surface of the rear housing is engaged with the groove of the side wall of the front housing;
The rear housing includes a convex portion projecting from the end of the bottom surface of the bottom surface to a side opposite to the front housing, and a projection formed on the side surface and supporting the frame of the front housing. and further comprising
The backlight , wherein the front housing further has a recess formed in the groove and capable of accommodating the projection . 2. The backlight according to claim 1 , wherein the front housing further has a rear surface portion provided on the side wall portion opposite to the frame portion and covering the rear side of the bottom surface portion of the rear housing. a backlight according to claim 1 or claim 2 ;
a display element arranged on the backlight;
A display device.

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