JP2724261B2 - Liquid crystal display - Google Patents

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 such as a dot matrix liquid crystal display having a high number of pixels (high definition), which is used for an image display such as a computer and a TV.

[0002]

2. Description of the Related Art A liquid crystal display device having a liquid crystal panel using liquid crystal as display pixels is characterized by being lighter, shorter in depth and more compact than a display device using a CRT. It has attracted attention as a display device and has been put to practical use. In recent years, in response to a demand for an increase in the number of picture elements in one liquid crystal panel, a large number of picture elements per one liquid crystal display panel range from 1.2 million to 150 million.
A product containing 10,000 pixels has been developed and commercialized. In recent years, a so-called backlight type liquid crystal display device that illuminates from the back of a liquid crystal panel has become common. In this type, each liquid crystal element functions as a shutter, and transmits or blocks (reflects) light emitted from the back of the liquid crystal element to form an image.

[0003]

However, as the number of pixels increases, the quality of a reproduced image may be locally deteriorated due to a defect of a transistor (FET) on a liquid crystal panel or a defect of a bus line. That is, the defective picture element portion cannot not only form an image, but also always transmits or blocks light, so that there is a problem that the picture element portion stands out as a dot such as white or black.

Defects of picture elements per liquid crystal panel decrease with the progress of technology. Today, the incidence of defects in manufactured liquid crystal panels is about 10 @ -6 to 10 @ -8.
It has not reached the point where it is completely zero. Moreover, it is almost impossible to repair or replace a defective picture element that has occurred once it has been manufactured.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a liquid crystal display device in which even if a defect occurs in an image element, the defect in the image element can be easily optically compensated. I do.

[0006]

According to the present invention, there is provided a liquid crystal display device which solves the above-described problems, controls transmission or blocking of light radiated from the back of a liquid crystal panel for each picture element to generate an image on the liquid crystal panel. In the liquid crystal display device, the liquid crystal panel is configured to guide a part of light transmitted through one or more neighboring picture elements to a transmission optical path of the defective picture element in front of the defective picture element of the liquid crystal panel. Separate from glass plate
In that the defective image element compensating member is disposed.

[0007]

According to the liquid crystal display device having the above structure, even if a defect occurs in an image element, an image reproduced by the defective image element is compensated by an image of a neighboring image element.
Deterioration and adverse effects on reproduced images due to defective image elements are substantially eliminated.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on illustrated embodiments. First, an example of a liquid crystal panel to which the present invention is applied will be described with reference to FIGS. FIG. 4 is a front view showing an arrangement of picture elements of a two-dimensional transmission type liquid crystal panel.
This liquid crystal panel has a picture element, that is, a transparent display electrode 11.
Are arranged in a matrix. One transparent flat plate-like common electrode 13 is disposed facing the surface of each display electrode 11.
The liquid crystal panel 15 is sandwiched between the two (see FIG. 5).
The display electrode 11 and the common electrode 13 are formed of a very thin glass plate or a nearly transparent film.

Each display electrode 11 is connected to an FET (a source electrode 17 and a drain electrode 1) formed adjacent to each other.
9 (only voltage 9 is shown). The drain electrode 19 is connected to the display electrode 11, and when the drain electrode 19 is turned on, a voltage is applied between the display electrode 11 and the common electrode 13, and a voltage between the display electrode 11 and the common electrode 13 is reduced. Pixels are formed by changing the orientation of the liquid crystal of the liquid crystal panel 15 to transmit and block light.
That is, each display electrode 11 constitutes one picture element 12.

Each source electrode 17 is connected to a source bus line 21.
, And a gate electrode (not shown) is connected to the gate bus line 23. An image signal to be reproduced is supplied to the source bus line 21, and a driving gate signal is supplied to the gate bus line 23. That is, according to the image signal supplied to the source bus line 21, the optical path of each pixel in the column to which the gate signal is supplied is controlled to transmit or block light. The drain signal is turned on / off in row units from the top, and a source signal is supplied in synchronization with the on / off operation.

The structure of the liquid crystal panel will be described in more detail with reference to FIG. FIG. 5 is a sectional view taken along the line VV of FIG. Display electrode 11, source electrode 1
7. Source bus line 21 and gate bus line 23
Are formed on the same transparent glass substrate 25.
A transparent glass plate 27 is provided above the glass substrate 25, and the common electrode 13 is formed by coating on a surface of the glass plate 27 facing the glass substrate 25. The liquid crystal panel 15 is disposed between the glass substrate 25 and the glass plate 27.

Further, outside the glass substrate 25 and the glass plate 27, a pair of polarizing plates 29 and 31 are provided. The polarization axes of the polarizing plates 29 and 31 are arranged in parallel or at right angles to each other. For example, in a mode in which a light is transmitted when a voltage is applied to the display electrode 11 and the common electrode 13, the polarization axis is arranged in a direction perpendicular to the polarization axis. It is arranged to be parallel. In addition, an illumination device (not shown) from below the polarizing plate 29.
Irradiates light.

Next, the structure of an embodiment in which the present invention is applied to a similar liquid crystal panel having the above-described defective pixels will be described with reference to FIGS. 1 and 2 are views showing the same parts as those in FIGS. 4 and 5, respectively. Members having the same functions as those of the liquid crystal panel shown in FIGS. 4 and 5 are denoted by the same reference numerals.

The picture elements 12a, 12b, 12 of the liquid crystal panel
It is assumed that the image element 12b of c is a defective image element. In other words, the defective image element 12b assumes that the liquid crystal in this part cannot be optically controlled because the display electrode 11 has a functional defect, that is, it is always in a light-shielded state regardless of the supply of the source signal and the gate signal. . In addition, the adjacent picture element 1
2a and 12c shall function normally.

A defective pixel compensator (defective pixel compensator) 41, which is a feature of the present invention, is provided in front of the defective image element 12b. This defective pixel compensator 41 is
7 and the polarizing plate 31, and is fixed to the upper surface of the glass plate 27.

The defective pixel compensator 41 includes a defective pixel element 12b.
A pair of legs (light introducing portions) 42 that straddle (display electrode 11b) 42
It has. The incident end faces 43 of the light introducing sections 42 face a part of the adjacent image elements 12a and 12c, respectively, and a part of light emitted from the image elements 12a and 12c is Incident on. The light I incident on one of the light introduction portions 42 is reflected by the first total reflection surface 44, further reflected by the second total reflection surface 45, exits from the exit end surface (exit portion) 46, and exits from the polarizing plate 31. And is emitted to the outside. Similarly, light II incident on the other light introduction part 42
Is also reflected by the first total reflection surface 44, further reflected by the second total reflection surface 45, exits from the exit end surface 46, and
And is emitted to the outside. Here, since the emission end face 46 is provided in front of the defective image element 12b, that is, in the transmitted light path, the light I and II emitted from the emission end face 46 become light transmitted through the defective image element 12b.

The defective image element 12 is detected when the display electrode 11 and the glass plate 27 are assembled. When the defective pixel element 12 (display electrode 11) is detected, the defective pixel compensator 41 is placed at a corresponding position on the glass plate 27.
Attach.

As described above, the defective pixel compensator 41 of this embodiment is used.
According to this, the normal picture element 12 on both sides of the defective picture element 12b
Since the light transmitted through a and 12c is guided to the defective picture element 12b, the defect is compensated by the adjacent picture elements 12a and 12c and becomes inconspicuous.

FIG. 3 shows an embodiment of the defective pixel compensator 41a when the defective picture element exists linearly. In this liquid crystal panel, three picture elements 12b1 to 12b3 have defects vertically, but picture elements 12a1 to 12a3,
c1 to 12c3 are normal. The basic structure of the defective pixel compensator 41a is substantially the same as that of the defective pixel compensator 41, for example, including a pair of light introduction portions 42a and an emission end surface 46a. The difference is that it is formed to cover.

As described above, in the illustrated embodiment, the cross section of the defective pixel compensator has a trapezoidal shape. However, the present invention is not limited to this shape. Further, in this embodiment, the light of two picture elements adjacent to the left and right of the defective picture element is used, but two picture elements vertically adjacent to each other may be used. Further, if one of them is used, the structure is simplified, and if the four picture elements at the top, bottom, left and right, or a plurality of neighboring picture elements are used, more accurate compensation becomes possible.

If the light introducing portion or the emitting portion of the defective pixel compensator has a lens function, the convergence and divergence of light can be improved. A light absorbing member or a diffusing surface for absorbing unnecessary light may be formed, or a diffusing element using a reflecting surface, for example, a device in which the reflecting surface 45 is a diffusing surface may be used.

Further, in the present invention, an optical fiber can be used as a defective pixel compensator. In this case, 1
One end face of the book or bundle of optical fibers is an incident end face, and the other end face is an emission end face.

[0023]

As described above, in the liquid crystal display device of the present invention, light to be transmitted through a defective picture element is compensated for by light transmitted through a neighboring normal picture element. Image quality and quality can be greatly improved, and the yield of liquid crystal panels can be greatly improved.

[Brief description of the drawings]

FIG. 1 is a front view showing a relationship between an image element, a defective image element, and a defective pixel compensator and a structure in an example in which the present invention is applied to a two-dimensional transmission type liquid crystal panel.

FIG. 2 is a sectional view taken along the line II-II in FIG. 1;

FIG. 3 is a front view showing the relationship and structure between a picture element, a defective picture element, and a defective pixel compensator in another embodiment.

FIG. 4 is a front view showing an arrangement of picture elements of a two-dimensional transmission type liquid crystal panel.

FIG. 5 is a sectional view taken along section line VV in FIG. 4;

[Explanation of symbols]

 REFERENCE SIGNS LIST 11 display electrode 13 common electrode 15 liquid crystal panel 17 source electrode 19 drain electrode 21 source bus line 23 gate bus line 25 glass substrate 27 glass plate 29, 31 polarizing plate 41 defective pixel compensator 42 light introduction part 43 incident end face 46 emission end face

Claims (2)

(57) [Claims] 1. Light emitted from the back of a liquid crystal panel is
In a liquid crystal display element for generating an image on a liquid crystal panel by controlling transmission or blocking for each picture element, a part of light transmitted through one or more neighboring picture elements in front of a defective picture element of the liquid crystal panel. Glass plate constituting the liquid crystal panel for guiding the liquid crystal panel to a transmission light path of the defective image element.
A liquid crystal display device, wherein a defective image element compensating member separate from the above is arranged. 2. The defective picture element compensating member according to claim 1, wherein the incident end face faces a part of the entire surface of a normal picture element adjacent to the defective picture element, and A liquid crystal display device comprising: an emission unit that emits incident light into a transmission optical path of the defective image element.