JP2006227117A - Liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal display device capable of attaining high luminance by efficiently and reliably irradiating a liquid crystal module with light emitted from LEDs. <P>SOLUTION: The liquid crystal display device 30 is provided with the liquid crystal module 32 display displaying a video image and a backlight device 33 irradiating the rear surface of the liquid crystal module 32 with light, wherein the backlight device 33 includes: a plurality of LEDs 46 to be light sources; parallel light conversion lenses 49 disposed in front of the LEDs 46 and converting light emitted from the LEDs 46 into parallel light; polarization conversion means 50 unifying light passing through the parallel light conversion lenses 49 in either one polarization state of a P wave and a S wave so that the polarization state is made coincident with the transmission axis of a polarizing plate 44 located on the rear side of the liquid crystal module 32; and luminance uniformizing lenses 56 dispersing light passing through the polarization conversion means 50 to irradiate the rear surface of the liquid crystal module 32 with the dispersed light, and one parallel light conversion lens 49, one polarization conversion means 50 and one luminance uniformizing lens 56 are provided for each of the LED 46. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a liquid crystal display device including a liquid crystal module and a backlight device.

As shown in FIG. 15, the liquid crystal display device 10 includes a liquid crystal module 14 having a liquid crystal material 13 sandwiched between a TFT array substrate 11 and a color filter substrate 12, and a liquid crystal module 14 disposed on the back side of the liquid crystal module 14. The module 14 includes a backlight device 15 that emits irradiation light. The backlight device 15 includes a light source 16 and a light guide plate 17 that guides light emitted from the light source 16 to the back surface of the liquid crystal module 14.
Note that the backlight device using LEDs as the light source can freely change the color of the backlight by using three colors of LEDs, can improve the moving image characteristics by facilitating lighting control, and can further improve mercury characteristics. Non-use (Hg-free) can also be handled.

An LED may be used as the light source 16 of the backlight device 15, but a luminance equal to or higher than that of a conventional cold cathode ray tube is required.
However, since a polarizing plate 18 having a transmission axis in a specific direction is provided in a portion receiving the irradiation light on the back side of the liquid crystal module 14, all of the light irradiated by the backlight device 15 is inside the liquid crystal module 14. In other words, the polarized light that does not coincide with the transmission axis of the polarizing plate 18 is merely converted into heat, and there is a problem that the efficiency is poor when aiming at high luminance.

  In order to solve such problems, Patent Document 1 discloses a polarization conversion unit that aligns the polarization of light emitted from an LED that is a light source. However, the device disclosed in Patent Document 1 is not a liquid crystal display device but a projector device.

JP 2000-212499 A

As disclosed in FIG. 1 and FIG. 2 of Patent Document 1, in a display device provided with polarization conversion means, one polarization conversion means and one condenser lens are provided for a plurality of LEDs. ing.
However, in such a configuration, there has been a problem that when performing polarization conversion or adjustment of light collection or the like on light emitted from a plurality of LEDs, there is a possibility that the light cannot be efficiently and reliably executed due to light leakage or the like.
Further, in recent years when liquid crystal modules are becoming larger in screen, when one polarization conversion means, one condenser lens, etc. are provided for a plurality of LEDs, the polarization conversion means and the condenser lens are extremely large. Must be adopted, leading to increased costs.

  Therefore, the present inventor has studied the arrangement of the LED and the polarization conversion means in various ways and has arrived at the present invention.

  That is, the present invention has been made to achieve the above object, and the object of the present invention is to provide a liquid crystal display device that can achieve high luminance by irradiating the liquid crystal module with light emitted from the LED efficiently and reliably. There is.

According to the liquid crystal display device of the present invention, in the liquid crystal display device including a liquid crystal module that displays an image and a backlight device that irradiates the back surface of the liquid crystal module, the backlight device is a light source. A plurality of LEDs, a parallel light conversion lens that is disposed on the front surface of the LED and converts light emitted from the LEDs into parallel light, and light that has passed through the parallel light conversion lens is provided on the back side of the liquid crystal module. A polarization converter that aligns with either the P-wave or S-wave polarization so as to coincide with the transmission axis of the polarizing plate, and disperses the light that has passed through the polarization converter to irradiate the back surface of the liquid crystal module. The parallel light conversion lens, the polarization conversion unit, and the brightness uniformizing lens are each 1 for each of the LEDs. It is characterized in that is provided by.
By adopting this configuration, light emitted from one LED is converted into parallel light by one parallel light conversion lens, polarized by one polarization conversion means, and converted by one luminance uniforming lens. Since it is dispersed, the conversion of the light irradiated by one LED is executed without fail and high brightness can be achieved. In addition, when there are a plurality of LEDs and each has a different color and characteristic, conversion suitable for the color and characteristic of each LED can be performed. Further, it is not necessary to use one large lens or the like, which contributes to cost reduction.

Further, the plurality of polarization conversion means may be characterized in that a half-wave plate is provided between adjacent beam splitters.
According to this configuration, the polarized light reflected by the beam splitter is incident on the adjacent beam splitter, but is polarized before being incident on the adjacent beam splitter, and in the same direction as the polarized light transmitted by the adjacent beam splitter. Reflected and emitted from the adjacent beam splitter. In this way, polarization conversion can be reliably performed with a compact configuration in which the beam splitter and the half-wave plate are continuously arranged.

In addition, a wavelength selection unit that transmits only light having a wavelength that considers the transmission wavelength of the color filter and does not transmit light having other wavelengths may be provided.
According to this configuration, it is possible to reflect or absorb an unnecessary wavelength portion of the light emitted from the LED, and to improve the color reproducibility of the image displayed on the liquid crystal module.

Further, the LED, the parallel light conversion lens, the polarization conversion means, and the brightness uniformizing lens are arranged in an up-down direction or a horizontal direction, respectively, and the optical axes of the aligned plurality of brightness uniformizing lenses are The LED, the parallel light conversion lens, and the polarization conversion means are arranged so as to be shifted from the optical axis toward the end of the row, and the direction of irradiation of the dispersed light is directed toward the center of the row of the aligned LEDs. It is good also as providing.
That is, conventionally, not all of the light emitted from the LEDs located near the outer periphery of the liquid crystal module is incident on the liquid crystal module, and the portion irradiated toward the outside of the liquid crystal module is wasted. However, according to this configuration, it is possible to irradiate the irradiation light from the LEDs located in the vicinity of the outer peripheral edge of the liquid crystal module toward the center direction of the LED rows without designing the lens for each LED position. This prevents light from being wasted and contributes to higher brightness.

The LEDs, the parallel light conversion lens, the polarization conversion means, and the brightness uniformizing lens are arranged in an up-down direction or a horizontal direction, and the plurality of aligned LEDs are adjacent in the vicinity of the center of the column. The distance between the adjacent LEDs may be long, and the distance between the adjacent LEDs may be shortened toward the end of the column.
According to this configuration, since the irradiation light of the LEDs existing on the end side of the column is provided so as to face the center of the liquid crystal module, sufficient irradiation light is incident near the center of the liquid crystal module. For this reason, the number of LEDs can be made smaller than the number outside the column in the vicinity of the center of the column, so that the irradiation light incident on the liquid crystal module can be balanced as a whole.

Further, the LED, the parallel light conversion lens, the polarization conversion means, and the luminance uniformizing lens are arranged in an up-down direction or a horizontal direction, respectively, and each LED is an LED of the same color with respect to the center of the column May be arranged symmetrically.
In the case of having a plurality of colors of LEDs, it is necessary to mix the colors of the LEDs. By adopting this configuration, the colors of the colors can be mixed evenly in the LED alignment direction.

A plurality of the LEDs, the parallel light conversion lens, the polarization conversion means, and the brightness uniformizing lens are irradiated with irradiation light from the upper side to the lower side and from the lower side to the upper side on the back side of the liquid crystal module. As described above, the liquid crystal module is arranged so as to be aligned in the horizontal direction at the back side upper side and the back side lower side, so that the light irradiated from the upper side to the lower side is reflected toward the back side of the liquid crystal module. One reflecting plate may be disposed, and a second reflecting plate may be disposed so as to reflect the light emitted from the lower side toward the upper side toward the back surface of the liquid crystal module.
By adopting this configuration, the backlight devices are arranged above and below the back side of the liquid crystal module, so that the entire depth of the liquid crystal display device can be shortened. Moreover, since several LED was divided and arrange | positioned at each upper and lower sides, the space | interval of adjacent LED can be opened and a condensing rate can be raised.

Note that a plurality of the LEDs, the parallel light conversion lens, the polarization conversion means, and the brightness uniformizing lens are irradiated from left to right and from left to right on the back side of the liquid crystal module. So that the light emitted from the right side to the left side is arranged on the back side right side and the back side left side of the liquid crystal module. A third reflector is disposed so as to reflect the light toward the left, and a fourth reflector is disposed so as to reflect the light emitted from the left to the right toward the back of the liquid crystal module. It is good also as a feature.
Also with this configuration, the depth of the liquid crystal display device can be shortened. Moreover, the space | interval of adjacent LED can be opened and a condensing rate can be raised.

In addition, the first to fourth reflectors may be formed such that an end portion located away from the liquid crystal module is curved in a direction approaching the liquid crystal module.
According to this configuration, the depth of the liquid crystal display device can be further shortened by the amount that the end portion of the reflecting plate is curved in a direction approaching the liquid crystal module.

The first to fourth reflectors may be characterized in that a flat base and a plurality of small reflectors that are non-parallel to the surface of the base with respect to the base are arranged.
According to this configuration, since the angle of the light applied to the liquid crystal module is adjusted by the small reflector, it is not necessary to increase the depth of the entire reflector, and the depth of the liquid crystal display device can be shortened.

  According to the liquid crystal display device of the present invention, the light emitted from the LED can be efficiently incident on the liquid crystal module, so that high brightness can be achieved without increasing the output of the LED itself or increasing the number of LEDs.

Example 1
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a plan view showing a schematic configuration of a liquid crystal display device of the present invention.
The liquid crystal display device 30 includes a liquid crystal module 32 and a backlight device 33. The backlight device 33 is disposed on the back side of the liquid crystal module 32 and irradiates the liquid crystal module 32 with illumination light.

The liquid crystal module 32 is configured by sandwiching a liquid crystal material 36 between a TFT array substrate 38 and a color filter substrate 40, and the TFT array substrate 38 is located on the back side and the color filter substrate 40 is located on the front side.
The TFT array substrate 38 is configured by arranging thin film transistors at intersections of matrix-like electrode lines formed on a transparent substrate.
A polarizing plate 42 is disposed on the front side of the color filter substrate 40, and a polarizing plate 44 is also disposed on the back side of the TFT array substrate 38.

The backlight device 33 irradiates irradiation light toward the polarizing plate 44 on the back side of the liquid crystal module 32, and employs an LED 46 as a light source. The LED 46 is preferably an RGB (red, green, blue) three-color LED. By mixing the light emitted from the three color LEDs and irradiating the liquid crystal module 32, the reproduction of the color of the display image becomes wider.
The number of RGB three-color LEDs 46 is not necessarily the same for all the colors, but may be different depending on the color.

The configuration of the backlight device 33 will be described with reference to FIGS. FIG. 2 is a plan view showing the configuration of the backlight device 33, and FIG. 3 is a rear view showing the arrangement of LEDs.
The backlight device 33 includes a plurality of LEDs 46, 46..., A plurality of parallel light conversion lenses 49, 49... Disposed on the front surface of each LED 46 for converting light emitted from the LEDs 46 into parallel light, A plurality of polarization conversion elements 50 arranged in front of the parallel light conversion lens 49 and aligning one of the two polarization components (P wave and S wave) of the irradiation light from the LED 46 with the other polarization axis. , 50... And a plurality of luminance equalizing lenses 56, 56... Disposed on the front surface of each polarization conversion element 50 to disperse and convert the parallel-converted parallel light into dispersed light.

The plurality of LEDs 46 according to the present embodiment are arranged in a horizontal direction at regular intervals.
As described above, one parallel light conversion lens 49, one polarization conversion element 50, and one luminance uniforming lens 56 are disposed on the front surface of each LED 46 aligned in the horizontal direction. Therefore, the parallel light conversion lens 49, the polarization conversion element 50, and the luminance uniformizing lens 56 are also provided in a line with a certain interval in the horizontal direction.

The parallel light conversion lens 49 employs a plano-convex lens provided with such a curvature and size that all the light emitted from the corresponding LED 46 is incident thereon. The plano-convex lens is arranged so that the plane side faces the LED 46.
Irradiation light from the LED 46 incident on the parallel light conversion lens 49 is converted into parallel light and emitted toward the polarization conversion element 50.

The polarization conversion element 50 is disposed on the front surface of the parallel light conversion lens 49, and one of the two polarization components (P wave and S wave) of the irradiation light from the LED 46 is aligned with the other polarization axis. It is what you have.
The polarization axis aligned by the polarization conversion element 50 is a direction that coincides with the transmission axis of the polarizing plate 44 provided on the back side of the liquid crystal module 32. For this reason, the light irradiated from LED46 can be used efficiently, and the heat_generation | fever by the polarization component reflected or absorbed by the polarizing plate 44 can be eliminated, and temperature rise can be prevented.

  The polarization conversion element 50 includes a beam splitter 52 and a half-wave plate 54. The beam splitter 52 is a component that separates the P wave and the S wave of parallel light, and the half-wave plate 54 delays the phase of one of the separated polarized light by ½ wavelength so that the polarized light matches the other polarized light. . The half-wave plate 54 is disposed between the beam splitters 52 aligned in the horizontal direction.

In the present embodiment, it is assumed that the P wave travels straight by the beam splitter 52 and the S wave is bent 90 degrees and reflected.
The S wave bent and reflected by 90 degrees is converted into a P wave by the half-wave plate 54 and enters the adjacent beam splitter 52 (broken arrow). The converted P wave incident on the adjacent beam splitter 52 is reflected by the reflecting surface of the adjacent beam splitter 52 and is output in the same direction as the P wave transmitted by the adjacent beam splitter 52.
In this way, a plurality of beam splitters 52 are arranged so that the adjacent beam splitters 52 are positioned in the outgoing direction of the polarized light to be reflected, and a half-wave plate 54 that converts the polarized light is arranged between the beam splitters 52. As a result, polarization conversion can be performed efficiently with a compact configuration.

  In the present embodiment shown in FIG. 2, the S wave separated by the beam splitter 52 is not used as it is at the end of the row, but a reflector (see FIG. (Not shown) and a half-wave plate for converting to a P wave may be provided so that light emitted from the end of the column is also incident on the liquid crystal module 32.

As shown in FIG. 4, a dichroic mirror 58 is provided on the optical axis of the irradiation light of the LED 46 as an example of wavelength selection means that transmits only light of a specific wavelength and reflects light other than the specific wavelength. Also good. By providing the dichroic mirror 58 and narrowing down the wavelength of light emitted by the LED 46, it can be expected that the color reproducibility is improved.
In consideration of the transmission wavelength of the color filter 40, different types of dichroic mirrors 58 are arranged for the colors of the LEDs 46. The arrangement location may be between the parallel light conversion lens 49 and the polarization conversion element 50 as shown in FIG. 4 or between the polarization conversion element 50 and the luminance uniforming lens 56.

Furthermore, as shown in FIG. 5, the arrangement of the LEDs 46 may be symmetric so that the colors of the LEDs 46 are the same color with respect to the center of the column. That is, LEDs 46 of the same color are arranged at both one end and the other end of the row, LEDs 46 of the same color are arranged at both the second from the one end and the second from the other end, For example, LEDs 46 of the same color are arranged on both the third end from the end and the third end from the other end.
With such a configuration, it can be expected that the colors can be mixed evenly in the alignment direction of the LEDs 46.

(Example 2)
Hereinafter, Example 2 is demonstrated based on FIG. In addition, the same code | symbol is attached | subjected about the component same as the Example mentioned above, and description may be abbreviate | omitted.
In the present embodiment, the optical axis of the luminance uniformizing lens 56 aligned in the horizontal direction coincides with the optical axis of the corresponding LED 46 near the center of the column, and the light of the luminance uniforming lens 56 approaches the end of the column. A feature is that the axis is gradually shifted from the optical axis of the corresponding LED 46.

  The deviation width of the optical axis is provided so as to gradually increase toward the end of the row. Further, by shifting the optical axis of the luminance uniforming lens 56 toward the center of the column, the light incident on the luminance uniforming lens 56 is refracted by the luminance uniforming lens 56 and is thus centered in the column of the LEDs 46 (as a result It is converted into dispersed light that is dispersed toward the center of the liquid crystal module 32. For this reason, the amount of light leaking to the outside of the outer peripheral edge of the liquid crystal module 32 at the end of the row can be reduced, which contributes to higher brightness.

Further, as shown in FIGS. 7 and 8, in this embodiment, the arrangement intervals of the plurality of LEDs 46 in one row may be different. That is, in this embodiment, the irradiation light near the end of the row of LEDs 46 is directed toward the center. For this reason, sufficient light is irradiated in the vicinity of the center of the liquid crystal module 32, and it is considered preferable to reduce the number of LEDs 46 in the vicinity of the center of the column in order to obtain a uniform irradiation light intensity as a whole. Because.
In view of this, the plurality of aligned LEDs 46 are arranged so that adjacent LEDs are spaced apart in the vicinity of the center, and the distance between adjacent LEDs is gradually reduced toward the end of the column. For this reason, the aligned LEDs 46 are arranged so that the vicinity of the center of the column is sparse and becomes denser toward the end.
With this configuration, it is easy to have a common lens design and have a plurality of LEDs on the LED array substrate, and it is possible to achieve an optimal arrangement that suppresses luminance unevenness.

(Example 3)
Next, Example 3 will be described with reference to FIG. In addition, about the component same as each Example mentioned above, the same code | symbol is attached | subjected and description may be abbreviate | omitted.
In the third embodiment, the plurality of LEDs 46 are directed downward so that light is emitted from above to below, and are aligned in the horizontal direction and arranged above the back side of the liquid crystal module 32, and the upper row 60 is formed. It is composed.
Further, the plurality of LEDs 46 are directed upward so that light is emitted from below to above, and are aligned in the horizontal direction and disposed below the back side of the liquid crystal module 32 to constitute the lower row 62. .

Although not shown in the drawing, the LED 46 in both the upper row 60 and the lower row 62 has one parallel light conversion lens 49 and one for one LED as in the above-described embodiment. The polarization conversion element 50 and one luminance uniforming lens 56 are arranged.
Therefore, the upper row 60 and the lower row 62 have polarized light that matches the transmission axis of the polarizing plate 44 on the back side of the liquid crystal module 32, and irradiates the dispersed light to the liquid crystal module 32.

Below the upper row 60 is provided a reflector 64 that reflects the irradiation light emitted from the upper row 60 so as to face the liquid crystal module 32. Further, a reflection plate 66 is provided above the lower row 62 to reflect the irradiation light emitted from the lower row 62 so as to face the liquid crystal module 32.
In this embodiment, the liquid crystal module 32 side end portion 64a of the reflector 64 and the liquid crystal module 32 side end portion 66a of the reflector plate 66 are connected, and both the reflector plates 64a and 66a have one reflector plate in the middle. It is configured like a bent shape.

Since the plurality of LEDs 46 are arranged separately in the upper and lower portions as in this embodiment, the number of LEDs 46 in each of the upper row 60 and the lower row 62 is compared with a case where they are aligned in one row. And can be cut in half.
For this reason, the space | interval of aligned LED can be taken larger compared with the case where it arranges in 1 row, and a condensing rate can be raised. Moreover, as a result (because the space | interval of LED became large), thermal design becomes easy.
Further, since only the reflectors 64 and 66 are disposed near the center of the back side of the liquid crystal module 32, the entire depth of the liquid crystal display device 30 can be shortened, contributing to the thinning of the liquid crystal display device 30. To do.

In addition, as a shape of the reflecting plates 64 and 66 in a present Example, it is not limited to the flat thing as mentioned above, A shape as shown in FIG.10 and FIG.11 may be sufficient.
The reflecting plates 64 and 66 shown in FIG. 10 are curved in a direction in which the end portions 64b and 66b on the side away from the liquid crystal module 32 approach the liquid crystal module 32 side. Therefore, the reflecting plates 64 and 66 are formed so that the reflecting surface is a curved surface. The curvatures of the reflecting plates 64 and 66 are formed so that the light emitted from the LEDs 46 in the upper row 60 and the lower row 62 is uniformly irradiated to the liquid crystal module 32.
Thus, the depth of the liquid crystal display device 30 can be further shortened by using a reflecting plate having a curved reflecting surface.

In addition, the reflectors 64 and 66 shown in FIG. 11 have a plurality of small reflectors 78 attached to a flat base 79. The small reflecting plate 78 is attached so as to be non-parallel to the surface of the base 79, and the reflecting plates 64 and 66 are formed so that stepped irregularities exist on the reflecting surface. The light emitted from the LEDs 46 in each of the upper row 60 and the lower row 62 is reflected by each small reflection plate 78 and is uniformly emitted to the liquid crystal module 32.
According to such a configuration, the angle of the light applied to the liquid crystal module 32 is adjusted by the small reflector 78, so that it is not necessary to take a long depth like the reflectors 64 and 66 shown in FIG. The depth of the display device 30 can be further shortened.

Example 4
In the above-described third embodiment, the plurality of LEDs 46, which is essentially one row, are divided into halves, and each of the halves is irradiated downward and upward so that light is irradiated from above to below and from below to above. The upper row 60 and the lower row 62 are configured by arranging them in the horizontal direction and disposing them above and below the back side of the liquid crystal module 32.
However, as shown in FIG. 10, the plurality of LEDs 46 are divided into halves, and each of the halves is turned left and right so that light is emitted from the right to the left and from the left to the right, Further, the right row 70 and the left row 72 may be configured by aligning them in the vertical direction and disposing them on the right side and the left side of the back side of the liquid crystal module 32.

Although not shown in the drawing, in each of the LEDs 46 in the right row 70 and the left row 72, one parallel light conversion lens 49 for each LED, as in the above-described embodiment, One polarization conversion element 50 and one luminance uniforming lens 56 are arranged.
Therefore, the right column 70 and the left column 72 have polarized light that coincides with the transmission axis of the polarizing plate 44 on the back side of the liquid crystal module 32, and irradiate dispersed light dispersed in the width direction of the liquid crystal module 32. .

On the left side of the right row 70, a reflection plate 74 that reflects the irradiation light emitted from the right row 70 so as to face the liquid crystal module 32 is provided. Further, on the right side of the left row 72, a reflection plate 76 that reflects the irradiation light emitted from the left row 72 so as to face the liquid crystal module 32 is provided.
Also in the present embodiment, the liquid crystal module 32 side end portion 74a of the reflection plate 74 and the liquid crystal module 32 side end portion 76a of the reflection plate 76 are connected, and both the reflection plates 74 and 76 are arranged in the middle of one reflection plate. The shape is bent at

Since the plurality of LEDs 46 are arranged separately on the right side and the left side as in this embodiment, the number of LEDs 46 existing in each of the right column 70 and the left column 72 is aligned in one column. Compared to the case, it can be reduced to half.
For this reason, also in the present embodiment, the interval between the aligned LEDs 46 can be made larger than in the case where they are aligned in one row, and the light collection rate can be increased.

Note that the reflectors 74 and 76 in the present embodiment are not limited to the flat plate shape as described above as in the third embodiment, and have the shapes shown in FIGS. May be.
That is, as shown in FIG. 10, the reflection plates 74 and 76 are curved so that the end portions on the side away from the liquid crystal module 32 approach the liquid crystal module 32 side, and the reflection surface becomes a curved surface. And the curvature of the reflecting surface is formed so that the light emitted from the LEDs 46 in each of the right column 70 and the left column 72 is uniformly irradiated to the liquid crystal module 32. Good (not shown).
Thus, the depth of the liquid crystal display device 30 can be further shortened by using a reflecting plate having a curved reflecting surface.

In addition, as shown in FIG. 11, the reflecting plates 74 and 76 have a flat base portion with a plurality of small reflecting plates attached so as to be non-parallel to the surface of the base portion, and a stepped shape on the reflecting surface. Concavities and convexities may be formed (not shown). The small reflectors are provided so that light emitted from the LEDs 46 in each of the right column 70 and the left column 72 is reflected by the small reflectors and is uniformly irradiated to the liquid crystal module 32. It is done.
According to such a configuration, the angle of the light applied to the liquid crystal module 32 is adjusted by the small reflector, so that it is not necessary to take a long depth like the reflectors 64 and 66 shown in FIG. The depth of the device 30 can be further shortened.

In addition, also in Example 3 and Example 4 mentioned above, the structure demonstrated in Example 1-Example 2 is employable.
That is, in each of the upper row 60, the lower row 62, the right row 70, and the left row 72, as shown in FIG. 4, only light having a specific wavelength is transmitted and light other than the specific wavelength is reflected. The dichroic mirror 58 may be provided on the optical axis of the irradiation light of the LED 46.
Further, in each of the upper row 60, the lower row 62, the right row 70, and the left row 72, as shown in FIG. 5, the LEDs 46 are arranged in the same color with respect to the center of the row. You may make it symmetrical.

  Further, in each of the upper row 60, the lower row 62, the right row 70, and the left row 72, as shown in FIG. 6, the optical axes of the aligned luminance uniformizing lenses 56 correspond in the vicinity of the center of the row. By gradually shifting the optical axis of the luminance uniformizing lens 56 from the corresponding optical axis of the LED 46 toward the end of the column, which coincides with the optical axis of the LED 46, the light incident on the luminance uniformizing lens 56 is The light may be refracted by the brightness uniformizing lens 56 and dispersed toward the center of each column of the LEDs 46.

  When the optical axis of the luminance uniformizing lens 56 is shifted as described above, the upper row 60, the lower row 62, the right row 70, and the left row 72 are arranged as shown in FIGS. In each row, the vicinity of the center may be arranged so that adjacent LEDs are spaced apart, and the distance between adjacent LEDs is gradually narrowed toward the end of the row.

(Other examples)
In the above-described first and second embodiments, only the plurality of LEDs 46, the parallel light conversion lens 49, the polarization conversion element 50, and the luminance uniformizing lens 56 are arranged in a line in the horizontal direction has been described.
However, a plurality of such rows may be provided as shown in FIG. 13, or may be arranged in the vertical direction as shown in FIG. Even when aligned in the vertical direction, a plurality of such rows may be provided.

  The liquid crystal display device of the present invention can be used for various applications such as PC monitors and TV receivers.

  While the present invention has been described in detail with reference to a preferred embodiment, the present invention is not limited to this embodiment, and it goes without saying that many modifications can be made without departing from the spirit of the invention. .

It is a top view which shows schematic structure of the liquid crystal display device of this invention. 1 is a plan view showing a configuration of a backlight device of Example 1. FIG. FIG. 3 is a rear view illustrating the arrangement of LEDs according to the first embodiment. 1 is a plan view showing a configuration in which a dichroic mirror is provided in Embodiment 1. FIG. In Example 1, it is a top view which shows the structure which provided the color arrangement | positioning of LED symmetrically with respect to the center of a row | line | column. 6 is a plan view showing a configuration of a backlight device of Example 2. FIG. In Example 2, it is a rear view which shows the structure which made the arrangement | sequence of LED different in the center and edge part of a row | line | column. In Example 2, it is a top view which shows the structure which made the arrangement | sequence of LED different in the center and edge part of a row | line | column. 10 is a side view illustrating the configuration of Example 3. FIG. In Example 3, it is a side view which shows the structure which employ | adopted the reflecting plate with a curved reflective surface. It is a side view which shows the structure which employ | adopted the reflecting plate which attached multiple small reflecting plates in Example 3, and shortened depth. 10 is a plan view illustrating a configuration of Example 4. FIG. It is a rear view which shows the structure which provided multiple rows of LED etc. in the horizontal direction. It is a rear view which shows the structure which provided LED etc. in the up-down direction. It is a top view which shows the structure of the conventional liquid crystal display device.

Explanation of symbols

30 Liquid crystal display device 32 Liquid crystal module 33 Backlight device 36 Liquid crystal material 38 TFT array substrate 40 Color filter substrates 42 and 44 Polarizing plate 49 Parallel light conversion lens 50 Polarization conversion element 52 Beam splitter 54 1/2 wavelength plate 56 Brightness uniformizing lens 58 Dichroic mirror 60 Upper row 62 Lower row 64, 66, 74, 76 Reflector 70 Right row 72 Left row 78 Small reflector 79 Base

Claims (18)

A liquid crystal module for displaying images;
In a liquid crystal display device comprising a backlight device for irradiating irradiation light on the back surface of the liquid crystal module,
The backlight device includes:
A plurality of LEDs as light sources;
A parallel light conversion lens that is disposed in front of the LED and converts light emitted from the LED into parallel light;
Polarization conversion means for aligning light that has passed through the parallel light conversion lens with either P-wave or S-wave polarization so as to coincide with the transmission axis of a polarizing plate provided on the back side of the liquid crystal module;
A brightness uniformizing lens that disperses the light that has passed through the polarization conversion means and irradiates the back surface of the liquid crystal module;
1. The liquid crystal display device according to claim 1, wherein each of the LEDs is provided with one each of the parallel light conversion lens, the polarization conversion unit, and the luminance uniformizing lens.   The liquid crystal display device according to claim 1, wherein the plurality of polarization conversion means are provided with half-wave plates between adjacent beam splitters.   3. A wavelength selection unit that selectively transmits light emitted from an LED located on the back surface of the polarization conversion element and does not transmit light of other wavelengths is provided. The liquid crystal display device described. The LED, the parallel light conversion lens, the polarization conversion unit, and the luminance uniformizing lens are arranged in the vertical direction or the horizontal direction, respectively.
The optical axes of the plurality of aligned luminance equalizing lenses are arranged so as to be shifted from the optical axes of the LEDs, the parallel light conversion lens, and the polarization conversion unit toward the end of the row, and are distributed light. 4. The liquid crystal display device according to claim 1, wherein the irradiation direction is directed toward a center direction of the array of the aligned LEDs. 5. The LED, the parallel light conversion lens, the polarization conversion unit, and the luminance uniformizing lens are arranged in the vertical direction or the horizontal direction, respectively.
The plurality of aligned LEDs are provided so that the distance between adjacent LEDs is long near the center of the column and the distance between adjacent LEDs is shortened toward the end of the column. The liquid crystal display device according to claim 4. The LED, the parallel light conversion lens, the polarization conversion means, and the brightness uniformizing lens are arranged in an up-down direction or a horizontal direction, respectively.
6. The liquid crystal display device according to claim 1, wherein the LEDs of the same color are arranged symmetrically with respect to the center of the column. A plurality of the LEDs, the parallel light conversion lens, the polarization conversion means, and the brightness uniformizing lens are irradiated with irradiation light from the upper side to the lower side and from the lower side to the upper side on the back side of the liquid crystal module. , The liquid crystal module is arranged in the horizontal direction at the back side upper side and the back side lower side, respectively,
A first reflector is disposed so as to reflect the light emitted from above to below toward the back of the liquid crystal module;
The second reflecting plate is disposed so as to reflect the light emitted from the lower side to the upper side toward the back surface of the liquid crystal module. A liquid crystal display device according to claim 1.   The optical axes of the plurality of brightness equalizing lenses aligned in the horizontal direction on the back side upper side and the back side lower side of the liquid crystal module are directed to the end of each column, the LEDs, the parallel light conversion lenses, and 8. The liquid crystal display device according to claim 7, wherein the liquid crystal display device is disposed so as to be shifted from the optical axis of the polarization conversion means so that the direction of irradiation of the dispersed light is directed to the center direction of the aligned LED rows.   The plurality of LEDs in each row aligned in the horizontal direction on the back side upper side and the back side lower side of the liquid crystal module have a long interval between adjacent LEDs near the center of each row and head toward the end of each row. The liquid crystal display device according to claim 8, wherein an interval between adjacent LEDs is shortened according to the above.   The LEDs in each row arranged in the horizontal direction on the back side upper side and the back side lower side of the liquid crystal module are characterized in that LEDs of the same color are arranged symmetrically with respect to the center of each row. The liquid crystal display device according to any one of claims 7 to 9.   8. The first reflecting plate and the second reflecting plate are formed such that end portions located at positions away from the liquid crystal module are curved in a direction approaching the liquid crystal module. Item 11. The liquid crystal display device according to any one of items 10 to 10.   The first reflecting plate and the second reflecting plate are characterized in that a flat base portion and a plurality of small reflecting plates which are not parallel to the surface of the base portion with respect to the base portion are arranged. The liquid crystal display device according to any one of claims 7 to 10. A plurality of the LEDs, the parallel light conversion lens, the polarization conversion means, and the brightness uniformizing lens are irradiated with irradiation light from the left side to the right side and from the left side to the right side of the back side of the liquid crystal module. So that the liquid crystal module is arranged in the vertical direction on the right side and the left side on the back side of the liquid crystal module,
A third reflector is arranged to reflect the light emitted from the right to the left toward the back of the liquid crystal module;
4. The fourth reflecting plate is disposed so as to reflect the light emitted from the left to the right toward the back surface of the liquid crystal module. 5. The liquid crystal display device according to any one of the above.   The optical axes of the plurality of brightness equalizing lenses aligned in the vertical direction on the right side and the left side of the liquid crystal module are directed toward the end of each column, and the LEDs and the parallel light conversion 14. The liquid crystal display according to claim 13, wherein the liquid crystal display is disposed so as to be shifted from the optical axis of the lens and the polarization conversion means, and the irradiation direction of the dispersed light is directed toward the center direction of the aligned LED columns. apparatus.   The plurality of LEDs arranged in the vertical direction on the back side right side and the back side left side of the liquid crystal module have long intervals between adjacent LEDs near the center of each row, and end portions of each row The liquid crystal display device according to claim 14, wherein an interval between adjacent LEDs is shortened toward the front.   The LEDs in each row arranged in the vertical direction on the right side on the back side and the left side on the back side of the liquid crystal module are characterized in that LEDs of the same color are arranged symmetrically with respect to the center of each row. The liquid crystal display device according to any one of claims 13 to 15.   The third reflector and the fourth reflector are formed such that an end portion located away from the liquid crystal module is curved in a direction approaching the liquid crystal module. Item 19. The liquid crystal display device according to any one of items 16. The third reflector and the fourth reflector comprise a flat base and a plurality of small reflectors arranged non-parallel to the surface of the base with respect to the base. The liquid crystal display device according to any one of claims 13 to 16.

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