JP2000047210A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to surely position a back light unit into a metallic armor case while assuring the gap component for expansion relief. SOLUTION: This liquid crystal display device has the metallic armor case 30 which has a display window on one surface and is opened on the other surface, a liquid crystal display panel which is arranged in this metallic armor case 30 so as to face this display window and the back light unit 20 which includes a unit case 21 made of a synthetic resin housed within the open surface of the metallic armor case 30 so as to exist on the rear surface side of the liquid crystal display panel 10. The device is provided with the prescribed gap G allowing for the thermal expansion of the unit case 21. In such a case, The flanks of the unit case 21 are partially provided with projections 50 having the height nearly equal to the gap G component described above. The unit case 21 is positioned into the metallic armor case 30 by these projections 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a backlight unit.
The present invention relates to a technique for positioning a backlight unit in a metal outer case.

[0002]

2. Description of the Related Art A backlight unit is disposed on the rear side of a transmissive or transflective liquid crystal display panel. In an actual product, as shown in the cross-sectional view of FIG. The liquid crystal display panel 1 in the case 30
0 and the backlight unit 20 are assembled.

The outer case 30 has a display window 31 on one surface (the upper surface side in FIG. 9), and the other surface is made of a metal such as a rectangular box-shaped iron plate having an open side. The liquid crystal display panel 10 is arranged along the window 31. Then, the backlight unit 20 is housed in the open surface of the outer case 30 via the spacer 40 so as to be located on the back side (the lower side in FIG. 9) of the liquid crystal display panel 10.

The liquid crystal display panel 10 is composed of a laminated substrate in which a pair of transparent electrode substrates 11 and 12 are laminated via a peripheral sealing material (not shown). Transparent electrode substrate 11, 1
Polarized films 13 are attached to 2 respectively.

[0005] The backlight unit 20 is made of a unit case 2 made of a synthetic resin, for example, polycarbonate.
1 is provided. In this example, the unit case 21
Is a sidelight type, the upper surface facing the liquid crystal display panel 10 is opened as a light irradiation window, and the light guide plate 22 is housed inside.

A light source housing 23 is provided on the light receiving surface 221 side of the light guide plate 22, and a straight tube type CFL (cold cathode tube) 231 as a light source is housed in the light source housing 23. The bottom of the unit case 21 is provided with an appropriate inclination for directing the light from the CFL 231 toward the liquid crystal panel 10, and a light reflection sheet 24 is provided from the bottom surface and the side surface of the light source housing 23 to the upper surface thereof. Have been. A light diffusion sheet 25 is provided on the upper surface of the light guide plate 22.

[0007]

The exterior case 30 is made of a metal such as a decorative iron plate, whereas the unit case 21 of the backlight unit 20 is made of a synthetic resin material such as polycarbonate. The linear expansion coefficients differ greatly.

Incidentally, the linear expansion coefficient of iron is 1.12 × 1
Whereas 0 ^-5, the linear expansion coefficient of polycarbonate is 6.60 × ^{10 -5.}

Explaining the measured values, both have a length of 11
Prepare a 2.8 mm iron plate and a polycarbonate plate.
When heating to 80 ° C. in consideration of the case where the temperature is set to 0 ° C. at normal temperature, for example, when exposed to a high-temperature state when mounted on a vehicle, the expansion of the iron plate is 0.0758 mm, whereas the expansion of the polycarbonate plate is 0%. .4467 mm, the difference being 0.3709 mm.

Therefore, in order to prevent the outer case 30 from being deformed due to the thermal expansion of the unit case 21, a gap for expansion and escape is conventionally provided between the outer case 30 and the unit case 21, including component tolerances. It is provided. For example, if the product width is 112.8 as described above
In the case of mm, the gap is set to about 0.3 mm.

However, in this case, the accuracy of the combination of the components may vary depending on the space of the expansion escape, which may cause a displacement or inclination of the display area of the liquid crystal display panel 10 with respect to the display window 31 of the outer case 30. Undesirable situations such as may occur.

The present invention has been made to solve such a problem, and an object of the present invention is to ensure that a backlight unit is securely positioned in a metal outer case while securing a clearance for expansion and escape. An object of the present invention is to provide a liquid crystal display device as described above.

[0013]

In order to achieve the above object, the present invention provides a metal outer case having a display window on one side and an open side on the other side; A liquid crystal display panel arranged in a metal outer case, and a backlight unit including a synthetic resin unit case housed in an open surface of the metal outer case so as to be located on the back side of the liquid crystal display panel. A liquid crystal display device provided with a predetermined gap between the side surface of the unit case and the inner surface of the side wall of the metal exterior case in consideration of the thermal expansion of the unit case. A protrusion having a height substantially equal to the minute is partially provided, and the unit case is positioned in the metal outer case by the protrusion.

According to this structure, even if a clearance for expansion is provided between the unit case and the metal outer case,
The unit case is reliably positioned in the metal outer case using the projection as a spacer. Further, since the projection is provided only partially, even if the unit case thermally expands, there is almost no possibility that the entire metal exterior case is deformed.

In this case, the projection is preferably deformable by the thermal expansion force of the unit case. According to this, the thermal expansion of the unit case is absorbed by the deformation of the projection. Therefore, it does not lead to deformation of the metal outer case.

It is preferable that the projection is provided on a side surface of the unit case, at a position closer to a side opposite to the open surface of the metal exterior case. That is, due to its shape, the metal outer case is more likely to be deformed on the open side. Therefore, even if a projection is provided on the side surface of the unit case, it is preferable that the projection is located closer to the side opposite to the opening surface.

Further, in the present invention, it is preferable that the unit case is made of a thermoplastic resin, and the protrusion is formed integrally with the unit case. That is, the present invention includes a mode in which the protrusion formed separately is attached to the unit case by, for example, an adhesive means. It is reasonable in terms.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS The invention will now be described in more detail with reference to an embodiment shown in the drawings. In this embodiment, the same reference numerals as those in the conventional example shown in FIG. 9 described above denote the same or the same parts.

FIG. 1 is a plan view of a liquid crystal display device 1 according to this embodiment as viewed from the back side (backlight unit side: the lower side in FIG. 9). The state where the unit 20 is housed is shown. In this case, the outer case 30 and the backlight unit 20 are designed so that a gap G of, for example, about 0.3 mm is generated between them as a space for expansion and escape. ing.

Although not shown, the outer case 3
0 has a display window as in the prior art, and a liquid crystal display panel is arranged along the display window. Refer to FIG. 9 for these configurations and the basic configuration of the backlight unit 20.

The unit case 21 of the backlight unit 20 is made of a thermoplastic synthetic resin such as polycarbonate.
Two legs 21A to 21D are provided.

The legs 21A to 21D extend both in the rear direction of the unit case 21 (front side in FIG. 1) and in the upper direction side of the liquid crystal display panel (rear side in FIG. 1). The liquid crystal display panel is positioned on the upper surface side, and a circuit board (not shown) for driving the liquid crystal or the backlight is mounted on the rear surface portion.

Of these legs, the legs 21A and 21B are formed substantially in an L shape in plan view, and are disposed so as to face both corners on one end side of the outer case 30. Remaining 2
The two legs 21 </ b> C and 21 </ b> D are formed at positions near the other end of the outer case 30 so as to face the side plates of the outer case 30.

In this embodiment, each of the legs 21A to 21A
A projection having a height substantially equal to the gap G is partially provided in 1D. Since the legs 21A and 21B have substantially the same configuration, one of the legs 21A will be described with reference to the perspective view of FIG. 2 and the plan view of FIG.

The leg portion 21A has two side surfaces 2 facing the side plates 301 and 302 adjacent to each other at the corner of the outer case 30.
11 and 212, and the respective side surfaces 211 and 212 are provided.
Are formed with protrusions 50, 50, respectively.

In this example, each projection 50 is formed as an elongated rib 501 having a semicircular cross section along the depth direction of the outer case 30. The rib 501
Is set to 0.3 mm, which is substantially equal to the gap G.

Since the legs 21C and 21D have substantially the same structure, one of the legs 21C will be described with reference to the perspective view of FIG. 4 and the sectional view of FIG. The leg portions 21C extend on the rear side (upper side in FIG. 4) and the upper side (lower side in FIG. 4) of the unit case 21, and
Side surface 213 facing the side plate 302 of the
A projection 50 is provided on 13.

This projection 50 is also an elongated rib 5 having a semicircular cross section.
02, and the protruding height is also 0.3 mm. In this case, the rib 502 is provided on the upper surface side of the side surface 213, that is, on a position closer to the side opposite to the open surface of the metal outer case 30.

In this embodiment, each projection 50 is formed integrally with the unit case 21 together with each of the legs 21A to 21D. Thus, each leg 21A-21
By providing the projection 50 on D, the unit case 21 can be reliably positioned in the outer case 30 without rattling.

When the ambient temperature rises, the unit case 2
Although 1 causes thermal expansion, according to the present invention, the presence of the projection 50 absorbs or escapes the expanded portion and prevents deformation of the outer case 30 as in the following two examples.

First, as a first example, the legs 21A, 21
The rib 501 provided on B will be described. The rib 501 is considerably smaller than the side peripheral surface of the unit case 21 and is formed only partially, and the side plates 301 and 302 of the contact surfaces are iron plates harder than the rib 501.

Therefore, the rib 501 is crushed by the expansion force of the unit case 21 as shown in FIG. 6, whereby the expansion of the unit case 21 is absorbed. After that, when the unit case 21 contracts due to a decrease in the ambient temperature, the rib 501 returns to the original projection state.

Next, as a second example, the rib 502 of FIG. 4 provided on the other leg portions 21C and 21D will be described with reference to the sectional view of FIG. The ribs 502 are arranged on the side opposite to the open side of the outer case 30, that is, on the side of the bent base of the side plate 302, whereby a gap G of 0.3 mm is secured on the open side of the side plate 302 in this example. I have.

Therefore, when the unit case 21 expands and the ribs 502 do not collapse, the expansion of that portion is suppressed by the ribs 502, and mainly the rear side of the unit case 21 expands. However, due to the above-mentioned gap G, the expanded portion is escaped, and the side plate 30
There is no deformation such that the open surface side of 2 is pushed open.

In the above embodiment, the ribs 501 and 502 having a semicircular cross section are used as the projections 50. However, the cross section of the rib may be triangular or quadrangular.
Further, in the above embodiment, the ribs 501 and 502 are so-called vertical ribs extending in the depth direction of the outer case 30. However, the ribs may be horizontal ribs.
D on the side peripheral surface (end surface) of the unit case 21 other than D
Of course, 0 may be formed.

The projection 50 may be a columnar boss 503 as shown in FIG. 8 or a semicircular projection, and other projection shapes can be adopted. On the other hand, unlike the above embodiment, the protrusion 50 may be formed as a separate body and attached to the unit case 21 by an adhesive means or the like.

[0037]

As described above, according to the present invention,
In a liquid crystal display device in which a unit case of a backlight unit is accommodated in a metal outer case with a predetermined gap provided, a projection having a height substantially equal to the gap is partially provided on a side surface of the unit case. Accordingly, the unit case can be reliably positioned in the metal exterior case using the projections as spacers.

Further, even if the unit case thermally expands, the expansion is absorbed or escaped due to the presence of the projections, so that the metal outer case is not likely to be deformed, and is used in a wide temperature range. Thus, a liquid crystal display device particularly suitable for in-vehicle use is obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of one embodiment of a liquid crystal display device according to the present invention as viewed from the back side thereof.

FIG. 2 is an enlarged perspective view of a first main part in the embodiment.

FIG. 3 is a plan view of the first main part.

FIG. 4 is an enlarged perspective view of a second main part in the embodiment.

FIG. 5 is a schematic sectional view of the second main part.

FIG. 6 is an explanatory diagram of an operation of the first main part.

FIG. 7 is an explanatory diagram of the operation of the second main part.

FIG. 8 is an enlarged perspective view showing a main part of another embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a liquid crystal display device as a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Liquid crystal display panel 11, 12 Transparent electrode substrate 20 Backlight unit 21 Unit case 30 Outer case 31 Display window 50 Projection 501, 502 Rib 503 Boss

Continued on the front page F term (reference) 2H089 HA40 JA10 KA15 QA06 QA11 QA12 TA18 TA20 2H091 FA16Z FA23Z FA42Z FB02 FD06 FD12 FD22 GA17 LA04 LA05 5G435 AA12 BB12 BB15 EE04 EE05 EE05 EE25 KK03

Claims (4)

[Claims] 1. A metal exterior case having a display window on one side and an open side on the other side; a liquid crystal display panel disposed in the metal exterior case facing the display window; A backlight unit including a unit case made of synthetic resin housed in the open surface of the metal outer case so as to be located on the back side of the display panel, and a side surface of the unit case and a side wall inner surface of the metal outer case; In the liquid crystal display device having a predetermined gap in consideration of thermal expansion of the unit case, a projection having a height substantially equal to the gap is partially provided on a side surface of the unit case. A liquid crystal display device wherein the unit case is positioned within the metal outer case by the protrusion. 2. The liquid crystal display device according to claim 1, wherein the protrusion is deformable by a thermal expansion force of the unit case. 3. The liquid crystal display device according to claim 1, wherein the projection is provided on a side surface of the unit case at a position closer to a side opposite to the open surface of the metal exterior case. 4. The liquid crystal display device according to claim 1, wherein the unit case is made of a thermoplastic resin, and the projection is formed integrally with the unit case.