Herein disclosed are a liquid crystal display device and a data processing device, which can have their frame portions reduced in area to reduce the size and weight by extracting the terminals of video signals to only one side of a liquid crystal display panel and by arranging a video signal line driving circuit substrate to be connected with the terminals, only at one side of the display panel. A liquid crystal display device includes a liquid crystal display panel, a light guide plate, a fluorescent tube, and a lamp reflector. first and second lamp cables of different length are connected to the fluorescent tube. One end of the fluorescent tube is inserted in a hole of a first rubber bush and a part of the one end of the fluorescent tube is connected to the first lamp cable in the hole of the first rubber bush and an other end of the fluorescent tube is inserted in a hole of a second rubber bush and a part of the other end of the fluorescent tube is connected to the second lamp cable in the hole of the second rubber bush. The first and second lamp cables are extracted from a same place of a mold case.
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0. 15. A liquid crystal display device comprising:
a liquid crystal display panel;
a light guide plate disposed below the liquid crystal display panel;
a fluorescent tube arranged on one side face of the light guide plate;
a lamp reflector reflecting light of the fluorescent tube to the light guide plate;
a first lamp cable connected to the fluorescent tube, and a second lamp cable connected to the fluorescent tube, the second lamp cable having a length which is shorter than a length of the first lamp cable; and
a mold case accommodating the light guide plate, the fluorescent tube, the lamp reflector, and the first lamp cable;
wherein one end of the fluorescent tube is inserted in a hole of a first rubber bush, and a part of one end of the fluorescent tube is connected to the first lamp cable in the hole of the first rubber bush, and an other end of the fluorescent tube is inserted in a hole of a second rubber bush, and a part of the other end of the fluorescent tube is connected to the second lamp cable in the hole of the second rubber bush;
wherein the first lamp cable is accommodated within a first groove of the mold case, and the second lamp cable is accommodated within a second groove of the mold case; and
wherein the first lamp cable and the second lamp cable are extracted from a same place of the mold case.
0. 1. A liquid crystal display device comprising:
a liquid crystal display panel, including an upper shield casing accommodating at least one insulating substrate and having at least first and second sides, and a lower casing being connectable to the upper shield casing, the lower casing having at least first and second sides with one of the first side of the upper shield casing and the lower casing being provided with hooks and the other of the first side of the upper shield casing and the lower casing being provided with projections for receiving the hooks and enabling connection of the upper shield casing and the lower casing, and one of the second side of the upper shield casing and the lower casing having fixing pawls and the other of the second side of the upper shield casing and the lower casing having recesses for receiving the fixing pawls so as to enable connection of the upper shield casing and the lower casing.
0. 2. A liquid crystal display device according to
wherein a video signal line driving circuit substrate is arranged on only one longer sides of said liquid crystal display panel and is connected with the terminals of said video signal lines.
0. 3. A liquid crystal display device according to
wherein no circuit substrate is arranged at the other side of said display panel which is arranged with said video signal line driving circuit substrate.
0. 4. A liquid crystal display device according to
a light guide plate arranged below said liquid crystal display panel,
a fluorescent tube arranged in the vicinity of at least one side face of said light guide plate,
and a plurality of tape carrier packages arranged on the outer peripheral portion of said liquid crystal display panel;
wherein said fluorescent tube is arranged below said plurality of tape carrier packages.
0. 5. A liquid crystal display device according to
0. 6. A liquid crystal display device according to
0. 7. A liquid crystal display device according to
0. 8. A liquid crystal display device comprising:
a first circuit substrate arranged outside of a first side of a liquid crystal display panel for driving signal lines,
a second circuit substrate arranged outside of a second side adjacent to and perpendicular to said first side and having a connector for connection with the outside,
a first casing having a first mounting hole in the vicinity of its corner for accommodating said liquid crystal display panel and said first and second circuit substrates,
a back light disposed with respect to said liquid crystal display panel,
and a second casing having a second mounting hole aligned with said first mounting hole for accommodating said back light;
wherein said first casing and said second casing are united together, said second circuit substrate is equipped with an electronic part disposed at its end portion most remote from said first circuit substrate, said connector of said second circuit substrate is arranged adjacent to said electronic part and extends in a direction substantially parallel to said second side;
a plurality of circuit substrates divided and arranged at the two, three or four sides of an outer peripheral portions of said liquid crystal display panel,
and a casing for accommodating said liquid crystal display panel and said circuit substrates together and formed with mounting holes,
wherein at least one of said mounting holes is arranged at a distance from a corner of said casing, and in that said circuit substrate having a generally rectangular shape with corners are divided into a plurality of sheets and are electrically connected in a vicinity of said corners by joiners.
0. 9. A liquid crystal display device according to
wherein said mounting holes are positioned at intermediate portions spaced at a predetermined distance from the corners of said casing and in a drawn portion which is made integral with a metal plate forming said casing and which forms a parallel plane at a different level as that of said metal plate,
said drawn portion is given generally a quadrant shape,
said quadrant shape is formed with a notch in its radial portion between said drawn portion and said metal plate adjacent to said drawn portion.
0. 10. A liquid crystal display device according to
wherein said circuit substrates are electrically connected with each other through at least two joiners which are superposed at two or more stages in a thickness direction of said display device.
0. 11. A liquid crystal display device comprising:
a first circuit substrate arranged outside of a first side of a liquid crystal display panel for driving signal lines,
a second circuit substrate arranged outside of a second side adjacent to and perpendicular to said first side and having a connector for connection with the outside, and a signal source integrated circuit,
a first casing having a first mounting hole in a vicinity of a corner for accommodating said liquid crystal display panel and said first and second circuit substrates,
and a second casing having a second mounting hole aligned with said first mounting hole for uniting said first casing;
wherein said connector disposed between said first circuit substrate and said signal source integrated circuit, said connector of said second circuit substrate is arranged adjacent to said signal source integrated circuit and extends in a direction substantially parallel to said second side.
0. 12. A liquid crystal display device comprising:
a liquid crystal display panel having longer sides and shorter sides;
a video signal line driving circuit substrate connected to only one of said longer sides of said liquid crystal display panel;
a light guide plate arranged below said liquid crystal display panel;
a fluorescent tube arranged on at least one side face of said light guide plate;
a shield casing for accommodating the circumferential portion of said liquid crystal display panel;
a mold casing monolithically molded for accommodating said light guide plate and said fluorescent tube;
two cables having respective one ends thereof connected with two ends of said fluorescent tube;
first and second retaining members for retaining the two ends of said fluorescent tube, respectively; and
first, second and third grooves integral with said mold casing;
wherein said first and second grooves respectively accommodate said first and second retaining members so that said first and second retaining members are snugly fitted therein;
at least one of said two cables is accommodated in said third groove which is integral with a side wall of said mold casing;
said shield casing and said mold casing being coupled together; and
said third groove and said fluorescent tube being arranged to extend along one of said longer sides of said liquid crystal display panel.
0. 13. A liquid crystal display device according to
0. 14. A liquid crystal display device according to
0. 16. A liquid crystal display device according to
0. 17. A liquid crystal display device according to
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wherein delta V1C indicates the variation of the central potential due to delta Vg. This variation delta V1c causes the DC component to be added to the liquid crystal LC and can be reduced the more for the higher additional capacitor Cadd. Moreover, the additional capacitor Cadd functions to elongate the discharge time and stores the video information for a long time after the thin film transistor TFT is turned off. The DC component to be applied to the liquid crystal LC can improve the lifetime of the liquid crystal LC, to reduce the so-called “printing”, by which the preceding image is left at the time of switching the liquid crystal display frame.
Since the gate electrode GT is enlarged to such an extent as to cover the semiconductor layer AS completely, as has been described hereinbefore, the overlapped area with the source electrode SD1 and the drain electrode SD2 is increased to cause an adverse effect that the parasitic capacity Cgs is increased to make the center potential V1c liable to be influenced by the gate (scanning) signal Vg. However, this demerit can be eliminated by providing the additional capacitor Cadd.
The latching capacity of the additional capacitor Cadd is set from the pixel writing characteristic to a level four to eight times as large as that of the liquid crystal capacity Cpix (4*Cpix<Cadd<8*Cpix) and eight to thirty two times as large as that of the capacity Cgs (8*Cgs<Cadd<32*Cgs).
<<Method of Connecting Electrode Line of Additional Capacitor Cadd>>
The initial stage scanning signal line GL (i.e., Y0) to be used only as the capacity electrode line is set to the same potential as that of the common transparent pixel electrode (Vcom) ITO2, as shown in FIG. 12. In the example of
<<Structure for Connection with External Circuit>>
In the same drawing, letters TTB designate an input terminal/wiring portion of the integrated circuit CHI, and letters TTM designate an output terminal/wiring portion of the integrated circuit CHI. These portions are made of Cu, for example, and have their individual inner leading end portions (as called the “inner leads”) connected with a bonding pad PAD of the integrated circuit CHI by the so-called “faced-down bonding method”. The terminals TTB and TTM have their outer leading end portion (as called the “outer leads”) corresponding to the input and output of the semiconductor integrated circuit chip CHI, respectively, and are connected with the CRT/TFT converter circuit and the power supply circuit SUP by the soldering method and with the liquid crystal display panel PNL through an anisotropic conductive film ACF. The package TCP is so connected with the panel that its leading end portion covers the passivation film PSV1 having the connection terminal DTM exposed at the side of the panel PNL. As a result, the external connection terminal DTM (GTM) is strong against the galvanic corrosion because it is covered with at least one of the passivation film PSV1 or the package TCP.
Letters BF1 designate a base film made of polyimide or the like, and letters SRS designate a solder resist film for masking to prevent the solder from leaking to an unnecessary portion at the soldering time. The gap between the upper and lower glass substrates outside of the seal pattern SL is protected after the rinsing step by the epoxy resin EPX or the like, and this protection is multiplexed by filling a silicone resin SIL between the package TCP and the upper substrate SUB2.
<<Manufacturing Process>>
Next, a process for manufacturing the side of the substrate SUB1 of the aforementioned liquid crystal display device will be described with reference to
Step A, FIG. 14(A)
A silicon dioxide film SIO is deposited by the dip treatment on both surfaces of a lower transparent glass substrate SUB1 made of 7059 glass (under the trade name), and then a baking is carried out at 500 degree for 60 minutes. A first conductive film g1 consisting of a 1,100 angstrom chromium film is deposited on the lower transparent glass substrate SUB1 by the sputtering. After the photolithographic treatment, the first conductive film g1 is etched selectively by the photoetching using a ceric ammonium nitrate solution as an etching solution, thereby forming a gate terminal GTM and a drain terminal DTM and forming also a power bus line SMg for anodization for connecting the gate terminal GTM, and a pad (although not shown) connected with the power bus line SHg for anodization.
Step B, FIG. 14(B)
A second conductive film g2 having a thickness of 2,800 angstroms and made of Al—Pd, Al—Si, Al—Si—Ti or Al—Si—Cu is formed by the sputtering. After the photolithographic treatment, the second conductive film g2 is selectively etched with a mixed acid solution of phosphoric acid, nitric acid and glacial acetic acid.
Step C, FIG. 14(C)
After the photolithographic treatment (i.e., after the formation of the aforementioned anodized mask AO), the substrate SUB1 is dipped in the anodizing liquid which is prepared by diluting a solution containing 3% of tartaric acid adjusted to PH 6.2 to 6.3 with a solution of ethylene glycol, and the anodizing current density is adjusted to 0.5 mA/cm2 (for anodization at a constant current). Next, an anodization is carried out till an anodization current of 125 V necessary for a predetermined Al2O3 film thickness is reached. After this, the substrate SUB1 is desirably held in this state for several ten minutes (for anodization at a constant voltage). This is important for achieving a uniform Al2O3 film. Thus, the conductive film g2 is anodized to form an anodized film AOF having a thickness of 1,800 angstroms over the scanning signal line GL, the gate electrode GT and the electrode PL1.
Step D, FIG. 15(A)
Ammonia gas, silane gas and nitrogen gas are introduced into a plasma CVD apparatus to form a Si nitride film having a thickness of 2,000 angstroms, and silane gas and hydrogen gas are introduced into the plasma CVD apparatus to form an i-type amorphous Si film having a thickness of 2,000 angstroms. After this, hydrogen gas and phosphine gas are introduced into the plasma CVD apparatus to form an N(+)-type amorphous Si film having a thickness of 300 angstroms.
Step E, FIG. 15(B)
After the photolithography, the N(+)-type amorphous Si film and the i-type amorphous Si film are selectively etched by the photoetching using SF6 and CCl4 as the dry etching gas to form an island of an i-type semiconductor layer AS.
Step F, FIG. 15(C)
After the photolithography, the Si nitride film is selectively etched by using SF6 as the dry etching gas.
Step G, FIG. 16(A)
A first conductive film d1 formed of an ITO film having a thickness of 1,400 angstroms is formed by the sputtering. After the photolithography, the first conductive film d1 is selectively etched by using a mixed acid solution of hydrochloric acid and nitric acid as the etching solution, to form the uppermost layer of the gate electrode GTM and the drain terminal DTM and the transparent pixel electrode ITO1.
Step H, FIG. 16(B)
A second conductive film d2 of Cr having a thickness of 600 angstroms is formed by the sputtering, and a third conductive film d3 of Al—Pd, Al—Si, Al—Si—Ti or Al—Si—Cu having a thickness of 4,000 angstroms is formed by the sputtering. After the photolithography, the third conductive film d3 is etched by a solution similar to that of Step B, and the second conductive film d2 is etched by a solution similar to that of Step A, to form the video signal line DL, the source electrode SD1 and the drain electrode SD2. Next, CCl4 and SF6 are introduced into a dry etching apparatus to etch the N(+)-type amorphous Si film thereby to remove the N(+)-type semiconductor layer d0 selectively from between the source and the drain.
Step I, FIG. 16(C)
Ammonia gas, silane gas and nitrogen gas are introduced into a plasma CVD apparatus to form a Si nitride film having a thickness of 1 micron. After the photolithography, the Si nitride film is selected by the photoetching technique using SF6 as the dry etching gas, to form the passivation film PSV1. <<Structure of Whole Liquid Crystal Display Module>>
Letters SHD designate a shield casing (which may also be called the “metal frame”) made of a metal plate; letters WD a display window; letters INS1 to INS3 designate insulating sheets; letters PCB1 to PCB3 designate circuit substrates (composed of a drain side circuit substrate PCB1, a gate side circuit substrate PCB2, and an interface circuit substrate PCB3); letters JN designate a joiner for electrically connecting the circuit substrates PCB1 to PCB3 with each other; letters TCP1 and TCP2 designate tape carrier packages; letters PNL a liquid crystal display panel; letters GC designate a rubber cushion; letters ILS designate a shade spacer ILS; letters PRS designate a prism sheet; letters SPS designate a diffusion sheet; letters GLB designate a light guide plate; letters RFS designate a reflecting sheet; letters MCA designate a lower casing (or mold casing) formed by the monolithic molding letters LP designate a fluorescent tube; letters LPC designate a lamp cable; and letters GB designate a rubber bush supporting the fluorescent tube LP; and letters BAT designate double sided adhesive tape. These members are individually stacked in the following arrangement relation, as shown, to assemble a liquid crystal display module MDL.
The module MDL has two kinds of accommodating and holding members of a lower casing MCA and a shield casing SHD. The module MDL is assembled by uniting the metallic shield casing SHD, which accommodates and fixes the insulating sheets INS1 to INS3, the circuit substrates PCB1 to PCB3 and the liquid crystal display panel PNL, and the lower casing MCA, which accommodates a back light BL composed of the fluorescent tube LP, the optical guide plate GLB and the prism sheet PRS.
Here will be described those individual members in detail in the following.
<<Metallic Shield Casing SHD>>
FIGS. 25(A)-25(D) present the upper side, front side, rear side, right hand side and left hand side of the shield casing SHD, and a perspective view, as taken obliquely from above the shield casing SHD.
The shield casing (or metal frame) SHD is fabricated by punching or folding a metal sheet by the pressing technique. Letters WD designate a window for exposing the display panel PNL to the field of view, as will be called the “display window”.
Letters NL designate fixing pawls (totally twelve in number) for fixing the shield casing SHD and the lower casing MCA, and letters HK also designate fixing hooks (totally four in number) integrally formed in the shield casing SHD. Before the fixing pawls NL shown in
Letters CH designate common through holes which are formed in common plan positions shared among the circuit substrates PCB1 to PCB3. At the manufacturing time, the shield casing SHD and the circuit substrates PCB1 to PCB3 are sequentially packaged by fitted the individual common through holes CH on fixed upright pins, so that they may be accurately positioned relative to each other. Moreover, the common through holes CH can be used as positioning references when the module MDL is to be packaged in an appliance such as a personal computer.
Letters FGN designate totally twelve frame ground pawls formed integrally with the metallic shield casing SHD. These frame ground pawls FGN are constructed of rectangular projections extending into square openings, i.e., the C-shaped openings which are formed in the side of the shield casing SHD. These slim projections, i.e., the pawls FGN are individually folded at their roots inward of the device and are soldered and connected to the frame ground pads FGP (as shown in
Letters SH1 to SH4 designate four mounting holes which are formed in the shield casing SHD so as to the module MDL as a display unit in a data processing device such as a personal computer or word processor. The lower casing MCA is also formed with mounting holes MH1 to MH4 which are aligned with the mounting holes SH1 to SH4 of the shield casing SHD (as shown in FIGS. 37 and 38), and screws are threaded into the two mounting holes to fix and package the data processing device. Incidentally, in case the mounting holes are to be formed in the corners of the metallic shield casing SHD, the drawn portions (i.e., the drawn portions which are integral with a metal plate forming the metallic shield casing SHD and which form a parallel plane at a level different from that of the metal plate) of the mounting holes can be formed into a quadrant shape. In case, however, the mounting holes SH are intended to be formed not in the corners but in intermediate portions at a predetermined distance from the corners from the standpoints of both the arrangement of the packaged parts of the circuit substrate PCB3 and the electric connection between the circuit substrates PCB1 and PCB2, the shape of the drawn portions DR of the mounting holes SHD cannot be the quadrant shape but a semicircular shape from the conveniences of the drawing operation so that the areas necessary for the mounting holes are enlarged. As shown in
<<Circuit Substrates PCB1 to PCB3>>
Letters CHI1 and CHI2 designate the drive IC (i.e., integrated circuit) chips (of which the lower five of
Specifically, the display panel PNL has its three outer peripheral portions arranged with the circuit substrates PCB1 to PCB3 of the display panel PNL in the shape of letter “C”. The outer peripheral portion of one longer side (as located at the left hand side of
Since the circuit substrates PCB1 to PCB3 are divided into three generally rectangular shapes, the stresses to be established in the directions of their longer axes due to the difference in the coefficients of thermal expansion between the display panel PNL and the circuit substrates PCB1 to PCB3 are absorbed at the portions of the joiners JN1 to JN3. As a result, the separations between the output leads (i.e., TTM of
The frame ground pads FGP, as connected to the individual ground wiring lines of the three circuit substrates PCB1 to PCB3, are provided, five, four and three, that is, totally twelve in number, as shown in FIG. 27. In case the circuit substrate is divided into a plurality, no electric problem will arise if at least one of the drive circuit substrates is connected with the frame ground in the DC manner. If the number of the drive circuit substrates is small in the higher frequency range, a potential for establishing the unnecessary radiative electric waves for causing the EMI (i.e., electromagnetic interference) is raised by the causes of the reflections of electric signals and the deflections of the potentials of the ground wiring lines due to the difference in the characteristic impedances of the individual drive circuit substrates. The counter-measures for that EMI are difficult especially in the module MDL of the active matrix type using thin film transistors. In order to prevent this, for each of a plurality of divided circuit substrates, the ground wiring lines (at the AC grounded potential) are connected with the common frame (i.e., the shield casing SHD) having a sufficiently low impedance. As a result, the ground wiring lines are strengthened in the higher frequency range, the electric field intensity is improved by 5 dB or more in the case of the twelve pads of the present embodiment, as compared with the case in which only one is connected with the shield casing SHD as a whole.
The frame grounding pawls FGN of the shield casing SHD are formed of the slender metal projections, as described, and can be connected to the frame ground pads FGP of the circuit substrates PCB1 to PCB3 by folding them, while requiring no special wires (or lead wires) for the connections. Moreover, the shield casing SHD and the circuit substrates PCB1 to PCB3 can be mechanically connected through the pawls FGN to improve the mechanical strengths of the circuit substrates PCB1 to PCB3.
In order to suppress the emission of the unnecessary radiative electric waves to cause the EMI, a plurality of resistors/capacitors for smoothing the signal wave forms are discretely arranged in the prior art in the vicinity of the signal source integrated circuit or in the course of the signal transmission route. As a result, there are required several spaces for interposing the resistors/capacitors in the vicinity of the signal source integrated circuit and between the taper carrier packages, so that the dead spaces are so enlarged that the electronic parts cannot be packaged in a high density. In the present embodiment, as shown in
<<Drain Side Circuit Substrate PCB1>>
One sheet of drain side circuit substrate PCB1 is arranged only at one longer side (i.e., at the left hand side of
In the module of the prior art, in which the video signal lines are alternately extracted to the upper and lower portions of the liquid crystal display panel and in which the two drain side circuit substrates are arranged at the upper and lower sides of the outer periphery of the liquid crystal display panel, the electronic parts are arranged along the flow of the signals which come from the external personal computer of the like into that module. Thus, there are arranged at the central portion of the interface circuit substrate with the connector to be connected with the personal computer or the like and the signal source integrated circuit TCON. In case the drain side circuit substrate PCB1 is arranged at one side of the liquid crystal display panel PNL, as in the present embodiment, the following layout is taken, if the arrangement of the electronic parts along the signal flow is taken as in the prior art. Specifically, the connector CT is arranged in the end portion closest to the corner of the shield casing SHD (as shown in
In the embodiment shown in
<<Gate Side Circuit Substrate PCB2>>
<<Tape Carrier Package TCP>>
The structure of the tape carrier package TCP and the connection structure with the liquid crystal display panel PNL have already been described in <<Connection Structure with External Circuit>> with reference to
The planar shape of the package TCP is shown in FIG. 33. The reason why the terminal portions TM and TB have small contour widths is to cope with the narrowing of the terminal pitch. Specifically, the output terminal portion TM to be connected with the display panel PNL has its size adjusted to the pitch of the input terminals of the panel PNL, and the input terminal portion TB to be connected with the circuit substrate PCB1 to PCB2 has its size adjusted to the pitch of the output terminals of the circuit substrate PCB1 or PCB2.
Incidentally, either the output terminal portion TM or the input terminal portion TB may have its width made smaller than the outermost width.
<<Interface Circuit Substrate PCB3>>
FIG. 29(A) presents the upper side of the interface circuit substrate PCB3 (i.e., having the connector CT and the hybrid integrated circuit HI packaged therein), and FIG. 29(B) presents the upper side having the signal source integrated circuit TCON and the parts such as the IC, capacitors or resistors packaged therein (and the connector CT and the hybrid integrated circuit HI in the portions, as indicated by dotted lines). On the interface circuit substrate PCB3, there are mounted not only the electronic parts such as the IC, capacitors or resistors but also: a power source circuit for achieving a plurality of stabilized voltage sources from one voltage source; and a circuit for transforming the data for the CRT (i.e., cathode ray tube) coming from the host (i.e., host processor) into the data for the TFT liquid crystal display device (as shown in FIG. 12). Letters CT designate a connector to be connected with the data processor such as the personal computer having that module MD packaged therein, and letters TCON designate a signal source integrated circuit for processing the image data sent from the host to transform them into the liquid crystal driving signals and for generating timing pulses to drive/control the gate side circuit substrate PCB2 and the drain side circuit substrate PCB1 thereby to display the data in the liquid crystal display device. Letters JP31 designate a connection portion to be connected with the joiner JN1, and letters JP32 designate a connection portion to be connected with the joiner JN2.
<<Electric Connections between Circuit Substrates PCB1 to PCB3>>
In accordance with development of recent years in the multiple colors of the color liquid crystal display device, the number of video signal lines for designating the gradations of red, green and blue colors increases together with the number of gradation voltages to that the portion having the function of the interface between that module and the setting side of the personal computer or the like to be assembled with that module is so complicated as to make difficult the electric connections between the drain side circuit substrate and the interface circuit substrate. Moreover, not only the number of video signal lines but also the number of connection lines are increased in accordance with the abrupt increase in the number of colors of the liquid crystal display device, because the connection lines effect the connections of the gradation voltages increasing in proportion to the color number, the clock and the power supply voltage.
At the corner of the shield casing SHD in which the two drain side circuit substrate PCB1 and interface circuit substrate PCB3 are adjacent to each other, as shown in
Incidentally, the stage number of joiners should not be limited to two but can be three or more. Moreover, the electric connections between the drain side circuit substrate PCB1 and the gate side circuit substrate PCB2 are effected by using one joiner JN3 (as shown in
The mounting holes of the module MDL are usually arranged in the corners of the module MDL. When, however, the circuit substrates PCB1 and PCB3 are to be electrically disconnected by using the joiners JN, one circuit substrate PCB3 takes not the rectangular shape, as shown in
<<Hybrid Integrated Circuit HI and Electronic Parts EP Packaged in Two Stages on Interface Circuit Substrate PCB3>>
The hybrid integrated circuit HI, as shown in
<<Insulating Sheet INS>>
Between the metallic shield casing SHD and the circuit substrates PCB1 to PCB3, there are arranged the insulating sheets INS1 to INS3, as shown in
<<Lower Casing MCA>>
The lower casing MCA, as molded, is a back light accommodating casing, i.e., a holding member for the fluorescent tube LP, the lamp cable LPC, the light conductive plate GLB and so on, and is monolithically molded of a synthetic resin by one mold. As has been described in detail in <Shield Casing SHD<>>, the lower casing MCA is firmly united with the metallic shield casing SHD by the actions of the individual fixing members and elastic members so that the module MDL can have its vibratory impulse resistance and thermal impulse resistances improved to improve the reliability.
The lower casing MCA is formed, in its bottom face at the central portion excepting the peripheral frame portion, with a large opening MO occupying a half or more area of the bottom face. As a result, after the module MDL has been assembled, the lower casing MCA can be prevented, by the repulsive force of the rubber cushion GC (of
Letters MLC designate a notch (includes the notch for connecting the connector CT, as shown in FIG. 27), which is so formed in the lower casing MCA as to correspond to the exothermic parts of the interface circuit substrate PCB3, i.e., a packaged portion such as the hybrid IC power source circuit (e.g., a DC-DC converter) in the present embodiment. Thus, the heat liberation of the exothermic portions of the interface circuit substrate PCB3 can be improved not by covering the exothermic portion of the circuit substrate PCB3 with the lower casing MCA but by forming that notch. Specifically, at present, the multiple gradations and the single power source are demanded for improving the performance and the facility of the liquid crystal display device using the thin film transistors TFT. The circuit for realizing these demands consumes a high power. If the circuit means is to be packaged is compact, the packaging becomes so highly dense to raise the problem of the heat generation. As a result, the dense packaging and the compactness of the circuit can be improved by forming the lower casing MCA with the notch MLC corresponding to the exothermic portions. On the other hand, the signal source integrated circuit TCON is also considered as the exothermic parts, above which the lower casing MCA may be notched.
Letters MH1 to MH4 designate four mounting holes for mounting that module MD in the appliance such as a personal computer. The metallic shield casing SHD is also formed with the mounting holes SH1 to SH4 aligned with the mounting holes MH1 to MH4 of the lower casing MCA, so that it can be fixed and packaged in the appliance.
<<Back Light>>
FIG. 40(A) is a top plan view of an essential portion of the fluorescent tube LP, lamp cables LPC1 and LPC2 and rubber bushes GB1 and GB2 of the back light BL, FIG. 40(B) is a section taken along line B—B of FIG. 40(A) and FIG. 40(C) is a section taken along line C—C of FIG. 40(A).
The back light BL for supplying the light to the display panel PNL is composed of: the cold-cathode fluorescent tube LP; the lamp cables LPC1 and LPC2 of the fluorescent tube LP; the rubber bushes GB1 and GB2 for holding the fluorescent tube LP and the lamp cables LPC; the light guide plate GLB; the diffusive sheet SPS arranged in contact with the whole upper surface of the light guide plate GLB; the reflective sheet RFS arranged all over the whole lower surface of the light guide plate GLB; and the prism sheet PRS arranged in contact with the whole upper surfaces of the diffusion sheet SPS.
In the module MLD, the slender fluorescent tube LP is arranged in the space below the drain side circuit substrate PCB1 and the tape carrier package TCP1, which are packaged in one longer side of the liquid crystal display panel PNL. As a result, the module MDL can have its external size reduced so that it can be small-sized and light-weighted to reduce the production cost.
The rubber bushes GB1 and GB2 hold both the single cold-cathode fluorescent tube LP and the lamp cables LPC1 and LPC2. Specifically, the fluorescent tube LP is held in a larger-diameter hole HL Of the hole (having a shape of a key hole joining the larger-diameter hole and a smaller-diameter hole, as shown in FIG. 40(B)), which is formed in the rubber bushes GB1 and GB2. The lamp cable LPC1, as connected with one end of the fluorescent tube LP, is inserted and held in the groove GBD formed in the rubber bush GB2. Moreover, the lamp cable LPC2, as extracted in the same direction as that of the lamp cable LPC1, is inserted and held in the smaller-diameter hole Hs of the hole GBH of the rubber bush GB2 at the cable extraction side. Incidentally, the main portion of the hole GBH does not extend through the rubber bushes GB1 and GB2, but at least the rubber bush GB2 at the cable extraction side is formed with a smaller-diameter through hole which has communication with the smaller hole Hs of the hole GBH so as to extract the lamp cable LPC2 from the rubber bush GB2. When the two lamp cables are to be extracted in one direction with that construction, according to the prior art, there is no space for threading the lamp cables, and the lamp cables are not threaded through the rubber bushes, so that the lamp cables bulge out of the module. According to the present embodiment, however, the lamp cable LPC1 does not bulge out of the lower casing MCA so that the module MDL can have its space reduced. As a result, the module MDL can be small-sized and light-weighted to reduce the production cost. Since, moreover, both the fluorescent tube LP and the lamp cables LPC are held by the rubber bushes GB1 and GB2, these rubber bushes GB1 and GB2 holding the fluorescent tube LP are held by the holding forces of the lamp cables LPC so that the holdability of the fluorescent tube LP can be improved. Incidentally, the rubber bush GB1 holds the fluorescent tube LP and one lamp cable LPC1, and the rubber bush GB2 holds the fluorescent tube LP and the two lamp cables LPC1 and LPC2. In order to reduce the kinds of parts, however, the rubber bush GB1 used is given a shape similar to that of the rubber bush GB2.
Incidentally, the holes or grooves, which are formed in the rubber bushes GB1 and GB2 for holding the fluorescent tube LP and the lamp cables LPC, should not have their shapes limited to the shown ones. For example, the holes or grooves for holding the fluorescent tube LP and the two lamp cables LPC may be made independent, or the holes or grooves of the fluorescent tube LP and one or two lamp cables LPC may be suitably shared. Moreover, the rubber bush GB1 and the rubber bush GB2 used may have different shapes such that the rubber bush GB1 is formed with a hole or groove for holding one lamp cable LPC1 whereas the rubber bush GB2 is formed with a hole or groove for holding the fluorescent tube LP and the two lamp cables LPC1 and LPC2.
<<Accommodations of Fluorescent Tube LP, Lamp Cables LPC and Rubber Bushes GB in Lower Casing MCA>>
FIG. 39(A) is a top plan view showing the state in which the back light BL (including the fluorescent tube LP, the lamp cables LPC, the rubber bushes GB and the light guide plate GLB) in the lower casing MCA; FIG. 39(B) is a section taken along line B—B of FIG. 39(A); and FIG. 39(C) is a section taken along line C—C of FIG. 39(A).
In
The back light BL is accommodated, as shown in FIGS. 39(A) to 39(C), in the lower casing MCA or the back light accommodating casing. Specifically, the rubber bushes GB1 and GB2 holding the fluorescent tube LP and the lamp cables LPC are fitted in the accommodation portion MG, which is formed to snugly fit the rubber bushes GB1 and GB2, as shown in
Incidentally, one fluorescent tube LP is arranged in the present embodiment, but two ore more can be arranged and at the shorter side of the light guide plate GLB.
<<Accommodation of Light Guide Plate GLB in Lower Casing MCA>>
The light guide plate of the prior art has many useless regions for the holding purposes in the module and is far larger than the size of the effective light emitting portion. As shown in FIG. 39(A), on the contrary, the light guide plate GLB of the present embodiment has a square (or rectangular) shape so that its entire size can be made as similar to that of the light emitting portion as possible. The light guide plate GLB -has as its three sides snugly held on the inner wall of its accommodating portion of the lower casing MCA and its remaining one side held by the two small projections (or pawls) PJ, which are integrally formed with the lower casing MCA, in the vicinity of the rubber bushes GB on the inner (or upper) face of the lower casing MCA between the light guide plate GLB and the fluorescent tube LP. Those projections PJ prevent the light guide plate GLB from moving toward the fluorescent tube LP and from impinging to break the fluorescent tube LP. Incidentally, the lamp reflecting sheet LS has a rectangular shape, before applied, but has its longer end portion bonded, after applied, to the lower end face of the reflective sheet RS to over the fluorescent tube LP throughout the whole length and its other longer end portion placed on and held by the upper end portion of the prism sheet PRS. The lamp reflecting sheet LS is formed to have a U-shaped section and such a length that it is arranged in the projections PJ. These projections PJ are made as small as possible so that they may not reduce the utilizing efficiency of the light.
Thus, the light guide plate GLB is made as small as the effective light emitting portion so that the electronic parts can be packaged in the space which has been occupied by the light guide plate of the prior art. At the same time, the light guide plate GLB is held by the projections PJ which are made integral with the lower casing MCA so that the it can be held in a small space. As a result, the module MDL can be small-sized and light-weighted to reduce the production cost. In other words, the light emitting efficiency of the light guide plate GLB can be improved while realizing the size reduction of the module MDL.
Incidentally, the projections PJ need not always be made integral with the lower casing MCA, but projections made of separate members of a metal may be attached to the lower casing MCA.
<<Diffusive Sheet SPS>>
The diffusive sheet SPS is placed on the light guide plate GLB to diffuse the light emitted from the upper face of the light guide plate GLB thereby to irradiate the liquid crystal display panel PNL uniformly with the light.
<<Prism Sheet>>
The prism sheet PRS is placed on the diffusive sheet SPS and has a lower smooth face and an upper prism face. This prism face is formed of a plurality of grooves which have V-shaped sections arrayed straight in parallel with each other. The prism sheet PRS is enabled to improve the brightness of the back light BL by collecting the light, which is diffused over a wide angular range from the diffusive sheet SPS, in a direction normal to the prism sheet PRS. As a result, the back light BL can be made to consume a low power so that the module MDL can be small-sized and light-weighted to reduce the production cost.
<<Reflective Sheet RFS>>
The reflective sheet RFS is arranged below the light guide plate GLB to reflect the light emitted from the lower face of the light guide plate GLB toward the liquid crystal display panel PNL.
<<Holding Structure of Light Guide Plate GLB and Liquid Crystal Display Panel PNL>>
As shown in
Here, both the prism sheet PRS and the diffusive sheet SPS are overhung from the light guide plate GLB, but one of them may be overhung. Here, moreover, the overhang is made over the whole periphery on four sides of the light guide plate GLB, but an effect can be achieved even the overhand is at one to three sides.
<<Holding Structure of Liquid Crystal Display Panel PNL>>
In the liquid crystal display module MDL of the prior art, as shown in
Incidentally, in the embodiment shown in
Although the present invention has been specifically described on the basis of its embodiments, it should not be limited thereto but can naturally be modified in various manners without departing from the gist thereof.
[Effects of the Invention]
As has been described hereinbefore, according to the liquid crystal display device of the present invention, the area of the frame portion around the display can be reduced by arraying the video signal line driving circuit substrate at only one of the sides of a display panel, so that the liquid crystal display device and the data processing device having the former assembled therein can be small-sized and light weighted. Moreover, the display unevenness can be prevented to improve the display quality, and the holding force of the liquid crystal panel in the device can be increased. As a result, the mechanical strength can be improved to improve the reliability. Thanks to the excellent using efficiency of the space for accommodating the fluorescent tube, still moreover, the liquid crystal display device can have its external size reduced so that it can be small-sized and light-weighted to reduce the production cost.
According to the present invention, on the other hand, the light guide plate and the liquid crystal display panel can be firmly held in the device without enlarging the external size to improve the mechanical strength. At the same time, the device can be small-sized and light-weighted to reduce the production cost. Since, moreover, the cables of the fluorescent tube of the back light can be accommodated without bulging out of the device, this device can be small-sized and light-weighted to reduce the production cost. Still moreover, it is possible to improve the holdability of the fluorescent tube. Furthermore, the light guide plate of the back light can be held in the small space so that the device can be small-sized and light-weighted to reduce the production cost. Furthermore, the bottom face of the mold casing has its central portion formed with a large opening so that it can be prevented from bulging out to reduce the size and weight of the liquid crystal display device. Furthermore, the cables and the inverter of the back light can be accommodated without bulging out of the device so that the liquid crystal display device can be small-sized and light-weighted to reduce the production cost.
According to the present invention, on the other hand, it is possible to provide a liquid crystal display device having such a circuit as can improve not only the heat liberation of the exothermic portions, the highly dense packageability of the circuit and the compactness and as can realize the multi-gradation, the single power source and the compact packaging. Moreover, the number of electronic parts can be reduced to reduce the cost for the material and the number of working steps. As a result, the production cost can be reduced to improve the reliability of the product.
According to the present invention, on the other hand, the plate extracting efficiency of the circuit substrate is enhanced to reduce the cost for the material of the circuit substrate thereby to reduce the production cost for the liquid crystal display device. Moreover, a plurality of circuit substrates can be electrically connected with a small space so that the liquid crystal display device can be small-sized and light-weighted to reduce the production cost and to take an advantage in the high performance of the device. Even in case, still moreover, the liquid crystal display device is formed at its intermediate portion with a mounting hole for mounting it in an appliance such as a personal computer, the drawn portion of the metallic casing to be formed with the mounting hole can be generally reduced to a quadrant shape. As a result, the liquid crystal display device can be small-sized and light-weighted to reduce the production cost.
According to the present invention, on the other hand, the pawls, as made integral with the side face of the metallic shield casing, are connected with the frame ground pads on the circuit substrate, as connected with the ground wiring lines. As a result, the harmful radiative electric waves can be suppressed, and the folding and soldering workability of the pawls can be improved to improve the connection reliability. Still moreover, the casing of the liquid crystal display device has its corner firmly held and fixed through the mounting holes by the screws or the like so that the mechanical strength is improved to improve the product reliability. Furthermore, a plurality of electronic parts for counter-measures of the EMI are arranged concentratedly on the circuit substrate so that the dead space can be reduced to package the electronic parts highly densely. As a result, the liquid crystal display device can be small-sized and light-weighted to reduce the production cost.
Imajo, Yoshihiro, Suzuki, Masahiko, Hasegawa, Kaoru, Toriyama, Yoshio, Kobayashi, Naoto, Yarita, Katsuhiko, Kondo, Hironori
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Jul 01 2003 | HITACHI DEVICE ENGINEERING CO , LTD | HITACHI ELECTRONIC DEVICES CO , LTD | DIVISION | 021194 | /0871 | |
Jul 01 2003 | HITACHI ELECTRONIC DEVICES CO , LTD | Hitachi Displays, Ltd | MERGER SEE DOCUMENT FOR DETAILS | 021205 | /0016 | |
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Apr 28 2008 | Hitachi, LTD | Hitachi Displays, Ltd | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 021205 | /0263 | |
Jun 30 2010 | Hitachi Displays, Ltd | IPS ALPHA SUPPORT CO , LTD | COMPANY SPLIT PLAN TRANSFERRING FIFTY 50 PERCENT SHARE OF PATENTS | 027063 | /0019 | |
Oct 01 2010 | IPS ALPHA SUPPORT CO , LTD | PANASONIC LIQUID CRYSTAL DISPLAY CO , LTD | MERGER SEE DOCUMENT FOR DETAILS | 027063 | /0139 |
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