CN100381912C - Backlight assembly for double-sided display - Google Patents

Abstract

A backlight assembly for a dual-sided display includes a plurality of external electrode fluorescent lamps disposed between two liquid crystal display panels. Each external electrode fluorescent lamp tube comprises a first electrode end and a second electrode end, and the first electrode ends and the second electrode ends are respectively and electrically connected in parallel.

Description

Backlight assembly for double-sided display

technical field

The invention relates to a backlight assembly applied to a double-sided display, in particular to a backlight assembly with a simplified structure.

Background technique

With the advancement of liquid crystal display technology, liquid crystal display panels have been widely used in consumer electronic products such as digital cameras, digital personal assistants (PDAs), mobile phones, and flat-screen thin TVs. The backlight component is one of the key components of the liquid crystal display, which is arranged on the back of a liquid crystal display panel to provide the light source required by the liquid crystal display panel.

Generally speaking, the backlight assembly usually includes a plurality of cold cathode fluorescent lamps (CCFL) arranged in parallel, combined with various optical components (such as diffuser plates, prisms, etc.) to provide a high-brightness and uniform light source for the liquid crystal display panel. Among them, cold cathode fluorescent lamps need a voltage converter (inverter) to supply high-voltage AC voltage. However, because the voltage converter cannot provide the driving voltage required by multiple parallel cold cathode fluorescent lamps at the same time, otherwise the stabilizing capacitor (ballast) in the voltage converter The capacity of the cold cathode fluorescent lamp will be unstable, resulting in uneven brightness of the cold cathode fluorescent lamp. Therefore, basically each cold cathode fluorescent lamp needs to be driven by an independent wire to be electrically connected to a different voltage converter. Difficulties in shell design and configuration of internal components. For a single-sided display with only a single liquid crystal display panel, although the above-mentioned cold cathode fluorescent lamps have many wires, since the single-sided display only needs to provide a single-directional display function, the wires and voltage converters can be arranged in the backlight assembly. Relative to the reflective plate or the rear of the back frame in another direction of the liquid crystal display panel, it will not affect the light-emitting function of the backlight assembly.

However, with the launch of the double-sided display, the above-mentioned wire problem of the CCFL tube cannot be easily solved, which causes difficulties in the design of the casing and the configuration of internal components. The double-sided display is composed of two parallel liquid crystal display panels, and uses the light source provided by the backlight assembly arranged between the liquid crystal display panels to exert the display effect. Therefore, the backlight assembly used in the double-sided display faces the two sides of the liquid crystal display panel. Open state, and cannot be provided with reflectors. In this case, the lead wires of the CCFL tubes cannot be hidden behind the reflector, and the position of the lead wires must be designed separately without affecting the light-emitting function of the backlight assembly. For example, the wires are usually arranged between the outside of the backlight assembly and the liquid crystal display case to avoid blocking the light source generated by the backlight assembly. However, the above-mentioned positions have limited space, and other necessary components of the liquid crystal display, such as the control circuit of the liquid crystal display panel, are originally arranged. In addition, since each cold cathode fluorescent lamp needs an independent voltage converter, it also increases the difficulty and cost of configuring the internal components of the double-sided display.

Referring to FIGS. 1 and 2 , FIG. 1 is a top view of a known backlight assembly 10 applied to a double-sided display, and FIG. 2 is a schematic cross-sectional view of the backlight assembly 10 shown in FIG. 1 . As shown in FIGS. 1 and 2 , the backlight assembly 10 is disposed between two parallel liquid crystal display panels 20 to provide the light source required by the liquid crystal display panels 20 . The backlight assembly 10 includes a frame 12 and a plurality of CCFL tubes 14 arranged in parallel and fixed on the frame 12 , and each CCFL tube 14 includes two electrodes 14A and 14B exposed outside the frame 12 . In addition, the backlight assembly 10 also includes voltage converters 16 having the same number as CCFL tubes 14 for converting DC voltage into high-voltage AC voltage, and each voltage converter 16 utilizes two power supply wires 16A and 16B and corresponding cold cathode fluorescent lamps respectively. The two electrodes 14A and 14B of the cathode fluorescent lamp 14 are electrically connected to supply a suitable driving voltage for the corresponding cold cathode fluorescent lamp 14 . In addition, the backlight assembly 10 generally includes two diffusion plates 18 disposed between the CCFL tubes 14 and the two LCD panels 20 to diffuse the light emitted by the CCFL tubes 14 .

From the above, it can be known that as the number of CCFL tubes 14 increases, the known backlight assembly 10 must be equipped with the same number of voltage converters 16 to provide an appropriate driving voltage. However, the increase in voltage converters 16 not only means an increase in the cost of the liquid crystal display, Moreover, the accommodation space for the voltage converter 16 and the configuration of the power leads 16A and 16B must also be arranged in the casing design, which cannot meet the current requirements for thin, light and small liquid crystal displays. In addition, because the voltage converter 16 is a high-frequency component, it is easy to generate electromagnetic wave interference and affect the normal operation of the liquid crystal display.

Therefore, for the double-sided display, if the number of voltage converters can be reduced, more room can be provided for the design of the casing, so as to meet the market demand for thin, light and small liquid crystal displays, and at the same time, the cost can be effectively reduced.

Contents of the invention

The main purpose of the present invention is to provide a backlight assembly with a simplified structure to solve the disadvantages of known backlight assemblies for double-sided displays.

The first preferred embodiment of the present invention discloses a backlight assembly applied to a double-sided display comprising two parallel liquid crystal display panels, the backlight assembly includes a plurality of external electrode fluorescent lamps (external electrode fluorescent lamp, EEFL), the external electrode The fluorescent tubes are disposed between the two liquid crystal display panels, and each of the external electrode fluorescent tubes includes a first electrode end and a second electrode end, and the first electrode ends and the second electrode ends are electrically connected in parallel.

The second preferred embodiment of the present invention discloses a backlight assembly applied to a double-sided display comprising two parallel liquid crystal display panels, the backlight assembly includes a double-sided flat fluorescent lamp (flat fluorescent lamp), the flat fluorescent lamp It is arranged between the two liquid crystal display panels.

Since the backlight assembly of the present invention uses external electrode fluorescent tubes and flat fluorescent tubes instead of cold cathode fluorescent tubes as the light source of the double-sided display, and the above-mentioned tubes can be driven by a single voltage converter, the voltage converter and power wires can be effectively reduced The number avoids the known difficulties applied to the design of double-sided displays.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and accompanying drawings of the present invention. However, the drawings are only for reference and auxiliary description, and are not intended to limit the present invention.

Description of drawings

FIG. 1 is a top view of a conventional backlight assembly applied to a double-sided display.

FIG. 2 is a schematic cross-sectional view of the backlight assembly shown in FIG. 1 .

FIG. 3 is a top view of a backlight assembly according to the first preferred embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view of the backlight assembly shown in FIG. 3 .

FIG. 5 is a schematic diagram of parallel connection of electrodes of an external electrode fluorescent lamp using a metal electrode.

FIG. 6 is a top view of a backlight assembly according to a second preferred embodiment of the present invention.

FIG. 7 is a schematic cross-sectional view of the backlight assembly shown in FIG. 6 .

Fig. 8 is a perspective view of a plane lamp tube according to the second preferred embodiment of the present invention.

Explanation of reference symbols:

10 Backlight Components 12 Frame

14 cold cathode fluorescent lamps 14A, 14B electrodes

16 Voltage Converter 16A, 16B Power Leads

18 Diffusion plate 20 Liquid crystal display panel

50 Backlight Components 52 Frame

54 External electrode fluorescent tubes 54A, 54B electrodes

56 Voltage Converter 56A, 56B Power Leads

58 Diffusion plate 60 LCD panel

70 Backlight assembly 72 Frame

74 flat lamp 74A, 74B electrode

16 Voltage Converter 76A, 76B Power Leads

78 Diffusion plate 80 LCD panel

Detailed ways

Referring to FIGS. 3 and 4 , FIG. 3 is a top view of a backlight assembly 50 according to a first preferred embodiment of the present invention, and FIG. 4 is a schematic cross-sectional view of the backlight assembly 50 shown in FIG. 3 . As shown in FIG. 3 and FIG. 4 , the backlight assembly 50 is disposed between two parallel liquid crystal display panels 60 to provide the light source required by each liquid crystal display panel 60 . The backlight assembly 50 includes a frame 52 and a plurality of external electrode fluorescent lamp tubes 54 arranged in parallel. Electrodes 54A and 54B. In addition, the backlight assembly also includes a voltage converter 56, which is connected to the electrodes 54A and 54B of the external electrode fluorescent lamps 54 respectively by two power supply wires 56A and 56B, thereby providing the starting voltage required by the external electrode fluorescent lamps 54. . Wherein, each of the external electrode fluorescent lamps 54 of the backlight assembly 50 of the present invention can be provided with a stabilizing capacitor, so a voltage converter 56 can be shared to drive all the external electrode fluorescent lamps 54 . The backlight assembly 50 further includes two diffusion plates 58 respectively disposed between the external electrode fluorescent lamps 54 and the two liquid crystal display panels 60 to diffuse the light source generated by the external electrode fluorescent lamps 54 to achieve a uniform lighting effect. In addition, optical components generally used to improve the luminous efficiency of the backlight assembly, such as prisms and brightness enhancement films, are arranged in the backlight assembly 50 as required.

As shown in Figures 3 and 4, since the backlight assembly 50 of the present invention uses an external electrode fluorescent tube 54 as a light source and is driven by a single voltage converter 56, the electrodes 54A and 54B of each external electrode fluorescent tube 54 are respectively connected in parallel. The power leads 56A and 56B connected to the voltage converter 56 effectively reduce the number of leads. It should be noted that the electrode 54A of the external electrode fluorescent tube 54 shown in FIG. not shown in ), so as to obtain the AC voltage provided by the voltage converter 56 . Wherein, the function of the voltage converter 56 is to provide a high voltage AC voltage to drive the external electrode fluorescent lamp 54 to emit light. The first preferred embodiment of the present invention utilizes a floating driving method, the principle of which is to input reverse-phase voltages respectively on the two electrodes 54A and 54B of the external electrode fluorescent lamp 54 to drive the lighting. For example, if the external electrode fluorescent lamp 54 The lamp voltage is 1KV, then the electrodes 54A and 54B are floatingly driven to apply +0.5KV and −0.5KV AC voltages respectively, thereby driving the external electrode fluorescent lamp 54 .

However, in addition to the parallel connection of the wires to the electrodes 54A and 54B of the external electrode fluorescent lamp 54, other parallel connection methods can also be used to achieve the same effect. Referring to FIG. 5 , FIG. 5 is a schematic diagram of electrodes 54A and 54B of an external electrode fluorescent lamp 54 connected in parallel by a metal electrode 59 . Compared with the parallel connection shown in FIG. 4 , the configuration of the backlight assembly 50 shown in FIG. 5 is substantially the same as that of the backlight assembly 50 shown in FIG. Metal electrodes 59 are used to achieve the effect of parallel connection, and one can be selected for implementation in actual operation.

As mentioned above, since the backlight assembly 50 of the present invention uses the external electrode fluorescent lamp 54 as the backlight light source, only one voltage converter 56 is needed to drive it. In this case, the electrodes 54A and 54B of the external electrode fluorescent lamp 54 only need to be connected in parallel to the power supply wires 56A and 56B of the voltage converter 56 by using a wire or a metal electrode 59 respectively, so the number of voltage converters can be effectively reduced. 56 and the number of wires solve the problems encountered in the application of conventional backlight assemblies to double-sided displays.

Referring to FIGS. 6 and 7 , FIG. 6 is a top view of a backlight assembly 70 according to a second preferred embodiment of the present invention, and FIG. 7 is a schematic cross-sectional view of the backlight assembly 70 shown in FIG. 6 . As shown in FIGS. 6 and 7 , the backlight assembly 70 is disposed between two parallel liquid crystal display panels 80 to provide the light source required by the liquid crystal display panels 80 . The backlight assembly 70 includes a frame 72 and a planar light tube 74 that emits light from both sides. The planar light tube 74 is fixed on the frame 72 , and the planar light tube 74 includes two electrodes 74A and 74B. The backlight assembly also includes a voltage converter 76, which is connected to the electrodes 74A and 74B of the flat lamp 74 by two power wires 76A and 76B, so as to provide a high voltage AC voltage to drive the flat lamp 74. The backlight assembly 70 further includes two diffusion plates 78 respectively disposed between the flat lamp tubes 74 and the two liquid crystal display panels 80 to diffuse the light source generated by the flat lamp tubes 74 to achieve a uniform lighting effect. In addition, optical components generally used to improve the luminous efficiency of the backlight assembly, such as prisms and brightness enhancement films, can be arranged in the backlight assembly 70 as needed. The planar light tube 74 is formed by various types of fluorescent tubes with curved or serpentine structures, so as to provide a high-brightness and uniform planar light source. Referring to FIG. 8 , FIG. 8 is a perspective view of a planar light tube 74 according to a second preferred embodiment of the present invention. As shown in FIG. 8, the planar lamp tube 74 is composed of a fluorescent lamp tube with a curved structure, and is electrically connected to a voltage converter (not shown in FIG. 8) by using the exposed electrodes 74A and 74B. The plate (not shown in FIG. 8 ) increases the uniformity of the light source, so it can produce a uniform light source with the same luminous efficiency as the conventional cold cathode fluorescent tubes arranged in parallel.

From the above, it can be seen that since the backlight assembly 70 only needs to be provided with one flat lamp tube 74, it can exert the luminous efficiency equivalent to several CCFL tubes. In this way, the backlight assembly 70 only needs to use a voltage converter 76 to drive the flat lamp tube 74, which greatly reduces the number of required voltage converters 76 and wires, thus effectively reducing the number of known backlights used in double-sided displays. Difficulties encountered by the component.

Compared with the known technology, the backlight assembly disclosed in the two preferred embodiments of the present invention can effectively reduce the number of voltage converters and wires, so it can solve the problem of how to arrange the voltage converters and wires in the known backlight assembly, and Effectively reduce costs.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the claims of the present invention shall fall within the scope of the patent of the present invention.

Claims (6)

1. A backlight assembly, which is applied to a double-sided display comprising two parallel liquid crystal display panels, the backlight assembly includes: A light-emitting device, the light-emitting device is used to generate a light source, the light-emitting device is a plurality of external electrode fluorescent tubes, each of the external electrode fluorescent tubes includes a first electrode end and a second electrode end, the first electrode end and the second electrode end The terminal is electrically connected to a voltage converter, so that the light emitting device obtains an AC voltage supply; a diffusion plate, the diffusion plate is arranged between the light emitting device and the liquid crystal display panel; and a frame, the frame is fixed with the diffusion plate and the light emitting device, Wherein, the first electrode terminal and the second electrode terminal are exposed outside the frame. 2. The backlight assembly as claimed in claim 1, wherein the first electrode terminals and the second electrode terminals are respectively electrically connected in parallel. 3. The backlight assembly as claimed in claim 1, wherein the voltage converter drives the external electrode fluorescent lamps in a floating manner. 4. The backlight assembly as claimed in claim 2, wherein the first electrode terminals and the second electrode terminals are respectively connected in parallel to a metal electrode. 5. The backlight assembly as claimed in claim 4, wherein each of the metal electrodes is a wire. 6. The backlight assembly as claimed in claim 1, wherein the light emitting device is used for double-side light emitting.

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