JPH0854510A - Light transmission plate for liquid crystal display - Google Patents

Abstract

PURPOSE:To provide a light transmission plate for liquid crystal display provided with reflection grooves most efficient for obtaining high brightness uniformly over the entire plate surface by using an L-shaped tube capable of irradiating the adjacent two sides of the light transmission plate as a light source. CONSTITUTION:This light transmission plate for liquid crystal display provided with the L-shaped tube 2 as the light source alongside the adjacent two sides of the light transmission plate 1 is formed by parting the plural reflection grooves 4 along the respective sides of the L-shaped tube 2 apart spaced intervals in each of the respective regions 3a, 3b bordering at the diagonal line 3 of the light transmission plate 1 on one side face of the light transmission plate 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light guide plate used for a liquid crystal display or the like, and a liquid crystal display light guide plate using an L-shaped tube as a light source.

[0002]

2. Description of the Related Art The characteristics required for a light guide plate used in a liquid crystal display or the like are that the light utilization rate of a light source is increased to increase the brightness of light transmitted to the front surface of the light guide plate. It is to exhibit uniform brightness over the entire surface.

An example of a conventional light guide plate is shown in FIG. 5. A light guide plate 20 is shown on one side of a transparent plate along a straight tube type light source 22 (CFL) provided on one side of the light guide plate 20. 6, a plurality of reflection grooves 21 each having a triangular cross section are formed at a predetermined interval. Light 23 from a light source 22 is incident along a plate surface, hits the inclined surfaces 21a of the respective reflection grooves 21, and is a transmission surface. Reflects to the side and transmits.

In such a conventional light guide plate 20,
In order to increase the reflection efficiency, the groove angle of the reflection groove is set to 45 °, or the plate width is narrowed as the distance from the light source 22 increases, so that the reflection frequency on the far side of the light source 22 is increased and the entire plate surface is covered. To obtain uniform brightness.

[0005]

However, in order to obtain a light guide plate of higher brightness, there is a limit even if the reflection groove shape and the plate width of the light guide plate are tapered, so that the light source itself is limited. It is necessary to increase the illuminance or to provide the light source in the other direction.

Therefore, the present invention has been made in view of the above circumstances, and the light L can enter from two adjacent sides of the light guide plate.
Provided is a liquid crystal display light guide plate using a mold tube as a light source. In such a light guide plate, a liquid crystal having a reflection groove most effective for obtaining uniform high brightness over the entire plate surface. An object is to provide a light guide plate for display.

[0007]

In order to solve the above problems, a liquid crystal display light guide plate according to the present invention is a liquid crystal display light guide plate having an L-shaped tube as a light source on the side of two adjacent sides of the light guide plate. In the light plate, a plurality of reflection grooves along each side of the L-shaped tube are formed at intervals on each side of the light guide plate on one side of the light guide plate. I am trying.

Further, it is preferable that the reflection groove is not formed on a diagonal line of the light guide plate.

Further, as the distance from the L-shaped tube increases,
It is preferable that the reflection groove is formed gradually deeper.

As the distance from the L-shaped tube increases,
It is preferable that the intervals between the reflection grooves are gradually narrowed.

Further, it is preferable that the reflection groove is blasted.

Further, it is preferable that the reflecting groove is provided with metal particles.

Further, it is preferable that the reflection groove is blasted and metal particles are applied.

Further, it is preferable that the flat surface formed in the reflection groove is a mirror surface.

[0015]

The liquid crystal display light guide plate of the present invention, as described above,
Since a plurality of reflection grooves along each side of the L-shaped tube are formed at intervals in each region with the diagonal line of the light guide plate as a boundary, the L-shaped tube having two adjacent sides is formed. Functions as the most effective reflection groove pattern.

That is, the light incident from one side of the L-shaped tube is
First, the light is incident in a direction perpendicular to the reflection groove in the adjacent region, is reflected here, and is transmitted through the plate surface.

Further, the light incident from the same side of the L-shaped tube passes through the above-mentioned near area and reaches the far side area. In this distant side region, the light incident from the same side of the L-shaped tube passes along the groove direction of the reflection groove, so it seems that the light is hardly reflected by the inclined surface of the reflection groove.

However, according to experiments, it has been confirmed that effective reflection is achieved even in the reflection groove in the far side region, which is useful for improving the brightness. It is considered that this is because the light that has entered along the reflection groove in the far side region has diffused reflection in the optical path up to that point.

In the liquid crystal display light guide plate of the present invention, such a light reflection state is generated in the two regions with the diagonal line of the light guide plate as a boundary by the light emitted from each of the two sides of the L-shaped tube. This achieves uniform high brightness over the entire plate surface.

Further, since the reflection groove is not formed on the diagonal line of the light guide plate, it is possible to eliminate the stripe pattern of light which may occur on the diagonal line. This is because, if the reflection grooves of both regions are formed on the diagonal line of the light guide plate as they are, the reflected light may be concentrated on the diagonal line compared to other places, and a light stripe pattern may be generated. There is a solution to this.

Further, when the reflection groove is formed deeper as the distance from the L-shaped tube increases, the reflection area per unit area of the light guide plate increases, so that the brightness that decreases as the distance from the L-shaped tube increases and This is effective in achieving a uniform brightness of the entire light plate.

Also, as the distance from the L-shaped tube is increased, the reflection area per unit area of the light guide plate is increased in the same manner as described above even when the intervals between the reflection grooves are gradually narrowed, so that the distance from the L-shaped tube is increased. The lowered brightness is improved, and the uniform brightness of the entire light guide plate is achieved.

When the reflecting groove is blasted or has metal particles, it has an effect of diffusing the reflected light in a diffused manner in the reflecting groove. By averaging the reflected light over the entire light guide plate, This is useful for achieving uniform brightness.

Furthermore, when the flat surface formed in the reflection groove is a mirror surface, diffuse reflection light due to irregular reflection does not occur on this flat surface, so the diffuse reflection light from the reflection groove is reflected light from the flat surface. The light is transmitted without being interfered with by the light and without being lost, which contributes to the achievement of high brightness of the light guide plate.

[0025]

Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing a state in which an L-shaped tube is provided on two adjacent sides of a liquid crystal display light guide plate according to the present invention. Figure 2
FIG. 2 is a partial sectional view taken along the line AA of FIG. FIG. 3 shows FIG.
FIG. 6B is a cross-sectional view taken along line BB of FIG. 9B, showing a case where a reflection groove having a trapezoidal cross section is formed. 4 is a sectional view taken along the line BB in FIG. 1, showing a case where a reflective groove having an arcuate cross section is formed.

The light guide plate 1 shown in FIG. 1 is made of a transparent plate material such as plastic, and the L-shaped tube 2 is provided on the side of two adjacent sides of the light guide plate 1. Virtual diagonal line 3 of light guide plate 1 that is equidistant from each side 2a, 2b
Each side 2a of the L-shaped tube 2 for each of the regions 3a and 3b with the
Reflection grooves 4 having a plurality of straight tracks along 2b are formed at intervals.

As shown in FIG. 2, the reflection groove 4 is gradually shallowed near the intersections of the reflection grooves 4a and 4b in the respective regions 3a and 3b. In the portion along the diagonal line 3, these reflection grooves 4
It is arranged that a and 4b are not formed at all. In the vicinity where the reflection grooves 4a and 4b are close to each other,
The reflected light from the incident light 12 from the L-shaped tube 2 tends to be concentrated and partially strengthened, but as described above, the reflective grooves 4a, 4
It is advisable to make the groove depth of b gradually shallow and to gradually reduce the reflectance so as to obtain uniform brightness on the entire plate surface.

Further, the reflection groove 4 is formed in a trapezoidal cross section having a flat surface 7 in a valley as shown in FIG. 3, and also as a reflection groove 4'having an arc cross section as shown in FIG. Good.

The method of forming the groove can be performed by a cutting tool or the like for either the reflection groove 4 having a trapezoidal cross section or the reflection groove 4'having a circular arc cross section.

In the light guide plate 1 having the reflection groove 4 formed as described above, for example, the light 12 incident from one side 2a of the L-shaped tube 2 is first perpendicular to the reflection groove 4a in the adjacent area 3a. The light enters in the direction, is reflected here, and is transmitted through the plate surface. Further, the light 12 incident from the same side 2a of the L-shaped tube 2 passes through the above-mentioned proximity area 3a and reaches the area 3b on the far side.

In this far side region 3b, the L-shaped tube 2
The light 12 incident from the same one side 2a of the light passes through along the groove direction of the reflection groove 4b, but since irregular reflection occurs in the optical path up to that time, the plate surface of the light guide plate 1 also with respect to the reflection groove 4b. As a result of acting as reflected light that passes through, the incident light 12 from one side 2a of the L-shaped tube 2 contributes to the improvement of the brightness in the far side region 3b.

This is because when the reflection groove 4 is subjected to sandblasting 5 or metal particles 6 which will be described later, the effect of diffusing and reflecting the light 12 incident along the reflection groove 4 is further enhanced.

In the liquid crystal display light guide plate of the present invention, such a light reflection state is caused by the light 12 emitted from each of the two sides 2a and 2b of the L-shaped tube 2 so that the diagonal line 3 of the light guide plate 1 can be obtained.
Occurs in the two regions 3a and 3b with the boundary as a boundary, thereby achieving uniform brightness on the entire plate surface.

The reflection grooves 4 and 4'are provided in the L-shaped tube 2
It is preferable that the reflection grooves 4 and 4'be formed gradually deeper with increasing distance. That is, in FIG. 3 or 4, when the groove depth D1 close to the L-shaped tube 2 and the groove depth D2 far from the L-shaped tube 2 are compared, it should be D1 <D2. Thereby, the reflection area per unit area at a position away from the L-shaped tube 2 can be increased.

In order to obtain the same effect, the L-shaped tube 2
As it moves away from the adjacent reflection grooves 4, 4 (4 ′,
The intervals between 4 ') may be formed to be gradually narrower. This is one side 2a of the L-shaped tube 2 as shown in FIG.
Or, when the distance L1 between the reflection grooves 4 and 4 close to 2b is compared with the distance L2 between the reflection grooves 4 and 4 away from one side 2a or 2b of the L-shaped tube 2, it should be L1 <L2. As a result, the reflection area per unit area at a position distant from the L-shaped tube 2 can be increased in the same manner as described above.

Further, by performing sandblasting 5 or metal particles 6 on the inclined surfaces or arcuate surfaces in the above-mentioned reflection grooves 4, 4 ', fine unevenness is formed on the inclined surfaces or arcuate surfaces of the reflection grooves 4, 4'. If the light incident on the reflection grooves 4 and 4 ′ is diffused (or scattered), the incident light 12 from the L-shaped tube 2 is diffused over the entire plate surface of the light guide plate 1 and the light guide plate 1 of Averaged over the entire surface.

In the above sandblasting method, the reflection groove 4 formed on the master plate (not shown) for the light guide plate 1,
It is preferable that fine sand particles mixed in high-pressure air are applied to the surface corresponding to 4'in the vertical direction and ejected.

In the step of producing the master plate, sand blasting is not performed, and sand particles are applied to the surfaces corresponding to the reflection grooves 4 and 4'of a mold (not shown) formed by the master plate in the same manner as above. It may be sandblasted.

Further, the sandblasting process by jetting sand particles may be directly applied to the reflection grooves 4 and 4'of the light guide plate 1 as a final product without applying the sandblasting process to both the master plate and the mold. .

However, in the light guide plate 1 having the reflection groove 4 having a trapezoidal cross section in FIG. 3, it is preferable that the flat surface 4 formed in the valley in the reflection groove 4 is mirror-finished by a cutting tool or the like. Thereby, in the light guide plate 1, diffuse reflection light is generated in the reflection groove 4 only in the inclined surface of the reflection groove 4, and the diffusion light 3a of the reflection groove 4 is not interfered with by others, and the diffusion effect in the reflection groove 4 is generated. Is demonstrated more effectively.

The individual reflection grooves 4, 4'and the reflection grooves 4,
By maintaining the specularity of each flat surface between 4 ', the diffuse reflection light generated in the reflection grooves 4, 4'is not lost and the diffuse reflection effect can be maximized. It contributes to the improvement of the brightness of the light plate.

The method of applying metal particles to the reflection grooves 4 and 4'is such that metal particles (fine metal powder) such as gold or silver are attached to the surfaces of the mold corresponding to the reflection grooves 4 and 4 '. When molding the light guide plate 1 from this mold, the above-mentioned metal particles are added to the light guide plate 1.
It is advisable to attach them to the reflection grooves 4, 4'of.

Further, metal particles may be adhered to the reflection grooves 4, 4'of the final product, the light guide plate 1, by printing, painting, vacuum deposition or the like.

When the metal particles are directly applied to the reflection grooves 4, 4'of the light guide plate 1, the metal particles are mixed in a fluid adhesive, and this solvent is mixed with the solvent. The metal particles may be attached to the entire surfaces of the reflection grooves 4 and 4'in a scattered state by causing the particles to flow down from the upper ends of the reflection grooves 4 and 4 '.

Further, at the time of molding the light guide plate 1 from the mold, a coating layer in which metal particles are mixed may be formed on the surface layers of the reflection grooves 4, 4'of the light guide plate 1.

Also in such a light guide plate 1, as in the case of the sandblasting described above, the reflecting grooves 4 and 4'can be provided with a diffusing surface having fine unevenness, and the reflecting grooves 4 and 4'can be formed.
4'can exhibit the same diffusion effect.

Also in the case of applying the metal particles, it is preferable that the flat surface 7 of the reflection groove 4 having a trapezoidal cross section is prevented from adhering the metal particles to secure the mirror surface property of the flat surface 7.

The reflection grooves 4 and 4'may be subjected to the above-mentioned blasting 5 and further may be subjected to the above-mentioned metal particles 6.

[0050]

As described above, according to the light guide plate for liquid crystal display of the present invention, it is possible to form the most effective reflection groove pattern in the light guide plate using the L-shaped tube as the light source. It is possible to efficiently utilize the incident light from the above and to exhibit uniform high brightness over the entire light guide plate.

Further, when the reflection groove is not formed on the diagonal line of the light guide plate, the stripe pattern of light which may occur on this diagonal line can be eliminated, and it is effective in making the brightness of the entire plate surface uniform. Target.

Further, when the reflection groove is formed deeper as the distance from the L-shaped tube increases, the reflection area per unit area of the light guide plate increases, so that the brightness which decreases as the distance from the L-shaped tube increases and This is effective in achieving a uniform brightness of the entire light plate.

Also, when the distance between the reflection grooves is gradually narrowed away from the L-shaped tube, the reflection area per unit area of the light guide plate is increased in the same manner as described above, so that the distance from the L-shaped tube is increased. This is effective in achieving a uniform brightness of the entire light guide plate by improving the decreased brightness.

When the reflection groove is blasted or metal particles are applied, the reflection groove has an effect of diffusing the reflected light in a diffused manner. It is useful for achievement.

Further, when the flat surface formed in the reflection groove is a mirror surface, diffuse reflection light does not occur on this flat surface, so that the diffuse reflection light from the reflection groove interferes with the reflection light from the flat surface. It is possible to effectively transmit diffused light without having to do so, which is useful for achieving uniform high brightness of the entire light guide plate.

[Brief description of drawings]

FIG. 1 is a plan view showing a state in which an L-shaped tube is provided on two adjacent sides of a light guide plate for liquid crystal display according to the present invention.

FIG. 2 is a partial cross-sectional view taken along the line AA of FIG.

FIG. 3 is a cross-sectional view taken along the line BB in FIG. 1, showing a case where a reflection groove having a trapezoidal cross section is formed.

FIG. 4 is a cross-sectional view taken along the line BB in FIG. 1, showing a case where a reflection groove having an arcuate cross section is formed.

FIG. 5 is a plan view showing a conventional light guide plate.

FIG. 6 is a partial cross-sectional view taken along the line CC of FIG.

[Description of sign]

1 ... Light guide plate, 2 ... L-shaped tube, 2a, 2b ... Each side of L-shaped tube,
3 ... Virtual diagonal lines, 3a, 3b ... Each region obtained by dividing the light guide plate by diagonal lines, 4 ... Reflection groove (having a trapezoidal cross section), 4 '... (Reflection groove having an arc cross section), 4a, 4b ... Reflection grooves in each region ,
5 ... Blasting, 6 ... Metal particles, 12 ... Light emitted from L-shaped tube, D1, D2 ... Depth of arbitrary reflection groove on the side near and far from the L-shaped tube, L1, L2 ... L-shaped tube The spacing between the optional reflection grooves on the near side and the far side.

Claims (8)

[Claims] 1. A light guide plate for a liquid crystal display, wherein an L-shaped tube (2) is provided as a light source on the side of two adjacent sides of the light guide plate (1). A plurality of reflection grooves (4) are formed along each side of the L-shaped tube (2) at intervals in each of the regions (3a, 3b) bordering the diagonal line (3) of the light plate (1). A light guide plate for a liquid crystal display, which is characterized in that 2. The light guide plate for a liquid crystal display according to claim 1, wherein the reflection groove (4) is not formed on a diagonal line (3) of the light guide plate (1). 3. As the distance from the L-shaped tube (2) increases,
The light guide plate for a liquid crystal display according to claim 1, wherein the reflection groove (4) is formed to be gradually deeper. 4. As the distance from the L-shaped tube (2) increases,
The light guide plate for a liquid crystal display according to claim 1, wherein the reflection grooves (4) are formed so that a space between them is gradually narrowed. 5. The light guide plate for a liquid crystal display according to claim 1, wherein the reflection groove (4) is blasted (5). 6. The light guide plate for a liquid crystal display according to claim 1, wherein the reflection grooves (4) are provided with metal particles (6). 7. The light guide plate for liquid crystal display according to claim 1, wherein the reflection groove (4) is blasted (5) and metal particles (6) are applied. 8. The light guide plate for a liquid crystal display according to claim 1, wherein the flat surface (7) formed in the reflection groove (4) is a mirror surface.