CN204462427U - Prismatic lens, the backlight module adopting this prismatic lens and liquid crystal display - Google Patents

Abstract

The utility model provides a prism sheet for LCD backlight modules, the prism sheet (10) is composed of a plurality of prism structures (12) arranged in parallel on a PET substrate (11), wherein the The prism structure (12) comprises at least three or more prism fringes with different pitches. In addition, the utility model also provides a backlight module for a liquid crystal display and a liquid crystal display equipped with the above-mentioned prism sheet. The utility model disrupts the regular arrangement of the prism stripes existing in the prior art by setting three or more prism stripes with different spacings, thereby eliminating the regularity of the prism stripes. Permanent brightness changes, thus reducing or eliminating the Moiré interference fringes generated between the prism sheet and the LCD panel.

Description

Prism sheet, backlight module and liquid crystal display using the prism sheet

technical field

The utility model relates to a prism sheet which can reduce or eliminate moiré interference fringes. The prism sheet is one of the components used in LCD (Liquid Crystal Display, liquid crystal display) backlight module. In addition, the utility model also relates to the use of A backlight module and a liquid crystal display of the prism sheet.

Background technique

In liquid crystal display (LCD), the LCD panel itself does not emit light, and a backlight module needs to be provided under the LCD panel to provide the surface light source required by the LCD panel, so that it can obtain sufficient brightness and contrast, and then realize the display function .

The existing backlight module usually consists of a light source (cold cathode fluorescent lamp CCFL, light-emitting diode LED, etc.), a light guide plate, a reflector plate and some optical films. These optical films include light diffusion films (lower diffusion film and upper diffusion film), prism films, and the like. The light emitted by the light source is reflected by the reflector to the light guide plate, then exits from the upper surface of the light guide plate to the lower diffusion film, and then converges through the prism sheet formed with prisms to reach the upper diffusion film, and finally forms a surface light source that provides illumination for the LCD panel.

Prism sheet, also known as Brightness Enhancement Film (BEF), is an optical film made by making a prism structure made of acrylic resin or the like on a transparent PET substrate. The function of the prism sheet is to use the slope of the prism structure formed on the transparent PET substrate to deflect the outgoing light within a certain angle range from the lower diffusion film to the front direction and refract it, and the rest of the light is rejected because it does not meet the refraction conditions. The edges of the prism reflect back to the light source and are re-reflected by a reflector at the bottom of the light source. In this way, the light in the backlight is continuously recycled under the action of the prism structure, and the light originally diverging in all directions is controlled to the direction of the front viewing angle after passing through the prism sheet, thereby achieving the effect of enhancing the axial brightness.

Existing prism sheets usually consist of a plurality of prism structures with isosceles triangle cross-section arranged in parallel at equal intervals on a PET substrate. When the prism structures arranged in parallel at equal intervals overlap with the pixel units of the liquid crystal panel also arranged at equal intervals, visible patterns called Moiré interference fringes may be formed, which will reduce the image definition of displayed images. Especially when the LCD pixel requirements are getting higher and higher, and the pixel size of the LCD panel is getting smaller and smaller, the pitch of the pixel units of the LCD panel is smaller, and the prism structure on the prism sheet used in the backlight module The higher the pitch, the easier it is to generate Moire interference fringes due to interference, and the smaller the pitch, the more interference fringes.

In the prior art, in order to suppress the generation of moiré interference fringes, a diffusion film is generally used to increase the haze of the diffusion film, but this will greatly sacrifice the brightness of the liquid crystal display, which runs counter to the trend of striving to improve the brightness of the display.

In order to solve the above defects, various solutions have been proposed in the prior art CN 203385878 U, CN 202171652 U and CN203117445 U, that is, by changing the regular arrangement pattern between the prisms on the prism sheet, the prisms in different regions of the prism sheet The difference in brightness of reflected light is evened out, thereby reducing the possibility of Moiré interference fringes. However, in the above-mentioned prior art, the scheme of prism periodic change arrangement provided by CN 203385878 U is too general, and does not provide accurate data for suppressing Moiré interference fringes, and the change period provided by it presents obvious regularity, which is still relatively easy to produce Moiré interference fringes. The prism structures provided in CN 202171652 U and CN 203117445 U are too complex, almost the same as scratch defects, and the effect of eliminating moiré interference fringes is difficult to evaluate, but there should be a greater possibility for the reduction of display brightness , Moreover, the production cost of such a prism with too high arbitrary structure is bound to be high, and the product quality is also difficult to control.

Utility model content

The technical problem to be solved by the utility model is to provide a prism sheet, a backlight module and a liquid crystal display using the prism sheet, so as to reduce or avoid the aforementioned problems.

Specifically, the utility model provides a prism sheet with an improved structure to achieve the purpose of reducing or eliminating moiré interference fringes and improving LCD brightness. At the same time, the utility model also provides a backlight module and a LCD Monitor.

In order to solve the above technical problems, the utility model proposes a prism sheet for LCD backlight module, the prism sheet is composed of a plurality of prism structures arranged in parallel on the PET base material, wherein the prism structure is at least Consists of three or more prismatic stripes with varying pitches.

Preferably, the prism structure includes three kinds of first prism stripes, second prism stripes and third prism stripes with pitches a, b, and c respectively, and the three pitches satisfy the following relationship: a≦70 μm; a≧2b; b≧1.5c.

Preferably, the numbers of the first prism stripes, the second prism stripes and the third prism stripes on the PET substrate are respectively Na, Nb, Nc, and the numbers satisfy the following relationship: Na≧Nb; Nb≧Nc.

Preferably, the LCD corresponding to the prism sheet has a pixel unit width P1 perpendicular to the length direction of the three prism stripes, and the pixel unit width P1 and the three pitches satisfy the following relationship: P1≧5a; P1≧ 10b; P1≧15c.

Preferably, the prism sheet is laminated with a second film through an adhesive to form a composite optical film structure, and the second film is one of the prism sheet, microlens film or diffusion film; the microlens Both the membrane and the diffuser membrane comprise a PET substrate.

Preferably, the thermal expansion coefficient of the PET substrate contained in the prism sheet, the microlens film and the diffusion film is Tp, the thermal expansion coefficient of the prism structure of the prism sheet is Ta, and the adhesive When the coefficient of thermal expansion is Tb, among them, Tp<Ta; Tp<Tb; Tb≧Ta.

Preferably, when the adhesive force of the prism structure of the prism sheet is Ba, and the adhesive force of the adhesive is Bb, wherein, Bb≧Ba.

In addition, the utility model also provides a backlight module for a liquid crystal display and a liquid crystal display equipped with the above-mentioned prism sheet.

The utility model disrupts the regular arrangement of the prism stripes existing in the prior art by setting three or more prism stripes with different spacings, thereby eliminating the regularity of the prism stripes. It can reduce or eliminate the moiré interference fringes generated between the prism sheet and the LCD panel. In addition, in order to overcome the defect that the prior art cannot accurately suppress Moire interference fringes, the utility model further provides a mathematical model that can be directly adopted by those skilled in the art, and those skilled in the art can realize the moiré interference fringes precision reduction.

Description of drawings

The following drawings are only intended to illustrate and explain the utility model schematically, and do not limit the scope of the utility model. in,

What Fig. 1 shows is the structural representation of the prism sheet according to a specific embodiment of the present utility model;

What Fig. 2 shows is the decomposed structure schematic diagram of the LCD panel corresponding to the prism sheet of the present utility model;

Fig. 3 shows a schematic diagram of the composite optical film structure according to a specific embodiment of the present invention.

Detailed ways

In order to have a clearer understanding of the technical features, purposes and effects of the utility model, the specific implementation of the utility model is now described with reference to the accompanying drawings. Wherein, the same parts adopt the same reference numerals.

FIG. 1 shows a schematic diagram of the structure of a prism sheet according to a specific embodiment of the present invention. The prism sheet has an improved structure to achieve the purpose of reducing or eliminating moiré interference fringes and improving LCD luminance. Specifically, the utility model provides a prism sheet 10 that can be used in LCD backlight modules, and the prism sheet 10 is one of components used in LCD (Liquid Crystal Display, liquid crystal display) backlight modules. In addition, the utility model A backlight module and a liquid crystal display using the prism sheet 10 are also provided.

As shown in Figure 1, the prism sheet 10 of the present utility model is made up of a plurality of prism structures 12 arranged in parallel on the PET base material 11, and different from the prior art, in a specific embodiment of the present utility model, The prism structure 12 includes at least three or more prism fringes with different pitches. The embodiment shown in FIG. 1 schematically shows three kinds of first prism stripes 121 , second prism stripes 122 and third prism stripes 123 with pitches a, b and c respectively. Of course, those skilled in the art should understand with reference to FIG. 1 that the present invention may also include more types of prism stripes with different pitches.

The above-mentioned specific embodiment of the utility model disrupts the regular arrangement of the prism stripes existing in the prior art through three or more than three kinds of prism stripes with different pitches, thereby eliminating the problem caused by the regular arrangement of the prism stripes. The resulting regular brightness changes can reduce or eliminate the Moiré interference fringes generated between the prism sheet and the LCD panel.

In addition, because the complex prism stripes are more likely to produce irregular arrangements and combinations, no additional diffusion film is required, and because the structure of the prism stripes is only changed from the existing technology to the stripe spacing, the advantages of production and manufacturing costs are significantly higher than those of the background technology. The irregular arrangement and combination of the prism stripes significantly improves the uniformity of the brightness of the light reflected by the prisms, improves the utilization rate of the illumination light and can further increase the luminance of the LCD.

Further, in order to overcome the defect that the existing technology cannot accurately suppress the Moiré interference fringes, the utility model provides a mathematical model that can be directly adopted by those skilled in the art, and those skilled in the art can realize the Moiré interference according to the following mathematical model Precise subtraction of streaks. That is, as shown in the specific embodiment in FIG. 1, when the prism structure 12 includes three kinds of prism stripes 121, 122, and 123 with pitches a, b, and c respectively, the three pitches satisfy the following relationship: a≦ 70μm; a≧2b; b≧1.5c.

It can be seen from the above-mentioned mathematical model that in the above-mentioned specific embodiments of the present utility model, three kinds of specific parameter relations of the pitch size are provided, and there is no technical suggestion in the prior art that can be used to obtain the above-mentioned parameter relations, and those skilled in the art can follow this The parameter relationship can precisely reduce the Moire interference fringes. Without the above-mentioned parameter relationship as a revelation, those skilled in the art cannot know what kind of experiment to use to obtain the above-mentioned parameter relationship. Therefore, the above-mentioned parameter relationship of the present utility model The parameter relationship provided by the specific embodiment is non-obvious to those skilled in the art. Compared with the random arrangement of different prism structures in the prior art, it has outstanding substantive features and significant progress, and has the patent law. creativity.

In another specific embodiment, the numbers of the first prism stripes 121, the second prism stripes 122 and the third prism stripes 123 on the PET substrate 11 are respectively Na, Nb, Nc, and the numbers satisfy the following relationship: Na≧Nb ; Nb≧Nc. In this embodiment, a further optimization is carried out on the basis of the aforementioned parameter relationship, so that those skilled in the art can obtain more optimized reduction control for the reduction of Moiré interference fringes.

In yet another specific embodiment, as shown in FIG. 2 , it shows a schematic diagram of an exploded structure of an LCD panel corresponding to the prism sheet 10 of the present invention. 1-2, the prism sheet 10 is arranged in parallel with the LCD panel, and a plurality of regularly arranged rectangular pixel units 20 of the same size are schematically drawn on the LCD panel. In this embodiment, in order to further eliminate moiré For interference fringes, set the pixel unit width of the pixel unit 20 perpendicular to the length direction of the three prism stripes 121, 122, and 123 as P1, and the pixel unit width P1 and the aforementioned three spacings satisfy the following relationship: P1≧5a; P1≧10b; P1≧15c. It should be pointed out that the attachment of the prism sheet 10 to the LCD panel has a certain directionality, and it is meaningful only if the prism stripe direction of the prism sheet 10 and the width of the pixel unit perpendicular to it have the above-mentioned parameter relationship of this embodiment.

Furthermore, each prism sheet 10 in the above specific embodiments of the present invention can be used alone in the LCD backlight module, and can also be laminated and bonded with other films to form a composite optical film structure. As mentioned above, since the prism sheet 10 of the present invention can eliminate moiré interference fringes by itself and does not require an additional diffusion film, it can be used alone in LCD backlight modules to reduce production costs. Of course, in order to provide a more optimized display effect, a composite optical film structure provided with the prism sheet 10 of the present invention may also be provided as described above. Specifically as shown in Figure 3, which shows a schematic diagram of a composite optical film structure according to a specific embodiment of the present invention, in this embodiment, the prism sheet 10 can be laminated with the second film by an adhesive 30 Joined to form a composite optical film structure 1, the second film can be one of the prism sheet 10, microlens film or diffusion film; wherein both the microlens film and the diffusion film contain PET substrates.

That is to say, in the above-mentioned embodiment, the composite optical film structure 1 can be the structure that two layers of prism sheets 10 possessing the structural features of the present utility model are bonded together, or it can be a layer of prism sheet 10 possessing the structural features of the present utility model. A structure bonded to a membrane such as a microlens film or a diffuser film. In the structure specifically shown in Fig. 3, the diaphragm that the upper and lower two layers are bonded all is the prism sheet 10 that possesses the structural characteristics of the present utility model, and those skilled in the art can obtain the prism sheet 10 and the microstructure with reference to the schematic structure shown in Fig. 3 A structure in which a lens film or a diffuser film is glued together (not shown in the figure). In addition, the prism sheet 10 of the present utility model itself is made up of a plurality of prism structures 12 arranged in parallel on the PET substrate 11, and the prism structure 12 can be made by using existing photosensitive resin (UV resin); and the microlens film Both the microlens film and the diffusion film are made of a PET substrate, so it can be said that both the microlens film and the diffusion film contain a PET substrate.

Further, in order to minimize the thermal deformation of the composite optical film structure 1, improve the optical brightness, improve production efficiency and quality, in a specific embodiment, set the prism sheet 10, the microlens film and the diffusion film contained The thermal expansion coefficient of the PET substrate is Tp, the thermal expansion coefficient of the prism structure 12 of the prism sheet 10 is Ta, and the thermal expansion coefficient of the adhesive 30 is Tb, wherein Tp<Ta; Tp<Tb; Tb≧Ta. Those skilled in the art can refer to the combination of the above parameters to select appropriate materials to manufacture the preferred composite optical film structure 1 of this embodiment, so as to realize the minimum deformation of the composite optical film structure 1 when heated, thereby improving the performance of the LCD backlight module. Optical brilliance, that is, improved product quality, reduced product defects and rework, and improved production efficiency.

Furthermore, in yet another specific embodiment, when the adhesion force of the prism structure 12 of the prism sheet 10 is set to Ba, and the adhesion force of the adhesive 30 is set to Bb, wherein Bb≧Ba. That is to say, in this embodiment, the adhesion of the adhesive 30 bonding the prism sheet 10 of the present utility model and the aforementioned second film is preferably greater than, or at least equal to, that the prism structure 12 is attached to the prism sheet. 10, so that it will have better characteristics in terms of structural strength and thermal deformation, further improving the optical brightness of the LCD backlight module, and improving product quality and production efficiency.

In addition, based on the foregoing detailed description, the present invention can also provide a backlight module for a liquid crystal display and a liquid crystal display equipped with the above-mentioned prism sheet.

Those skilled in the art should understand that although the present invention is described in terms of multiple embodiments, not each embodiment only includes an independent technical solution. Such narration in the description is only for the sake of clarity, and those skilled in the art should understand the description as a whole, and understand the technical solutions involved in each embodiment as a way that can be combined into different embodiments to understand the present invention. A new type of protection.

The above descriptions are only illustrative specific implementations of the present utility model, and are not intended to limit the scope of the present utility model. Any equivalent changes, modifications and combinations made by those skilled in the art without departing from the concept and principle of the present utility model shall fall within the scope of protection of the present utility model.

Claims (9)

1. a prism sheet for LCD backlight module, said prism sheet (10) is made up of a plurality of prism structures (12) arranged in parallel on the PET substrate (11), it is characterized in that said prism The structure (12) comprises at least three or more prism fringes with different pitches. 2. The prism sheet according to claim 1, characterized in that, the prism structure (12) comprises three kinds of pitches respectively a, b, the first prism stripe (121), the second prism stripe (122) And the third prism stripes (123), the three pitches satisfy the following relationship: a≦70 μm; a≧2b; b≧1.5c. 3. The prism sheet according to claim 2, characterized in that, the first prism stripes (121), the second prism stripes (122) and the third prism stripes on the PET substrate (11) The numbers of the stripes (123) are respectively Na, Nb, and Nc, and the numbers satisfy the following relationship: Na≧Nb; Nb≧Nc. 4. The prism sheet according to claim 2, wherein the LCD corresponding to the prism sheet (10) has a pixel unit width P1 perpendicular to the length direction of the three kinds of prism stripes (121, 122, 123). , the pixel unit width P1 and the three pitches satisfy the following relationship: P1≧5a; P1≧10b; P1≧15c. 5. The prism sheet according to any one of claims 1-4, characterized in that, the prism sheet (10) is laminated and bonded with the second film through an adhesive (30) to form a composite optical film structure (1) , the second film is one of the prism sheet (10), microlens film or diffusion film; both the microlens film and the diffusion film include a PET substrate. 6. prism sheet as claimed in claim 5, is characterized in that, the thermal expansion coefficient of the PET base material that described prism sheet (10), described microlens film and described diffusion film comprise is Tp, and described prism sheet In (10), when the thermal expansion coefficient of the prism structure (12) is Ta, and the thermal expansion coefficient of the adhesive (30) is Tb, Tp<Ta; Tp<Tb; Tb≧Ta. 7. The prism sheet according to claim 6, characterized in that, the adhesion of the prism structure (12) of the prism sheet (10) is Ba, and the adhesion of the adhesive (30) is Bb , where Bb≧Ba. 8. A backlight module for a liquid crystal display, characterized in that the backlight module comprises the prism sheet (10) according to any one of claims 1-4. 9. A liquid crystal display, characterized in that the liquid crystal display comprises the backlight module as claimed in claim 8.