TWM625157U - display device - Google Patents

Abstract

A display device, suitable for a large-sized display panel, includes an image display unit, an upper polarizing unit, and a lower polarizing unit. The image display unit includes an image display surface. The upper polarizing unit includes a retardation wave plate group disposed on the image display surface side of the image display unit, and an upper polarizing film disposed on the retardation wave plate group. The upper polarizing film has an absorption axis extending in the mechanical direction, the optical axis of the retardation wave plate group is sandwiched by 90 degrees with the absorption axis of the upper polarizing film, and the in-plane retardation value is between 80 nm and 120 nm, and the thickness direction retardation value is between 80 nm and 120 nm. between 240nm and 300nm. The lower polarizing unit is disposed on the opposite side of the image display unit to the upper polarizing unit, and includes a lower polarizing film, the lower polarizing film has an absorption axis extending laterally, and is sandwiched 90 degrees with the absorption axis of the upper polarizing film.

Description

display device

The present invention relates to a display device, in particular to a large-sized liquid crystal display device.

At present, the structure of the VA mode (Vertical Alignment) liquid crystal display device includes a liquid crystal display unit, and two polarizing units respectively sandwiching opposite sides of the liquid crystal display unit, and each polarizing unit is sequentially directed from the liquid crystal display unit to the A retardation wave plate and a polarizing film are stacked on the outside, and the absorption axes of the polarizing films on opposite sides of the liquid crystal display unit are perpendicular to each other, so as to compensate the phase difference generated by the light output of the liquid crystal display unit, so as to improve the effect of different viewing angles. formed deviations.

Among them, these polarizing films are usually made by stacking and stretching polymer films. Most of these polarizing films are made by extending in the machine direction (MD direction extension), and have an absorption axis extending in the machine direction. . Since the width of the production equipment used to make these polarizing films is fixed, when manufacturing liquid crystal display devices, the industry usually directly sets the two absorption axes as the machine direction by cutting and rotating 90 degrees. The extended polarizing films are respectively arranged on both sides of the liquid crystal display unit. However, the larger the size of the liquid crystal display device to be produced, to produce a liquid crystal display device that meets the expected size, additional production equipment with larger width must be added to manufacture the large-sized polarizing film, and the cost is extremely high. .

Therefore, the purpose of the present invention is to provide a display device suitable for making a large-sized display panel.

Therefore, the novel display device, which is suitable for a large-sized display panel, includes an image display unit, an upper polarizing unit, and a lower polarizing unit.

The image display unit includes an image display surface.

The upper polarizing unit includes a retardation wave plate set arranged on one side of the image display surface of the image display unit, and an upper polarizing film arranged on the retardation wave plate The absorption axis of the polarizing film is clamped by 90 degrees, and the retardation wave plate group has an in-plane retardation value ranging from 80 nm to 120 nm, and a thickness direction retardation value ranging from 240 nm to 300 nm.

The lower polarizing unit is disposed on the opposite side of the image display unit to the upper polarizing unit, and includes a lower polarizing film. The absorption axis of the lower polarizing film extends laterally and is clamped at 90 degrees with the absorption axis of the upper polarizing film.

The effect of the present invention lies in that the lower polarizing film has a laterally extending absorption axis, and at the same time, the image display surface is equipped with the retardation wave plate set having a specific range of in-plane retardation value and a thickness direction retardation value. It can be used to produce large-sized display devices without additionally adding larger-width production equipment, which can reduce production costs, and the contrast value of the displayed images is higher, so the positional aberration caused by the enlarged viewing angle is better. good compensation effect.

Before the present invention is described in detail, it should be noted that in the following description, similar elements are designated by the same reference numerals. In addition, it should be noted that the drawings of the present invention only show the relative structure and/or positional relationship among the elements, and are not related to the actual size of each element.

Referring to FIG. 1 , the novel display device of the present invention is suitable for large-sized display panels. The display device includes an image display unit 2 , an upper polarizing unit 3 , a lower polarizing unit 4 , and a protection unit 5 .

The image display unit 2 includes a driving layer 22 with a circuit structure (not shown), a liquid crystal light emitting layer 23 disposed on the driving layer 22 , and a liquid crystal light emitting layer 23 opposite to the driving layer 22 A filter layer 24 on one side, and an image display surface 21 located above the filter layer 24 for displaying images.

In this embodiment, the image display unit 2 is a VA mode liquid crystal display element, the driving layer 22 has a plurality of thin film transistors for introducing current to establish an electric field to drive the liquid crystal light emitting layer 23 , the filter layer 24 Located on one side of the image display surface 21 , it can be used to convert the light emitted by the liquid crystal light-emitting layer 23 into different wavelengths, or can be used to filter out light of a specific wavelength, so that the image display unit 2 can emit a desired color light to the outside. . It should be noted that the detailed structure of the image display unit 2 has been known in the related art, and details are not repeated here.

The upper polarizing unit 3 is disposed on a side of the image display unit 2 adjacent to the filter layer 24 , and includes a retardation wave plate group 31 disposed on one side of the image display surface 21 , and a retardation wave plate group 31 disposed on the retardation wave plate group 31 . the upper polarizing film 32.

It should be noted that, the retardation wave plate group 31 may only have a single or a plurality of superimposed upper retardation wave plates 311 . When the retardation wave plate set 31 has a plurality of upper retardation wave plates 311, the property parameters (ie, the in-plane retardation value, the thickness direction retardation value) of the upper retardation wave plates 311 can be the same or different from each other, as long as the The in-plane retardation value of the retardation wave plate group 31 as a whole may be in the range of 80 nm to 120 nm, and the retardation value in the thickness direction may be in the range of 240 nm to 300 nm, which is not limited thereto.

In the present embodiment, the constituent material of the retardation wave plate set 31 is selected from triacetate cellulose film (TAC), and the retardation wave plate set 31 has two superposed upper retardation wave plates 311 as an example for illustration . Wherein, the in-plane retardation value of each upper retardation wave plate 311 is between 40 nm and 60 nm, the thickness direction retardation value is between 120 nm and 150 nm, and the in-plane retardation value of the entire retardation wave plate group 31 is between 80 nm and 80 nm. From 120 nm to 120 nm, the thickness direction retardation value ranges from 240 nm to 300 nm, but is not limited thereto.

The upper polarizing film 32 is selected from iodine-adsorbed polyvinyl alcohol film (PVA), is made of machine direction (Machine Direction, MD direction extension), and has an absorption axis extending in the machine direction (ie, longitudinal extension), and the The absorption axis of the upper polarizing film 32 and the optical axis of the retardation wave plate group 31 are arranged at an angle of 90 degrees.

The lower polarizing unit 4 is disposed on one side of the image display unit 2 opposite to the upper polarizing unit 3 and adjacent to the driving layer 22 , and includes a lower polarizing film 42 , and a lower polarizing film 42 disposed on the image display unit 2 and the lower polarizing film The lower retardation wave plate 41 between 42 . The lower polarizing film 42 has an absorption axis extending in a transverse direction (Transverse Direction, extending in the TD direction), and the absorption axis of the lower polarizing film 42 and the absorption axis of the upper polarizing film 32 are sandwiched by 90 degrees. The in-plane retardation value of the lower retardation wave plate 41 is between -4nm and 4nm, and the thickness direction retardation value is between 20nm and 40nm, which are used to adjust the phase difference generated by the display device of the present application at different viewing angles, and further enhance the compensation effect. .

In other embodiments, the in-plane retardation value of the lower retardation wave plate 41 and the retardation value in the thickness direction may also be between -3 nm and 3 nm.

In this embodiment, the lower polarizing film 42 is a laminated structure, and has an absorbing polarizing layer 421 disposed adjacent to the image display unit 2 , and an absorbing polarizing layer 421 disposed on the side opposite to the image displaying unit 2 . The reflective polarizing layer 422 is integrated with the absorbing polarizing layer 421 and the reflective polarizing layer 422 . The absorbing polarizing layer 421 is a polyvinyl alcohol (PVA) film adsorbed with iodine, the reflective polarizing layer 422 is formed by laminating many polymer films with birefringence, and the lower retardation wave plate 41 is selected from Triacetate cellulose film (TAC).

It should be noted that the aforementioned in-plane retardation value (R ₀ ) is calculated according to the following formula: R ₀ =(nx-ny)×d; the thickness direction retardation value (R _th ) is calculated according to the following formula And get: R _th =((nx+ny)/2-nz)×d. Among them, d is the film thickness, nx is the refractive index in the direction with the largest in-plane refractive index (ie, the slow axis direction), ny is the in-plane refractive index in the direction perpendicular to the slow axis, and nz is the thickness direction.

Referring to FIG. 2 , it can be seen from FIG. 2 that the extension direction of the absorption axis of the upper polarizing film 32 is the absorption axis direction X, the optical axis of the retardation wave plate group 31 and the extension direction of the absorption axis of the lower polarizing film 42 For the absorption axis direction Y, they are respectively sandwiched by 90 degrees with the absorption axis of the upper polarizing film 32 .

The protection unit 5 is disposed on the side of the upper polarizing unit 3 opposite to the image display unit 2 to provide protection to prevent the upper polarizing unit 3 from being damaged or falling off from the image display unit 2 .

In this embodiment, since the lower polarizing film 42 of the lower polarizing unit 4 is a film with a transversely extending absorption axis, which is directly produced by lateral extension (TD direction extension), it can be directly disposed on the image display unit 2 . The upper polarizing film 32 (that is, has a longitudinally extending absorption axis) is sandwiched by 90 degrees with the absorption axis of the upper polarizing film 32 extending in the machine direction (MD direction extension), so it is not necessary to configure the lower polarizing film as in the conventional liquid crystal display device. It is obtained by using a polarizing film with an absorption axis extending in the machine direction, and then performing procedures such as cutting and rotating 90 degrees. Therefore, when the display device of the present invention is used to manufacture a large-sized display panel, there is no need to add additional production equipment with a larger width, which can save costs.

The new type of display device is manufactured by extending the upper polarizing film 32 and the lower polarizing film 42 directly through the machine direction (MD direction extension) and lateral extension (TD direction extension), respectively. Therefore, the lower polarizing film 42 does not need to be If known, additional turning is required, that is, the absorption axis is sandwiched by 90 degrees with the extending direction of the upper polarizing film 32 . In addition, the present invention further cooperates to control the in-plane retardation value (R ₀ ) and the thickness direction retardation value (R _th ) of the retardation wave plate group 31 adjacent to the image display surface 21 (that is, R ₀ is between 80 nm and 120 nm, R _th is between 240 nm and 300 nm), so that the image presented by the display device of the present invention can maintain a good contrast value.

In some embodiments, the lower polarizing unit 4 can also only be provided with a lower polarizing film 42 extending laterally as shown in FIG. 3 , and the lower retardation wave plate 41 does not need to be provided, which can reduce the thickness of the display device and production costs. In this embodiment, the visual effect presented by the display device without the lower retardation wave plate 41 is similar to the configuration of a lower retardation wave plate whose in-plane retardation value and thickness direction retardation value are both close to 0 41 display device.

Hereinafter, the novel display device will be further described in the following specific examples 1-2 and a comparative example 1 by conoscopic method to measure and detect the luminous viewing angle distribution of these display devices, but it should be understood that , the specific examples and their test data are only used for illustration and should not be construed as a limitation of the implementation of the present invention.

Specific example 1

The configuration of the display device of the specific example 1 is shown in FIG. 1 .

The retardation wave plate group 31 has two upper retardation wave plates 311 , each of the upper retardation wave plates 311 has an in-plane retardation value of 50 nm and a thickness direction retardation value of 137 nm, so that the retardation wave plate group 31 as a whole is The in-plane retardation value is 100 nm, and the thickness direction retardation value is 274 nm.

The upper polarizing film 32 has an absorption axis extending in the machine direction, the lower polarizing film 42 has an absorption axis extending laterally, and is sandwiched by 90 degrees with the absorption axis of the upper polarizing film 32 . And, the in-plane retardation value of the lower retardation wave plate 41 is 0.6 nm, and the thickness direction retardation value is 23.7 nm.

Specific example 2

The structure of the display device of the specific example 2 is roughly the same as the display device of the specific example 1, and the only difference is that the in-plane retardation value of the lower retardation wave plate 41 of the specific example 2 is 0 nm, and the thickness direction retardation value is 0 nm. -2.4nm.

Comparative Example 1

The structure of the display device of the comparative example 1 is similar to the display device of the specific example 1, and the difference lies in that: the lower polarizing film of the comparative example 1 has an absorption axis extending in the mechanical direction and extending in the mechanical direction (extending in the MD direction), After being turned, it was placed on one side of the reverse image display unit of the lower retardation wave plate, so that the absorption axis of the lower polarizing film of Comparative Example 1 and the absorption axis of the upper polarizing film were sandwiched by 90 degrees. In addition, the retardation wave plate group of Comparative Example 1 has only a single upper retardation wave plate, and the in-plane retardation of the upper retardation wave plate (equivalent to the retardation wave plate group of Comparative Example 1) is 50 nm in the thickness direction. The phase difference value is 137 nm. And, the in-plane retardation value of the lower retardation wave plate of Comparative Example 1 was 50 nm, and the thickness direction retardation value was 137 nm.

Referring to FIG. 4 , the measurement is performed by the conoscopic method to obtain the maximum and minimum luminance values and the maximum contrast value of the display devices of the specific examples 1 to 2 and the comparative example 1 in the dark state, respectively. value and minimum value. After that, voltages with the same parameters were applied to the display devices, and a spectroradiometer (Spectroradiometer, model: CS-2000, KONICA-MINOLTA) was used to measure the states of the display devices before and after the voltage was applied (namely, the bright state and the dark state of the display devices), and a first-class iso luminance viewing angle distribution diagram as shown in FIG. 4 can be obtained (for example, a schematic diagram of light leakage in a dark state of a full viewing angle and a comparison diagram of a full viewing angle). The spectrophotometer is then analyzed and calculated to obtain the chromaticity values (x, y), luminance values (Lv), and the like of the display devices of the specific examples 1 to 2 and the display device of the comparative example 1 in the bright state and the dark state, respectively. The central contrast value of the luminance viewing angle distribution map, and the test results are arranged in Table 1. 4(a), (c) and (e) are schematic diagrams of full viewing angle dark state light leakage of the specific example 1, the specific example 2 and the comparative example 1, respectively, and FIGS. 4(b), (d) and (f) The schematic diagrams of the full viewing angle comparison of the specific example 1, the specific example 2 and the comparative example 1 are respectively.

Table 1 Specific example 1 Specific example 2 Comparative Example 1 Upper polarizing unit Delayed wave plate set R ₀ (nm) 100 100 50 Delayed wave plate set R _th (nm) 274 274 137 Number of upper delay wave plates 2 2 1 Upper polarizing film MD direction extension MD direction extension MD direction extension Lower polarizing unit Lower retardation plate R ₀ (nm) 0.6 0 50 Lower retardation plate R _th (nm) 23.7 -2.4 137 Number of lower delay wave plates 1 1 1 Lower polarizing film TD direction extension TD direction extension MD to extend and then turn Upper/lower polarizing film absorption axis angle 90° 90° 90° bright state x 0.2769 0.2776 0.2771 y 0.2920 0.2932 0.2917 Lv 251.1 255.1 256.8 Brightness maximum 1.348 2.601 0.440 Brightness minimum 0.050 0.053 0.048 dark state x 0.2219 0.2268 0.2234 y 0.1899 0.1981 0.1922 Lv 0.0307 0.0331 0.0373 Brightness maximum 1.348 2.601 0.440 Brightness minimum 0.050 0.053 0.048 Compared Central contrast value 8117.7 7702.9 6889.3 Contrast max 4922.381 4614.996 4612.183 Compare the minimum 13.210 10.399 21.936

Compared with the conventional liquid crystal display device (ie, the display device of Comparative Example 1), the absorption axes of the upper and lower polarizing films both extend in the machine direction. The upper polarizing film 32 of the display device of the present invention (ie, the display devices of the specific examples 1 and 2) has an absorption axis extending in the machine direction, and the lower polarizing film 42 has an absorption axis extending in the lateral direction. Therefore, the lower polarizing film of the specific examples 1 and 2 The film 42 does not need an additional turning process, that is, the film 42 has an absorption axis sandwiched by 90 degrees with the extending direction of the upper polarizing film 32 , and can be directly cut and disposed on the outer side of the lower retardation wave plate 41 . In addition, it can be seen from Table 1 that the present invention further controls the in-plane retardation value and the thickness direction retardation value of the retardation wave plate group 31, so that the image presented by the display device of the present invention is better than that of Comparative Example 1. Display devices have higher contrast values. 4(a), (c) and (e), it can be seen that, compared with the display device of Comparative Example 1, the display devices of Specific Examples 1 and 2 have viewing angles of 45 degrees, 135 degrees and 225 degrees at large viewing angles. It also has a good visual contrast effect with 315 degrees. 4(b), (d) and (f) and Table 1, it can be seen that the center contrast value of the display devices of the specific examples 1 and 2 is obviously better than the center contrast value of the comparative example 1.

That is to say, by setting the retardation wave plate set 31 and the lower retardation wave plate 41 with a specific range of in-plane retardation value and retardation value in the thickness direction, the lower polarizing film 42 of the present invention is configured with a laterally extending absorption axis. The display device of the present invention not only exhibits a visual compensation effect not lower than that of the existing liquid crystal display device (ie, Comparative Example 1) equipped with a lower polarizing film with a mechanically extending absorption axis, but also improves its central contrast value, so that the viewer can When viewing the display device from a viewing angle, it has better picture quality.

It should be noted here that the in-plane retardation value and the thickness direction retardation value of the lower retardation wave plate 41 of the specific example 2 are both very close to 0, and the display device shown in FIG. The visual effects presented are very similar, and compared with the display device without the lower retardation wave plate 41 as shown in FIG. 3, the example 2 additionally configures the lower retardation wave plate 41, which can not only further improve the lower polarized light The stiffness of the unit 4 can also be used to protect the lower polarizing film 42 .

To sum up, the lower polarizing film 42 of the novel display device is directly fabricated by lateral extension, and has a laterally extending absorption axis, which can be connected with the absorption axis of the upper polarizing film 32 through the mechanical extension direction without the need for turning and other processes. It intersects at 90 degrees, so when it is used to make a large-sized display panel, it is not necessary to add a larger width production equipment, and the production cost can be reduced. In addition, the retardation wave plate set 31 and the lower retardation wave plate 41 By cooperating with each other, the phase difference generated by the image display surface 21 of the display device at different angles can be adjusted, and has a good visual compensation effect, so the purpose of the present invention can indeed be achieved.

However, the above are only examples of the present invention, which should not limit the scope of implementation of the present invention. Any simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the contents of the patent specification are still included. within the scope of this patent.

2: Image display unit 21: Image display surface 22: Driver layer 23: Liquid crystal light-emitting layer 24: filter layer 3: Upper polarizing unit 31: Delayed wave plate set 311: Upper Delay Wave Plate 32: Upper polarizing film 4: Lower polarizing unit 41: Lower delay wave plate 42: Lower polarizing film 421: Absorption polarizer 422: Reflective polarizing layer 5: Protection unit X, Y: Absorption axis direction

Other features and effects of the present invention will be clearly presented in the embodiments with reference to the drawings, wherein: FIG. 1 is a schematic side view illustrating an embodiment of the display device of the present invention; FIG. 2 is an exploded view illustrating the The absorption axis directions of an upper polarizing film and a lower polarizing film of the embodiment, and the optical axis direction of a retardation wave plate group; FIG. 3 is a schematic side view illustrating another embodiment of the novel display device; and FIG. 4 It is a first-class luminance viewing angle distribution diagram, illustrating specific examples 1 to 2 of the display device, and a comparative example 1 with contrast values at different viewing angles.

2: Image display unit

21: Image display surface

22: Driver layer

23: Liquid crystal light-emitting layer

24: filter layer

3: Upper polarizing unit

31: Delayed wave plate set

311: Upper Delay Wave Plate

32: Upper polarizing film

4: Lower polarizing unit

41: Lower delay wave plate

42: Lower polarizing film

421: Absorption polarizer

422: Reflective polarizing layer

5: Protection unit

Claims (8)

A display device, comprising: an image display unit, including an image display surface; An upper polarizing unit, comprising a retardation wave plate set on one side of the image display surface of the image display unit, and an upper polarizing film set on the retardation wave plate set, the absorption axis of the upper polarizing film being the mechanical direction Extending, the optical axis of the retardation wave plate group and the absorption axis of the upper polarizing film are sandwiched by 90 degrees, and the in-plane retardation value of the retardation wave plate group is between 80nm and 120nm, and the thickness direction retardation value is between 240nm and 300nm. ;and The lower polarizing unit is disposed on the opposite side of the image display unit to the upper polarizing unit, and includes a lower polarizing film. The absorption axis of the lower polarizing film extends laterally and is clamped by 90 degrees with the absorption axis of the upper polarizing film. The display device according to claim 1, wherein the retardation wave plate group has two superimposed upper retardation wave plates, and the in-plane phase difference of each of the upper retardation wave plates is between 40 nm and 60 nm, and the thickness is between 40 nm and 60 nm. The directional retardation value is between 120nm and 150nm. The display device according to claim 1, wherein the lower polarizing unit further comprises a lower retardation wave plate disposed between the image display unit and the lower polarizing film, and the in-plane retardation value of the lower retardation wave plate is Between -4nm and 4nm, the thickness direction retardation value is between 20nm and 40nm. The display device according to claim 1, wherein the lower polarizing unit further comprises a lower retardation wave plate disposed between the image display unit and the lower polarizing film, and the in-plane retardation value of the lower retardation wave plate is Between -3nm to 3nm, the thickness direction retardation value is between -3nm to 3nm. The display device according to any one of claims 1 to 4, wherein the lower polarizing film of the lower polarizing unit has an absorbing polarizing layer disposed adjacent to the image display unit, and an absorbing polarizing layer disposed on the absorbing polarizing layer The reflective polarizing layer on one side of the image display unit is reversed, and the absorbing polarizing layer and the reflective polarizing layer are integrated. The display device according to claim 5, wherein the absorbing polarizing layer of the lower polarizing film is an iodine-based polyvinyl alcohol film, and the reflective polarizing layer is formed by laminating many polymer films having birefringence. The display device according to claim 1, wherein the image display unit comprises a driving layer with a line structure, a liquid crystal light emitting layer disposed on the driving layer, and a liquid crystal light emitting layer disposed on the liquid crystal light emitting layer opposite to the driving A filter layer on one side of the layer, the upper polarizing unit is arranged on the side of the image display unit adjacent to the filter layer, and the lower polarizer unit is arranged on the side of the image display unit adjacent to the driving layer. The display device of claim 1, further comprising a protection unit disposed on the side of the upper polarizing unit opposite to the image display unit.

Images