JP3556478B2 - Liquid crystal display - Google Patents

Description

[0001]
TECHNICAL 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 backlight having high luminance, uniform over the entire display screen, and having a long life suitable for a large screen.
[0002]
[Prior art]
2. Description of the Related Art Liquid crystal display devices have begun to be widely used as display terminals for information processing devices (OA devices) 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.
[0003]
This liquid crystal display device (that is, a liquid crystal display module) includes, for example, two transparent insulating substrates made of glass or the like, each having a display electrode provided on at least one of the opposing surfaces thereof, with a predetermined gap therebetween. 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 substrates, and the liquid crystal sealing opening provided in a part of the sealing material is placed inside the sealing material between the two substrates. A liquid crystal display panel (that is, a liquid crystal display element, LCD: Liquid Crystal Display) in which a liquid crystal is sealed and a polarizing plate that transmits only a certain amount of polarized light is provided outside both substrates; A backlight, which is arranged under the panel and emits surface light, supplies light from the back to the liquid crystal display panel and serves as a light source for displaying images, and a liquid crystal A driving circuit board that is disposed outside the outer peripheral portion of the display panel and applies a voltage corresponding to a display image signal to the electrodes, a plastic mold case that houses and holds a liquid crystal display panel and a backlight, It is composed of a metal upper shield case that is housed and has a display window opened, a metal lower shield case, and the like.
[0004]
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 bright color display with high contrast.
[0005]
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 when used for a long time. Also, it is required that the luminance does not decrease.
[0006]
In general, the brightness of a cold cathode or hot cathode fluorescent tube decreases with the elapse of use time.
[0007]
As a countermeasure against the decrease in luminance due to the long-term use, a light guide plate having substantially the same size as that of the light guide plate is disposed immediately 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. Edge lamps), and a method in which the linear lamps are easily inserted and removed, and the linear lamps are replaced when the brightness is reduced.
[0008]
Such a side-edge type backlight is described in, for example, Japanese Patent Application Laid-Open No. Hei 7-181489 and academic literature (IDU 96-59, 1996, IDY 96-147, pp. 43-48).
[0009]
In the side edge type backlight, there is a problem that the screen brightness 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, a 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.
[0010]
Although it is possible to increase the number of fluorescent tubes arranged on the side of the light guide plate in order to prevent this decrease in luminance, in the case of a light guide plate having a rectangular planar shape, the fluorescent light is basically provided on the four side surfaces of the light guide plate. There is a limit in arranging tubes, and such an arrangement increases the length in the vertical and horizontal directions of the liquid crystal display device, and in response to recent demands to reduce the width of a so-called frame portion which is an outer peripheral portion of a display screen. Contrary. It is also possible to arrange a plurality of fluorescent tubes on the side surface of the light guide plate, but in this case, even the cold cathode fluorescent tubes concentrate heat and have adverse effects such as uneven display due to the heat of the liquid crystal display panel. Cannot be ignored.
[0011]
As a backlight having a high luminance, there is a direct type in which a plurality of linear lamps are arranged in parallel on a reflector having a wavy or sawtooth cross section.
[0012]
Documents describing such a backlight include, for example, JP-A-1-169482, JP-A-3-219278, and JP-A-4-20989.
[0013]
In the backlight of the direct type, if the number of linear lamps is small, the luminance of the entire backlight does not increase, and it is necessary to increase the luminance of the linear lamp. 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 in order 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.
[0014]
In a liquid crystal display device, a case for accommodating a liquid crystal display panel, a backlight, and the like is formed of, for example, a metal shield case. The display quality is prevented from being adversely affected by heat generation, and the metal plate shields electromagnetic waves.
[0015]
[Problems to be solved by the invention]
As described above, the display screen size of the monitor liquid crystal display device is increasing year by year, and the backlight is also increasing in size accordingly.
[0016]
Further, there is a strong demand for higher luminance, and a brighter, that is, stronger backlight is required. As described above, there are two types of backlights, the side edge type and the direct type, but for high luminance (especially on a large screen), the direct type in which the number of linear lamps can be easily increased is advantageous. It is.
[0017]
FIG. 9 is a schematic plan view of a direct-type backlight in a conventional liquid crystal display device.
[0018]
6 is a linear lamp (fluorescent tube), 9 is a high-voltage high-frequency AC generating circuit board, 13 is a high-voltage generating transformer, 14 is a low-voltage lamp cable, 15 is a high-voltage lamp cable, and 16 is a high-voltage high-frequency AC generator. The connectors provided on the ends of the lamp cables 14 and 15 are inserted into the connectors provided on the circuit board 9 to establish electrical connection.
[0019]
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 luminance, conventionally, a high-voltage high-frequency AC generation circuit board is used. As shown in FIG. 9, two parts 9 are divided and arranged on both sides of six linear lamps 6. 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. In order to prevent the cable from being seen, the cable is routed in a mold case (not shown; see FIGS. 2 and 3), which is a backlight holding member, so as not to pass right below the display screen, as shown in FIG. The lamp cables 14 and 15 have different lengths for each lamp 6. Therefore, the lamp tube current changes for each lamp 6 due to the difference in resistance due to the difference in the length of the lamp cables 14 and 15, a luminance difference occurs in each lamp 6, and further, each lamp 6 is controlled by a dimming circuit. It is difficult to adjust the balance of the luminance, and it is difficult to obtain a display quality with uniform luminance over the entire screen.
[0020]
If the lamp cable 14 connecting the lamp 6 and the high-voltage generating transformer 13 is routed longer than necessary due to the reason described above, the influence of electrical noise generated from the cable 14 increases. In addition, there is a problem that the display is adversely affected, and further, a high voltage current leaks from the lamp cable 14 to lower the luminous efficiency of the backlight.
[0021]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display device in which a backlight has a high luminance, a display screen has high uniformity of luminance, and furthermore, a decrease in display quality due to noise generated from a lamp cable is suppressed, and a leak from the lamp cable is suppressed. It is an object of the present invention to provide a liquid crystal display device in which current is reduced and light emission efficiency of a backlight is high.
[0022]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the present invention provides a liquid crystal display device having a liquid crystal display panel and a backlight provided thereunder and supplying light to the liquid crystal display panel, wherein the backlight is the liquid crystal display panel. A plurality of linear lamps arranged underneath, a high-voltage high-frequency AC generation circuit board for emitting the linear lamps, a lamp cable provided at each end of each of the linear lamps, and the two lamp cables. A first connector is provided at the end of the first connector, 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; There is provided a second connector to be connected, and the lamp, and the high voltage generating transformer, wherein the second connector, their respective be arranged at the same pitch, the linear And both ends of the electrodes of the lamp, the length and the resistance value of the two lamp cables for connecting the high voltage high frequency AC generating circuit board, wherein the equal correct it up with all of the plurality of linear lamp .
Further, a liquid crystal display panel is disposed under that, the liquid crystal in the display panel liquid crystal display device having a backlight for supplying light, said backlight, respectively a plurality of it under the liquid crystal display panel same A high-frequency high-frequency AC generation circuit board for emitting the linear lamps, and a lamp cable provided at each end of each of the linear lamps, and a tip of the two lamp cables. A high-voltage high-frequency alternating-current generating circuit, a high-voltage generating transformer is connected to the output of the high-voltage generating transformer for each of the linear lamps on the high-voltage high-frequency AC generating circuit board, and the first connector is connected to the high-voltage high-frequency AC generating circuit. provided in the second connector and the same pitch, respectively it is, the length and the resistance value of the two lamp cables, etc. Shikuna up with all of the plurality of linear lamp It is characterized in.
Further, it is characterized by having a dimming circuit for making the luminance of the plurality of linear lamps uniform.
In addition, a reflector is provided under the linear lamp, and the reflector has a chevron shape having a downwardly convex cross section for each of the linear lamps. Among them, at least the longer lamp cable is arranged below the reflector.
Further, the longer lamp cable is arranged between the peaks or directly below the peak.
Further, the reflection plate is disposed in an electrically insulating frame.
Further, the longer lamp cable is disposed on the right side with respect to the linear lamp on the left side of the liquid crystal display device, and is disposed on the left side with respect to the linear lamp on the right side. I do.
[0028]
In the present invention, as described above, by making the lengths and resistances of the two lamp cables of the linear lamps substantially equal for all of the plurality of linear lamps, the tube current flowing through each linear lamp becomes uniform. In addition, the luminance of each linear lamp becomes uniform, and the uniformity of the in-plane luminance of the liquid crystal display screen can be improved. Further, the brightness of each linear lamp can be easily adjusted by the dimming circuit.
[0029]
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.
[0030]
In addition, 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.
[0031]
Also, by arranging 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 at approximately the same pitch, respectively. The length and resistance of the two lamp cables of the linear lamps are made substantially equal for all of the plurality of linear lamps, so that the cable length can be easily reduced.
[0032]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described 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 repeated description thereof will be omitted.
[0033]
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 in which a lamp cable of a linear lamp is connected via a connector, and FIG. Indicates a state in which the connector of the lamp cable is disconnected. FIG. 2 is an exploded schematic perspective view of a liquid crystal display module according to an embodiment of the present invention, and FIG. 3 is a schematic sectional view taken along line AA in FIG.
[0034]
2, reference numeral 1 denotes a metal upper frame, 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, and 20 denotes a DC / DC converter / controller board. 3, 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)), and 7 is a circuit board For example, a white plastic mold case for storing and holding the attached liquid crystal display panel 2 and a backlight, 8 is a lower frame made of, for example, metal, 9 is a high-voltage high-frequency AC generation circuit board, and 13 is a high-voltage generation transformer.
[0035]
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 side lamp cable. , 16 are connectors.
[0036]
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. 1B) is provided at the tip of the lamp cables 14 and 15 of each linear lamp 6. The connector (cable socket) 16 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.
[0037]
In a general liquid crystal display device, a change in applied voltage causes a change from white display to black display or black display to white display. In the present embodiment, for example, the liquid crystal layer has a twist angle of about 90 °. Twisted nematic (TN) type or vertical alignment type TFT (thin film transistor) drive may be used, and super twisted nematic (STN) type time-division drive with a twist angle of 200 to 260 ° may be used. A lateral electric field system that responds with an electric field may be used.
[0038]
The product Δnd of the refractive index anisotropy Δn of the liquid crystal layer and the cell gap d is in the range of 0.2 μm to 0.6 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. Preferably, in the case of the STN type, the range is 0.5 μm to 1.2 μm, and in the case of the lateral electric field type, the range is 0.2 μm to 0.5 μm.
[0039]
Further, as the transparent insulating substrate 11, for example, two substrates obtained by polishing a surface of a glass substrate having a thickness of 0.7 mm and forming transparent electrodes made of ITO (indium tin oxide) by a sputtering method were used. A nematic liquid crystal composition having a positive dielectric anisotropy Δnε, a value of 4.5, and a refractive index anisotropy Δn of 0.19 (589 nm, 20 ° C.) was sandwiched between these substrates. Since the cell gap was 6 μm, Δnd was 1.41 μm. After a polyimide-based orientation control film is applied to the substrate surface, it is baked at 250 ° C. for 30 minutes, and a rubbing treatment is performed on the orientation control film to obtain a pretilt angle of 3.5 degrees (by a rotation crystal (crystal rotation) method). Measurement). 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 torsion angle has a maximum value limited to 260 degrees as an upper limit, and a lower limit is limited by contrast, and 200 degrees is a limit, because the lighting state near the threshold value becomes an orientation that scatters light. . 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, between the transparent insulating substrate 11 and the polarizing plate 10, one retardation film made of polycarbonate and having Δnd = 0.4 μm was disposed (not shown).
[0040]
In the present embodiment, as shown in FIGS. 1 to 3, eight linear lamps 6 are arranged below the liquid crystal display panel 2, so that the brightness is high, especially a large size of 15 inches or more (15 to 21 inches). This is advantageous in a liquid crystal display device having a screen. 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, the eight linear lamps, the eight high-voltage generating transformers 13, the eight connectors 16, and the eight dimming circuits provided respectively corresponding to the eight linear lamps are all arranged at the same pitch. With 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 brightness 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, the number of ICs provided for each of the eight linear lamps is reduced to one for every two linear lamps.
[0041]
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 the electric noise generated by the electric noise is reduced. A decrease in display quality can be suppressed. Further, the leakage of the high voltage current from the lamp cable 14 can be reduced, the loss of power consumption can be reduced, and the luminous efficiency of the backlight can be improved.
[0042]
FIG. 4 is a perspective view showing a structure for holding the high-voltage high-frequency AC generation circuit board 9.
[0043]
4, reference numeral 21 denotes an opening for accommodating the high-voltage high-frequency AC generation circuit board 9 provided on the metal lower frame 8, reference numeral 22 denotes a holder for the high-voltage high-frequency AC generation circuit board 9 provided integrally with the lower frame 8, Reference numeral 23 denotes a fixing screw hole provided in the high-voltage high-frequency AC generation circuit board 9, reference numeral 24 denotes a screw hole provided in the mold case 7, and reference numeral 25 denotes a screw. In FIG. 4, electronic components such as the high-voltage generating transformer 13 and the connector 16 mounted on one side on the lower surface of the high-voltage high-frequency AC generating circuit board 9 facing upward are not shown (see FIG. 1).
[0044]
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. 4, the high-voltage high-frequency AC generation circuit board 9 is housed in the housing opening 21 of the lower frame 8, and is formed with two holding parts 22 formed together with the opening 21 by pressing. Thus, two corner portions of the circuit board 9 are held, and are fixed to the mold case 7 by two screws 25 and screw holes 23 and 24.
[0045]
As shown in FIGS. 3 and 2, a lamp reflector 5 is disposed below each of the eight linear lamps 6, and the lamp reflector 5 has a cross-sectional shape that is downwardly convex for each linear lamp 6. , And have a waveform as a whole. Note that a sawtooth shape may be used instead of the waveform. Further, 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. A transparent acrylic diffusion plate 4 having a white or white dot print of 1 to 3 mm is provided.
[0046]
Further, between the liquid crystal display panel 2 and the diffusion plate 4, the light is condensed and the shadow of the linear lamp 6 is prevented from being seen when observing from the oblique direction of the display screen. Therefore, one or two diffusion sheets 3 are arranged. One or more brightness enhancement sheets may be arranged between the liquid crystal display panel 2 and the linear lamp 6.
[0047]
As shown in FIG. 3, the low-voltage side cable 14 of the linear lamp 6 is arranged 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 disposed 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.
[0048]
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.
[0049]
6a to 6f indicate the linear lamps 6, 14a to 14f indicate the low voltage side cables, and a to f indicate the cables of the linear lamps. As shown in FIG. 5, the low voltage side cables 14a to 14c of the linear lamps 6a to 6c are arranged on the right side of the linear lamps 6a to 6c, and the low voltage side cables 14d to 14f of the linear lamps 6d to 6f. Are arranged on the left side of the linear lamps 6d to 6f.
[0050]
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 figure shows an example in which there are six linear lamps.
[0051]
As shown in FIG. 6, the low-voltage side cable 14 of the linear lamp 6 is disposed directly below the linear lamp 6. With this arrangement, the positions of the lamp cables 14 are exactly the same, which is further advantageous for making the length of each cable 14 of each linear lamp 6 the same.
[0052]
《Overview of LCD 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, and FIG. 8 is a diagram in which the pixel portion of the matrix is located at the center (b) (8 in FIG. 7). FIG. 8 is a diagram showing a cross section near a panel angle on the left side (a) and a cross section near a video signal terminal DTM to which a video signal drive circuit is connected on the right side (c).
[0053]
As shown in FIG. 7, each pixel includes 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. It is arranged in the intersection area (in the area 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 the figure, and a plurality of scanning signal lines GL are arranged in the up-down direction. The video signal lines DL extend in the up-down direction, and a plurality of video signal lines DL are arranged in the left-right direction.
[0054]
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 black matrix pattern are formed on the upper transparent glass substrate SUB2 side. 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.
[0055]
A light-shielding film BM, a color filter FIL, a protective film PSV2, a common transparent pixel electrode ITO2 (COM), and an upper alignment film ORI2 are sequentially provided on the inner surface (the liquid crystal LC side) of the upper transparent glass substrate SUB2. I have.
[0056]
Although the present invention has been specifically described based on the embodiments, the present invention is not limited to the embodiments, and it is needless to say that various changes can be made without departing from the gist of the present invention. For example, the present invention can be applied to a simple matrix type liquid crystal display device, a vertical electric field type or 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]
【The invention's effect】
As described above, according to the present invention, the backlight has high luminance, the luminance of the display screen has high uniformity, and furthermore, the deterioration of the display quality due to the noise generated from the lamp cable is suppressed, It is possible to provide a liquid crystal display device in which a leakage current is reduced and the light emission efficiency of a backlight is high, and which is particularly advantageous for a large screen.
[Brief description of the drawings]
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, and FIG. 1A shows a state in which a connector of a lamp cable of a linear lamp is connected. , (B) shows a state in which 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 for 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 main part plan view showing one pixel of an active matrix type color liquid crystal display panel and the periphery thereof;
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 ... Height Voltage high-frequency AC generating circuit board, 10: polarizing plate, 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.

Claims (7)

In a liquid crystal display device having a liquid crystal display panel and a backlight disposed below and supplying light to the liquid crystal display panel,
The backlight includes a plurality of linear lamps arranged below the liquid crystal display panel, and includes a high-voltage high-frequency AC generation circuit board that causes the linear lamps to emit light,
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 generator is provided on the high voltage high frequency AC generation circuit board for each of the linear lamps. A transformer and a second connector connected to the output of the high-voltage generating transformer and connected to the first connector;
And the lamp, and the high voltage generating transformer, wherein the second connector, their respective be arranged at the same pitch, and the opposite electrodes of the linear lamp, and the high voltage high frequency AC generating circuit board the length and the resistance value of the two lamp cables connected to the liquid crystal display device according to claim equal correct it up with all of the plurality of linear lamp. In a liquid crystal display device having a liquid crystal display panel and a backlight disposed below and supplying light to the liquid crystal display panel,
The backlight comprises a linear lamps arranged in the plurality of their respective same pitch under the liquid crystal display panel having a high-voltage high-frequency AC generation circuit board to emit the said linear lamp,
A lamp cable is provided at each end of each of the linear lamps, and a first connector is provided at a tip of the two lamp cables,
On the high-voltage high-frequency AC generation circuit board, for each of the linear lamps, a high-voltage generation transformer, and a second connector connected to an output of the high-voltage generation transformer and connected to the first connector. their respective arranged at the same pitch,
The liquid crystal display device the length and the resistance value of the two lamp cables, characterized by comprising equal properly with all of the plurality of linear lamp. 3. The liquid crystal display device according to claim 1, further comprising a dimming circuit for making the luminance of the plurality of linear lamps uniform. A reflector is provided under the linear lamp,
The reflector has a downwardly convex chevron shape for each linear lamp.
3. The liquid crystal display device according to claim 1, wherein at least a longer one of the two lamp cables of each of the linear lamps is disposed below the reflector. 4. The liquid crystal display device according to claim 4, wherein the longer lamp cable is disposed between the peaks or immediately below the peaks. 5. The liquid crystal display device according to claim 4, wherein the reflection plate is disposed in an electrically insulating frame. The said longer lamp cable is arrange | positioned at the right side with respect to the said linear lamp of the said liquid crystal display device, and is arrange | positioned at the left side with respect to the said linear lamp. Item 6. A liquid crystal display device according to item 5.

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