JP4506358B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device including a backlight system that irradiates a liquid crystal panel from the back side.

  In recent years, liquid crystal display devices using a liquid crystal panel made of TFT or STN are being commercialized mainly in (color) notebook PCs (personal computers) in the OA field. In such a liquid crystal display device, a so-called backlight method, in which a light source is disposed on the back side of the liquid crystal panel and the liquid crystal panel is irradiated with light from the light source, has been conventionally employed. Such a backlight system is roughly classified by attaching a light source lamp such as a cold cathode fluorescent lamp (CCFT) along a side end portion of a flat light guide plate made of acrylic resin or the like having excellent light transmittance. There are a light guide plate light guide method (so-called edge light method) in which light from the multiple light is reflected in the light guide plate and a direct type method without using the light guide plate. Recently, a light guide light guide type backlight system has become mainstream because it is easy to reduce the thickness.

  As a liquid crystal display device on which a light guide plate light guide type backlight system is mounted, for example, one having a configuration as shown in FIG. 5 is generally known. In this, a liquid crystal panel 72 sandwiched between polarizing plates 71 and 73 is provided at the upper part, and a light guide plate 79 made of a substantially rectangular plate-like PMMA (polymethyl methacrylate) or the like is provided on the lower surface side thereof. A diffusion film (diffusion layer) 78 is provided on the upper surface (light emitting surface) of the light guide plate. Further, on the lower surface of the light guide plate 79, a scattering reflection pattern portion 82 for efficiently scattering and reflecting the light introduced into the light guide plate 79 in the direction of the liquid crystal panel 72 is provided by printing or the like. In addition, a reflection film (reflection layer) 77 is provided below the scattering reflection pattern portion 82. In addition, a light source lamp 76 is attached to the light guide plate 79 along the side end portion, and the back side of the light source lamp 76 is arranged so that the light from the light source lamp 76 is efficiently incident on the light guide plate 79. A lamp reflector 81 having a high reflectivity is provided so as to cover it. The scattering reflection pattern portion 82 is a mixture of white titanium dioxide (TiO2) powder mixed in a solution such as a transparent adhesive, printed in a predetermined pattern, for example, a dot pattern, dried, and formed. This is a means for providing directivity to the light incident on the light guide plate 79 and guiding the light toward the light exit surface, thereby increasing the brightness.

  Further, recently, a prism film (prism layer) having a light condensing function between the diffusion film 78 and the liquid crystal panel 72 as shown in FIG. It has been proposed to provide 74 and 75. The prism films 74 and 75 are for condensing the light emitted from the light emitting surface of the light guide plate 45 and diffused by the diffusion film 78 on the effective display area of the liquid crystal panel 72 with high efficiency.

However, in these methods, the control of the visual field range is entrusted only to the diffusibility of the diffusion film 78, which is difficult to control. For this reason, when the liquid crystal screen is viewed from the side, the luminance is greatly reduced, which causes a reduction in light use efficiency.
Further, in the method using a prism film, two prism films are required, so that the amount of light is greatly reduced due to absorption of the film, and the cost is increased.

  By the way, in such a liquid crystal display device, it is strongly demanded as a market need to be thin, low power consumption and high brightness, and accordingly, a backlight system mounted on the liquid crystal display device is also thin. In addition, low power consumption and high luminance are required. In particular, in a color liquid crystal display device that has recently made remarkable progress, the panel transmittance of the liquid crystal panel is much lower than that of a monochrome-compatible liquid crystal panel. Therefore, improving the luminance of the backlight system can reduce the device itself. It has become an indispensable issue for obtaining power consumption. However, in the conventional configuration as described above, it is difficult to say that the demand for high brightness and low power consumption is sufficiently met today, where the liquid crystal display device is further reduced in thickness. The development of a backlight system capable of realizing a liquid crystal display device with high brightness, high display quality, and low power consumption is awaited. Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide a low-cost, high-brightness, high-display quality, and low-power-consumption liquid crystal display device that can meet user demands. .

  In order to solve the above problems, a liquid crystal display device according to the present invention includes a liquid crystal panel, a light source means for irradiating light from the back side of the liquid crystal panel, a liquid crystal panel, and a light source means. A lens layer that guides light from the light source means to the liquid crystal panel, and has a plurality of lenses on one side of the lens layer, and an opening in the vicinity of each lens focal plane between the lens layer and the light source means. The liquid crystal display device has a light shielding portion, and the irradiation light from the light source means passes through the aperture and enters the liquid crystal panel through a lens.

  According to a second aspect of the present invention, there is provided a liquid crystal panel, a light source means for irradiating the liquid crystal panel with light from the back side, and a lens layer for guiding light from the light source means to the liquid crystal panel between the liquid crystal panel and the light source means. A light-shielding portion having a plurality of lenses on one side of the lens layer, and having an opening in a positional relationship between the lens layer and the light source means outside the lens focal plane and imaged inside the liquid crystal layer by the lens The light emitted from the light source means passes through the aperture and enters the liquid crystal panel through a lens.

  According to a third aspect of the present invention, in the liquid crystal display device according to the first or second aspect, the light shielding portion is a reflective layer.

  According to a fourth aspect of the present invention, in the liquid crystal display device according to the third aspect, the reflection layer is a scattering reflection surface.

  According to a fifth aspect of the present invention, in the liquid crystal display device according to any one of the first to fourth aspects, the pitch a of the lenses constituting the lens layer and the pitch b of the openings respectively corresponding to the lenses are a < It is characterized by being in the relationship of b.

  According to a sixth aspect of the present invention, in the liquid crystal display device according to any one of the first to fifth aspects, the shape of the opening is wider in the horizontal direction than in the vertical direction.

  According to a seventh aspect of the present invention, in the liquid crystal display device according to any one of the first to fifth aspects, the number of the apertures is two or more with respect to one lens of the lens layer.

  According to an eighth aspect of the present invention, in the liquid crystal display device according to any one of the first to fifth aspects, the opening includes at least two types of openings having different sizes with respect to one lens of the lens layer. It is characterized by.

  In the light source means for irradiating light from the back side to the liquid crystal panel of the liquid crystal display device of the present invention, the light source means is provided with a lens layer for guiding the light from the light source to the liquid crystal panel. By providing a light-shielding part with an aperture outside the focal plane of the lens layer that is in a positional relationship to form an image inside the liquid crystal layer by the lens layer, the light usage efficiency from the light source that could not be realized with the conventional liquid crystal display device configuration Can be improved. In addition, by making the shape of the opening larger in the horizontal direction than in the vertical direction, the viewing area in the vertical direction is generally small as liquid crystal characteristics. Therefore, by setting the backlight characteristics to be narrow in the vertical direction in advance, the liquid crystal characteristics can be reduced. It is possible to have an observation region that matches the characteristics, and the use efficiency of light can be further increased. Further, by having a plurality of openings for one lens of the lens layer, the observation area of the liquid crystal panel can be divided to have a plurality of observation areas. Further, by making the size of the opening different, the observation region can be changed depending on the region. Furthermore, the viewing zone can be freely controlled by the shape of various apertures. As described above, according to the present invention, it is possible to provide a liquid crystal display device with low cost, high luminance, high display quality, and low power consumption.

  An embodiment of the present invention will be described in detail below based on FIG. In FIG. 1, a liquid crystal panel 12 sandwiched between polarizing plates 11 and 13 is provided at the top, and a light guide plate 79 made of a substantially rectangular plate-like PMMA (polymethyl methacrylate) or the like is disposed on the lower surface side thereof. On the lower surface of the light guide plate 79, a scattering reflection pattern portion 82 for efficiently scattering and reflecting the light introduced into the light guide plate 79 in the direction of the liquid crystal panel 12 is provided by printing or the like. In addition, a reflective film (reflective layer) 77 is provided below the scattering reflection pattern portion 82.

  In addition, a light source lamp 76 is attached to the light guide plate 79 along the side end portion, and the back side of the light source lamp 76 is arranged so that the light from the light source lamp 76 is efficiently incident on the light guide plate 79. A lamp reflector 81 having a high reflectivity is provided so as to cover it.

  The scattering reflection pattern portion 82 is formed by printing a mixture of white titanium dioxide (TiO2) powder in a solution such as a transparent adhesive in a predetermined pattern, for example, a dot pattern, and drying. Light scattered by the scattering pattern portion 82 and the like is emitted from the upper surface of the light guide plate 79. A lens layer 15 composed of a plurality of lenses is disposed on the light emission side, and a light shielding layer 18 having an opening corresponding to each lens is disposed in the vicinity of the focal plane of the lens constituting the lens layer 15. The light emitted from the light guide plate 79 passes only through the opening of the light shielding layer 18 and enters the lens layer 15. Since the light shielding layer is disposed in the vicinity of the focal point, the light emitted from one point of the light shielding layer 18 is emitted from the lens layer 15 as light in a certain direction by the lens. Therefore, the direction of light emitted from the lens layer can be determined by the size of the opening of the light shielding layer 18.

That is, as the size of the opening of the light shielding layer 18 is reduced, the directivity of the backlight is increased. Conversely, when the size is increased, the directivity is reduced and the degree of diffusion is increased. Further, by changing the shape of the opening, it is possible to change the diffusibility depending on the direction. For example, if an opening that is large in the horizontal direction and small in the vertical direction is used, a wide observation area can be taken in the horizontal direction with respect to the vertical direction. Since the viewing area in the vertical direction is generally small as liquid crystal characteristics, the light utilization efficiency can be further improved by setting the backlight characteristics to be narrow in the vertical direction in advance. Furthermore, the observation region of the liquid crystal panel can be divided by setting the number of openings for one lens to a plurality. In this way, the viewing zone can be freely controlled by various aperture shapes. An example of the shape of this opening is shown below.
FIG. 7 shows an example of an observation region that is long in the horizontal direction, FIG. 8 shows an example of an observation region that is long in the horizontal direction and spreads in an ellipse, and FIG. 9 shows an example having two viewing zones of different sizes. An example in which the viewing zone for each lens is changed is shown in FIG.

  The light emitted from the light guide plate 79 passes only through the opening of the light shielding layer 18, and the light incident outside the opening is reflected and reenters the light guide plate 79. The light reflected by the light shielding layer 18 is reflected again by the reflective layer 77 or the like, and is repeatedly reused until it passes through the opening of the light shielding layer 18. Therefore, if the absorption of the light shielding portion of the light shielding layer 18 is reduced and the reflection layer is used, the utilization efficiency is further improved. Further, if the reflection of the light shielding layer 18 is scattering reflection, the probability of entering the opening of the light shielding layer 18 after being reflected by the reflective layer 77 or the like may be improved, so that the light utilization efficiency can be further improved. The light emitted from the lens layer 15 as described above is transmitted through the diffusion layer 14 as necessary, and then enters the liquid crystal sandwiched between the polarizing plates 13 and 11, and the observer modulates the light intensity and the like, thereby allowing the observer to change the image. By observing.

  Further, as shown in FIG. 3, by arranging the diffusion pattern portion 82 in the vicinity of the opening of the light shielding layer 18, the diffused light from the diffusion pattern portion 82 can be efficiently emitted from the opening. In the example shown in FIG. 1, the lens layer 15 is disposed on the light guide plate 79 side. However, the same effect can be obtained even when the lens layer 15 is disposed on the liquid crystal side as shown in FIG. In FIG. 2, a liquid crystal panel 32 sandwiched between polarizing plates 31 and 34 is provided on the upper side, and a substantially rectangular plate having a diffusion film (diffusion layer) 36 provided on the upper surface (light emitting surface) on the lower surface side thereof. A light guide plate 79 made of PMMA (polymethyl methacrylate) or the like is provided. Further, on the lower surface of the light guide plate 79, a scattering reflection pattern portion 82 for efficiently scattering and reflecting the light introduced into the light guide plate 79 in the direction of the liquid crystal panel 72 is provided by printing or the like. In addition, a reflection film (reflection layer) 77 is provided below the scattering reflection pattern portion 82. In addition, a light source lamp 76 is attached to the light guide plate 79 along the side end portion, and the back side of the light source lamp 76 is arranged so that the light from the light source lamp 76 is efficiently incident on the light guide plate 79. A lamp reflector 81 having a high reflectivity is provided so as to cover it.

The scattering reflection pattern portion 82 is formed by printing a mixture of white titanium dioxide (TiO2) powder in a solution such as a transparent adhesive in a predetermined pattern, for example, a dot pattern, and drying. Light scattered by the scattering pattern portion 82 and the like is emitted from the upper surface of the light guide plate 79. A light shielding layer 38 having a plurality of openings is disposed on the light emission side, and light emitted from the openings is transmitted through the diffusion layer 34 as necessary. A lens layer 33 having a lens corresponding to the opening of the light shielding layer 38 is disposed. At this time, the light shielding layer 38 is positioned outside the focal plane of the lens layer 33. It becomes possible to control the diffusibility of the light emitted from the lens layer 33 according to the size of the opening in the light shielding layer 33.
When the lens layer 33 and the light shielding layer 38 are arranged so as to form an image of the opening in the liquid crystal layer 32, the light is condensed in the liquid crystal layer 32 as shown in FIG. By matching with the pitch of the liquid crystal, the energy of light lost by the black matrix of the liquid crystal can be reduced, and light can be used more efficiently.

  In this embodiment, when the lens layer is arranged on the light guide plate as shown in FIG. 1, the light shielding layer is arranged near the focal plane of the lens, and when the lens layer is arranged on the liquid crystal as shown in FIG. Although arranged outside the focal plane of the lens, the effect is not limited to this, and the light shielding layer may be arranged outside the lens focal plane in the configuration of FIG. The layer may be placed near the focal point of the lens.

  Further, although the light transmission density of the light shielding element changes in a binary manner in FIGS. 7 to 10, it may be configured such that the transmittance gradually changes. Furthermore, the transmittance may be changed using a technique such as dithering.

  Furthermore, as shown in FIG. 4, by setting the pitch b of the openings of the light shielding layer 52 to be larger than the lens pitch a of the lens layer 51, it is possible to bring the effect of collecting the observation range for each lens at the viewpoint position 54. . If this is utilized, light can be concentrated in a certain area, so that the light utilization efficiency can be further improved in the case of a relatively large screen.

  If the viewing zone is controlled only in one direction, this effect can be realized with a simpler configuration by using a lenticular lens sheet as the lens layer and an aperture in the form of a slit.

FIG. 4 is a schematic cross-sectional view illustrating a configuration in which a light shielding portion having an opening is provided in the vicinity of a lens layer focal plane in an example of the liquid crystal display device of the present invention. FIG. 3 is a schematic cross-sectional view illustrating a configuration in which a light-shielding portion having an opening is provided outside a lens layer focal plane in an example of the liquid crystal display device of the present invention. The schematic sectional drawing which showed the structure which has arrange | positioned the diffused pattern part to the opening vicinity of the light shielding layer in an example of the liquid crystal display device of this invention. Explanatory drawing which showed the relationship between the pitch of the lens of a lens layer, and the pitch of the opening provided in the light shielding layer in the liquid crystal display device of this invention. FIG. 10 is a schematic cross-sectional view illustrating an example of a configuration of a conventional liquid crystal display device. FIG. 10 is a schematic cross-sectional view showing another example of the configuration of a conventional liquid crystal display device. The top view which showed the example of the shape where the shape of the opening provided in the light shielding part was long in the horizontal direction in the liquid crystal display device of this invention. The top view which showed the example of the shape of the opening provided in the light-shielding part in the liquid crystal display device of this invention with the shape of an ellipse long in a horizontal direction. The top view which showed the example which has two viewing zones from which the magnitude | size of opening differs in the liquid crystal display device of this invention. The top view which showed the example which changed the shape of opening variously and changed the visual field for every lens in the liquid crystal display device of this invention.

Explanation of symbols

11, 13, 31, 34, 71, 73 ... Polarizing plates 12, 32, 72 ... Liquid crystal panels 14, 36, 78 ... Diffusion films 15, 33, 51 ... Lens layers 18, 38, 52 ... Shading layer 54 ... Viewpoint position 74, 75 ... Prism film (prism layer)
76 ... light source lamp 77 ... reflective film (reflective layer)
79 ... Light guide plate 81 ... Lamp reflector 82 ... Scatter reflection pattern a ... Pitch of one lens constituting the lens layer b ... Pitch of aperture corresponding to one lens constituting the lens layer

Claims (4)

In a liquid crystal display device having a wider viewing area in the horizontal direction than in the vertical direction, the liquid crystal panel, the light source means for irradiating light from the back side of the liquid crystal panel, and the light from the light source means between the liquid crystal panel and the light source means A lens layer that leads to the panel, and has a plurality of lenses on one side of the lens layer, and a light-shielding portion having a wider opening in the horizontal direction than in the vertical direction between the lens layer and the light source means in the vicinity of each lens focal plane. The liquid crystal display device is characterized in that the irradiation light from the light source means passes through the opening, enters the liquid crystal panel through the lens, and emits diffused light wider in the horizontal direction than in the vertical direction from the liquid crystal panel. A liquid crystal panel, a light source means for irradiating light to the liquid crystal panel from the back side, and a lens layer for guiding light from the light source means to the liquid crystal panel between the liquid crystal panel and the light source means, on one side of the lens layer Has a plurality of lenses, and has a light-shielding portion having an opening in a positional relationship where the lens forms an image inside the liquid crystal layer outside the lens focal plane between the lens layer and the light source means,
A light shielding part having an opening between the lens layer and the light source means, and the lens layer and the light shielding part are arranged so that the opening forms an image inside the liquid crystal layer;
The liquid crystal display device, wherein the light emitted from the light source means passes through the opening and enters the liquid crystal panel through a lens. 3. The liquid crystal display device according to claim 1, wherein the light shielding portion is a reflective layer. The liquid crystal display device according to claim 3, wherein the reflection layer is a scattering reflection surface.

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