JP2000047169A - Liquid crystal display - Google Patents

Abstract

(57) [Summary] [Problem] To provide a backlight with high luminance, high uniformity of luminance of a display screen, and to suppress a decrease in display quality due to noise generated from a lamp cable, and to reduce a leakage current from the lamp cable. Provided is a liquid crystal display device which has reduced emission efficiency of a backlight. Under the liquid crystal display panel, eight linear lamps are arranged at substantially the same pitch, lamp cables are provided at both ends of each linear lamp, and a connector is provided at a tip of the lamp cables. On a high-voltage high-frequency AC generation circuit board 9 for emitting linear lamps 6, a high-voltage generating transformer 13 and a connector 1 to which a connector 17 is connected for each linear lamp 6
6 are provided at substantially the same pitch, and the lengths and resistances of the lamp cables 14 and 15 are equal for all the linear lamps 6.

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, and more particularly, to a liquid crystal display device having a high luminance and uniform over a display screen.
The present invention relates to a liquid crystal display device having a long-life backlight suitable for a large screen.

[0002]

2. Description of the Related Art Liquid crystal display devices have begun to be widely used as display terminals for information processing equipment (OA equipment) such as office computers and personal computers because of their features of being thin and lightweight and having high image quality comparable to a cathode ray tube.

In this liquid crystal display device (ie, liquid crystal display module), a transparent insulating substrate made of, for example, two sheets of glass having display electrodes provided on at least one opposing surface is overlapped with a predetermined gap. The two substrates are bonded together by a liquid crystal sealing material provided in a frame shape (a square shape) on the peripheral portion between the two substrates, and a sealing material between the two substrates is provided through a liquid crystal sealing opening provided in a part of the sealing material. A liquid crystal display panel (ie, a liquid crystal display element, LCD: liquid crystal display (Liq)) in which a liquid crystal is sealed inside the liquid crystal panel and a polarizing plate that transmits only a certain amount of polarized light is provided outside the two substrates.
uid Crystal Display)), a backlight which is arranged below the liquid crystal display panel, emits light from the surface, supplies light from the back to the liquid crystal display panel, and serves as a light source for displaying an image, and a liquid crystal display panel. A driving circuit board that is disposed outside the outer peripheral portion and applies a voltage corresponding to a display image signal to the electrodes, a liquid crystal display panel and a plastic mold case that stores and holds a backlight, and stores the respective members, It consists of a metal upper shield case with an open display window, a metal lower shield case, and the like.

As a backlight of a liquid crystal display device, there is a backlight having a built-in linear lamp such as a cold cathode or hot cathode fluorescent tube in order to obtain a high contrast and bright color display.

In particular, there is an increasing demand for a liquid crystal display device having a large screen size (for example, 15 to 21 inches) for a computer monitor, and the backlight of the liquid crystal display device is bright and has been used for a long time. In this case, it is required that the luminance does not decrease.

Generally, a cold cathode or hot cathode fluorescent tube is
There is a characteristic that the luminance decreases as the use time elapses.

As a countermeasure against the decrease in luminance due to long-term use, a light guide plate having substantially the same size as that of the light guide plate is disposed directly below the liquid crystal display panel, and a linear lamp is disposed near the side surface of the light guide plate along the side surface. However, there is a method in which the linear lamp is replaced when the luminance is lowered by adopting a structure in which the linear lamp can be easily inserted and removed, which is called a side edge method.

[0008] Such a side-edge type backlight is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 7-181489, and the academic literature (IDU96-59, 1996, IDY9).
6-147, p. 43-48).

In the backlight of the side edge type, there is a problem that the brightness of the screen decreases as the screen size increases. In this method, there is a limit to this measure, and in particular, the brightness decreases at the center of the screen, which is contrary to the demand for uniform brightness on a large screen. Further, the light guide plate made of an acrylic plate or the like is heavy, and is very heavy on a large screen. For this reason, the strength of the frame holding the light guide plate must be increased, and the weight is further increased.

Although it is possible to increase the number of fluorescent tubes arranged on the side surface of the light guide plate in order to prevent this decrease in luminance, a light guide plate having a rectangular planar shape basically has four light guide plates. It is the limit to arrange fluorescent tubes in each,
Such an arrangement is contrary to recent demands for increasing the length of the liquid crystal display device in the vertical and horizontal directions and reducing the width of a so-called frame portion, which is the outer peripheral portion of the display screen. It is also possible to arrange a plurality of fluorescent tubes on the side of the light guide plate,
In this case, heat is concentrated even in the cold cathode fluorescent tube, and it is not possible to disregard adverse effects such as display unevenness caused by heat of the liquid crystal display panel.

[0011] Further, as a backlight having a high luminance,
There is a direct type in which a plurality of linear lamps are respectively arranged in parallel on a reflecting plate having a wavy or sawtooth cross section.

References describing such a backlight include, for example, JP-A-1-169482, JP-A-3-219278, and JP-A-4-209.
No. 89 publication.

In the backlight of the direct type, if the number of linear lamps is small, the brightness of the entire backlight does not increase and the brightness of the linear lamp needs to be increased. However, in this case, the shadow of the linear lamp is seen from the display screen. If the distance between the liquid crystal display panel and the linear lamp is increased to avoid this, the thickness of the liquid crystal display device increases. Further, when the number of linear lamps is reduced to increase the brightness, adverse effects such as uneven display due to heat of the liquid crystal display panel occur.

In the liquid crystal display device, a case for accommodating a liquid crystal display panel, a backlight, and the like is constituted by, for example, a metal shield case, and a heat source of a metal plate constituting the shield case serves as a light source line. To prevent adverse effects on display quality due to heat generated by the lamp, and
Electromagnetic waves are shielded by the metal plate.

[0015]

As described above, the size of a display screen of a liquid crystal display device for a monitor is increasing year by year, and the size of a backlight is also increasing accordingly.

Further, there is a strong demand for higher luminance, and a brighter, that is, stronger backlight is required. As described above, there are a side edge type and a direct type backlight as described above, but for a higher luminance (especially in a large screen), a direct type method which can easily increase the number of linear lamps is advantageous. It is.

FIG. 9 is a schematic plan view of a direct type backlight in a conventional liquid crystal display device.

6 is a linear lamp (fluorescent tube), 9 is a high-voltage high-frequency AC generation circuit board, 13 is a high-voltage generation transformer,
4 is a low-voltage side lamp cable, 15 is a high-voltage side lamp cable, 16 is a connector provided on the high-voltage high-frequency AC generation circuit board 9, and a connector provided at the tip of the lamp cables 14 and 15 is inserted. Connection has been established.

In this direct backlight, when four or more (six in this figure) linear lamps 6 are arranged directly below the liquid crystal display panel in order to obtain high brightness, conventionally,
As shown in FIG. 9, two high-voltage high-frequency AC generating circuit boards 9 are arranged on both sides of six linear lamps 6 so as to be divided into two. The lamp cables 14 and 15 for connecting the electrodes at both ends of the linear lamp 9 and the secondary output of the high-voltage generating transformer 13 for generating a high-voltage high-frequency AC voltage for lighting are respectively provided from the display screen. To prevent cables from being seen, do not pass directly under the display screen.
The lamp cables 14 and 15 have different lengths for each lamp 6 as shown in FIG. 9, which are drawn around in a mold case (not shown; see FIGS. 2 and 3) which is a holding member of the backlight. Therefore, this lamp cable 14,
The lamp tube current changes for each lamp 6 due to the difference in resistance value due to the difference in the length of the lamps 15, and a difference in brightness occurs between the lamps 6.
Furthermore, it is difficult to adjust the balance of the brightness of each lamp 6 by the dimming circuit, and it is difficult to obtain a display quality with uniform brightness over the entire screen.

If the lamp cable 14 connecting the lamp 6 and its high-voltage generating transformer 13 is unnecessarily long because it is routed for the above-described reason, the influence of electric noise generated from the cable 14 is also required. And the display has an adverse effect, and further, a high voltage current leaks from the lamp cable 14 and the luminous efficiency of the backlight is reduced.

An object of the present invention is to provide a liquid crystal display device,
The backlight has high brightness, and the brightness of the display screen is highly uniform.In addition, it suppresses the deterioration of display quality due to the noise generated from the lamp cable, reduces the leak current from the lamp cable, and improves the luminous efficiency of the backlight. It is to provide a high liquid crystal display device.

[0022]

In order to solve the above problems, the present invention provides a liquid crystal display panel and a liquid crystal display panel disposed under the liquid crystal display panel.
In a liquid crystal display device having a backlight for supplying light to the liquid crystal display panel, the backlight includes a plurality of linear lamps arranged below the liquid crystal display panel, and a high-voltage high-frequency device for causing the linear lamps to emit light. An AC generating circuit, wherein the length and resistance of two lamp cables connecting the electrodes at both ends of the linear lamp and the high-voltage high-frequency AC generating circuit are the plurality of linear lamps. Are substantially equal to each other.

Further, the backlight includes a plurality of linear lamps arranged at substantially the same pitch under the liquid crystal display panel, and a high-voltage high-frequency AC generating circuit board for emitting the linear lamps. A lamp cable is provided at each end of each of the linear lamps, a first connector is provided at a tip of the two lamp cables, and a high voltage is provided on the high-voltage high-frequency AC generation circuit board for each of the linear lamps. A voltage generating transformer, and a second connector connected to the output of the high voltage generating transformer and connected to the first connector are provided at substantially the same pitch, and the length and the resistance of the two lamp cables are provided. The value is substantially equal for all of the plurality of linear lamps.

[0024] Further, there is provided a light control circuit for making the luminance of the plurality of linear lamps uniform.

A reflector is provided below the linear lamps, and each reflector has a downwardly convex mountain shape for each linear lamp, and the two reflectors of each linear lamp are provided. At least the longer one of the lamp cables is arranged below the reflector.

Further, the longer lamp cable is arranged between the peaks or just below the peak.

Further, the reflection plate is disposed in an electrically insulating frame.

In the present invention, as described above, the linear lamp 2
By making the lengths and resistances of the two lamp cables substantially the same for all of the plurality of linear lamps, the tube current flowing through each linear lamp becomes uniform, the brightness of each linear lamp becomes uniform, and the The uniformity of the in-plane luminance of the display screen can be improved. Further, the brightness of each linear lamp can be easily adjusted by the dimming circuit.

Further, since a large number of linear lamps can be arranged, a high-luminance backlight can be provided, which is particularly advantageous when applied to a large-screen liquid crystal display device.

Further, since the length of the lamp cable can be shortened, electric noise generated from the cable is reduced, and a decrease in display quality due to the electric noise can be suppressed. Further, since the cable length can be shortened, the leakage of high voltage current from the cable can be reduced, the loss of power consumption can be reduced, and the luminous efficiency of the backlight can be improved.

A plurality of linear lamps, the same number of high-voltage generating transformers provided corresponding to the linear lamps, and connectors for electrically connecting the linear lamps and the high-voltage generating transformer are arranged at substantially the same pitch. By doing so, it is easy to make the lengths and resistance values of the two lamp cables of the linear lamps substantially the same for all of the plurality of linear lamps, and to shorten the cable length.

[0032]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the drawings described below, those having the same functions are denoted by the same reference numerals, and the repeated description thereof will be omitted.

FIGS. 1A and 1B are schematic plan views of a direct-type backlight according to an embodiment of the present invention. FIG. 1A shows a state where a lamp cable of a linear lamp is connected via a connector. (B) shows a state where the connector of the lamp cable is disconnected. FIG. 2 is an exploded schematic perspective view of the liquid crystal display module according to one embodiment of the present invention, and FIG. 3 is a schematic sectional view taken along line AA of FIG.

In FIG. 2, reference numeral 1 denotes an upper frame made of, for example, a metal, 2 denotes a liquid crystal display panel, 18 denotes a scanning signal electrode side driving circuit board, 19 denotes a video signal electrode side driving circuit board,
0 is a DC / DC converter controller board, 3 is a diffusion sheet (only one is shown in FIG. 3), 4 is a diffusion plate, 5 is a lamp reflector (reflection plate), 6 is a linear lamp (for example, a cold cathode fluorescent tube) (CFL)), 7 is, for example, a white plastic molded case for storing and holding the liquid crystal display panel 2 with a circuit board and a backlight, 8 is, for example, a metal lower frame, 9 is a high-voltage high-frequency AC generation circuit board, 13 Is a high voltage generating transformer.

In FIG. 3, reference numeral 10 denotes a polarizing plate, 11 denotes a transparent insulating substrate made of glass or the like constituting the liquid crystal display panel 2, 12 denotes a liquid crystal layer sandwiched between two transparent insulating substrates 11, and 14 denotes a low voltage. The side lamp cable 16 is a connector.

In FIG. 1, 13 is a high voltage generating transformer, 14 is a low voltage side lamp cable, 15 is a high voltage side lamp cable, and 17 (FIG. 1 (b)) is a lamp cable 14 and 15 of each linear lamp 6. A connector (cable socket) 16 provided at the tip is a connector (cable socket) provided on the high-voltage high-frequency AC generation circuit board 9 and into which the connector 17 of the linear lamp 6 is inserted.

In a general liquid crystal display device, the display changes from white display to black display or from black display to white display due to a change in applied voltage. In this embodiment, for example, the liquid crystal layer has a twist angle of 90%. ° Twisted nematic (TN) type or vertical alignment type TFT (thin film transistor) drive may be used, and the twist angle may be 200 to 26.
Super-twisted nematic (STN) type time-division driving at 0 ° may be used, or a horizontal electric field method that responds to a substrate surface with a horizontal electric field may be used.

The product Δnd of the refractive index anisotropy Δn of the liquid crystal layer and the cell gap d is 0.2 μm in the case of the TN type and the lateral electric field type in order to make the contrast ratio and the brightness compatible.
The range is preferably from m to 0.6 μm, more preferably from 0.5 μm to 1.2 μm for the STN type, and preferably from 0.2 μm to 0.5 μm for the transverse electric field type.

As the transparent insulating substrate 11, for example, the surface of a glass substrate having a thickness of 0.7 mm is polished,
Two transparent electrodes made of TO (indium tin oxide) formed by sputtering were used. The dielectric anisotropy Δnε between these substrates is positive and the value is 4.
5, and the refractive index anisotropy Δn is 0.19 (589 nm,
(20 ° C.). Since the cell gap was 6 μm, Δnd was 1.41 μm.
After applying a polyimide-based orientation control film on the substrate surface, 25
The alignment control film was baked at 0 ° C. for 30 minutes to perform a rubbing treatment to obtain a pretilt angle of 3.5 ° (measured by a rotating crystal method). The rubbing directions of the alignment control films on the upper and lower substrates were set so that the twist angle (twist angle) of the liquid crystal molecules was 240 degrees in order to perform time-division driving. Here, the twist angle is defined by the rubbing direction and the type and amount of the optical rotatory substance added to the nematic liquid crystal. The maximum value of the torsion angle is limited because the lighting state near the threshold value is oriented to scatter light.
60 degrees is the upper limit, the lower limit is limited by contrast, and 200 degrees is the limit. In this embodiment mode, the torsion angle is set to 240 degrees in order to provide a liquid crystal display device capable of monochrome display with sufficient contrast even when the number of scanning lines is 200 or more. In addition, a single retardation film of Δnd = 0.4 μm made of polycarbonate was disposed between the transparent insulating substrate 11 and the polarizing plate 10 (not shown).

In the present embodiment, as shown in FIGS. 1 to 3, eight linear lamps 6 are arranged under the liquid crystal display panel 2, so that the brightness is high, and especially 15 inches or more (15 to 2).
This is advantageous in a liquid crystal display device having a large screen (1 inch). The high-voltage high-frequency AC generation circuit board 9 for lighting the linear lamp 6 includes a high-voltage generation transformer 13, a connector 16, a dimming circuit (not shown), and the like. Also, 8
The linear lamps, the eight high-voltage generating transformers 13, the eight connectors 16, and the eight dimming circuits provided for the lamps are all arranged at the same pitch. By this arrangement, the lengths of the low-voltage lamp cable 14 and the high-voltage lamp cable 15 of each linear lamp 6 are the same, and therefore, the conditions such as the material and diameter of each cable are the same. Therefore, the wiring resistance values are the same. As a result, the tube current flowing through each linear lamp 6 becomes uniform, the luminance of each linear lamp 6 becomes uniform, and the uniformity of the luminance of the display screen can be improved. Further, since the difference between the tube currents of the linear lamps 6 is small, the luminance balance adjustment of each linear lamp 6 by the dimming circuit, which adjusts by feedback so as to make the tube current of the linear lamps 6 constant, is performed by the feedback. It becomes easier because it is easier to apply. Further, the number of ICs constituting the dimming circuit can be reduced, for example, instead of providing eight ICs for each of the linear lamps, one IC is provided for every two linear lamps.

Further, since the lamp cables 14 and 15 are arranged with a minimum length and the length of the lamp cable, especially the low voltage side lamp cable 14, is short, electric noise generated from the cable is reduced, and Degradation of display quality due to dynamic noise can be suppressed. Further, the leakage of the high voltage current from the lamp cable 14 can be reduced, the loss of power consumption is reduced, and the luminous efficiency of the backlight is improved.

FIG. 4 is a perspective view showing a structure for holding the high-voltage high-frequency AC generation circuit board 9.

In FIG. 4, reference numeral 21 denotes a metal lower frame 8.
, An opening 22 for accommodating the high-voltage high-frequency AC generation circuit board 9 provided on the lower frame 8, a holding portion for the high-voltage high-frequency AC generation circuit board 9 provided integrally with the lower frame 8, and a high-frequency high-frequency AC generation circuit board 9 The fixing screw holes provided, 24 are screw holes provided in the mold case 7, and 25 is a screw. In addition,
In FIG. 4, the high-voltage generating transformer 1 mounted on one side on the lower surface of the high-voltage high-frequency AC generating circuit board 9 facing upward.
3. Electronic components such as the connector 16 are not shown (see FIG. 1).

As shown in FIGS. 2 and 3, the high-voltage high-frequency AC generation circuit board 9 is fixed to the lower metal frame 8 located on the back side of the liquid crystal display module. For example, as shown in FIG.
The two corner portions of the circuit board 9 are held by the two holding portions 22 housed in the housing opening 21 of the lower frame 8 and formed together with the opening 21 by press working, and It is fixed to the mold case 7 by two screws 25 and screw holes 23 and 24.

As shown in FIGS. 3 and 2, a lamp reflector 5 is arranged below each of the eight linear lamps 6, and the lamp reflector 5 has a lower sectional shape for each linear lamp 6. It is convex in the direction and has a waveform as a whole. Note that a sawtooth shape may be used instead of the waveform. In addition, between the liquid crystal display panel 2 and the linear lamp 6 and the lamp reflector 5, a thickness is set to prevent damage to the linear lamp 6, improve the strength of the mold case 7, and make the luminance of the light emitting region uniform. 1-3m
A transparent acrylic diffusion plate 4 on which m white or white dot printing is applied is arranged.

Further, between the liquid crystal display panel 2 and the diffusion plate 4, light is condensed and the shadow of the linear lamp 6 at the time of observation from an oblique direction of the display screen is prevented from being seen. For uniformity, one or two diffusion sheets 3 are arranged. In addition, one or more brightness enhancement sheets may be arranged between the liquid crystal display panel 2 and the linear lamp 6.

As shown in FIG. 3, the low-voltage side cable 14 of the linear lamp 6 is disposed between the mountains below the lamp reflector 5 so as not to be seen from the display screen. In FIG. 3, the low-voltage side cable 14 of each linear lamp 6 is arranged on the left side of each linear lamp 6 between the peaks below the lamp reflector 5. Further, the low-voltage side cable 14 is spaced apart from the metal lower frame 8 to prevent a leak current from the cable 14.

FIG. 5 is a cross-sectional view of a main part showing how to arrange the low-voltage side cable 14 of the linear lamp 6 different from FIG.
This figure shows a case where there are six linear lamps.

6a to 6f are linear lamps 6, 14a to 14
f indicates a low-voltage side cable, and a to f indicate cables of the linear lamp. As shown in FIG. 5, the low-voltage side cables 14a to 14c of the linear lamps 6a to 6c are provided.
14c is disposed on the right side of the linear lamps 6a to 6c, and the low-voltage side cables 14d to 14c of the linear lamps 6d to 6f.
14f is arranged on the left side of the linear lamps 6d to 6f.

FIG. 6 is a cross-sectional view of a main part showing how to arrange the low-voltage side cable 14 of the linear lamp 6 different from FIGS. This drawing shows an example in which there are six linear lamps.

As shown in FIG. 6, the low-voltage side cable 14 of the linear lamp 6 is disposed immediately below the linear lamp 6. With this arrangement, the positions of the lamp cables 14 are exactly the same, and each cable 14 of each linear lamp 6 is
It is further advantageous to make the lengths of

<< Outline of Liquid Crystal Display Panel >> FIG. 7 is a plan view showing one pixel of an active matrix type color liquid crystal display panel as an example to which the present invention is applied and its periphery.
FIG. 8 shows an image in which the pixel portion of the matrix is located at the center (b) (cross section taken along the line 8-8 in FIG. 7), the left side (a) is near the panel angle, and the right side (c) is connected to the video signal drive circuit. FIG. 3 is a diagram illustrating a cross section near a signal terminal DTM.

As shown in FIG. 7, each pixel has two adjacent scanning signal lines (gate signal lines or horizontal signal lines) GL.
And two adjacent video signal lines (drain signal lines or vertical signal lines) DL (in a region surrounded by four signal lines). Each pixel includes a thin film transistor TFT, a transparent pixel electrode ITO1, and a storage capacitor Cadd. The scanning signal lines GL extend in the left-right direction in FIG. Video signal line DL
Extend in the up-down direction and are arranged in a plurality in the left-right direction.

As shown in FIG. 8, a thin film transistor TFT and a transparent pixel electrode ITO1 are formed on the lower transparent glass substrate SUB1 side with respect to the liquid crystal layer LC, and a color filter FIL and a light shielding A black matrix pattern BM is formed. A silicon oxide film SIO formed by dipping or the like is provided on both surfaces of the transparent glass substrates SUB1 and SUB2.

A light shielding film BM and a color filter FI are provided on the inner surface (the liquid crystal LC side) of the upper transparent glass substrate SUB2.
L, protective film PSV2, common transparent pixel electrode ITO2 (CO
M) and an upper alignment film ORI2 are sequentially laminated.

Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the spirit of the present invention. It is. For example, the present invention can be applied to a simple matrix type liquid crystal display device, a vertical electric field type or a horizontal electric field type active matrix type liquid crystal display device, or a COG (chip-on-glass) type liquid crystal display device. Needless to say.

[0057]

As described above, according to the present invention,
The backlight has high brightness, and the brightness of the display screen is highly uniform.In addition, it suppresses the deterioration of display quality due to the noise generated from the lamp cable, reduces the leak current from the lamp cable, and improves the luminous efficiency of the backlight. It is possible to provide a liquid crystal display device which is high, particularly advantageous for a large screen.

[Brief description of the drawings]

FIGS. 1A and 1B are schematic plan views of a direct-type backlight of a liquid crystal display device according to an embodiment of the present invention.
Shows a state where the connector of the lamp cable of the linear lamp is connected, and (b) shows a state where the connector of the lamp cable is disconnected.

FIG. 2 is an exploded schematic perspective view of the liquid crystal display module according to one embodiment of the present invention.

FIG. 3 is a schematic sectional view taken along the line AA of FIG. 2;

FIG. 4 is a perspective view showing an example of a holding structure of a high-voltage high-frequency AC generation circuit board.

FIG. 5 is a cross-sectional view of a main part showing how to arrange a low-voltage side cable of a linear lamp different from FIG. 3;

FIG. 6 is a cross-sectional view of a main part showing how to arrange a low-voltage side cable of a linear lamp different from FIGS. 3 and 5;

FIG. 7 is a plan view of a principal part showing one pixel of an active matrix type color liquid crystal display panel and its periphery.

8A and 8B are cross-sectional views of a pixel portion of the matrix of FIG. 7 in the center (b), a left side (a) near a panel angle, and a right side (c) near a video signal terminal to which a video signal drive circuit is connected. It is.

FIG. 9 is a schematic plan view of a direct-type backlight of a conventional liquid crystal display device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Upper frame, 2 ... Liquid crystal display panel, 3 ... Diffusion sheet, 4 ... Diffusion plate, 5 ... Lamp reflector (reflection plate), 6 ... Linear lamp, 7 ... Mold case, 8 ... Lower frame, 9 ...
High voltage high frequency AC generation circuit board, 10 ... polarizer, 11 ...
Transparent insulating substrate, 12: liquid crystal layer, 13: high voltage generating transformer, 14: low voltage side lamp cable, 15: high voltage side lamp cable, 16, 17: connector, 18: scanning signal electrode side driving circuit board, 19 ... video signal electrode side driving circuit board, 20 ... DC / DC converter controller board, 21 ... storage opening, 22 ... holding part, 23, 24 ...
Screw holes, 25 ... screws.

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shunsuke Morishita 3300 Hayano, Mobara-shi, Chiba F-term (reference) 2H093 NA16 NC05 NC34 NC42 ND09 ND40 NE06 NE10 NF05 NF13 5G435 AA02 AA03 AA16 BB12 BB15 EE03 EE04 EE05 EE26 EE29 EE34 EE37 FF03 FF06 GG24 GG26

Claims (6)

[Claims] 1. A liquid crystal display device having a liquid crystal display panel and a backlight disposed below the liquid crystal display panel to supply light to the liquid crystal display panel, wherein a plurality of the backlights are arranged below the liquid crystal display panel. And a high-voltage high-frequency AC generation circuit for emitting light from the linear lamp, and two lamps connecting the electrodes at both ends of the linear lamp and the high-voltage high-frequency AC generation circuit A liquid crystal display device, wherein a length and a resistance value of a cable are substantially equal for all of the plurality of linear lamps. 2. A liquid crystal display device having a liquid crystal display panel and a backlight disposed below the liquid crystal display panel to supply light to the liquid crystal display panel, wherein a plurality of the backlights are provided below the liquid crystal display panel. A linear lamp arranged at substantially the same pitch, and a high-voltage high-frequency AC generation circuit board for emitting the linear lamp; a lamp cable is provided at each end of each of the linear lamps; A first connector is provided at a tip of a cable, and a high-voltage generating transformer is connected to an output of the high-voltage generating transformer for each of the linear lamps on the high-voltage high-frequency AC generating circuit board; A second connector to which the connector is connected is provided at substantially the same pitch, and the length and resistance value of the two lamp cables are equal to the total length of the plurality of linear lamps. A liquid crystal display device characterized in that: 3. A dimming circuit for equalizing the brightness of the plurality of linear lamps.
The liquid crystal display device as described in the above. 4. A reflecting plate is provided below the linear lamp, and the reflecting plate has a downwardly convex chevron shape for each of the linear lamps. Of the lamp cables,
3. The liquid crystal display device according to claim 1, wherein at least a longer lamp cable is disposed below the reflector. 5. The liquid crystal display device according to claim 4, wherein said longer lamp cable is arranged between said peaks or immediately below said peaks. 6. The liquid crystal display device according to claim 4, wherein said reflection plate is disposed in an electrically insulating frame.