JP2009300582A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent influence of external light made incident from the aperture of one liquid crystal panel on video display of the other liquid crystal panel while using a light source in common with both liquid crystal panels in a liquid crystal display device including display surfaces on both front and rear surfaces. <P>SOLUTION: U-shaped cathode-ray tubes 17a1 to 17a4 are disposed between the liquid crystal panels 10a and 10b so that the legs thereof are arranged in a direction nearly vertical to the display surfaces of the liquid crystal panels 10a and 10b, bending ends and electrode ends of the U-shaped cathode-ray tubes are positioned on outer sides of display regions of the liquid crystal panels 10a and 10b, a reflection plate 17b is disposed between respective legs of the U-shaped discharge tubes to shield light and light radiated from respective legs of the U-shaped discharge tubes is reflected on only rear surfaces of the corresponding liquid crystal panels. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that includes a first liquid crystal panel and a second liquid crystal panel that are arranged back to back and displays an image on each liquid crystal panel.

Conventionally, as this type of liquid crystal display device, a liquid crystal display device disclosed in Patent Document 1 and a (double-sided display type) liquid crystal display device disclosed in Patent Document 2 are known.
In the liquid crystal display device disclosed in Patent Document 1, the first liquid crystal display panel and the second liquid crystal display panel are housed back to back in a housing, and the first liquid crystal display panel and the second liquid crystal display panel are Between the two, a backlight unit is disposed and shared, and the display driving unit has two display driving units in a hierarchical configuration at the bottom of the device corresponding to the first liquid crystal display panel and the second liquid crystal display panel. A circuit is provided.
In the liquid crystal display device disclosed in Patent Document 2, two liquid crystal panels are arranged corresponding to the front and back surfaces of the double-sided backlight device, respectively.
JP-A-6-289384 JP 2005-107071 A

  The above-mentioned conventional liquid crystal display device has screens on both the front and back sides, and can be viewed from a wide range of surroundings. It can be used. However, in the above-described conventional liquid crystal display device, the front and rear liquid crystal panels share a backlight. Therefore, external light may enter the opening of one liquid crystal panel, mix with backlight light, and affect the display of the other liquid crystal panel.

  The present invention has been made in view of the above problems, and includes a first liquid crystal panel and a second liquid crystal panel arranged back to back, and a liquid crystal display device that displays an image on each liquid crystal panel. An object of the present invention is to provide a liquid crystal display device in which external light incident from the opening of one liquid crystal panel does not affect the image display of the other liquid crystal panel while sharing a light source.

  In order to solve the above problems, in the liquid crystal display device of the present invention, the back surfaces are opposed to each other with a predetermined interval, and the display surfaces are substantially aligned so that the display surfaces are substantially parallel to each other. In a liquid crystal display device that includes the first liquid crystal panel and the second liquid crystal panel, and displays an image on each liquid crystal panel, the bent end and the electrode end are positioned outside the display area of each liquid crystal panel. A U-shaped discharge tube disposed between the first and second liquid crystal panels; and a reflector having a size that blocks at least a display area of each of the liquid crystal panels. In the discharge tube, the alignment direction of the legs is substantially perpendicular to the liquid crystal panel surface, and the reflector is disposed between the legs of the U-shaped discharge tube. The light between each leg is shielded, and the light emitted from each leg is liquid crystal panel on the corresponding side. It is constituted to be reflected toward the Le rear.

  In the liquid crystal panel, a side on which an image is displayed is a display surface, and a side on which light from the backlight is irradiated is a back surface. The liquid crystal display device of the present invention is a so-called direct-type backlight system, and displays an image using light emitted from a light source disposed on the back side of the liquid crystal panel. The predetermined interval between the liquid crystal panels may be an interval necessary for arranging the U-shaped discharge tube and the reflecting plate. The U-shaped discharge tube is a discharge tube in which a discharge tube is bent substantially in half and an electrode for applying a power supply voltage to the discharge tube is aligned at one end to form a U shape. The bent portion of the U-shaped discharge tube is the bent end, and the side where the electrodes are aligned is the electrode end. Each straight portion extending to each electrode with the bent end of the U-shaped discharge tube as a boundary is used as a leg. The discharge tube includes a hot cathode fluorescent tube and a cold cathode fluorescent tube.

  There is a gap between the legs of the U-shaped discharge tube, and a flat reflector is inserted into the gap. As a result, one leg of the U-shaped discharge tube is located on each side of the reflector, and the direction in which the legs of the U-shaped discharge tube are arranged and the display surface of each liquid crystal panel are substantially parallel. Become. The reflecting plate shields light between the legs of the U-shaped discharge tube, reflects light emitted from one leg to the back of the liquid crystal panel on the one leg side, and It has reflectivity to reflect the emitted light to the back surface of the liquid crystal panel on the other leg side. The reflection plate reflects not only light emitted from the U-shaped discharge tube but also external light incident from the opening of the liquid crystal cell of the liquid crystal panel toward the liquid crystal panel on which the external light is incident.

  The first liquid crystal panel and the second liquid crystal panel have the vertical direction and the left-right direction matched when the direction perpendicular to the panel surface is the depth direction, and U is located at a position where light emission can be effectively used on one panel surface. When the U-shaped discharge tube is disposed, the U-shaped discharge tube is disposed at a position where the light emission can be effectively used also on the other panel surface. Further, since the light emission amount of the bent end and the electrode end is different from that of the straight line portion, these end portions are positioned outside the display area where the image of the liquid crystal panel is displayed and are not used for display. This prevents uneven brightness of the liquid crystal panel.

  As a selective one aspect of the present invention, the first engagement portion that supports the bent end of the U-shaped discharge tube and the second engagement portion that supports the electrode end of the U-shaped discharge tube include the reflection. The first engagement portion and the second engagement portion are formed integrally with a plate so that the arrangement direction of the legs of the U-shaped discharge tube and the display surface of the liquid crystal panel are substantially perpendicular to each other. It is good also as a structure which supports the said U-shaped discharge tube. That is, in the liquid crystal display device, the first engagement portion and the second engagement portion that are integrally formed with the reflector are not provided separately for supporting the U-shaped discharge tube at a predetermined position. Supports the U-shaped discharge tube at a predetermined position. According to this configuration, the reflector and the U-shaped discharge tube can be handled integrally, and the assembly work of the liquid crystal display device is facilitated.

  As a selective one aspect of the present invention, a rectangular frame body having upper, lower, left and right surfaces is provided, and the reflecting plate partitions the substantially center in the front-rear direction inside the rectangular frame body, and the U-shape is formed on the left and right side surfaces of the rectangular frame body. It is good also as a structure which formed the some hole which penetrates each leg of a character-shaped discharge tube, and was set as the said 1st engaging part and the said 2nd engaging part. The holes formed in the left and right side surfaces of the rectangular frame correspond to the first engaging portion and the second engaging portion. In assembling the liquid crystal display device, the U-shaped discharge lamp has each electrode end inserted into the hole from the outside of the first engaging portion of the rectangular frame, and the reflector is positioned between the legs as it is. The electrode end is protruded from the hole of the second engaging portion to the outside of the rectangular frame. That is, the bent end and the electrode end of the U-shaped discharge tube are located outside the rectangular frame, and prevent unevenness of light irradiated on the back surface of the liquid crystal panel. Further, the rectangular frame and the reflector plate surround the display area of each liquid crystal panel from the back, and light emitted from each leg of the U-shaped discharge tube does not leak to the other leg side. .

  As a selective one aspect of the present invention, the U-shaped discharge tube is formed by connecting one end of two straight tubes with electric wires and bending the electric wires so that the respective straight tubes are substantially parallel. Also good. Since a straight tube is used, the U-shaped discharge tube can be realized at low cost, and the bent end of the U-shaped discharge tube is realized by an electric wire instead of a glass tube. It is.

  As a selective aspect of the present invention, the luminance information of the video signal for one screen is acquired, the luminance and contrast of the video signal are adjusted based on the luminance information, and the U-shape is determined based on the luminance information. A brightness adjusting means for adjusting the brightness of the discharge tube may be further provided, and the same image may be displayed on the first liquid crystal panel and the second liquid crystal panel. If the images displayed on the first liquid crystal panel and the second liquid crystal panel are the same, at least the average luminance is the same. Therefore, the luminance and contrast of the video signal can be adjusted based on the luminance information of the video signal, and the luminance of the U-shaped discharge tube can be adjusted in accordance with the adjustment of the video signal.

  In addition, it is more preferable that the U-shaped discharge tube is disposed long on the left and right. The reason for this is that the images displayed on the first liquid crystal panel and the second liquid crystal panel are horizontally reversed, but the top and bottom are the same, and each U-shaped fluorescent tube is long and has a substantially constant height. This is because, even if different brightness is adopted for each U-shaped discharge tube, the horizontally reversed image is not affected.

As described above, according to the present invention, in a liquid crystal display device having display surfaces on both front and rear surfaces, external light incident from the opening of one liquid crystal panel is shared by the liquid crystal panel while the light source is shared by both liquid crystal panels. It is possible to provide a liquid crystal display device that can prevent the video display from being affected.
According to the second aspect of the invention, the reflector and the U-shaped discharge tube can be handled integrally, and the assembly work of the liquid crystal display device is facilitated.
According to the invention of claim 3, the reflector and the U-shaped discharge tube can be handled integrally, and the assembly work of the liquid crystal display device is facilitated. Each leg of the U-shaped discharge tube The light emitted from the other side does not leak to the other leg side.
Furthermore, the invention according to claim 4 is easy to handle because there is no breakage during assembling work or transportation.
Further, according to the fifth aspect of the present invention, it is possible to prevent black floating and increase the image quality, and further reduce power consumption.
And according to the invention concerning Claim 6, there exists an effect similar to 1,2,3,5,6 mentioned above.

Hereinafter, embodiments of the present invention will be described in the following order.
(1) Configuration of the liquid crystal display device:
(2) Configuration of backlight:
(3) Modification of U-shaped fluorescent tube:
(4) Modification of backlight:
(5) Summary:

(1) Configuration of the liquid crystal display device:
FIG. 1 is a front view and a rear view of a liquid crystal display device 100 according to an embodiment of the present invention. As shown in the figure, the liquid crystal display device 100 has rectangular openings on both front and rear sides of the cabinet C, the display surface of the liquid crystal panel 10a is exposed from the front opening, and the display surface of the liquid crystal panel 10b is exposed from the rear opening. Is exposed. The cabinet C is supported by a stand S so that the display surface of the liquid crystal panel is oriented substantially vertically.

  Images are displayed on the display surfaces of the liquid crystal panel 10a and the liquid crystal panel 10b, respectively. Although it is preferable to display the same image on each display surface as will be described later, it goes without saying that different images may be displayed on each liquid crystal panel. When the same image is displayed on each display surface, the surrounding angle at which the liquid crystal display device can be viewed is doubled. Therefore, the display device according to the present invention can be arranged in the center of the store when displaying the advertisement image at the store, and the advertising effect per video display device can be enhanced. In the following embodiment, an example in which the same image is displayed on each liquid crystal panel will be described.

  FIG. 2 is a block diagram showing a schematic electrical configuration of the liquid crystal display device 100. In FIG. 1, a liquid crystal display device 100 includes an input terminal 19 to which a video signal and an audio signal are input, a video processing unit 11 that performs various video processes on the input video signal, and a liquid crystal based on the input video signal. A first driving circuit 12a that generates a panel driving signal, a first liquid crystal panel 10a in which the aperture ratio of each liquid crystal cell is controlled by a liquid crystal panel driving signal output from the first driving circuit 12a, and an input video A second drive circuit 12b that generates a liquid crystal panel drive signal based on the signal; a second liquid crystal panel 10b in which the aperture ratio of each liquid crystal cell is controlled by the liquid crystal panel drive signal output from the second drive circuit 12b; The sound processing unit 15 that controls the frequency characteristics and signal strength of the input sound signal, the speaker 16 that reproduces sound based on the sound signal, the first liquid crystal panel 10a and the first liquid crystal panel 10a A backlight 17 that is disposed between the liquid crystal panels 10b and irradiates light from the back surfaces of the two liquid crystal panels; an inverter circuit 18 that supplies power to the backlight 17 to turn on the backlight; and various power supply voltages A power supply circuit 20 that generates and supplies each part of the liquid crystal display device and a control circuit 13 that controls the liquid crystal display device are provided. In FIG. 2, configurations and connection relationships unnecessary for the following description are omitted.

  In the above configuration, the video processing unit 11 performs various video processes on the video signal input from the input terminal 19. More specifically, the video processing unit 11 digitizes the input video signal according to the signal level and performs matrix conversion processing based on the luminance signal and the color difference signal extracted from the video signal, thereby RGB (red, green, blue) signals as data are generated. Then, the RGB signal is subjected to a scaling process in accordance with the number of pixels (aspect ratio, m: n) of the first and second liquid crystal panels 10a and 10b, and the first and second liquid crystal panels 10a and 10b. Video data for one screen to be displayed is generated, and the generated video data is output to the first drive circuit 12a and the second drive circuit 12b. In the present embodiment, the first liquid crystal panel 10a and the second liquid crystal panel 10b have the same number of pixels.

  Further, in the present embodiment, in addition to the above configuration, a luminance detection circuit 14 that obtains the maximum value, the minimum value, the average value, etc. of the luminance for each screen of one field or one frame of the input signal may be provided. Good. The luminance detection circuit 14 outputs the calculated luminance value to the control circuit 13. The maximum value, minimum value, average value, and the like of the luminance for each screen correspond to the luminance information of the present invention.

  The control circuit 13 is configured by a microcomputer or the like, calculates an image quality control amount based on luminance information, and controls the contrast and luminance of the video signal in the video processing unit based on the image quality control amount. Further, the control circuit 13 obtains a luminance control amount of the backlight 17 based on the luminance information, and controls the luminance of the backlight 17 through the inverter circuit 18. In other words, the control circuit 13 controls the luminance of the backlight 17 in conjunction with the control of the contrast and luminance of the video signal, solves problems such as “black floating”, achieves high image quality, and reduces power consumption. To do. That is, based on the luminance information output from the luminance detection circuit 14, the control circuit 13 that controls the contrast and luminance of the video signal and the luminance control of the backlight 17 constitutes the luminance adjusting means in this embodiment.

  Note that the liquid crystal display device 100 according to the present embodiment is realized as a liquid crystal television having a tuner to which a television broadcast signal is input, or a reading that reads and reproduces a video signal or an audio signal from a disk recording medium such as an optical disk or a hard disk. It may be configured to include a playback unit, or may be arbitrarily combined with other known techniques.

(2) Configuration of backlight:
The backlight 17 of the present invention generally corresponds to a configuration in which two direct type backlights are arranged back to back. However, not only the two backlights are arranged back to back, but the backlight 17 of the present invention shares the reflector and discharge lamp used for each backlight when the two backlights are arranged back to back. There is a feature. Hereinafter, a backlight sharing a reflector and a discharge lamp will be described.

  FIG. 3 is a cross-sectional view of the liquid crystal display device 100 of FIG. 1 cut along the line AA. As shown in the figure, in the liquid crystal display device 100, the liquid crystal panel 10a and the liquid crystal panel 10b have their display surfaces facing outward, the display surfaces are substantially parallel, and the back surfaces face each other with a predetermined interval between the panels. The vertical and horizontal positions of the display surface are substantially matched. A light control sheet (a diffusion sheet that diffuses light, a lens sheet that collects light diffused by the diffusion sheet on the back of the liquid crystal panel, a polarizing plate, and the like) is disposed in close contact with the back of each liquid crystal panel. A backlight is disposed between the light control sheets.

  FIG. 4 shows that the cabinet C and the stand S of the liquid crystal display device 100 are removed, and the backlight 17, the liquid crystal panels 10a and 10b, the inverter circuit board B1, the video / audio processing board B2, and the drive circuit boards B3 to B6 are disassembled. It is the shown perspective view. In the figure, the backlight 17 roughly includes U-shaped fluorescent tubes 17a1 to 17a4 and a reflecting plate 17b. These U-shaped fluorescent tubes 17a1 to 17a4 correspond to the U-shaped discharge tube of the present invention.

  The reflection plate 17b is slightly wider than the display surfaces of the liquid crystal panels 10a and 10b, and is disposed at a position that blocks between the display surfaces of the liquid crystal panels. The reflection plate 17b is made of, for example, a white resin and has high reflectance and light shielding properties. That is, the reflecting plate 17b reflects the light emitted from the U-shaped fluorescent tubes 17a1 to 17a4 toward the reflecting plate 17b to the back of each liquid crystal panel, the light on the liquid crystal panel 10a side, and the liquid crystal panel 10b side. It has the effect | action which shields light so that it may not mix with light. External light incident from the outside of the liquid crystal panel through the opening of the liquid crystal cell is blocked by the reflecting plate 17b and is not reflected on the opposite liquid crystal panel.

  The U-shaped fluorescent tubes 17a1 to 17a4 are discharge tubes formed so that one discharge tube is bent substantially in half and two electrodes are arranged at one end. That is, one end is a portion where the glass tube is bent, and the other end is a portion where two electrodes are arranged side by side. Hereinafter, a bent end of the U-shaped fluorescent tube is referred to as an electrode end, an end where the electrodes are arranged side by side is referred to as a bent end, and a portion extending linearly from the bent end to each electrode end is referred to as a leg. To.

  In the stand S, an inverter circuit board B1 and a video / audio processing board B2 are arranged. In the present invention, since the board configuration assumes analog video / audio signal input, in FIG. 4, the video / audio processing board B2 is provided with video / audio input terminals and is in charge of analog video signal processing and analog audio signal processing. The analog board is divided into a digital board that performs A / D conversion on the input analog video signal and performs digital video signal processing. The digital board also serves as a timing controller for driving the liquid crystal panel. Control signals (data start pulse (DSP), data clock (DCK), gate start pulse (GSP), gate clock ( GCK)) and the data signal are transmitted to the drive circuit through a digital high-frequency transmission cable such as LVDS (Low voltage differential signaling).

  The drive circuit in the present embodiment includes a first drive circuit 12a that drives the first liquid crystal panel 10a and a second drive circuit 12b that drives the second liquid crystal panel 10b. The first drive circuit 12a includes a data driver and a gate driver. The data driver is mounted on the drive circuit board B3 and disposed on the lower surface of the first liquid crystal panel 10a. The gate driver is mounted on the drive circuit board B4. The first liquid crystal panel 10a is arranged on either one of the left and right side surfaces. On the other hand, the second drive circuit 12b also includes a data driver and a gate driver. The data driver is mounted on the drive circuit board B5 and disposed on the lower surface of the first liquid crystal panel 10b, and the gate driver is provided on the drive circuit board B6. It is mounted and arranged on either the left or right side surface of the first liquid crystal panel 10b.

  Two LVDS cables are led out from the digital board, and each LVDS cable is connected to the drive circuit board B3 and the drive circuit board B5, respectively. The drive circuit board B3 and the drive circuit board B4, and the drive circuit board B5 and the drive circuit board B6 are each connected by a digital high-frequency transmission cable. The control signal and the data signal are input to the drive circuit board B3 and the drive circuit board B5 through each LVDS, and a gate start pulse (GSP) and a gate clock (GCK) necessary for the gate driver among the control signals are supplied to the drive circuit. The signal is transmitted to the substrate B4 and the drive circuit substrate B6.

  The video / audio processing board B2 is also equipped with a power supply circuit 20, and the inverter circuit board B1 supplied with the power supply voltage generated by the power supply circuit 20 generates a high-frequency AC voltage and solves the inverter harness. Then, an inverter voltage is supplied to each U-shaped fluorescent tube. In this embodiment, the inverter circuit board B1 is arranged inside the stand S. However, the inverter circuit board B1 may be arranged inside the cabinet C. For example, when the U-shaped fluorescent tubes 17a1 to 17a4 are arranged on the electrode end side, the length of the inverter harness connecting the inverter circuit board B1 and the U-shaped fluorescent tubes 17a1 to 17a4 can be shortened, and the cost can be reduced. In addition, since a high-frequency AC voltage is supplied to the U-shaped fluorescent tubes 17a1 to 17a4, unevenness of the harness length connected to each U-shaped hair fluorescent tube may cause flickering, but the harness length is shortened. This makes it easier to prevent flickering.

  FIG. 5 is a perspective view of the backlight 17 in a state where a U-shaped fluorescent tube is set on the reflector, and FIG. 6 is a front view, a top view, a right side view, and a left side view of the backlight 17 of FIG. The backlight 17 includes a rectangular frame 17c having upper, lower, left and right side surfaces, a reflecting plate 17b that partitions the approximate center of the rectangular frame 17c in the front-rear direction, and U-shaped fluorescent tubes 17a1 to 17a4. A plurality of holes through which the legs of the U-shaped fluorescent tubes are passed are formed on the left and right side surfaces of the rectangular frame 17c. One pair of holes is formed at each height at the same height on the front and back sides of the reflector 17b, and four pairs are formed corresponding to the U-shaped fluorescent tubes 17a1 to 17a4. In the present embodiment, the holes formed in the rectangular frame 17c constitute a first engagement portion and a second engagement portion.

  To attach the U-shaped fluorescent tubes 17a1 to 17a4 to the rectangular frame 17c, the two electrode ends of the U-shaped fluorescent tube are respectively inserted into a pair of holes on the left side of the rectangular frame 17c, and the right side of the same height The electrode ends are projected from a pair of holes in the surface. As a result, both legs of the U-shaped fluorescent tube are supported at substantially the same height before and after the partition plate, so that the alignment direction of the legs of the U-shaped fluorescent tube is substantially perpendicular to the liquid crystal panel surface. Be placed. The bent end of the U-shaped fluorescent tube is outside the left side surface of the rectangular frame 17c, and the electrode end protrudes outside the right side surface of the rectangular frame 17c. Similarly, a plurality of U-shaped fluorescent tubes are arranged on the reflector at different heights. As a result, the bent end of the U-shaped fluorescent tube is located slightly outside the liquid crystal panel display area. That is, the light at the bent end is not used as light for irradiating the liquid crystal panel.

  In FIG. 5, the number of U-shaped fluorescent tubes is four, but any number of two or more can be adopted. Regardless of the number of U-shaped fluorescent tubes, each U-shaped fluorescent tube is arranged at regular intervals above and below, and irradiates light uniformly on the display area of the liquid crystal panel. The reflection plate 17b and the rectangular frame 17c may be made of metal or resin as long as it reflects light easily, and is made of, for example, white resin. The electrode ends of the U-shaped fluorescent tube are arranged so as to be aligned with one side surface of the reflector.

  According to the above configuration, one leg of one U-shaped fluorescent tube irradiates the liquid crystal panel 10a, and the other leg irradiates the liquid crystal panel 10b. Therefore, the luminance distribution of each liquid crystal panel is substantially the same. When the same image is displayed on both liquid crystal panels and the luminance and contrast control of the video signal and the luminance control of the backlight are executed based on the luminance value detected by the luminance detection circuit 14, the black floating of the image is prevented. Therefore, if the image is dark, the brightness of the backlight can be reduced, so that power consumption can be reduced.

(3) Modification of U-shaped fluorescent tube:
FIG. 7 is a perspective view showing a modification of the U-shaped fluorescent tube of the present invention. The U-shaped fluorescent tube is not necessarily formed by bending one discharge lamp, and may be realized by combining two straight tube discharge lamps. One end of each of the two discharge lamps is connected by an electric wire to be a portion corresponding to the bent end, and an end of each discharge lamp that is not connected is a portion corresponding to the electrode end. That is, a pseudo U-shaped fluorescent tube is created from two straight tubes. The pseudo U-shaped fluorescent tube is resistant to breakage of the bent end due to vibration or the like, and the unit price is lower than that of a U-shaped fluorescent tube formed by bending glass. That is, handling becomes easy and the cost can be reduced.

(4) Modification of backlight:
In the above embodiment, the description has been made by adopting the rectangular frame 17c for the backlight 17, but the structure of the backlight 17 is not limited to this. For example, the structures of FIGS. 8 and 9 and the structures of FIGS. 10 and 11 can be employed.
The structure of FIG. 8 has a shape in which the top and bottom surfaces are removed from the rectangular frame of the above embodiment, and FIG. 9 is a front view, a right side view, a left side view, and a top view of the backlight of FIG. With the structure of FIGS. 8 and 9, the material cost of the rectangular frame can be reduced while achieving the effects of the above embodiment.
10 is a structure without the rectangular frame itself of the above embodiment, and FIG. 11 is a front view, a right side view, and a top view of the backlight of FIG. 10 and 11, a notch is formed in the left end portion of the reflector, and the bent end of the U-shaped fluorescent tube is engaged with the notch. Further, a protrusion that engages with the U-shaped fluorescent tube is formed in the vicinity of the right end of the reflecting plate, and a portion close to the electrode end of the U-shaped fluorescent tube is supported at a predetermined height. According to this configuration, it is possible to delete the rectangular frame and reduce the material cost of the rectangular frame.

(5) Summary:
According to the embodiment described above, the arrangement direction of the legs of the U-shaped cathode tubes 17a1 to 17a4 arranged between the liquid crystal panels 10a and 10b is substantially perpendicular to the display surface of the liquid crystal panels 10a and 10b. The bent end and electrode end of the U-shaped cathode tube are positioned outside the display area of the liquid crystal panels 10a and 10b, and the reflector 17b is disposed between the legs of the U-shaped discharge tube to shield the light. The light emitted from each leg of the discharge tube is reflected only on the back surface of the corresponding liquid crystal panel. Therefore, in a liquid crystal display device with display surfaces on both the front and back sides, both liquid crystal panels share a light source and prevent external light incident from the opening of one liquid crystal panel from affecting the video display of the other liquid crystal panel. It becomes possible to do.

Needless to say, the present invention is not limited to the above embodiments. It goes without saying for those skilled in the art,
・ Applying mutually interchangeable members and configurations disclosed in the above embodiments by appropriately changing the combination thereof.− Although not disclosed in the above embodiments, it is a publicly known technique and the above embodiments. The members and configurations that can be mutually replaced with the members and configurations disclosed in the above are appropriately replaced, and the combination is changed and applied. It is an embodiment of the present invention that a person skilled in the art can appropriately replace the members and configurations that can be assumed as substitutes for the members and configurations disclosed in the above-described embodiments, and change the combinations and apply them. It is disclosed as.

It is the front view and back view of a liquid crystal display device. It is a block diagram which shows the schematic electric constitution of a liquid crystal display device. It is sectional drawing cut | disconnected and shown along the AA cross section of FIG. It is a schematic exploded perspective view of a liquid crystal display device. It is a perspective view of a backlight. It is the front view, top view, right side view, and left side view of the backlight. It is a perspective view which shows the modification of a U-shaped fluorescent tube. It is a perspective view concerning the 1st modification of a backlight. It is the front view concerning the 1st modification of a backlight, a right view, a left view, and a top view. It is a perspective view concerning the 2nd modification of a back light. It is the front view concerning the 2nd modification of a backlight, a right view, and a top view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10a ... 1st liquid crystal panel, 10b ... 2nd liquid crystal panel, 11 ... Image processing part, 12a ... 1st drive circuit, 12b ... 2nd drive circuit, 13 ... Control circuit, 14 ... Luminance detection circuit, 15 DESCRIPTION OF SYMBOLS ... Audio processing part, 16 ... Speaker, 17 ... Back light, 17a1-17a4 ... U-shaped fluorescent tube, 17b ... Reflector, 17c ... Rectangular frame, 18 ... Inverter circuit, 19 ... Input terminal, 20 ... Power supply circuit, DESCRIPTION OF SYMBOLS 100 ... Liquid crystal display device, B1 ... Inverter circuit board, B2 ... Audio / video processing board, B3 ... Drive circuit board, B4 ... Drive circuit board, B5 ... Drive circuit board, B6 ... Drive circuit board, C ... Cabinet, S ... Stand

Claims (6)

There are provided a first liquid crystal panel and a second liquid crystal panel which are arranged so that the back surfaces thereof face each other with a predetermined interval and the display surfaces are substantially parallel with each other so that the vertical and horizontal positions of the display surfaces are substantially coincident with each other. In a liquid crystal display device that displays an image on each liquid crystal panel,
A U-shaped discharge tube disposed between the first and second liquid crystal panels such that a bent end and an electrode end are positioned outside a display area of each liquid crystal panel;
A reflector having an area that blocks at least the display area of each liquid crystal panel;
Comprising
In the U-shaped discharge tube, the alignment direction of the legs is substantially perpendicular to the liquid crystal panel surface,
The reflector is disposed between the legs of the U-shaped discharge tube to shield between the legs of the U-shaped discharge tube, and the liquid crystal panel rear surface corresponding to the light emitted from the legs A liquid crystal display device that reflects toward the surface. A first engaging portion for supporting a bent end of the U-shaped discharge tube and a second engaging portion for supporting an electrode end of the U-shaped discharge tube are formed integrally with the reflecting plate;
The first engagement portion and the second engagement portion support the U-shaped discharge tube so that the alignment direction of the legs of the U-shaped discharge tube and the display surface of the liquid crystal panel are substantially perpendicular to each other. The liquid crystal display device according to claim 1. It has a rectangular frame with top, bottom, left and right sides,
The reflecting plate partitions the center in the front-rear direction inside the rectangular frame,
The said 1st engaging part and said 2nd engaging part are formed by forming the some hole which penetrates each leg of the said U-shaped discharge tube in the right-and-left side surface of the said rectangular frame. The liquid crystal display device described.   The U-shaped discharge tube is formed by connecting each end of two straight tubes with an electric wire and bending the electric wire so that the straight tubes are substantially parallel to each other. The liquid crystal display device according to item. Luminance adjustment means for acquiring luminance information of a video signal for one screen, adjusting the luminance and contrast of the video signal based on the luminance information, and adjusting the luminance of the U-shaped discharge tube based on the luminance information Further comprising
The liquid crystal display device according to any one of claims 1 to 4, wherein the same image is displayed on the first liquid crystal panel and the second liquid crystal panel. It has a rectangular frame with top, bottom, left and right sides,
The reflecting plate partitions the center in the front-rear direction inside the rectangular frame,
A plurality of holes through which the legs of the U-shaped discharge tube are inserted are formed on the left and right side surfaces of the rectangular frame to obtain luminance information of the video signal for one screen, and the luminance of the video signal is based on the luminance information. And a luminance adjusting means for adjusting the contrast and adjusting the luminance of the U-shaped discharge tube based on the luminance information,
The liquid crystal display device according to claim 1, wherein the same image is displayed on the first liquid crystal panel and the second liquid crystal panel.

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