JPH11271767A - Liquid crystal display device with lighting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the power consumption by making the light from an LED lamp linear by a light source light guide body and plane by a display part light guide body, and lighting up the entire part of the display part of a liquid crystal display element by a small number of LED lamps. SOLUTION: The liquid crystal display device 1 with lighting is composed of the light guide part light guide body 4 having a reflecting means 4c which emits the light from the LED lamp 3 to irradiation width corresponding to the width of the display surface of the liquid crystal display element 2 and the display part light guide body 5 which has a reflecting means emits the light from the light guide body 4 toward the display surface to irradiation area almost corresponding to the area of the display surface of the liquid crystal display element 2 and then the light from the LED lamp 2 is made linear by the light guide body 4 and then made plane by the display part light guide body 5 to lighten up the entire surface of the display part of the liquid crystal display element 2 with a small number of LED lamps, thereby reducing the power consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device. The present invention relates to a liquid crystal display device in which illumination is performed by a low power consumption LED lamp.

[0002]

2. Description of the Related Art A conventional illuminated liquid crystal display device 90 of this kind.
FIG. 7 shows an example of the configuration of the liquid crystal display element 91.
The LED lamp 92 is arranged facing the display surface 91a outside the display surface 91a and at an appropriate position in front of the display surface 91a, and when necessary, such as at night, the LED lamp is turned on to read the display.

[0003]

However, in the above-mentioned conventional liquid crystal display device 90 with illumination, the display surface is illuminated by an LED lamp 92 having characteristics close to a point light source. Therefore, there is a problem in that the difference in brightness of the display surface due to the distance from the LED lamp 92 increases, and the display quality deteriorates.

Second, when the liquid crystal display element 91 to be illuminated has a relatively large display area for portable information terminal equipment, for example, one LED lamp 9 is provided.
2, the entire display surface 91a cannot be covered,
As shown in FIG. 8, the use of a plurality of LED lamps 92 is inevitable. This results in an increase in power consumption and a problem of shortening the usable time of a device employing this type of illuminated liquid crystal display device 90,
The solution of these points is an issue.

[0005]

According to the present invention, as a specific means for solving the above-mentioned conventional problems, there is provided a illuminated liquid crystal display device comprising a liquid crystal display element provided with an illuminating device using an LED lamp as a light source. , The lighting device is LE
A reflecting means for attaching a D lamp to the LED lamp to emit light in a direction substantially parallel to the width of the display surface of the liquid crystal display element and emitting light in a direction parallel to the display surface; A light source unit light guide provided, and a reflection unit that emits light from the light source unit light guide to an irradiation area substantially equivalent to an area of a display surface of the liquid crystal display element and emits the light in a direction perpendicular to the display surface. The present invention solves the problem by providing a liquid crystal display device with illumination, comprising: a display unit light guide provided at a position overlapping with the display surface.

[0006]

Next, the present invention will be described in detail based on an embodiment shown in the drawings. 1 and FIG.
Is a first embodiment of an illuminated liquid crystal display device (hereinafter abbreviated as display device 1) according to the present invention. This display device 1 illuminates a liquid crystal display element 2 with an LED lamp 3. Some points are similar to those of the conventional example.

In the present invention, the light source unit light guide 4 and the display unit light guide 5 are interposed between the liquid crystal display element 2 and the LED lamp 3. Reference numeral 4 denotes a transparent member such as a colorless transparent resin, which is formed in a substantially rectangular column shape as a whole. They are opposed to each other as a direction to be incident on the inside of the optical body 4.

Then, one side face 4b of the light source unit light guide 4
Is provided with a suitable light source reflecting means 4c such as a V-shaped groove or a V-shaped recess, and the light that reaches the side surface 4b of the light incident from the LED lamp 3 is transmitted to the side surface 4b.
Therefore, the light reflected on the side surface 4b is emitted to the outside of the light source unit light guide 4 from the opposite side surface 4d. still,
The light source unit light guide 4 can be provided with a reflection sheet 7 and the like as necessary.

At this time, the length of the light source unit light guide 4 corresponds to the width W (or may be the height H) of the display surface of the liquid crystal display element 2, and Since the light source unit reflecting means 4c is provided over the entire side surface 4b, the light radiated to the outside from the opposite side surface 4d is a linear light source corresponding to the width W (or height H) of the display surface. Will be converted to

The display unit light guide 5 is made of a transparent member similar to the light source unit light guide 4 and is formed in a plate shape that covers the display surface of the liquid crystal display element 2. One side of the plate thickness surface 5a having a corresponding length is installed so as to face the side surface 4d of the light source unit light guide 4 from which light is emitted. Here, when the liquid crystal display element 2 is of a reflection type, the display unit light guide 5 is installed on the viewing side so as to cover the display surface of the liquid crystal display element 2 (see FIG. 2). .

The V-shaped groove or the above-mentioned V-shaped groove is formed on the surface of the display light guide 5 opposite to the surface facing the liquid crystal display element 2, that is, the front surface 5b viewed from the viewer side. , A V-shaped concave portion or the like, a display section reflecting means 5c is provided over the entire surface. Therefore, the light emitted from the light source unit light guide 4 and incident on the inside of the display unit light guide 5 from the plate thickness surface 5a is emitted to the outside from the entire rear surface 5d by the display unit reflecting means 5c, and the liquid crystal display element 2 Is converted into a surface light source shape that illuminates the entire display surface of.

At this time, the display of the liquid crystal display element 2 is read through the display unit light guide 5 having the display unit reflecting means 5c on the viewing side surface 5b. It is preferable that the display unit reflection means 5c be as fine as possible so as not to impair the readability of the display.

Next, the operation and effects of the display device 1 of the present invention having the above-described configuration will be described. According to the present invention, the light emitted from the LED lamp 3 is emitted from the light source unit light guide 4.
The light is converted into a linear light source by the light source unit reflecting means 4c applied to the display unit 5 and is incident on the display unit light guide 5.

At this time, since the density of the V-shaped groove and the V-shaped recess provided as the light source unit reflecting means 4c can be freely set, the density is adjusted according to the distance from the LED lamp 3, for example. For example, it is possible to make the brightness uniform when converted into the above-described linear light source shape by such means as performing the above-described process.

The light converted into a linear light source having uniform brightness is converted into a surface light source corresponding to the area of the display surface of the liquid crystal display element 2 by the display reflecting means 5c of the display light guide 5. In this case, the display surface is illuminated. At this time, the brightness can be made uniform by means such as adjusting the density of the display unit reflecting means 5c. Therefore, in the present invention, it is possible to illuminate the display surface of the liquid crystal display element 2 with uniform brightness even when the number of LED lamps 3 is small (two in this embodiment).

FIG. 3 shows a second embodiment of the present invention, in which the liquid crystal display element 6 is of a transmission type. In this case, the display unit light guide 5 may be provided on the back side of the liquid crystal display element 6, the display unit reflection means 5c may be provided on the back surface 5d, and light may be emitted from the front surface 5b side. Note that the other points are the same as those in the first embodiment described above, and a detailed description thereof will be omitted.

FIGS. 4 and 5 show a third embodiment of the present invention. This third embodiment is performed in consideration of the characteristics of the LED lamp 3. The LED lamp 3 has a case. As shown in FIG. 4, the lens has a directivity, a narrow irradiation angle, and a light distribution characteristic Q having a maximum luminance on the optical axis P as shown in FIG. .

In order to effectively use the light distribution characteristic Q,
In the third embodiment, as shown in FIG. 5, the optical axis P of the LED lamp 3 is installed so as to be inclined toward the reflection means 4c of the light source unit light guide 4, and by doing so, , The amount of light reaching the reflection means 4c can be increased, and as a result, the amount of illumination for the liquid crystal display element 2 (or 6) can be increased.

As means for tilting the optical axis P of the LED lamp 3 toward the reflection means 4c, as shown in FIG. 6 as a fourth embodiment, the end face 4 of the light source unit light guide 4 is used.
a may be cut at an acute angle with respect to the side surface 4b provided with the reflection means 4c, and the light from the LED lamp 3 may be refracted and directed toward the reflection means 4c.

[0020]

As described above, according to the present invention, an illumination device is provided with an LED lamp, and the light from the LED lamp has an irradiation width substantially corresponding to the width of the display surface of the liquid crystal display element. A light source unit light guide provided at a position outside the display surface having a reflecting means for emitting light in a parallel direction, and light from the light source unit light guide having an irradiation area substantially corresponding to the area of the display surface of the liquid crystal display element; The liquid crystal display device with illumination includes a reflection unit that emits light in a direction perpendicular to the display surface and a display unit light guide that is provided at a position that overlaps the display surface. The light from the LED lamps is made into a line light source in the body, and the surface light source is made in addition to the display martial arts retreat. This type of illuminated liquid crystal display In which exhibits the excellent effect of allowing the extension of the continuously usable time of the appliance to be.

Second, it is possible to illuminate the entire surface of the display section of the liquid crystal display element with uniform brightness by adjusting the density of the reflection means provided on the light source section light guide and the display section light guide. Also, this type of liquid crystal display device with illumination is extremely effective in improving the display quality.

[Brief description of the drawings]

FIG. 1 is a front view showing a first embodiment of an illuminated liquid crystal display device according to the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view showing a second embodiment of the liquid crystal display device with illumination according to the present invention.

FIG. 4 is an explanatory diagram showing light distribution characteristics of an LED lamp.

FIG. 5 is a cross-sectional view showing a main part of a third embodiment of a liquid crystal display device with illumination according to the present invention.

FIG. 6 is a cross-sectional view showing a main part of a liquid crystal display device with illumination according to a fourth embodiment of the present invention.

FIG. 7 is a side view showing a conventional example.

FIG. 8 is a front view of the same conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device with illumination 2, 6 ... Liquid crystal display element 3 ... LED lamp 4 ... Light source part light guide 4a ... End surface 4b, 4d ... Side surface 4c ... Light source part reflection means 5 ... Display Partial light guide 5a ... thick surface 5b ... front 5c ... display unit reflection means 5d ... back 7 ... reflection sheet H ... height of display surface of liquid crystal display element W ... display of liquid crystal display element Surface width P: Optical axis of LED lamp

Claims (4)

[Claims] 1. An illuminated liquid crystal display device comprising a liquid crystal display element provided with an illuminating device using an LED lamp as a light source.
A light source unit light guide provided at a position outside the display surface, the light source portion having a reflection means for irradiating light from the D lamp with an irradiation width substantially equivalent to the width of the display surface of the liquid crystal display element and emitting the light in a direction parallel to the display surface And a reflecting means for irradiating light from the light source unit light guide with an irradiation area substantially equivalent to the area of the display surface of the liquid crystal display element and emitting the light in a direction perpendicular to the display surface. A liquid crystal display device with illumination, comprising: a display unit light guide provided at a position. 2. An illuminated liquid crystal display device according to claim 1, wherein the LED lamp has an optical axis directed toward the reflection means of the light source unit light guide. 3. The liquid crystal display element according to claim 1, wherein the liquid crystal display element is of a transmission type, and the display unit light guide is disposed on a back side of a display surface of the liquid crystal display element. Illuminated liquid crystal display. 4. The liquid crystal display device according to claim 1, wherein the liquid crystal display element is of a reflection type, and the display unit light guide is disposed on a front side of a display surface of the liquid crystal display element. Illuminated liquid crystal display.