JPH06230382A - Back light device and liquid crystal device constituted by using the same - Google Patents

Abstract

PURPOSE:To provide the back light device having a uniform brightness distribution without being affected by wiring stages, etc., by keeping the inter-wire distances of wirings and the distance between the wirings and conductive members fixed in potential respectively at prescribed distances. CONSTITUTION:The plural wiring materials 52 are juxtaposed having respectively the prescribed spacing D and they are disposed having a prescribed spacing H from a heat radiation plate 3. The floating capacities possessed by the respective wiring materials 52 are set at <=10pF. The spacings D between the respective wiring materials 52 are regulated by lead retainers 51. The complication of the wiring materials 52 is averted by using these lead retainers 51. Then, the setting of the floating capacities possessed by the individual wiring materials 52 at <=10pf is possible. The fluctuation in the floating capacities is prevented by using the lead retainers 51 even if the device is assembled by a manual operation. In addition, the maintenance of the small floating capacities is possible. The back light device which is compact and has the smaller brightness distribution is produced without forming a power source to a large size. The quality of the liquid crystal device is thus improved.

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 which is provided on the back surface of a liquid crystal panel and a liquid crystal device using the same, and more particularly to a wiring member for supplying electric power to a light source. The present invention relates to a regulation means for reducing stray capacitance.

[0002]

2. Description of the Related Art In recent years, downsizing of electronic equipment has been remarkable, and there is a similar demand for liquid crystal devices. In particular,
In liquid crystal devices, there is an increasing demand for larger display areas, that is, larger screens, and thinner displays.

FIG. 8 shows a cross section of a liquid crystal device. The liquid crystal device includes a protective part 10 having a transparent protective plate, a display part 20 having a liquid crystal panel and a driving IC, and a liquid crystal panel for irradiating light. The light source unit 30, a control unit 40 for controlling the light source unit 30 and the display unit 20, and a wiring unit 50 in which a plurality of wiring members are bundled to supply power to the light source 32.
And these are housed and arranged in the casings 60a and 60b. FIG. 9 shows a bottom view of the liquid crystal device with the housing portion 60b removed. As can be understood from these figures, the space occupied by the light source unit 30 is large, and the free space between the light source unit 30 and the housing unit 60b is almost eliminated. Therefore, as described above, the plurality of wiring members are bundled to form the wiring portion 50, and are closely contacted with the heat dissipation plate 31 to be wired in a slight free space.

[0004]

However, it is difficult for the above-mentioned wiring method to exhibit predetermined characteristics. This is because downsizing reduces the distance between adjacent electronic components and causes interactions between the components. For example, a wiring material that sends a signal to an electronic component is capacitively coupled to another electronic component, but the parasitic capacitance (stray capacitance) has a property of increasing in inverse proportion to the distance as the distance between the electronic components decreases. Since the current flowing through the wiring material and the applied voltage change with time, displacement current, eddy current, etc. are generated, which causes signal delay, signal attenuation, or noise. It is easy to cause problems such as occurrence.

Therefore, when a plurality of wiring members are bundled as shown in FIGS. 8 and 9, a parasitic capacitor having a large stray capacitance is generated between the wiring members. Further, on the bottom of the light source unit 30, a metal heat dissipation plate 31 is provided for radiating the heat generated by the light source 32 and for making the temperature distribution of the display unit 20 uniform. The heat dissipation plate 31 is at the ground potential for reasons such as noise countermeasures. For this reason, the wiring material also interacts with the heat dissipation plate 31, and the predetermined power is not supplied to the light source 32.

FIG. 10 is a diagram for explaining the stray capacitance of the wiring material, which is a simplified cross-sectional view of the AA portion in FIG. A parasitic capacitor C _PW is parasitic between the wiring members 50a and 50b, and C _PG and C _PG ′ are parasitic between the wiring members 50a and 50b and the heat dissipation plate 31, respectively. Then, the displacement current flows through the parasitic capacitor because the current flowing through the wiring members 50a and 50b is an alternating current (for example, as indicated by an arrow in FIG. 10). That is, the power to be supplied is lost on the way and power loss occurs.

If the wiring member 50 is arranged as indicated by the broken line 50 'so as to avoid the wiring member 50 from being arranged on the heat dissipation plate 31, the wiring member becomes longer or the size around the heat dissipation plate 31 is increased. It becomes necessary to secure the area of (1), which is disadvantageous for downsizing.

Particularly, in the case of a liquid crystal device, the following problems have become apparent. Since a liquid crystal device having a large area is required, a region where power loss occurs becomes large, and a large capacity power supply is required. As shown in FIG. 9, since a plurality of light sources 32 are used and the length of the wiring material to each light source 32 is different, the power loss is also different, and the light emission amount of the light source 32 is different, and the brightness of the information display surface is increased. Distribution is generated, and the display quality of the liquid crystal device is degraded. When the device is made thinner, the adjacent distance between the parts becomes shorter and the parts interact more strongly, and the variation due to the manual work such as the wiring process and the assembly process becomes remarkable.

Therefore, the present invention uses a wiring method which is not affected by a wiring process even in a thin and large-screen liquid crystal device and has a small power loss, and a backlight device having a uniform luminance distribution, and a liquid crystal using the same. The purpose is to provide a device.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and includes a plurality of light sources for irradiating a liquid crystal panel with light, a plurality of wirings connected to the light sources, and adjacent wirings. And a conductive member kept at a predetermined potential, the plurality of wirings are juxtaposed at a predetermined interval, respectively, and a predetermined distance is maintained between the conductive member and the conductive member. And the stray capacitance of each of the wirings is set to 10 pF or less.
It is characterized by

For example, the distance between the wirings and the distance between the wirings and the conductive member are each separated by 2 mm or more,
A fixed regulating means is provided.

Further, as a liquid crystal device using the backlight device according to the present invention, there is provided control means for driving and controlling the liquid crystal panel in which the ferroelectric liquid crystal is sandwiched between two transparent substrates, and the control means is provided. It is characterized in that the alignment state of the ferroelectric liquid crystal is changed based on display information, and light from the backlight device of the present invention irradiates the liquid crystal panel to display information.

[0013]

According to the above structure, the wiring member is separated by the regulating means that separates the distance between the plurality of wirings connected to the light source by a predetermined distance and the wiring and the conductive member whose potential is fixed by a predetermined distance. Support and fix.

[0014]

Embodiments of the present invention will be described with reference to the drawings. Figure 1
1 is a cross-sectional view of a liquid crystal device, which includes a protective unit 10 having a transparent protective plate, a display unit 20 having a liquid crystal panel and a driving IC, a light source unit 30 for irradiating light to the liquid crystal panel, A control unit 40 for controlling the light source unit 30 and the display unit 20, a wiring unit 50 having a plurality of wiring members for supplying electric power to the light source 32, and a light source 32 having 30 k
A power supply unit 41 for supplying electric power of 30 Hz and 30 Hz is provided,
These are housed and arranged in the casings 60a and 60b.
FIG. 2 shows a bottom view of the liquid crystal device with the housing 60b removed. A metal heat dissipation plate 31 (conductive member) is provided at the bottom of the light source unit 30 to dissipate heat generated by the light source 32 and to make the temperature distribution of the display unit 20 uniform. The heat dissipation plate 31 is at the ground potential for reasons such as noise countermeasures.

As can be seen from this figure, the wiring members 52 of the wiring portion 50 are wired at predetermined intervals. This interval is regulated by the lead retainer 51 (regulating means). 3 (a) is a top view of the lead retainer 51, and FIG. 3 (b) is a cross-sectional view of the lead retainer 51. The wiring members 52 are arranged in parallel with each other with a distance D, and are separated from the heat sink 31 by a distance H. There is. By using this lead retainer 51, the wiring material 52 is prevented from becoming complicated (intersection of wiring materials and fluctuation of the spacing, etc.). Therefore, the stray capacitance of each wiring member 52 can be set to a predetermined amount. 4 and 5 show the stray capacitance between the wiring members 52 when the diameter of the conductor portion of the wiring member 52 is 0.7 mm and the length thereof is 200 mm and the stray capacitance between the wiring members 52 of the same specifications and the heat dissipation plate 31. 3 shows the result of measurement at the operating frequency of 30 kHz.

In the present embodiment, a lead retainer 51 having a distance D of 2 mm and a distance H of 2 mm was used. As a result, the stray capacitance between the wiring members 52 having the same polarity was reduced to 15 pF or less and was reduced to 10 pF or less, and the stray capacitance between the different wiring members 52 was reduced to 10 pF or less and was reduced to 5 pF or less.

Next, an embodiment of a liquid crystal device having a backlight device using the lead retainer 51 will be described. FIG. 6 is a block diagram of the liquid crystal device.
A drive control circuit 43, a scanning signal control circuit 44, an information signal control circuit 45, a scanning signal applying circuit 46, and an information signal applying circuit 47.

The data and scanning method signal output from the graphic controller 42 are output to the scanning signal control circuit 44 and the information signal control circuit 45 by the drive control circuit 43. At this time, the data is converted into address data and display data, and the scanning method signal is directly applied to the scanning signal applying circuit 4.
6 and the information signal application circuit 47. The scanning signal application circuit 46 scans a scanning signal waveform determined by a scanning method signal, and a scanning electrode (not shown) determined by address data.
The information signal applying circuit 47 outputs an information signal waveform determined by two of the scanning method signal and the display content of white or black sent by the display data to the information electrode (not shown).
Then, the liquid crystal panel is driven and the information is displayed by the light of the backlight device.

FIG. 7 is a sectional view of a liquid crystal panel. The liquid crystal panel of the liquid crystal panel has a glass substrate 21 having a thickness of 1.1 mm, and the glass substrate 21 has a plurality of strip-shaped transparent electrodes 22. Has been formed. In ₂ O is used as the transparent electrode 22.
₃ and ITO are used, and the film thickness is set to about 1500Å.

After that, as the insulator film 23 for preventing short circuit, SiO ₂ was formed by 1000 Å by the sputtering method. As the insulator film 23, 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 onto the insulator film 23 by a spinner and heated at 270 ° C. for 1 hour to form an alignment control film 24 of polyimide of about 200 Å.
As the orientation control film 24, 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. Then, by rubbing the surface of the orientation control film 24 in one direction with a nylon rubbing cloth,
A uniaxial orientation axis that serves as an orientation regulating force substantially in the same direction as the rubbing direction is provided.

The glass substrate 21 produced in this way
On one of the glass substrates 21 with a bead spacer 25 (silica beads, alumina beads, etc.) having an average particle size of about 1.5 μm.
And a seal adhesive 26, which is an adhesive of epoxy resin, is formed on the other glass substrate 21 by a screen printing method, and these two glass substrates 21 are 0.1 μm to 3 μm.
The seal adhesive 26 was solidified by heat treatment by holding it at the intervals of 2 and facing each other. After that, a ferroelectric liquid crystal 27 was injected to manufacture a liquid crystal panel. In addition, 28 is a polarizing plate.

With the structure described above, the stray capacitance due to the wiring material and the like can be reduced, whereby the power source for supplying power to the light source can be made compact, and a liquid crystal device having a small luminance distribution can be manufactured.

In this embodiment, the heat radiating plate has been described as an example of the conductive member, but the present invention is not limited to this.

[0025]

As described above, by using the lead retainer that separates the wiring members and the heat sink from each other by a distance of 2 mm, the stray capacitance can be changed even if the assembly is performed manually. In addition, a small stray capacitance can be achieved, a compact backlight device with a small luminance distribution can be manufactured without increasing the power source, and the quality of the liquid crystal device is improved.

[Brief description of drawings]

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

FIG. 2 is a bottom view of the liquid crystal device applied to the description of the embodiments of the present invention.

3A and 3B are explanatory views of a lead retainer applied to an embodiment of the present invention, in which FIG. 3A is a top view and FIG. 3B is a sectional view.

FIG. 4 is a diagram showing a relationship between a distance between wiring members and a stray capacitance applied to the description of the embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a stray capacitance and a distance between a wiring member and a heat dissipation plate applied to the description of the embodiment of the present invention.

FIG. 6 is a block diagram of a liquid crystal device applied to the description of an embodiment of the present invention.

FIG. 7 is a sectional view of a liquid crystal panel applied to the description of the embodiments of the present invention.

FIG. 8 is a cross-sectional view of a liquid crystal device applied to the description of the conventional technique.

FIG. 9 is a bottom view of a liquid crystal device applied to the description of the conventional technique.

FIG. 10 is a diagram illustrating stray capacitance applied to the description of the problem of the conventional technique.

[Explanation of symbols]

 20 Liquid Crystal Panel 21 Glass Substrate (Transparent Substrate) 27 Ferroelectric Liquid Crystal 30 Backlight Device 31 Heat Sink (Conductive Member) 32 Light Source 40 Control Section (Control Means) 51 Lead Presser (Regulation Means) 52 Wiring Material

Claims (3)

[Claims] 1. A liquid crystal panel, comprising: a plurality of light sources for irradiating light; a plurality of wirings connected to the light sources; and a conductive member provided adjacent to the wirings and kept at a predetermined potential. In the backlight device configured as described above, the plurality of wirings are arranged in parallel at predetermined intervals,
Further, the backlight device is arranged with a predetermined space from the conductive member, and the stray capacitance of each of the wirings is set to 10 pF or less. 2. The backlight device according to claim 1, further comprising a regulation unit that fixes and fixes the distance between the wirings and the distance between the wiring and the conductive portion by 2 mm or more. 3. A control means for driving and controlling the liquid crystal panel in which a ferroelectric liquid crystal is sandwiched between two transparent substrates is provided, and the alignment state of the ferroelectric liquid crystal is changed based on the display information by the control means. A liquid crystal device, characterized in that light from the backlight device according to claim 1 or 2 irradiates the liquid crystal panel to display information.