CN100389348C - Backlight module with holographic diffusion plate - Google Patents

Abstract

The present invention relates to a back lighting module which comprises a light source, a light guiding plate, a prismatic lens and a holographic diffusing piece, wherein the light source is arranged at one end of the light guiding plate; the prismatic lens is positioned above the light guiding plate; the holographic diffusing piece is positioned above the prismatic lens. When the prism angle of the prismatic lens is between 46 DEG and 70 DEG, the diffusing angle of the holographic diffusing piece is between 8 DEG to 21 DEG*3 DEG to 8 DEG.

Description

Backlight module with holographic diffusion plate

Technical field

The present invention relates to a kind of light beam and decompose or combined system, particularly relate to a kind of backlight module with holographic diffusion plate.

Background technology

Backlight module is one of key part and component of display panels.Because liquid crystal itself can't be luminous, therefore need to use backlight module to supply light source, so that liquid crystal panel can show normal and the well-balanced image of brightness.Usually have many blooming pieces in the backlight module, for example diffusion sheet and brightening piece can increase the directivity of emergent ray, make the distribution of emergent ray can be more even.

Known diffusion sheet is to add particulate in blooming piece, reaches the effect of diffusion light in order to scattered beam.The diffusion property that density that can be by particulate and size are controlled diffusion sheet, and the particulate that often is used is generally spherical bead.Yet the light that passes this known diffusion sheet can be covered by its particulate in large quantities, and its backscattering loss is quite high, and makes also wayward its diffusion angle of difficulty.

Have, because light can be redistributed and hide the factor of moire effect (Moir é Effect) with high mist degree, the mode of above-mentioned application diffusion sheet will make the brightness of emergent ray reduce more than 20% significantly again.Therefore, consider the how too many brightness of unlikely loss when using diffusion sheet, and take into account moire effect, be one of research and development emphasis of backlight module at present.

Summary of the invention

One aspect of the present invention is to provide a kind of backlight module, can improve the brightness of emergent ray, reduces cost, and has thin thickness.

According to a preferred embodiment of the invention, this backlight module comprises light source, light guide plate, prismatic lens and holographic diffusion plate.Light source is disposed at an end of light guide plate.Prismatic lens is positioned at the light guide plate top.Holographic diffusion plate is positioned at the prismatic lens top.When the prism angle of prismatic lens between 46 ° between 70 ° the time, the spread angle of this holographic diffusion plate is between 8 ° to 21 ° * 3 ° to 8 °.

By holographic diffusion plate and and the spread angle in prismatic lens when combination and the selective rule between prism angle, the brightness that can improve the backlight module emergent ray effectively.Have again,, therefore can reduce the manufacturing cost of backlight module, and can reduce the thickness of backlight module, meet the more and more frivolous small and exquisite trend of present electronic product because holographic diffusion plate can be made integrated single blooming piece with prismatic lens.

For making above-mentioned and other purpose of the present invention, feature and advantage can more obvious easy to understand, be elaborated especially exemplified by preferred embodiment and conjunction with figs. below.

Description of drawings

Fig. 1 represents the synoptic diagram of a preferred embodiment of the present invention;

Fig. 2 represents the synoptic diagram of the prism angle α of prismatic lens in a preferred embodiment; And

Fig. 3 represents the synoptic diagram of the spread angle β of holographic diffusion plate in a preferred embodiment.

Embodiment

The present invention uses a holographic diffusion plate to make up a prismatic lens, and the selective rule between spread angle and prism angle when stipulating that both make up, and is higher than the brightness that known technology is provided to provide.And, the present invention is specially adapted to have the V-cut light guide plate in the LCD backlight module of (light guide plate) with V-arrangement grooving.

Fig. 1 represents the synoptic diagram of a preferred embodiment of the present invention.Fig. 2 is illustrated in the synoptic diagram of the prism angle α of prismatic lens 106 in the preferred embodiment.Fig. 3 then is illustrated in the synoptic diagram of the spread angle β of holographic diffusion plate 108 in the preferred embodiment.

At first explanation is, prism angle α is defined as the drift angle angle (as shown in Figure 2) of the concaveconvex structure of prismatic lens 1 06, and spread angle β then is defined as the angle (as shown in Figure 3) that light vertical incidence holographic diffusion plate 108 backs are spread apart.And the expression mode of spread angle β generally includes the spread angle of two mutual vertical direction, for example 10 ° * 5 ° (first direction * second direction), wherein all horizontal parallel is in holographic diffusion plate 108 for first direction and second direction, and both are vertical mutually.

Backlight module 100 comprises a light source 102, a light guide plate 104, a prismatic lens 106 and a holographic diffusion plate 108.Light source 102 is configured in an end of light guide plate 104.Prismatic lens 106 is positioned at light guide plate 104 tops.Holographic diffusion plate 108 is positioned at prismatic lens 106 tops.When the prism angle α of prismatic lens 106 between 46 ° between 70 ° the time, the spread angle β of holographic diffusion plate 108 is between 8 ° to 21 * 3 ° to 8 °.

Backlight module 100 imports light source 102 by light guide plate 104, via behind the above-mentioned multi-disc blooming piece (as light guide plate 104, prismatic lens 106 and holographic diffusion plate 108), produces uniform face light source again.Light source 102 generally can use fluorescent tube, light emitting diode or cold-cathode tube.Light guide plate 104 mainly in order to the direction of guiding light diffusion, can make the light of light source 102 distribute fifty-fifty.The material of prismatic lens 106 can be a resin, its usually on flat panel substrates by pasting polypropylene (acryl) resin or directly penetrate the jagged lines of generation, reaching the effect of light harvesting, thereby can increase the brightness of backlight module 100.

In the preferred embodiment, light guide plate 104 can be the V-cut light guide plate.The material of holographic diffusion plate 108 can be polycarbonate (PC), polymethylmethacrylate (PMMA) or polyethylene terephthalate (PET).By the control of hologram record program, can design and manufacture holographic diffusion plate 108 with required optical property.For instance, use the hologram record program to make holographic diffusion plate 108 have micro structured pattern, make its diffraction and refraction incident ray randomly like this.

More particularly, the shape of this micro structured pattern with and in the distribution situation of holographic diffusion plate 108, can determine the light diffusion property of holographic diffusion plate 108.For example, when the micro structured pattern in the unit area was intensive more, the angle of spread angle β was also big more thereupon.In addition, prismatic lens 106 and holographic diffusion plate 108 can be two other blooming pieces of branch, for example prismatic lens 106 and holographic diffusion plate 108 that can be bonding mutually.Perhaps, because the hologram record program can't influence the optical characteristics of prismatic lens 106, therefore prismatic lens 106 and holographic diffusion plate 108 can be made into integrated single blooming piece, can reduce cost, the weight reduction of backlight module like this and make optical module have thin thickness.

In the preferred embodiment, the prism angle α of prismatic lens 106 is selected between 46 ° to 70 °, preferably between 68 ° to 70 °.Have again, corresponding above-mentioned prism angle α, the spread angle β of holographic diffusion plate 108, the angle of its first direction is between 8 ° to 21 °, and the angle of second direction is between 3 ° to 8 °.

Following table one is listed independent light guide plate 104, light guide plate 104 adds the brightness variable quantity that prismatic lens 106, light guide plate 104 add prismatic lens 106 and add a plurality of laboratory samples of the holographic diffusion plate 108 that has different spread angle β respectively separately, with the relation between the brightness of explanation spread angle β of holographic diffusion plate 108 and backlight module 100.Wherein, laboratory sample one is independent light guide plate 104; Laboratory sample two comprises light guide plate 104 and prismatic lens 106; Three, four, five, six of laboratory samples are respectively the combination that light guide plate 104, prismatic lens 106 are added the holographic diffusion plate 108 of different spread angle β.

The comparison of the brightness variable quantity of table one different experiments sample

Laboratory sample	One	Two	Three	Four	Five	Six
							Guide plate	Have	Have	Have	Have	Have	Have
Prism	Do not have	Have	Have	Have	Have	Have
							The holographic sheet that looses	Do not have	Do not have	1.5°× 1.5°	6°× 6°	11°× 11°	21 °× 5°

Brightness	3709	4773	4410	4256	3800	4104
							Brightness variable quantity (%) (comparing) with sample one	Do not have	+28.7	+18.9	+14.7	+2.5	+10.7
Brightness variable quantity (%) (comparing) with sample two	-22.3	Do not have	-7.6	-11	-20	-14

As shown in Table 1, compare with laboratory sample one (independent light guide plate), the laboratory sample three, four, five, six of the preferred embodiment, the different spread angle β according to its holographic diffusion plate 108 can promote 18.9%, 14.7%, 2.5%, 10.7% respectively with brightness.On the other hand, compare with laboratory sample two (light guide plate adds prismatic lens), the laboratory sample three, four, five, six of preferred embodiment, the different spread angle β according to its holographic diffusion plate 108 reduce by 7.6%, 11%, 20%, 14% respectively with brightness.Yet the brightness that the preferred embodiment is lost is lost the problem of too many brightness haply all less than the brightness (more than 20%) that known technology lost in the time of therefore can improving the known application diffusion sheet really.

From the above, spread angle during by holographic diffusion plate and prismatic lens combination and the selective rule between prism angle, the preferred embodiment can improve the brightness of backlight module emergent ray.And, because holographic diffusion plate and prismatic lens can be made into integrated blooming piece, therefore can reduce the manufacturing cost of backlight module, and can reduce the weight and the thickness of backlight module, meet the more and more frivolous small and exquisite trend of present electronic product.

Though the present invention discloses as above with preferred embodiment; but it is not that any those skilled in the art is not breaking away from design of the present invention and scope in order to qualification the present invention; can make various changes and retouching, so protection scope of the present invention is as the criterion with accompanying claims.

Claims (6)

1. backlight module comprises:

Light source;

Light guide plate, described light source are disposed at an end of described light guide plate;

Prismatic lens is positioned at described light guide plate top; And

Holographic diffusion plate is positioned at described prismatic lens top, wherein when the prism angle of described prismatic lens between 46 ° between 70 ° the time, the spread angle of described holographic diffusion plate is between 8 ° to 21 ° * 3 ° to 8 °.

2. backlight module as claimed in claim 1, the material of wherein said holographic diffusion plate are polymethylmethacrylate, polycarbonate or polyethylene terephthalate.

3. backlight module as claimed in claim 1, wherein said prismatic lens and holographic diffusion plate are formed in one.

4. backlight module as claimed in claim 1, wherein said holographic diffusion plate has micro structured pattern.

5. backlight module as claimed in claim 1, wherein said light guide plate are the light guide plate with V-arrangement grooving.

6. backlight module as claimed in claim 1, the prism angle of wherein said prismatic lens is between 68 ° to 70 °.

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