JP2000187449A - Display device and back light for display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption of a back light even in normal operation. SOLUTION: The display device comprises a display part 3 which has display areas 3a to 3g and makes a display by varying the intensity of transmitted light and a back light 10 which is arranged behind the display part 3 and performs surface light emission by applying high-frequency electric power to its internal high-dielectric material to supply the emitted light to the display part 3. The back light 10 is composed of light emission areas 10a to 10g which are able to emit lights individually and equipped with a light emission intensity varying means which individually varies the light emission intensity of the light emission areas 10a to 10g corresponding to the display areas 3a to 3g associatively with the display contents of the display part 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to various information devices,
In particular, the present invention relates to a display device used in a small information device such as a portable device and a backlight for the display device.

[0002]

2. Description of the Related Art Conventionally, display devices such as information devices, especially small information devices such as portable devices, are thin and space-saving, and have low power consumption. 2. Description of the Related Art In many cases, a liquid crystal display that performs display by applying a voltage to a liquid crystal sealed between glass substrates and orienting the liquid crystal to change the liquid crystal is often used.

Since these liquid crystal displays perform display by changing the intensity of light passing therethrough as described above, they do not have a light emitting function themselves, and the display cannot be confirmed in darkness. A backlight, which is a surface light emitter for supplying light to the liquid crystal display, is disposed on the back of the liquid crystal display to form a display device.

[0004] Many types of backlights have been proposed for these display devices. Among them, among them, the advantages of a relatively simple structure and a low profile have been proposed.
2. Description of the Related Art Electroluminescent (EL) type backlights that emit surface light by applying a high-frequency current to a high dielectric material have been put to practical use.

[0005]

However, in these backlights, if there is a difference in the luminous intensity at each part of the luminous surface, the visibility of the display on the liquid crystal display is reduced, so that the luminous intensity is usually low. Although the entire light-emitting surface is made to be uniform, the emission intensity of the display area with the most important display contents must be reduced in order to make effective use of the limited display area and display with appeal. It has been considered that display is performed at a higher height than other display areas. However, there has been no display device or display device backlight capable of changing the light emission intensity corresponding to these display regions.

Further, since the mobile terminal or the like is a portable device, it is necessary to effectively use limited electric power such as a battery to enable long-time operation. Since the power consumption is relatively large, reducing the power consumption of these backlights is a major issue. As a method for reducing the power consumption of these backlights, there is no input for a predetermined time. In Japanese Patent Application Laid-Open No. H11-157, lighting of a backlight, stopping display on a liquid crystal display, and the like are performed.

However, even in the above-mentioned methods, it is impossible to extend the effective working time in continuous operation because the backlight emits light over the entire surface during normal operation. At the same time, the display on the liquid crystal display is rarely the display required for the entire surface of the display, and therefore, even during operation by illuminating only the minimum area required for these displays. Nothing could reduce the power consumption of the backlight.

Accordingly, the present invention has been made in view of the above-mentioned problems, and the display is performed by increasing the light emission intensity of the display area of the display content having high importance as compared with other display areas. It is an object of the present invention to provide a display device and a backlight for a display device capable of performing display excellent in appealing power and visibility and reducing power consumption of the backlight even in a normal operation.

[0009]

In order to solve the above-mentioned problem, a display device according to the present invention has a plurality of display areas,
A display portion that performs display by changing the intensity of transmitted light, and is disposed on the back surface of the display portion, and emits surface light when high-frequency power is applied to an internal high-dielectric material, and the display portion has A backlight that supplies emitted light, the backlight includes a plurality of light-emitting areas that are individually enabled to emit light, and is provided in each display area in conjunction with the display content of the display unit. It is characterized by comprising a light emission intensity varying means that can individually change the light emission intensity of the corresponding light emitting region. According to this feature, the backlight has a plurality of light-emitting regions that can individually emit light, and the light-emitting intensity variable unit can individually change the light-emitting intensity of the light-emitting region corresponding to each display region. Therefore, it is possible to increase the light emission intensity of the light emitting region corresponding to the display region of the display content with high importance compared to the light emitting intensity of the light emitting region corresponding to the other display region, and to enhance the appealing power and the visibility. In addition to being able to perform excellent display, the light emission intensity of a light emission area corresponding to a display area where no display is performed or a display area of low importance is set to “0” or lower than normal, thereby enabling normal operation. Even inside, the power consumption of the backlight can be reduced.

[0010] It is preferable that the display device of the present invention has a transparent touch panel disposed on the front surface of the display section.
With this configuration, the user can increase the light emission intensity of the light emitting region corresponding to the display item related to the input, which is the display content with high importance, more than the light emission intensity of the light emitting region corresponding to the other display items. Since the display items related to the input can be instantly recognized, the operability in the input can be improved.

A backlight for a display device according to the present invention has a plurality of display areas, is disposed on a back surface of a display section for performing display by changing the intensity of transmitted light, and has a high dielectric material contained therein. Surface emission occurs when power is applied,
A backlight that supplies the emitted light to the display unit, and has a plurality of light-emitting regions that can be individually emitted,
It is characterized by comprising a light emission intensity varying means that can individually change the light emission intensity of the light emitting region. According to this feature, the backlight has a plurality of light-emitting regions that can individually emit light, and the light-emitting intensity variable unit can individually change the light-emitting intensity of each light-emitting region. By arranging the backlight on the back of the display unit, the luminous intensity of the luminous area corresponding to the display area of the display content of high importance displayed on the display unit is changed to the luminous intensity of the luminous area corresponding to another display area. It is possible to increase the emission intensity compared to the emission intensity, and it is possible not only to perform a display with excellent appealing power and visibility, but also to perform the display of the emission region corresponding to the display region where no display is performed or the display value is low. By setting the light emission intensity to “0” or lower than normal, power consumption in the backlight can be reduced even during normal operation.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example in which the display device of the present invention is applied to a portable information terminal will be described with reference to the drawings, but the display device of the present invention is not limited to these portable information terminals.

(Embodiment) FIG. 1 is an external perspective view showing a portable information terminal using a display device of the present invention in this embodiment, and FIG. 2 is a development showing the configuration of the display device in this embodiment. FIG. 3 is a perspective view, FIG. 3 is a sectional view showing the configuration of a liquid crystal panel and a backlight used in the display device of the present embodiment, and FIG. 4 is a portable information terminal using the display device of the present embodiment. FIG. 5 is a plan view showing a display state of the display device of the present embodiment.

The portable information terminal of this embodiment is an information terminal having an electronic organizer function. As shown in FIG. 1, a display unit 3 is provided at an opening of a housing 2 having an opening at the center of the upper surface thereof. The display unit 3 includes a display title display area 3a, a propriety display area 3b, a sub menu display area 3b.
The display area is divided into c, a date display area 3d, an information display area 3e, an input display area 3f, and a main menu display area 3g, and a boundary 11 is formed at a predetermined boundary of the display area.

The display unit 3 of the present embodiment is constituted by a display device shown in FIG. 2, and the uppermost position of the front surface of the display unit 3 is detected by a capacitance to allow an operator to operate. A transparent touch panel 4 capable of detecting pressed coordinates on a display portion to be pressed; a liquid crystal panel 8 arranged at a lower position of the transparent touch panel 4 to display various information; An EL backlight 10 that is disposed and supplies light to the liquid crystal panel 8 by emitting light from the surface.
It is connected to a substrate (not shown) arranged below the L backlight 10.

In the transparent touch panel 4 used in this embodiment, a comb-shaped indium oxide thin film (ITO) electrode 6 having transparency is formed on one surface of a transparent resin film 7 having a predetermined thickness such as a polyester film. A flexible printed board (FPC) 5 for connecting the ITO electrode 6 and a touch panel driver 20 mounted on the board, which will be described later, is provided at a predetermined end position of the touch panel driver 20. The capacitance of each of the comb-shaped ITO electrodes 6 is scanned, and the coordinates of the transparent touch panel 4 pressed by the operator are output from the change in the capacitance. I have.

The liquid crystal panel 8 used in this embodiment has a transparent Y-side scanning electrode made of an indium oxide thin film similar to that used for the transparent touch panel 4 as shown in FIGS. Upper glass substrate 8a formed and lower glass substrate 8 formed with X-side scanning electrodes
b, a normal dot matrix type super twisted nematic (STN) liquid crystal panel in which a liquid crystal material is sealed.

In the liquid crystal panel 8 of the present embodiment, as shown in FIG. 3, a boundary line 11 indicating the boundary of the display area is formed on the upper glass substrate 8a by printing, which will be described later. The gap formed between the light emitting regions is masked by the boundary line 11.

One end of the upper glass substrate 8a and one end of the lower glass substrate 8b of the liquid crystal panel 8 is connected to a liquid crystal driver IC 2 for controlling a display operation of the liquid crystal panel 8.
1 is a flexible printed circuit board (TAB-FPC) mounted by tape auto bonding (TAB)
9a and 9b, which are connected to the board, connected to a microcomputer (CPU) 23 mounted on the board,
Various displays are performed based on the output of the CPU 23.

The EL backlight 10 used in the present embodiment has a configuration as shown in FIGS. 2 and 3, and is provided at a position corresponding to each of the display areas 3a to 3g of the display section 3. Light-emitting area 10a that can be individually lit
To 10 g, and each light emitting region 10a
Wiring 1 for individually applying high frequency power for every 10 g
3 is formed, and each of the light emitting regions 10 is
a to 10 g are connected to an EL driver 22 as a light emission intensity varying means for controlling the light emission intensity of each of these units.

The EL driver 22 has a built-in inverter (not shown) for converting a direct current into a high-frequency power, and can change the frequency of the power applied to each of the light emitting regions 10a to 10g. And the CPU 2
By changing these frequencies based on the output of 3,
The luminous intensity of each of the luminous regions 10a to 10g can be individually changed.

The EL backlight 1 used in this embodiment
As shown in FIG. 3, the structure of the upper transparent film 1 on which the wiring 13 is formed and which allows the emitted light to pass through is shown in FIG.
2 and a lower film 16 on one side of which an aluminum foil layer 15 serving as a ground electrode is laminated, applying a paste mainly composed of a high dielectric material powder such as piezoelectric ceramics,
The structure is such that the upper transparent film 12 and the lower film 16 are adhered around the high dielectric layer 14 formed by drying, and the inside thereof is sealed.

In the present embodiment, as described above,
Each of the light emitting regions 10a to 10g is formed in the L backlight 10. As a method of forming each of the light emitting regions 10a to 10g, the wiring 13 connected to each of the light emitting regions 10a to 10g is made of a conductive paste. After forming the upper transparent film 12 using a silver paste or the like, each light emitting region 10a to 10g is formed by printing a paste containing the high dielectric material powder as a main component, as shown in FIG. A gap 17 is formed between adjacent light emitting regions, and the EL driver 22 applies high frequency power to the wiring 13 connected to each of the light emitting regions based on the output of the CPU 23. Thereby, these individual light emitting regions 10a to 10g can independently adjust light emission and the light emission intensity.

In the present embodiment, the wirings 13 for routing are provided in the gaps 17 and the gaps 17 provided with these wirings are left as spaces. The space may be eliminated by burying the space to improve the flatness of the EL backlight 10 and also prevent air from entering the gap.

The display operation of the display device of the present embodiment will be described below. First, when the portable information terminal is activated, the CPU 23 controls all the light emitting areas of the EL backlight 10 as shown in FIG. The display is performed by emitting light.

When the activation is completed, the CPU 23
Indicates that the light emission intensity of the main menu display area 3g, which is a display item to be input by the operator, and the light emission areas 10g, 10c, and 10b corresponding to the submenu area 3c and the availability display area 3b are set. As it is, an instruction to lower the light emission intensity of the other light emission areas is output to the EL driver 22.

Based on the output, the EL driver 22
Reduces the frequency of the high-frequency power applied to the wiring connected to the light-emitting regions other than the light-emitting regions 10g, 10c, and 10b, thereby lowering the light-emitting intensity thereof.
The light emission intensities of c and 10b are set to be relatively higher than those of other display units.

Based on this, the operator can intuitively recognize that it is sufficient to perform an operation in the display areas 3g, 3c and 3b having relatively high light emission intensity. After the recording icon is pressed and selected, the "OK" display area of the availability display area is pressed.

Based on the operation, the transparent touch panel 3
The touch panel driver 20 connected to the CPU 23 detects the coordinates pressed by the operation and outputs the coordinates to the CPU 23.

The CPU 23 compares the output coordinate data with the display data to determine the content of the input, and recognizes that the address book icon has been selected by the input.

Next, as shown in FIG. 5, the CPU 23 displays, in the submenu area 3c, a display area for the selected address book icon, an information display area 3e for displaying the selected address book data, and the availability display. The light emitting area corresponding to the area 3b is set to a normal lighting state via the EL driver 22, and the light emitting intensity of the light emitting area corresponding to the other display area is reduced.

According to the present embodiment, even when the information terminal is in normal operation, as described above, the light emission intensity of the display area in which necessary information is displayed is set to normal, and By lowering the light emission intensity of the backlight, the power consumption of the backlight can be reduced, and not only the limited power of the battery and the like can be effectively used to operate for a long time, but also By providing a difference between the brightness of the display area for the important information and the brightness of the display area for the other information, the user can change the information having high necessity (importance) in the display content displayed on the display unit 3 according to the brightness. It is possible to enhance the effect of appealing to the user in these recognitions, and to improve the operability of the operator by using a transparent touch panel as in the present embodiment.

Although the present invention has been described with reference to the drawings, the present invention is not limited to the above embodiment.
It goes without saying that changes and additions without departing from the gist of the present invention are included in the present invention.

Further, in the above embodiment, the display is formed by the difference in brightness by lowering the luminous intensity. However, the present invention is not limited to this. A difference may be formed, or a difference in brightness may be formed by setting the light emission intensity to “0”.

In the above embodiment, each of the light emitting regions is formed by printing. However, the present invention is not limited to this, and a method of forming each of the light emitting regions is arbitrary.

In the above embodiment, the material of the high-dielectric material in each light emitting region is the same, but the present invention is not limited to this. The high-dielectric material in one region may be different from the high-dielectric material in another light-emitting region to change the emission color or the like.

In the above-described embodiment, a dot matrix type STN liquid crystal is used as the liquid crystal panel 8, but the present invention is not limited to this. The display device of the present invention uses a backlight. It goes without saying that the present invention can be applied to any liquid crystal panel as long as it is a transmissive liquid crystal panel.

In the above embodiment, a capacitive touch panel is used as the transparent touch panel. However, the present invention is not limited to this, and any type of transparent touch panel may be used. Can be.

[0039]

The present invention has the following effects.

(A) According to the first aspect of the present invention, the backlight has a plurality of light-emitting areas each of which can emit light individually, and the light-emitting intensity varying means includes a light-emitting area corresponding to each display area. Since the light emission intensity can be individually varied, the light emission intensity of the light emission region corresponding to the display region of the display content with high importance is increased as compared with the light emission intensity of the light emission region corresponding to other display regions. Becomes possible,
In addition to being able to perform display with excellent appealing power and visibility, the luminous intensity of a luminous area where no display is made or corresponds to a less important display area is set to “0” or lower than usual. Thus, the power consumption of the backlight can be reduced even during normal operation.

(B) According to the second aspect of the invention, the luminous intensity of the luminous area corresponding to the display item related to the input, which is the display content of high importance, is changed to the luminous intensity of the luminous area corresponding to the other display items. By increasing the strength, the user can instantly recognize the display items related to the input, so that the operability in the input can be improved.

(C) According to the third aspect of the present invention, the backlight has a plurality of light-emitting areas that can individually emit light, and the light-emitting intensity varying means individually adjusts the light-emitting intensity of each light-emitting area. Since the backlight is variable, by arranging the backlight on the back of the display unit, the light emission intensity of the light emitting region corresponding to the display region of the display content of high importance displayed on the display unit can be changed. It is possible to increase the luminous intensity of the luminous area corresponding to the display area of not only, it is possible to perform a display excellent in appealing power and visibility, not to display or the importance of By setting the light emission intensity of the light emitting region corresponding to the low display region to “0” or lower than normal, power consumption in the backlight can be reduced even during normal operation.

[0043]

[Brief description of the drawings]

FIG. 1 is an external perspective view showing an information terminal using a display device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view showing the configuration of the display device according to the embodiment of the present invention.

FIG. 3 is a cross-sectional view illustrating a configuration of a liquid crystal panel and a backlight according to an embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of an information terminal using a display device according to an embodiment of the present invention.

FIG. 5 is a plan view showing a display state of the display device according to the embodiment of the present invention.

[Explanation of symbols]

1 portable information terminal 2 housing 3 display section 3a display title display area 3b availability display area 3c submenu display area 3d date display area 3e information display area 3f input display area 3g main menu display area 4 transparent touch panel 5 flexible printed circuit board (FPC) 6) Indium oxide thin film (ITO) electrode 7 Transparent film 8 Liquid crystal panel 8a Upper glass substrate 8b Lower glass substrate 8c Liquid crystal material 9a, b Flexible printed circuit (TAB-FP)
C) 10 EL backlight 10a light emitting region 10b light emitting region 10c light emitting region 10d light emitting region 10e light emitting region 10f light emitting region 10g light emitting region 11 boundary line 12 upper transparent film 13 wiring 14 high dielectric layer 15 aluminum foil layer 16 lower film 17 gap Reference Signs List 20 touch panel driver 21 liquid crystal driver 22 EL driver 23 microcomputer (CPU)

Claims (3)

[Claims] 1. A display section having a plurality of display areas and performing display by changing the intensity of transmitted light, and a high frequency power applied to an internal high dielectric material disposed on the back of the display section. A backlight that emits surface light by being performed and supplies the emitted light to the display unit, wherein the backlight is configured by a plurality of light-emitting regions that are individually enabled to emit light; A display device comprising: a light-emitting intensity varying unit that can individually vary the light-emitting intensity of the light-emitting region corresponding to each display region in conjunction with display contents of a display unit. 2. The display device according to claim 1, wherein a transparent touch panel is arranged on a front surface of the display unit. 3. A display device having a plurality of display areas, which is arranged on a back surface of a display unit for performing display by changing the intensity of transmitted light, and which is applied with high-frequency power to an internal high-dielectric material. A backlight that emits light and supplies the emitted light to the display unit, the backlight having a plurality of individually light-emitting areas, and the light-emitting intensity of the light-emitting areas being individually variable. A backlight for a display device comprising variable means.