JP2008204641A - Field emission lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a field emission lamp capable of illuminating a liquid crystal display device as its back light with low power consumption and high luminance and without causing uneven emission. <P>SOLUTION: In this field emission lamp, a conductor film is provided on the inner surface of a planar front glass 12, a linear cathode conductor 20 with an electron field emitting film 18 and linear gate conductors 22 holding the cathode conductor 20 from its both sides are separated from the inner surface of the front glass 12 and alternately disposed parallel to each other, a planar or grooved rear glass 14 which is in parallel with the front glass 12 while facing it in the rear of the front glass 12 with the cathode conductor 20 placed between, and an anode conductor 26 with a phosphor film 24 is provided on the inner surface of the rear glass 14. In this structure, a high potential is impressed on the anode conductor 26 when the lamp is driven, and the conductor film 16, the cathode conductor 20, and the gate conductor 22 are grounded. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a field emission lamp suitable for use in a backlight that illuminates a liquid crystal display device from the back.

  Liquid crystal display devices are widely used as display devices for a wide range of electronic devices such as televisions, portable terminals, personal computers, electronic notebooks, and camera-integrated VTRs because they are thin, light, and have low power consumption. Unlike a cathode ray tube or a plasma display, a liquid crystal display device does not emit light itself, but displays an image or the like by controlling the amount of light incident from the outside. In such a liquid crystal display device, a backlight for the liquid crystal display device that illuminates the liquid crystal display device is installed on the back surface thereof (see Patent Document 1).

  In the electronic devices, low power consumption is regarded as important, and it is said that the backlight for the liquid crystal display device accounts for about half of the total power consumption of the electronic devices. Therefore, it is important to achieve low power consumption of a backlight for a liquid crystal display device. On the other hand, for example, when a large-sized display screen such as a liquid crystal television is advanced, a demand for low power consumption in a backlight for a liquid crystal display device becomes higher.

  In view of the technical background of such a backlight for a liquid crystal display device, the present applicant intends to reduce the power consumption of the backlight for the liquid crystal display device while simultaneously illuminating the liquid crystal display device with high luminance. Research on backlights for display devices was underway.

By the way, a cold cathode fluorescent lamp (CCFL) has been adopted for a backlight for a liquid crystal display device, and a required luminance is 10,000 cd / m ² in a typical backlight for a liquid crystal display device, and a screen size. Regardless of this, in order to obtain this required brightness, an arc tube (cold cathode tube) is placed on the side of a conventional liquid crystal display device, and a liquid crystal display is made using a reflector, light guide plate, diffusion sheet, prism sheet, etc. The so-called edge-light type backlight that illuminates the device is difficult to obtain the required luminance, and a so-called direct-type arrangement form in which an arc tube is arranged directly under the back portion of the liquid crystal display device is being adopted.

  In view of such circumstances, the present applicant arranges a plurality of cathode conductors with a field electron emission film at a predetermined interval in parallel to the inner surface on the rear side of the planar windshield, and behind the windshield. A field emission lamp has been developed in which a planar rear glass facing the front glass in parallel with the cathode conductor is disposed and an anode conductor with a phosphor film is provided on the inner surface of the rear glass. This field emission lamp is a reflection type having a flat shape, and has a structure that can be used as a direct type backlight that can be compactly arranged on the back of a liquid crystal display device.

  In this field emission lamp, the cathode conductor is arranged on the windshield side as the structure, the anode conductor is arranged on the rear glass side, and electrons are emitted from the field electron emission film from the cathode conductor toward the anode conductor on the rear glass side. The upper phosphor film is excited to emit light, and the emitted light is reflected toward the windshield and emitted in the front direction.

  However, in the above field emission lamp structure, since the cathode conductor is arranged closer to the inner surface on the windshield side, the structure is such that charges are easily charged up on the inner surface of the windshield. The light emission unevenness is likely to occur on the entire outer surface of the windshield.

  Therefore, as a result of various trials to solve the problems of the above structure, the present applicant has been able to complete the present invention described below.

In addition, the present applicant, as a flat type that is not a reflection type, arranges an anode conductor with a phosphor film on a flat front glass inner surface, and on the rear side of the front glass is a flat surface facing the front glass in parallel. Has been developed, and a field emission lamp has been developed in which a linear cathode conductor with a field electron emission film is arranged near the inner surface of the rear glass. As a result of performing various trials on this type of field emission lamp, the present invention described below has been completed.
Japanese Patent Laid-Open No. 06-242439

  That is, the present invention provides a field emission lamp that can illuminate with high brightness without light emission and with low power consumption as a backlight of a liquid crystal display device.

  In the field emission lamp according to the first aspect of the present invention, a conductor film is provided on the inner surface of a flat windshield, and a linear cathode conductor with a field electron emission film is disposed apart from the inner surface of the windshield. A rear glass having a flat or grooved inner surface facing the windshield is disposed behind the windshield with the cathode conductor in between, and an anode conductor with a phosphor film is provided on the inner surface of the rear glass to drive the lamp. In some cases, a high potential is applied to the anode conductor and the conductor film and the cathode conductor are grounded.

  According to the first aspect of the present invention, since the conductor film is provided on the inner surface of the windshield, it is possible to suppress the electrons emitted from the field electron emission film on the cathode conductor surface from being charged up on the inner surface of the windshield. . In this case, since the conductor film is grounded together with the cathode conductor when the lamp is driven, the inner surface of the windshield is not effectively charged up.

  As described above, according to the first aspect of the present invention, the front glass can emit light with reduced light emission unevenness. Therefore, when used as a backlight of a liquid crystal display device, the field emission lamp illuminates with high brightness with low power consumption. Thus, it is possible to provide a field emission lamp that is effective as a backlight that can illuminate the display screen of the liquid crystal display device with high luminance and brightness without unevenness.

  Preferably, a linear gate conductor that sandwiches the cathode conductor from both sides thereof is arranged so that the potential of the gate conductor can be controlled when the lamp is driven.

  Preferably, the gate conductor is grounded when the lamp is driven.

  Preferably, the gate conductor is arranged in parallel with the cathode conductor.

  Preferably, the conductor film is composed of a conductive tin oxide thin film. This conductive tin oxide may or may not contain antimony. Antimony-containing tin oxide (ATO) has low surface resistivity when made into a coating film and excellent conductivity, and high transparency when made into a coating film.

  Preferably, the windshield is made of a conductive glass having antistatic properties.

  The field emission lamp according to the second aspect of the present invention is provided with a mesh conductor film on the inner surface of a planar windshield, and a linear cathode conductor with a field electron emission film is disposed on the mesh conductor film. A rear glass having a planar or grooved inner surface facing the front glass in parallel with the cathode conductor in the back is disposed, and an anode conductor with a phosphor film is provided on the inner surface of the rear glass. A high potential is applied to the anode conductor and the mesh conductor film and the cathode conductor are grounded.

  According to the second aspect of the present invention, since the mesh conductor film is provided on the inner surface of the windshield and the cathode conductor is disposed on the mesh conductor film, it is possible to prevent the windshield inner surface from being charged up by the mesh conductor film. become able to. In this case, since the mesh conductor film is grounded together with the cathode conductor when the lamp is driven, the charge-up can be more effectively prevented and suppressed.

  As a result, according to the second aspect of the present invention, since light emission unevenness is suppressed from the windshield by suppressing the charge-up, when used as a backlight of a liquid crystal display device, low power consumption and high luminance are achieved. It is possible to provide a field emission lamp effective as a backlight that can illuminate a display screen of a liquid crystal display device with high brightness without causing unevenness while taking advantage of the characteristics of the field emission lamp to be illuminated.

  In the field emission lamp according to the third aspect of the present invention, an anode conductor with a phosphor film is disposed on the inner surface of the windshield, a rear glass is disposed behind the windshield, and a conductor film is formed on the outer surface of the rear glass and the rear glass. A linear cathode conductor with a field electron emission film on the inner surface side and a linear gate conductor sandwiching the cathode conductor from both sides are arranged, and a negative potential is applied to the cathode conductor and the gate conductor when the lamp is driven. And a ground potential is applied to the anode conductor on the windshield side and the conductor film on the rear glass.

  According to the third aspect of the present invention, a conductor film is provided on the outer surface of the rear glass. When the lamp is driven, the negative side of the DC power source is applied to the cathode conductor and the gate conductor, and the anode conductor on the front glass side and the conductor film on the rear glass are grounded. Thus, the potential of the cathode conductor disposed on the inner surface of the rear glass is fixed by the conductor film on the outer surface of the rear glass, and charging of the inner surface of the windshield can be suppressed. In this case, safety from contact can be maintained as a whole field emission lamp by grounding the anode conductor on the front glass side and the conductor film of the rear glass.

  As a result, according to the third aspect of the present invention, since light emission unevenness can be suppressed from the windshield by suppressing the charge-up, when used as a backlight of a liquid crystal display device, low power consumption and high luminance are achieved. It is possible to provide a field emission lamp effective as a backlight that can illuminate a display screen of a liquid crystal display device with high brightness without causing unevenness while taking advantage of the characteristics of the field emission lamp to be illuminated.

  ADVANTAGE OF THE INVENTION According to this invention, it can illuminate with high brightness | luminance without light emission unevenness with low power consumption as a backlight of a liquid crystal display device.

  Hereinafter, a field emission lamp according to an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows a front configuration of the field emission lamp of the embodiment, and FIG. FIG. 3 shows a planar configuration of the field emission lamp. However, FIG. 1 schematically shows electrical wiring, a DC power source, and the like for the description of lamp driving.

  With reference to these drawings, the field emission lamp 10 includes a planar windshield 12 and a planar rear glass 14. The front glass 12 and the rear glass 14 are arranged to face each other in parallel with a predetermined interval. The gap between the front glass and the rear glass can be held by a spacer (not shown) or the like. The facing space between the front glass 12 and the rear glass 14 is vacuum-sealed. This vacuum sealing structure is not shown.

  A conductor film 16 is provided on the inner surface of the windshield 12. The conductor film 16 is preferably made of antimony-doped tin oxide conductive powder (ATO).

  A linear cathode conductor 20 with a field electron emission film 18 and a linear gate conductor sandwiching the cathode conductor 20 from both sides thereof are separated from the conductor film 16 on the inner surface of the windshield 12 by a predetermined gap. 22 are arranged alternately in parallel. An anode conductor 26 with a phosphor film 24 is provided on the inner surface of the rear glass 14. The field electron emission film 18 is made of a carbon film formed on the surface of the cathode conductor 20. This carbon film has fine nanometer-order projections such as carbon nanotubes, carbon nanowalls, carbon nanofibers, diamond-like carbon, amorphous diamond, crystalline diamond, graphite, fullerene, acicular carbon film, etc. The electric field can be radiated by applying a high electric field to H.26.

  In the above configuration, when the lamp is driven, a high potential is applied to the anode conductor 26 by the DC power supply 28, and the negative side of the DC power supply 28, the conductor film 16, the cathode conductor 20, and the gate conductor 22 are grounded.

  In the field emission lamp 10 according to the embodiment, the inner surface of the windshield 12 is prevented from being charged up by the conductor film 16 that is grounded when the lamp is driven. When used as a backlight of the device, it can be effectively used as a backlight that illuminates the display screen of the liquid crystal display device evenly.

  Further, since the cathode conductor 20 is sandwiched between the gate conductors 22 from both sides, the gate conductor 22 spreads the electrons emitted from the field electron emission film 18 on the surface of the cathode conductor 20 in the form of voltage application at the time of driving the lamp. It becomes possible to control, and light emission from the phosphor film 24 on the anode conductor 26 can be emitted while restricting the area in the direction of the windshield 12. Therefore, it is useful when the display screen of the liquid crystal display device is divided into a plurality of pixel areas for backlighting, and when the light emitting area with an adjacent field emission lamp is divided.

  FIG. 4 shows a side configuration of a field emission lamp according to another embodiment, and FIG. 5 shows a plan configuration of the field emission lamp. However, FIG. 4 schematically shows electrical wiring, a DC power source, and the like for the description of lamp driving. 4 and 5, the same reference numerals are given to the portions corresponding to those in FIGS. 1 to 3.

  Referring to these drawings, this field emission lamp 10A includes a flat windshield 12 and a flat rear glass 14. The front glass 12 and the rear glass 14 are arranged to face each other in parallel with a predetermined interval. The facing space between the front glass 12 and the rear glass 14 is vacuum-sealed. This vacuum sealing structure is not shown.

  A mesh conductor film 30 is provided on the inner surface of the windshield 12. A linear cathode conductor 20 with a field electron emission film 18 is provided on the mesh conductor film 30.

  An anode conductor 26 with a phosphor film 24 is provided on the inner surface of the rear glass 14.

  In the above configuration, when the lamp is driven, a high potential is applied to the anode conductor 26 by the DC power supply 28, and the negative side of the DC power supply 28, the mesh conductor film 30 and the cathode conductor 20 are grounded. The mesh size of the mesh conductor film 30 is not particularly limited.

  In the field emission lamp 10A of the embodiment, since the mesh conductor film 30 is provided on the inner surface of the windshield 12 and the cathode conductor 20 is disposed on the mesh conductor film 30, the mesh conductor film 30 causes the inner surface of the windshield 12 to It becomes possible to suppress charging up. In this case, since the mesh conductor film 30 is configured to be grounded together with the cathode conductor 20 when the lamp is driven, charge-up can be more effectively prevented and suppressed.

  As a result, in this embodiment, light emission with reduced unevenness from the windshield 12 can be performed by suppressing charge-up, so that when used as a backlight of a liquid crystal display device, low power consumption and high luminance are achieved. It is possible to provide a field emission lamp effective as a backlight that can illuminate a display screen of a liquid crystal display device with high brightness without causing unevenness while taking advantage of the characteristics of the field emission lamp to be illuminated.

  FIG. 6 shows a front configuration of a field emission lamp of still another embodiment. However, FIG. 6 schematically shows electrical wiring, a DC power source, and the like for the explanation of lamp driving. In FIG. 6, parts corresponding to those in FIGS. 1 to 3 are denoted by the same reference numerals.

  Referring to these drawings, this field emission lamp 10B includes a planar windshield 12 and a planar rear glass 14. The front glass 12 and the rear glass 14 are arranged to face each other in parallel with a predetermined interval. The facing space between the front glass 12 and the rear glass 14 is vacuum-sealed. This vacuum sealing structure is not shown.

  A conductor film 32 is formed on the outer surface of the rear glass 14, and the linear cathode conductors 20 with the field electron emission films 18 and the linear gate conductors 22 are alternately arranged on the inner surface side of the rear glass 14. The gate conductor 22 is arranged in such a manner as to sandwich the cathode conductor 20 from both sides thereof.

  When the lamp is driven, the negative side of the DC power supply 28 is applied to the cathode conductor 20 and the gate conductor 22 and the positive side of the DC power supply 28, the anode conductor 26 on the windshield 12 side, and the conductor film 32 of the rear glass 14 are grounded. It is said.

  In this embodiment, a conductor film 32 is provided on the outer surface of the rear glass 14, and when the lamp is driven, a negative potential is applied to the cathode conductor 20 and the gate conductor 22 by a DC power source 28, and the anode conductor 26 and the rear glass on the front glass 12 side. 14 is grounded, so that the potential of the cathode conductor 20 disposed on the inner surface of the rear glass 14 is fixed by the conductor film 32 on the outer surface of the rear glass 14, and the inner surface of the windshield 12 is charged up. Can be suppressed. In this case, safety from contact can be maintained as a whole field emission lamp by grounding the anode conductor 26 on the front glass 12 side and the conductor film 32 of the rear glass 14.

  As a result, in this embodiment, light emission with reduced unevenness from the windshield 12 can be performed by suppressing charge-up, so that when used as a backlight of a liquid crystal display device, low power consumption and high luminance are achieved. It is possible to provide a field emission lamp effective as a backlight that can illuminate a display screen of a liquid crystal display device with high brightness without causing unevenness while taking advantage of the characteristics of the field emission lamp to be illuminated.

  The rear glass 14 has a groove-like inner surface shape as shown in FIG. 7, and the light emitted from the phosphor film 24 is directly emitted from the windshield 12, and is reflected by the anode conductor 26 and emitted from the windshield 12. It is good.

FIG. 1 is a diagram showing a front configuration of a field emission lamp according to an embodiment of the present invention. FIG. 2 is a diagram showing a cross-sectional configuration along the line AA in FIG. FIG. 3 is a diagram showing a planar configuration of the field emission lamp. FIG. 4 is a diagram showing a side configuration of a field emission lamp of another embodiment. FIG. 5 is a diagram showing a planar configuration of the field emission lamp. FIG. 6 is a diagram showing a front configuration of a field emission lamp of still another embodiment. FIG. 7 is a diagram showing a main configuration of the front surface of a field emission lamp according to still another embodiment.

Explanation of symbols

10, 10A, 10B Field emission lamp 12 Front glass 14 Rear glass 16 Conductor film 18 Field electron emission film 20 Cathode conductor 22 Gate conductor 24 Phosphor film 26 Anode conductor

Claims (8)

A conductor film is provided on the inner surface of the planar windshield, and a linear cathode conductor with a field electron emission film is disposed apart from the inner surface of the windshield,
The rear surface of the windshield is placed between the cathode conductor and the rear surface of the inner surface facing the windshield is flat or grooved and the anode conductor with a phosphor film is provided on the inner surface of the rear glass.
A field emission lamp characterized in that a high potential is applied to an anode conductor and a conductor film and a cathode conductor are grounded when the lamp is driven.   2. The field emission lamp according to claim 1, wherein a linear gate conductor sandwiching the cathode conductor from both sides thereof is disposed, and the potential of the gate conductor can be controlled when the lamp is driven.   The field emission lamp according to claim 2, wherein the gate conductor is controlled to a ground potential when the lamp is driven.   4. The field emission lamp according to claim 2, wherein the gate conductor is arranged in parallel with the cathode conductor.   2. The field emission lamp according to claim 1, wherein the conductor film on the inner surface of the windshield is made of a conductive tin oxide thin film.   2. The field emission lamp according to claim 1, wherein the windshield is made of conductive glass having antistatic properties. A net-like conductor film is provided on the inner surface of the planar windshield, and a linear cathode conductor with a field electron emission film is disposed on the net-like conductor film,
A rear glass having a planar or grooved inner surface facing the front glass in parallel with the cathode conductor behind the front glass is disposed, and an anode conductor with a phosphor film is provided on the inner surface of the rear glass,
A field emission lamp characterized in that a high potential is applied to an anode conductor and a mesh conductor film and a cathode conductor are grounded when the lamp is driven. While arranging the anode conductor with the phosphor film on the inner surface of the windshield, the rear glass is placed behind the windshield,
Forming a conductor film on the outer surface of the rear glass and arranging a linear cathode conductor with a field electron emission film on the inner surface side of the rear glass, and a linear gate conductor sandwiching the cathode conductor from both sides,
A field emission lamp characterized in that a negative potential is applied to the cathode conductor and the gate conductor when the lamp is driven, and a ground potential is applied to the anode conductor on the windshield side and the conductor film on the rear glass.

Images