JPH06230383A - Back light device and liquid crystal device constituted by using the same - Google Patents

Abstract

PURPOSE:To facilitate mounting and disassembling at the time of mounting a polarizing plate, transparent member, diffusion plate, light curtain, etc., to a reflection plate, preventing the deformation failure by the thermal expansion of these members in the case of a rise of environmental temp. and to prevent the disturbance in the orientability of a ferroelectric liquid crystal. CONSTITUTION:The reflection plate 15 is provided with a level difference 15b. The polarizing plate 17, the transparent member 28, the diffusion plate 24, the light curtain 25, etc., are housed into the level difference part 15b and are retained by using fixing members 23. These fixing members 23 are fixed by means of screws, etc., to the reflection plate 15. The size of the window part 15a of the reflection plate 15 and the sizes of the polarizing plate 17, the transparent member 28, the diffusion plate 24, the light curtain 25, etc., are determined by taking the thermal expansion difference by the thermal expansion between the max. temp. and min. temp. which the liquid crystal device experiences, into consideration.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight device for irradiating a liquid crystal panel with light and a liquid crystal device using the same, and more particularly to a method of attaching a diffusing / polarizing means.

[0002]

2. Description of the Related Art In recent years, liquid crystal devices using ferroelectric liquid crystals, which are relatively large in screen size, have been vigorously developed in response to the demand for larger display areas of liquid crystal devices.

FIG. 6 is a cross-sectional view of a liquid crystal device using a nematic liquid crystal that is conventionally and often used. The liquid crystal device is roughly divided into a liquid crystal panel and a backlight device.
The liquid crystal panel 11 has a transparent electrode and also has two glass substrates sandwiching a liquid crystal. Polarizing plates 17 and 18 are attached to this glass substrate. Further, a drive element 13 for driving the liquid crystal panel 11 and a wiring board 12 are provided so as to be connected to the liquid crystal panel 11.

Further, the backlight device is a fluorescent lamp 1.
4, the reflection plate 15 and the diffusion plate 24 are provided. The reflection plate 15 reflects the light from the fluorescent lamp 14 and guides it to the liquid crystal panel 11, and the diffusion plate 24 displays the brightness of the light incident on the liquid crystal panel 11. To make it uniform. These are fixed to a cover 10 made of sheet metal, resin or the like by a cushioning member 9 such as rubber.

On the other hand, when the ferroelectric liquid crystal is used as the liquid crystal, the ferroelectric liquid crystal is more susceptible to mechanical stress than the nematic liquid crystal, and it is difficult to produce a liquid crystal device having sufficient performance with the above configuration.

That is, the mechanical stress applied by assembly or the like disturbs the orientation of the ferroelectric liquid crystal. Therefore, the orientation is restored by performing a heat treatment (reorientation heat treatment) in which the temperature is raised to 80 ° C. to 100 ° C. in a short time and gradually cooled to room temperature over about 1 hour.

However, since the polarizing plates 17 and 18 undergo thermal contraction at a temperature of about 100 ° C., if the re-orientation heat treatment is performed with the above-mentioned configuration, even if the stress during assembly is released, Unrecoverable stress is added due to heat shrinkage. Therefore, as shown in FIG. 7, it is possible to dispose the polarizing plate 17 on the transparent member 28 and fix the peripheral portion with an adhesive, a double-sided tape or the like, and to attach the polarizing plate 18 to the protective plate 25 or the like. Has been done. In addition,
26 is a light curtain, and 27 is a pin for supporting it.

[0008]

However, in the assembly process, if dust or the like enters between the diffuser plate 24 and the polarizing plate 17, it can be easily disassembled by fixing it with the above-mentioned adhesive or double-sided tape. Not only that, but also the polarizing plate 17
There is a risk that the transparent member 28 such as glass or acrylic on which the polarizing plate 17 is attached may be damaged.

Further, the pins 27 supporting the light curtain 26 may thermally expand due to the reorientation heat treatment or the like, pushing up the transparent member 28 and possibly damaging it.

Therefore, according to the present invention, even if dust enters between the polarizing plate and the diffusion plate, it can be easily disassembled and assembled, and even if heat treatment is applied, the transparent member 28 and the like are damaged due to the thermal expansion of the pin 27. An object of the present invention is to provide a non-backlight device and a liquid crystal device using the same.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a plurality of light sources, a reflecting member for reflecting the light emitted from the light sources, and a uniform brightness of the light reflected by the reflecting members. In addition, in a backlight device having a diffusing / polarizing means for deflecting light, the diffusing / polarizing means being attached to the reflecting member, the diffusing / polarizing means can be attached to and detached from the reflecting member by a fixing member. It is characterized by being attached to.

For example, when the diffusing / polarizing means is attached to the reflecting member, the reflecting member has a step portion for accommodating the diffusing / polarizing means.

Further, the dimension of the step portion is set to be larger than the dimension of the diffusing / polarizing means by a variable amount.

Further, the liquid crystal device includes a liquid crystal panel in which two transparent substrates sandwich a ferroelectric liquid crystal, and a backlight device according to the present invention for irradiating the liquid crystal panel with light.
It is characterized by displaying.

[0015]

According to the above structure, when the diffusing / polarizing means including the polarizing plate, the transparent member, the diffusing plate, the light curtain and the reflecting plate is attached to the reflecting member, the diffusing / polarizing means is attached to the reflecting member by being pressed by the fixing member.

Further, when attaching the diffusing / polarizing means to the reflecting member, the reflecting member accommodates the diffusing / polarizing means and diffuses the diffusing / polarizing means.
A step portion is provided which regulates the storage position of the polarizing means, and the dimension of the step portion is set larger than the dimension of the diffusion / polarizing means by a variable amount.

[0017]

Embodiment 1 Embodiment 1 of the present invention will be described with reference to the drawings. FIG. 1 shows a cross section of a liquid crystal device, which is a liquid crystal panel 11.
And a backlight device 30. FIG. 2 is a detailed sectional view of the liquid crystal panel 11, where the liquid crystal panel 11 is 1.1 m long.
A glass substrate 40 (transparent substrate) having a thickness of m is provided, and a plurality of strip-shaped transparent electrodes 41 are formed on the glass substrate 40. In ₂ O ₃ or ITO is used for the transparent electrode 41, and its film thickness is set to about 1500 Å.

Thereafter, as the short-circuit preventing insulating film 42, SiO ₂ was formed by 1000 Å by the sputtering method. As the insulator film 42, in addition to SiO ₂ , Ta ₂
An inorganic insulating material such as O ₅ may be used, and Si, Ti, T
It is also possible to use an inorganic insulating film obtained by coating and firing an organometallic compound containing at least one element of a, Zr, Al and the like. Also, the film thickness is 200Å ~ 3000Å
It should be in the range of.

Further, a polyimide forming liquid was applied on the insulator film 42 by a spinner and heated at 270 ° C. for 1 hour to form a polyimide orientation control film 43 of about 200 Å.
As the orientation control film 43, polyvinyl alcohol,
Polyimide, polyamide imide, polyester imide,
Organic insulating substances such as polyparaxylylene, polyester, polycarbonate, polyvinyl acetal, polyvinyl chloride, polyamide, polystyrene, cellulose resin, melamine resin, urea resin and acrylic resin may be used, and the film thickness is 50 Å to 1000 Å. It only needs to be in the range.

By rubbing the surface of the orientation control film 43 in one direction with a nylon rubbing cloth, a uniaxial orientation axis serving as an orientation regulating force substantially in the same direction as the rubbing direction is provided. .

The glass substrate 40 produced in this way
On one of the glass substrates 40, a bead spacer 44 (silica beads, alumina beads, etc.) having an average particle diameter of about 1.5 μm.
And a sealing adhesive 45, which is an epoxy resin adhesive, is formed on the other glass substrate 40 by a screen printing method, and these two glass substrates 40 are formed in a thickness of 0.1 μm to 3 μm.
The seal adhesive 45 was solidified by heat treatment by holding it at an interval of 2 and facing each other. After that, the ferroelectric liquid crystal 46 was injected to manufacture.

The drive element 13 is connected to the transparent electrode 41, and the wiring board 12 is connected to the drive element 13. The liquid crystal panel 11 is adhered to the fixing plate 19 with an elastic adhesive 16, and the wiring board 12 is fixed to the fixing plate 19 with screws (not shown) or the like. A transparent protective plate 25 is provided on the front surface of the liquid crystal panel 11, and a polarizing plate 18 is attached to the protective plate 25.

The backlight device 30 includes a plurality of fluorescent lamps 14 (light sources), a reflector 15 (reflection member), a light curtain 26 (diffusing / polarizing means), a pin 27, and a diffuser 24.
It has (diffusing / polarizing means). Then, the light emitted from the fluorescent lamp 14 is reflected by the reflection plate 15 and enters the liquid crystal panel 11. At this time, a light curtain 26 and a diffusion plate 24 are provided in order to equalize the brightness in the display area of the liquid crystal panel 11.

A transparent member 28 is provided on the diffusion plate 24.
(Reflecting / diffusing means) is provided, and the polarizing plate 17 (diffusing / polarizing means) is attached to the transparent member 28. The light curtain 26, the diffusion plate 24, the transparent member 28, and the polarizing plate 17 are arranged in this order from the bottom by the fixing member 23.
It is fixed by 3. Therefore, when disassembling, the fixing member 23 can be easily removed (the fixing member 23 is attached to the reflecting plate 15 by a screw or the like).

When the polarizing plate 17 contracts due to a heat treatment such as a reorientation heat treatment or a change with time, the transparent member 28 warps from the four corners toward the polarizing plate 17. In such a case, when the sticking surface of the polarizing plate 17 is attached to the surface of the transparent member 28 on the opposite side of the liquid crystal panel 11, there is a portion where the gap between the liquid crystal panel 11 and the liquid crystal panel is reduced, and when shock or vibration is applied to the liquid crystal device, The liquid crystal panel 11 and the transparent member 28 may come into contact with each other, or stress may be applied to the liquid crystal panel 11 to deteriorate the display characteristics. Therefore, the mounting surface of the polarizing plate 17 is preferably on the liquid crystal panel 11 side, and the position when the fixing member 23 is pressed is preferably at the four corners.

FIG. 3 is a perspective view showing this state.
4, the transparent member 28 and the like are mounted so as to be fitted (stored) in the step portion 15b of the window portion 15a of the reflection plate 15 and then pressed by the fixing member 23 described above. FIG. 4 is a view for explaining the step portion 15b in detail. The step portion 15 is provided so that each member can be placed at a predetermined interval (almost close to each other).
b is configured in a staircase shape.

The size of the window portion 15a of the reflection plate 15 for accommodating the transparent member 28, the diffusion plate 24, etc., should be taken into consideration by the apparatus, taking into consideration the difference in linear expansion coefficient (assuming re-orientation heat treatment etc.). It is necessary to determine the difference in thermal expansion and the tolerance at the maximum temperature and the minimum temperature. Therefore, at room temperature, there is a gap between the size of the window 15a and the size of each member. In the present invention, this gap is referred to as a dimension variable amount S (see FIG. 4).

In the first embodiment, the material of the reflection plate 15 and the diffusion plate 24 is polycarbonate (coefficient of linear expansion 6.6 ×).
10 ^-5 / deg) and the size of the window portion 15a on which the transparent member 28 is placed is 25 Omm × 31 Omm, the window portion 1 is increased when the ambient temperature rises by 70 ° from room temperature (25 ° C.).
The gap on one side between 5a and the diffuser plate 24 is 0.58 mm. Therefore, the dimension variable amount S including the tolerance is set to 0.6 mm. In addition, the gap on one side on the long side (31 Omm side) is
Since it is 0.72 mm, the dimension variable amount S is set to 0.8 mm. When the linear expansion coefficient of the transparent member 28, the diffusion plate 24, the reflection plate 15, etc. is different, it is necessary to determine the dimensions by the above-mentioned method.

As described above, by assembling the polarizing plate 17, the transparent member 28, the diffusion plate 24, the light curtain 25, the reflection plate 15 and the like with the fixing member 23 and screwing, the assembly and disassembly are facilitated. Become. Further, even if each member has a different linear expansion coefficient, if the dimension is determined in consideration of re-orientation heat treatment or the like, the distance between the liquid crystal panel 11 and the polarizing plate 17 may change due to the thermal expansion of the pin 27 or the like. Without
It is possible to prevent the orientation of the ferroelectric liquid crystal from being disturbed even if there is vibration or shock from the outside. <Second Embodiment> A second embodiment of the present invention will be described with reference to the drawings.
The configuration of the liquid crystal device according to the second embodiment is basically the same as that of the first embodiment, so the same reference numerals are given and the description thereof is omitted.

In the second embodiment, as shown in FIG. 5, a transparent member 28 such as glass or acrylic with a polarizing plate 17 attached is slid into a guide rail 29 provided on the reflection plate 15 and inserted. Then, the insertion port may be closed and fixed by a fixing member (not shown) made of sheet metal or resin. The method of determining the dimensions at this time is also set in consideration of the linear expansion coefficient of each member as described in the first embodiment.

[0031]

As described above, the polarizing plate, the transparent member,
By assembling and disassembling the diffuser plate, the light curtain, the reflector plate, etc. by pressing them with a fixing member, it is easy to assemble and disassemble, and even if dust is mixed during assembly, it can be easily removed. As a result, workability is improved and damage to members can be prevented.

Even if each member has a different coefficient of linear expansion, the distance between the liquid crystal panel and the polarizing plate is determined by determining the size of each member in consideration of the reorientation heat treatment or the like and considering the dimensional variation amount. It does not change due to the thermal expansion of pins, etc., and prevents the liquid crystal panel and the polarizing plate from contacting with each other even if there is external vibration or shock, and prevents the orientation of the ferroelectric liquid crystal from being disturbed. Became possible.

As a result, the yield of the liquid crystal device was improved, the productivity was improved, and the reliability was also improved.

[Brief description of drawings] [Explanation of symbols]

FIG. 1 is a sectional view of a liquid crystal device applied to the description of a first embodiment of the present invention.

FIG. 2 is a sectional view of a liquid crystal panel applied to the description of the first embodiment of the present invention.

FIG. 3 is an explanatory diagram for attaching a polarizing plate and the like applied to the description of the first embodiment of the present invention.

FIG. 4 is an explanatory diagram of a stepped portion of a reflection plate applied to the description of the first embodiment of the present invention.

FIG. 5 is an explanatory diagram for attaching a polarizing plate and the like applied to the description of Example 2 of the present invention.

FIG. 6 is a cross-sectional view of a liquid crystal device using a TN type liquid crystal or the like applied to the description of the related art.

FIG. 7 is a cross-sectional view of a liquid crystal device using a ferroelectric liquid crystal applied to the description of the conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid crystal panel 14 Fluorescent lamp (light source) 15 Reflector (reflecting member) 15b Step portion 17 Polarizing plate (diffusing / polarizing means) 23 Fixing member 24 Diffusing plate (diffusing / polarizing means) 25 Light curtain (diffusing / polarizing means) 28 Transparent member (diffusing / polarizing means) 30 Backlight device 40 Glass substrate (transparent substrate) 46 Ferroelectric liquid crystal S Dimension variable amount

Claims (4)

[Claims] 1. A diffuser / polarizer which has a plurality of light sources, a reflecting member for reflecting the light emitted from the light source, and a diffusing / polarizing means for making the reflected light by the reflecting member a uniform brightness and deflecting the light. A backlight device in which polarizing means is attached to the reflecting member, wherein the diffusing / polarizing means is detachably attached to the reflecting member by a fixing member. 2. The backlight device according to claim 1, wherein when the diffusion / polarization means is attached to the reflection member, the reflection member has a stepped portion that accommodates the diffusion / polarization means. 3. The backlight device according to claim 2, wherein the size of the step portion is set to be larger than the size of the diffusing / polarizing means by a variable amount. 4. A liquid crystal panel in which two transparent substrates sandwich a ferroelectric liquid crystal, and the liquid crystal panel is irradiated with light.
4. A liquid crystal device, comprising: the backlight device according to any one of 3 to 3, and performing display.