JP2008226543A - Field emission lamp, backlight unit, and display panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve display contrast at an interface of adjacent unit emission areas, in case a panel is divided into a plurality of unit emission areas and light is controlled by a light source arranged at each unit emission area. <P>SOLUTION: In case the panel is divided into a plurality of unit emission areas each equipped with a light source, and light is controlled by each light source, it is so structured that field emission type light sources making phosphors emit light by making electrons released from the light sources in field emission collide with phosphor films are used to clarify each mission display region of each unit emission area with the use of repulsion of electrons themselves from the field emission type light sources at an interface of adjacent unit emission areas. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a display device such as a field emission lamp, a backlight unit for a liquid crystal display panel, and characters.

  In the backlight of the LCD panel, the panel is divided and dimming control is performed for each divided area to control the backlight light according to the dark place and the bright place in one image, and the necessary area is bright and unnecessary. A technology has been proposed to realize power saving and high contrast by darkening the area. In this backlight light area control, for example, the backlight is composed of light-emitting parts consisting of a plurality of resin-molded parts, and these light-emitting parts are tiled (spread) according to the liquid crystal display panel to form a backlight and each light emission. There has also been proposed a technique for dimming a backlight by controlling light emission of components.

However, in the above case, the partition wall for confining the backlight light of the partner area in the adjacent areas does not leak into the area side but is confined in the area is necessary as a black matrix. Stands out. Moreover, when resin molded parts with a built-in LED are used in each area, the LED is a point light source and cannot illuminate the entire area uniformly and brightly. There is a big dark place.
JP2001-075120 JP2003-150075 JP 2006-148036 A

  The present invention has been made in view of the above, and when a panel is divided into a plurality of areas (unit light emitting areas), a dark place is inconspicuous without a partition wall at the boundary between adjacent unit light emitting areas, and the boundary is defined. Clearly, the area can be dimmed in one or two dimensions.

  A field emission lamp according to the present invention divides a light emitting area on a flat light emitting panel into a plurality of unit light emitting areas in a one-dimensional or two-dimensional direction, and includes a plurality of field emission light sources inside each unit light emitting area. The light emission from the light emission side panel can be controlled one-dimensionally or two-dimensionally for each unit light-emitting area by controlling the field electron emission operation of each field emission light source.

  In the above, it is preferable that the field emission type light source is configured by arranging the anode conductor with a phosphor and the cathode conductor with a field electron emission film facing each other.

  In the above, it is preferable that the anode conductor is planar and the cathode conductor is linear.

  In this case, it is preferable that the anode conductor is provided in a planar shape inside the light emitting panel constituting the unit light emitting area, and the cathode conductor is provided in a straight line parallel to the boundary between adjacent unit light emitting areas. .

  In the above, it is preferable that the anode conductor with a phosphor is provided separately for each unit light emitting area, and a boundary between adjacent unit light emitting areas is a positively charged region.

  In the present invention, electrons emitted from the field emission light sources of adjacent unit light emitting areas repel each other at the boundary between both unit light emitting areas, and an electron depletion layer is self-generated, so that the unit light emitting area on the self side at the boundary. As a result, the light emission of the phosphor in the inside is divided into other unit light emission areas that are not adjacent to each other. As a result, the boundary between adjacent unit light emission areas is clarified and each unit light emission area is not blurred optically and clearly with a high contrast ratio. The light can be emitted. Further, a black matrix is not required at the boundary between adjacent unit light emitting areas, and a black matrix-less structure is obtained.

  In the present invention, the field emission operation of each field emission light source is controlled to emit light from the light-emitting side panel for each unit light emitting area in one-dimensional dimming (line-sequential dimming, 1 Dimming) or two-dimensional dimming ( Area dimming and 2 dimming) are possible. The dimming frequency can be area-controlled by controlling this field electron emission operation. Also, this field electron emission operation can be PWM controlled. Further, for example, when this field emission lamp is used as a backlight of a liquid crystal display panel and a moving image is displayed on the liquid crystal display panel, the driving frequency (frame frequency) of the liquid crystal display panel is 60 Hz for improving the moving image quality. For example, if the backlight is blinked at about 120 Hz instead of blinking the backlight, flicker is not felt and the quality of the moving image can be improved.

  The backlight unit according to the present invention includes the field emission lamp disposed on the back of the liquid crystal display panel, and controls the light emission of each unit light emitting area included in the field emission lamp by a field emission light source. It is characterized in that light can be dimmed one-dimensionally or two-dimensionally.

  In the backlight unit of the present invention, the field emission lamp is used in the backlight unit of the liquid crystal display panel. Therefore, when the liquid crystal display panel is divided and dimming control is performed for each divided area, a dark place and a bright light in one image are displayed. It is possible to achieve low power consumption, high contrast ratio, and high image quality by controlling the backlight light according to the location and making necessary areas bright and unnecessary areas dark. In the backlight unit of the present invention, when the backlight is dimmed to adjust the screen brightness according to the scene, the display screen is dimmed two-dimensionally according to the input video signal to be displayed ( (Brightness adjustment), contrast in the liquid crystal display panel can be improved, and image quality can be improved.

  In particular, when the OCB mode liquid crystal is used for the liquid crystal display panel, when the backlight is dimmed one-dimensionally or two-dimensionally in the unit light-emitting area, the luminance unevenness in the liquid crystal display can be reduced or eliminated, and the image quality is improved. Will be able to contribute. The OCB mode liquid crystal is a liquid crystal suitable for displaying moving images because the response speed of liquid crystal molecules is remarkably improved as compared with the case of a TN alignment liquid crystal display panel.

  The display panel according to the present invention is characterized in that characters and the like can be displayed by dimming light emitted from each unit light emitting area of the field emission lamp with a field emission light source.

  Characters include characters, numerical values, figures, symbols, and the like.

  In the display panel of the present invention, an electron depletion layer is automatically generated as a result of electrons emitted from the field emission light sources of adjacent unit light emitting areas repelling each other at the boundary between both unit light emitting areas. In, the emission of phosphors is not divided into adjacent unit emission areas, and the emission of each adjacent unit emission area is clear without blurring without blurring at the boundary between them. Can be displayed with high contrast ratio and high quality.

  In the field emission lamp of the present invention, the electrons emitted from the field emission light sources of the adjacent unit light emitting areas repel each other at the boundary between the two unit light emitting areas, so that the phosphor light emission is adjacent at the boundary. As a result, the light emitted from the adjacent unit light-emitting areas does not blur at the boundary between them, and is not clearly blurred, but is clearly classified with a high contrast ratio.

  Therefore, when the field emission lamp is used as a backlight unit, when the liquid crystal display panel is divided and dimming control is performed for each divided area, the backlight light is adjusted according to the dark place and the bright place in one image. It is possible to realize high contrast by controlling the necessary areas and darkening unnecessary areas.

  In addition, when the field emission lamp is used for a display board, it is possible to display characters and the like with a high contrast ratio by combining light emission of a plurality of unit light emitting areas arranged two-dimensionally.

  Hereinafter, a field emission lamp according to an embodiment of the present invention, a backlight unit using the same, and a character display device will be described with reference to the accompanying drawings.

  FIG. 1 shows a front configuration of the field emission lamp of the embodiment, FIG. 2 shows a cross section taken along the line AA in FIG. 1, and FIG. 3 is an electron emission for explaining the operation of the field emission lamp. The state is conceptually shown.

  Referring to these drawings, this field emission lamp 10 includes a planar front panel (light emission side panel) 12 and a planar rear panel 14. The front panel 12 and the rear panel 14 are arranged to face each other in parallel with a predetermined interval. The gap between the front panel 12 and the rear panel 14 can be held by a spacer (not shown). The facing space between the front panel 12 and the rear panel 14 is vacuum-sealed. This vacuum sealing structure is not shown. The front panel 12 is not physically divided, but is divided into two unit light emitting areas 16 in one direction as indicated by broken lines in FIG. That is, the front panel 12 is divided into two one-dimensional unit light emitting areas 16.

  Cathode conductors 18 are individually arranged on the inner surface side of the front panel 12 for each of the unit light emitting areas 16 divided into two. The cathode conductors 18 of both unit light emitting areas 16 are linear in parallel to each other and also to the boundary 16a of the adjacent unit light emitting areas 16. A field electron emission film 20 is formed on the outer surface of these cathode conductors 18.

  An anode conductor 26 with a phosphor 24 is provided on the inner surface of the rear panel 14. The anode conductor 26 is formed on the entire inner surface of the front panel 12.

  The field electron emission film 20 is made of a carbon film. 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, the field emission type light source 27 composed of the cathode conductor 18 with the field electron emission film 20 and the anode conductor 26 with the phosphor 24 is arranged in each unit light emitting area 16, and both the unit light emitting areas 16 are respectively driven when the lamp is driven. When the cathode conductor 18 is grounded and a high potential is applied to the anode conductor 26, electrons are drawn out from the field electron emission film 20 on the surfaces of both cathode conductors 18 as shown by the line arrows in FIGS. The phosphor 24 is excited to emit light. In this case, electrons emitted from the cathode conductor 18 in each unit light emitting area 16 repel each other at the boundary 16a between the unit light emitting areas 16 as shown by the line arrows in FIG. The phosphor 24 at the boundary 16a does not emit light, and the boundary between adjacent unit light emitting areas 16 is clarified. Thus, in the embodiment, the light emission colors of the two adjacent unit light emitting areas 16 are on the other side even without providing a thick light leakage prevention wall to partition the adjacent unit light emitting areas 16 as in the prior art. It is not necessary to ooze out, and each of the unit light emitting areas 16 can be displayed with high contrast.

  FIG. 4 shows a plan configuration of a field emission lamp according to another embodiment of the present invention, and FIG. 5 shows a cross-sectional configuration taken along line BB of FIG. The configuration in FIG. 5 is the same as the cross-sectional configuration along the line CC or EE in FIG.

  In the field emission lamp 10a of this embodiment, the front panel 12 is equally divided into a plurality of unit light-emitting areas 16 having a plurality of two-dimensional directions on display in a two-dimensional direction as viewed from the plane. The

  Each cathode conductor 18 preferably has a rectangular shape in plan view arranged at the center of each unit light emitting area 16, and its four sides are straight lines parallel to the boundary 6 a of adjacent unit light emitting areas 16. Each cathode conductor 18 has a field electron emission film 20 formed on its outer surface. The anode conductor 26 with the phosphor film 24 is formed on the entire inner surface of the front panel 12.

  In the above configuration, in the field emission light source 27 of this embodiment, when the cathode conductor 18 of each of the four unit light emitting areas 16 in the two-dimensional direction is grounded and a high potential is applied to the anode conductor 26 when the lamp is driven, Electrons are extracted from the field electron emission film 20 on the surface of the conductor 18 to the anode conductor 26 and acceleratedly collide with the phosphor 24, and the phosphor 24 emits excitation light. In this case, electrons emitted from the cathode conductors 18 in each unit light emitting area 16 are repelled at the boundary 16a between adjacent unit light emitting areas 16 to form an electron depletion layer, and the phosphor on the boundary 16a is divided. No excitation light is emitted when electrons do not collide with each other, and each of the unit light emitting areas 16 can be displayed with high contrast.

  FIG. 6 shows a plan configuration of a field emission lamp according to still another embodiment of the present invention, and FIG. 7 shows a cross-sectional configuration taken along line FF in FIG. The configuration in FIG. 7 is the same as the cross-sectional configuration along the lines GG and II in FIG. The field emission lamp 10b of this embodiment is characterized in that the boundary 16a between adjacent unit light emitting areas 16 is a positive charging boundary. An electrode 30 is formed at the boundary 16a, and the positive side of the DC power supply 32 is applied to the electrode 30. The negative side of the DC power supply 32 is grounded. On the other hand, the negative side of the DC power supply 34 is applied to the cathode conductor 18. The positive side of the DC power supply 34 is grounded.

  In the above configuration, in the field emission type light source 27 of this embodiment, the boundary 16a between the adjacent unit light emitting areas 16 is a positively charged boundary due to the electrode 30, so that each cathode conductor in the adjacent unit light emitting area 16 is used. As a result of the electrons emitted from 18 being repelled at the positively charged boundary, the boundary is divided into unit light emitting areas 16. As a result, also in the embodiment, each of the unit light emitting areas 16 can be displayed with high contrast in the same manner as described above.

  The field emission lamp described with reference to FIGS. 1 to 7 can be used for the backlight of a transmissive or transflective liquid crystal display panel having a color filter as shown in FIG. In FIG. 8, reference numeral 40 denotes a liquid crystal display panel. The field emission lamp 10 c of the embodiment can be disposed on the back of the liquid crystal display panel 40 to illuminate the liquid crystal display panel 40 from the rear. Dimming control can be performed by the field emission type light source 27 in each unit light emitting area 16 of the emission lamp 10c.

  FIG. 9 shows a planar configuration of the display panel of the embodiment. The display board 50 can be simply referred to as a character display device. In this display board 50, the unit light emitting area 16 is divided into a front panel 12 in a matrix of 6 rows and 6 columns, for example. In the field emission type light source 27 of this display panel embodiment, an electric field is applied to the cathode conductor 18 and the anode conductor 26 on the unit light emitting area 16 side indicated by hatching, while the other cathodes on the unit light emitting area 16 side are applied. By not applying an electric field to the conductor 18 and the anode conductor 26, for example, as shown by hatching in FIG. 9, a character such as a numerical value “2” can be displayed with a clear boundary.

FIG. 1 is a diagram showing a planar 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 an enlarged view showing a main part of FIG. FIG. 4 is a diagram illustrating a planar configuration of a field emission lamp according to another embodiment. FIG. 5 is a diagram showing a cross-sectional configuration along the line BB in FIG. FIG. 6 is a diagram showing a planar configuration of a field emission lamp of still another embodiment. FIG. 7 is a diagram illustrating a cross-sectional configuration along the line FF in FIG. 6. FIG. 8 is a diagram showing an example in which the field emission lamp of the embodiment is used for a backlight of a liquid crystal display panel. FIG. 9 is a diagram illustrating an example in which the field emission lamp of the embodiment is used in a display device for characters and the like.

Explanation of symbols

10, 10a, 10b Field emission lamp 12 Front panel 14 Rear panel 16 Conductor film 18 Cathode conductor 20 Field electron emission film 24 Phosphor 26 Anode conductor 40 Backlight unit 50 Display panel

Claims (6)

  A light emitting area on a flat light emitting panel is divided into a plurality of unit light emitting areas in a one-dimensional or two-dimensional direction, and a plurality of field emission light sources are arranged inside corresponding to each unit light emission area. A field emission lamp characterized in that light emission from the light-emitting side panel is dimmable for each unit light emitting area by controlling the field electron emission operation.   2. The field emission lamp according to claim 1, wherein the field emission type light source is configured by arranging an anode conductor with a phosphor and a cathode conductor with a field electron emission film facing each other.   The anode conductor is provided in a planar shape inside the light-emitting panel constituting the unit light-emitting area, and the cathode conductor is provided in a straight line parallel to the boundary between adjacent unit light-emitting areas. The field emission lamp according to claim 2.   The field emission lamp according to claim 2, wherein the anode conductor with a phosphor is provided separately for each unit light emitting area, and a boundary between adjacent unit light emitting areas is a positively charged region.   5. The field emission lamp according to claim 1, wherein the field emission lamp is disposed on a back portion of a liquid crystal display panel, and light emission of each unit light emitting area provided in the field emission lamp is controlled by a field emission light source. A backlight unit characterized in that the backlight of the liquid crystal display panel can be dimmed one-dimensionally or two-dimensionally.   A field emission lamp according to any one of claims 1 to 4, wherein each unit light-emitting area provided in the field emission lamp is two-dimensionally arranged, and light emitted from each light-emitting area is dimmed by a field emission light source. A display board characterized by being capable of displaying, etc.

Images