JP2001154193A - Liquid crystal display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal display device easily and surely preventing light leakage with a simple construction. SOLUTION: The liquid crystal display device is characterized by forming the light emitting region LA1 of a backlight 13 with the same area as, or a little larger area than, a display dot region HAD of a liquid crystal display panel 12 by controlling the size of an opening part 14 of a reflection plate 15 in a downside placed backlight 13 or by controlling the size of a light diffusing part 20 in a sidelight type backlight 13A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a negative type liquid crystal display device which performs bright display against a dark background.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display device using a liquid crystal display panel in which liquid crystal is sealed between two transparent substrates has been known as one type of display device for displaying various images such as characters and figures. ing.

As such a liquid crystal display device, there is a liquid crystal display device having a negative display with a bright display. This negative type liquid crystal display has a high light transmittance of a display portion and a low light transmittance of a non-display portion, so that the background is dark and the visibility in a dark place is good. Are often used for display of a display unit, an in-vehicle audio, a meter, a clock, and the like. In addition, in a liquid crystal display device of a negative type display, a display portion of a liquid crystal display panel is brightly displayed by using external illumination light from a backlight called a backlight. In addition,
As the backlight, there are various types such as a direct type and a sidelight type.

[0004] However, the conventional liquid crystal display device is formed based on a design concept of making the light emitting area of the backlight the same as the effective display area of the liquid crystal display panel. As exaggeratedly shown in FIG. 4, the liquid crystal display device is practically formed so that the light emitting area LA of the backlight is slightly larger than the effective display area YHA of the liquid crystal display panel in consideration of manufacturing errors. In the display state,
The space 3 between the connection portions 2 of the transparent electrodes 1 located outside the display dot region HDA connecting the outermost periphery of the display dots D
However, due to the retardation (Δnd) of the liquid crystal layer, light is easily transmitted, and light leaks from the space 3 between the lines, and as a result, there is a problem that visibility and aesthetics are reduced.

In order to cope with such a problem of light leakage, in the conventional liquid crystal display device 4, as shown in FIG. Preventing. As a configuration for preventing light leakage, the light-shielding portion 6 may be provided at a position facing the backlight 5 of the liquid crystal display panel 7 in some cases.

[0006]

By the way, in recent years, cost reduction has been demanded for various devices, and cost reduction has also been demanded for liquid crystal display devices. In order to reduce the cost of the liquid crystal display device, a liquid crystal display device capable of preventing light leakage without performing light-shielding printing has been demanded. In other words, there is a need for a liquid crystal display device that can easily and reliably prevent light leakage with a simple configuration.

The present invention has been made in view of these points, and an object of the present invention is to provide a liquid crystal display device that can easily and reliably prevent light leakage with a simple configuration.

[0008]

According to a first aspect of the present invention, there is provided a liquid crystal display device according to the first aspect of the present invention, wherein a light emitting area of a backlight is set to a display dot area of a liquid crystal display panel. The point is that they are formed to be the same or slightly larger. By adopting such a configuration, in the display state, most of the inter-line space of the connection portion of the transparent electrode is located outside the light emitting region, so that light leakage can be easily and reliably prevented. can do. Furthermore, since the light emitting area of the backlight itself is controlled, light leakage can be easily and reliably prevented with a simple configuration without increasing the cost.

A feature of the liquid crystal display device of the present invention according to claim 2 is that in claim 1, the backlight is a direct type in which a light source is housed inside a reflector, and the backlight of the backlight has The size of the opening facing the liquid crystal display panel is such that the light emitting area of the backlight is formed to be equal to or slightly larger than the display dot area of the liquid crystal display panel. By adopting such a configuration, light leakage can be easily and reliably prevented with a simple configuration using a direct-type backlight without increasing the cost.

A third aspect of the present invention is a liquid crystal display device according to the first aspect, wherein the backlight is a sidelight type having a light guide having a diffusion portion. Is formed so that the light emitting area of the backlight is the same as or slightly larger than the display dot area of the liquid crystal display panel. By adopting such a configuration, light leakage can be easily and reliably prevented with a simple configuration using a sidelight type backlight without increasing the cost.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings.

FIGS. 1 and 2 show a first embodiment of a liquid crystal display device according to the present invention. FIG. 1 is a partially enlarged sectional view showing the structure of a main part, and FIG. 2 is a liquid crystal display shown in FIG. FIG. 4 is a partially enlarged plan view illustrating a positional relationship between a display dot region of a liquid crystal display panel of a display device and a light emitting region of a backlight.

The liquid crystal display device of this embodiment is a negative type display in which a direct-type backlight is provided on the back of a liquid crystal display panel.

As shown in FIG. 1, a liquid crystal display device 11 according to the present embodiment is provided with a direct-type backlight 13 for back lighting below a liquid crystal display panel 12.

The configuration of the liquid crystal display panel 12 is the same as the conventional one, and a detailed description thereof will be omitted.

The backlight 13 has a reflector 15 having a substantially U-shaped cross section in which an upper portion facing the liquid crystal display panel 12 has a flat rectangular opening 14.
A light source 16, in this embodiment, a plurality of point light sources 16a are arranged at predetermined intervals on a bottom surface 15a of the light emitting device. That is, the light source 16 is housed inside the reflection plate 15. Note that a linear light source may be used as the light source 16.

The bottom surface 15a of the reflector 15 which is farthest from the liquid crystal display panel 12 and the top surface 15b which are closest to each other are connected by an inclined surface 15c of a predetermined angle. Starting point 1 of 15c
1 and 2 in consideration of the parallax from within the display dot area HDA of the liquid crystal display panel 12.
As shown in the figure, the light emitting area LA1 of the backlight 13 is set to be slightly larger than the display dot area HDA of the liquid crystal display panel 12.

That is, the reflection plate 15 of the backlight 13
The size of the opening 14 facing the liquid crystal display panel 12 is controlled based on a new design concept of the present invention in which the light emitting area LA1 of the backlight 13 is made the same as the display dot area HDA of the liquid crystal display panel 12. It has become.

The size of the opening 14 of the backlight 13 is determined by changing the light emitting area LA1 of the backlight 13 to the display dot area HDA of the liquid crystal display panel 12 in consideration of manufacturing errors.
It is practically formed to be slightly larger.

Further, an optical screen and a diffusion plate (not shown) are arranged in this order in the opening 14 of the backlight 13.

In the case where the display dot D located at the outermost periphery of the display dot area HDA of the liquid crystal display panel 12 is not used for display, the starting point of the inclined surface 15c is considered in consideration of the parallax from the display dot area HDA. Since 15 ca can be provided at a position closer to the center of the reflection plate 15, the light emitting LA1 area of the backlight 13 can be closer to the display dot area HDA of the liquid crystal display panel 12. In this case, the number of arrayed point light sources 16a can be reduced.

Next, the operation of the present embodiment having the above-described configuration will be described.

According to the liquid crystal display device 11 of the present embodiment,
The light emitting area LA1 of the backlight 13 is
The light emitting area LA1 of the backlight 13 is based on a new design concept of making the same as the display dot area HDA.
Is practically formed in consideration of a manufacturing error so that is slightly larger than the display dot area HDA of the liquid crystal display panel 12, and in the display state, as shown in FIG. Since most of the space 3 between the lines is located outside the light emitting area LA1, the area where light leaks from the space 3 can be reduced, so that light leakage can be easily and reliably prevented. Can be.

Furthermore, according to the liquid crystal display device 11 of the present embodiment, since the light emitting area LA1 of the backlight 13 is controlled, light leakage can be easily and reliably prevented with a simple configuration without increasing the cost. be able to.

Further, the liquid crystal display device 1 of the present embodiment
According to 1, light leakage can be easily and reliably prevented with a simple configuration using the direct-type backlight 13 without increasing the cost.

FIG. 3 is a partially enlarged sectional view showing the structure of a main part of a second embodiment of the liquid crystal display device according to the present invention.

The liquid crystal display device of the present embodiment is of a negative display type in which a sidelight type backlight is provided on the back of a liquid crystal display panel.

As shown in FIG. 3, the liquid crystal display device 11A according to the present embodiment is provided with a side light type backlight 13A for back lighting below the liquid crystal display panel 12. The backlight 13A has a light guide 19 for transmitting light from a light source 16A composed of a linear light source such as a fluorescent lamp, and a diffusion unit (diffusion processing unit) 20 provided in the light guide 19. Of the light emitting area LA2 of the backlight 13A in consideration of the parallax from within the display dot area HDA of the liquid crystal display panel 12,
Is made practically larger than the display dot area HDA of the liquid crystal display panel 12.

That is, the diffusion section 2 of the backlight 13A
The size of 0 is controlled based on a new design concept of the present invention in which the light emitting area LA2 of the backlight 13A is made the same as the display dot area HDA of the liquid crystal display panel 12.

As shown in FIG. 2, the size of the diffusion portion 20 is determined by taking the manufacturing error into consideration.
The light emitting area LA2 of A is practically formed so as to be slightly larger than the display dot area HDA of the liquid crystal display panel 12.

Other configurations are the same as those of the liquid crystal display device 11 of the first embodiment described above, and detailed description thereof will be omitted.

According to the liquid crystal display device 11A of the present embodiment having such a configuration, the light emitting area LA2 of the backlight 13A is displayed on the liquid crystal display panel 12 similarly to the liquid crystal display device 11 of the first embodiment. Based on a new design concept of making the same as the dot area HDA, the light emitting area LA2 of the backlight 13A is practically formed in consideration of manufacturing errors so as to be slightly larger than the display dot area HDA of the liquid crystal display panel 12. Therefore, in the display state, as shown in FIG. 2, most of the inter-line space portion 3 of the connection portion 2 of the transparent electrode 1 has the light emitting area LA.
2, the area where light leaks from the space 3 between lines can be reduced, so that light leaks can be easily and reliably prevented.

Further, the liquid crystal display device 11A of the present embodiment
According to the method, since the light emitting area LA2 of the sidelight type backlight 13A is controlled, light leakage can be easily and reliably prevented with a simple configuration without increasing the cost.

Further, the liquid crystal display device 1 of the present embodiment
According to 1A, the backlight 13A of the sidelight type
By using this, light leakage can be easily and reliably prevented with a simple configuration without increasing the cost.

The light source 16 in each of the above embodiments is selected from a wide variety of light sources such as a tungsten lamp, an LED, a CFL, and an EL as required according to the design concept and the like.

The present invention is not limited to the above embodiment, but can be variously modified as needed.

[0037]

As described above, according to the liquid crystal display device of the first aspect of the present invention, in the display state, most of the inter-line space of the connection portion of the transparent electrode is located outside the light emitting region. Therefore, the occurrence of light leakage can be easily and reliably prevented. Furthermore, since the light emitting area of the backlight itself is controlled, an extremely excellent effect is obtained such that light leakage can be easily and reliably prevented with a simple configuration without increasing the cost.

Further, according to the liquid crystal display device of the present invention, it is possible to easily and surely prevent light leakage with a simple configuration using a direct-type backlight without increasing the cost. It has extremely excellent effects such as the ability to produce

According to the liquid crystal display device of the present invention, light leakage can be easily and reliably prevented with a simple structure using a sidelight type backlight without increasing the cost. It has an extremely excellent effect, such as being able to do so.

[Brief description of the drawings]

FIG. 1 is a partially enlarged sectional view showing a configuration of a main part of a first embodiment of a liquid crystal display device according to the present invention.

FIG. 2 is a partially enlarged plan view illustrating a positional relationship between a display dot area of a liquid crystal display panel of the liquid crystal display device shown in FIG. 1 and a light emitting area of a backlight.

FIG. 3 is a view similar to FIG. 1, showing a configuration of a main part of a second embodiment of the liquid crystal display device according to the present invention;

FIG. 4 is a partially enlarged plan view illustrating a positional relationship between a display dot area and an effective display area of a liquid crystal display panel and a light emitting area of a backlight in a conventional liquid crystal display device.

5 is a partially enlarged cross-sectional view showing a configuration of a main part of the liquid crystal display device of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transparent electrode 2 Connection part 3 Interline space part 11, 11A Liquid crystal display device 12 Liquid crystal panel 13, 13A, backlight 14 Opening part 15 Reflection plate 16, 16A, 16B Light source 19 Light guide 20 Diffusion part D Display dot HDA display Dot area LA1, LA2 Light emitting area

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H091 FA23Z FA31Z FA42Z FA44Z FA45Z FD06 FD11 LA03 LA30 5G435 AA00 BB12 BB15 CC09 DD09 EE26 EE27 EE33 FF03 FF06 FF08 GG23 GG24 GG26 LL04 LL07 LL17 LL17

Claims (3)

[Claims] 1. A negative type liquid crystal display device having a backlight disposed on the back surface of a liquid crystal display panel, wherein a light emitting area of the backlight is formed to be equal to or slightly larger than a display dot area of the liquid crystal display panel. A liquid crystal display device characterized in that: 2. The backlight is of a direct type in which a light source is housed inside a reflection plate, and the size of an opening of the reflection plate of the backlight facing the liquid crystal display panel is determined by a light emitting area of the backlight. 2. The liquid crystal display device according to claim 1, wherein the liquid crystal display device is formed so as to be equal to or slightly larger than a display dot area of the liquid crystal display panel. 3. The backlight according to claim 1, wherein the backlight is a sidelight type having a light guide having a diffusion part, and the size of the diffusion part of the backlight is determined by adjusting the size of the light emission area of the backlight to the display dots of the liquid crystal display panel. 2. The structure according to claim 1, wherein the area is formed to be equal to or slightly larger than the area.
3. The liquid crystal display device according to 1.