TWI494662B - Surface light source device and liquid crystal display device - Google Patents

Description

Surface light source device and liquid crystal display device

The present invention relates to a surface light source device having a planar light-emitting surface, and a liquid crystal display device having a surface light source device and a liquid crystal panel.

The liquid crystal display element provided in the liquid crystal display device itself does not emit light. Therefore, the liquid crystal display device has a backlight disposed on the back surface of the liquid crystal display element as a light source for illuminating the liquid crystal display element. In recent years, with the dramatic improvement in the performance of a blue light-emitting diode (hereinafter, a light-emitting diode called an LED), a backlight device using a blue LED as a light source has been widely used.

A light source using a blue LED will have a blue LED, and a phosphor that absorbs the light emitted by the blue LED and emits a blue complementary color (that is, a color containing green and red, that is, yellow). Such LEDs are referred to as white LEDs.

The white LED has high electro-optical conversion efficiency, which is quite helpful for low power consumption. The term "electro-optical conversion efficiency" refers to the efficiency when converting electricity into light. On the other hand, however, white LEDs have a wide wavelength band, and the range of color reproduction is narrower than that of lasers. The liquid crystal display device has a color filter inside the liquid crystal display element. The liquid crystal display device extracts the red, green, and blue spectrums by the color filters to exhibit colors. To use a wavelength band like a white LED A field-wide continuum of light sources to extend the range of color rendering must increase the color purity of the color of the color filter. That is to say, the wavelength band passing through the color filter must be set to be narrower in accordance with the desired color purity. In this case, the amount of light transmitted through the color filter is reduced, so that the light utilization efficiency is lowered. This is because the amount of light that is not used for the liquid crystal display element to display an image increases. That is, since the amount of light for displaying an image is reduced, the brightness of the display surface of the liquid crystal display element is lowered. Therefore, in a liquid crystal display in which the wavelength band of the color filter is narrowed to expand the color presentation range, in order to exhibit brightness equivalent to that of the conventional liquid crystal display device, it is necessary to increase the power supplied to the white LED. As a result, there is a problem that the power consumption of the liquid crystal display device increases.

In order to solve the above problem of the color reproduction range, the conventional technique proposes to use a red, green, and blue monochromatic LED having a higher color purity instead of the white LED as a backlight device (Patent Document 1). Alternatively, a red, green, or blue laser having a higher color purity than a monochrome LED is used as a backlight device (Patent Document 2). Here, "high color purity" means that the wavelength band is narrow and has excellent monochromaticity. By using these light sources as a backlight device, it is possible to expand the range in which the color display of the liquid crystal display device is presented.

Advanced technical literature:

[Patent Document 1] 2009-26635

[Patent Document 2] 2010-101912

However, a light source composed of a monochromatic LED of 3 primary colors or a monochromatic laser of 3 primary colors is less efficient than electrolight conversion of a white LED. Therefore, the luminance on the display surface of the liquid crystal display element is lowered compared to the liquid crystal display device using the white LED. And if In order to exhibit the same brightness as a liquid crystal display device using a white LED, it is necessary to increase the power supplied to the monochrome LED light source or the monochrome laser light source, so that the power consumption of the liquid crystal display device is increased. As described above, in the conventional liquid crystal display device, it is difficult to obtain a liquid crystal display device having a wide color reproduction range and low power consumption.

In order to solve the above problems, the present invention proposes a surface light source device and a liquid crystal display device capable of maintaining a low power consumption similar to that of a device using a conventional white LED light source, and having a wide range of color reproducibility. That is, the liquid crystal display device of the present invention has a wider color reproduction range than the liquid crystal display device of the conventional white LED light source. Further, the liquid crystal display device of the present invention can achieve the same brightness as a liquid crystal display device using only a conventional white LED light source with a lower power consumption than a liquid crystal display device using only a single-color LED light source or a laser light source.

The surface light source device of the present invention comprises: a laser light source having a plurality of laser light emitting elements and emitting laser light generated by the plurality of laser light emitting elements; and an optical path changing element having the laser light source a light incident surface incident on the laser beam, and a light exiting surface, wherein the optical path changing element adjusts a direction perpendicular to the traveling direction of the laser light emitted by the laser light source and incident on the light incident surface a spatial intensity distribution on a plane, and the laser light emitted from the laser light source and incident on the light incident surface is changed to a linear lightning beam having a linear cross-sectional shape of the laser light on the first plane Shooting light, emitting the linear laser light from the light exit surface; a first surface light-emitting light guide, adjusting parallel to the laser light including the linear laser light and the linear light a spatial intensity distribution on the second plane of the plane of the direction, the linear laser beam emitted from the optical path changing element being converted into planar laser illumination light, and the laser illumination light is directed perpendicular to the second An LED light source having a plurality of LED elements and emitting LED light generated by the plurality of LED elements; and a second surface light-emitting light guide plate disposed parallel to the first surface light-emitting light guide layer to adjust the LED light source Transmitting the spatial intensity distribution of the LED light in a third plane parallel to the second plane and converting the LED light emitted by the LED light source into planar LED illumination light, so that the LED illumination light is the same as the lightning The direction in which the illumination light is emitted is emitted.

A liquid crystal display device of the present invention includes a liquid crystal panel and a light source device that illuminates the liquid crystal panel. The surface light source device comprises: a laser light source having a plurality of laser light emitting elements and emitting laser light generated by the plurality of laser light emitting elements; and an optical path changing element having the laser light emitted by the laser light source a light incident surface incident on the light, and a light exiting surface, wherein the optical path changing element adjusts a first plane of the laser light emitted by the laser light source and incident on the light incident surface perpendicular to a traveling direction of the laser light a spatial intensity distribution, and the laser beam emitted from the laser light source and incident on the light incident surface is changed to a linear laser beam having a linear cross-sectional shape of the laser beam on the first plane And emitting the linear laser beam from the light exit surface; and the first surface light-emitting light guide plate is adjusted to be parallel to the second plane including the linear laser light and the plane of the linear laser light traveling direction a spatial intensity distribution, the linear laser light emitted from the optical path changing element being converted into planar laser illumination light, and the laser illumination light is emitted in a direction perpendicular to the second plane; an LED light source Having a plurality of LED elements, LED elements and emit the plurality of light generated by the LED And a second surface light-emitting light guide plate disposed parallel to the first surface light-emitting light guide layer to adjust a spatial intensity distribution of the LED light emitted by the LED light source in a third plane parallel to the second plane and The LED light emitted by the LED light source is converted into planar LED illumination light, and the LED illumination light is emitted in the same direction as the laser illumination light emission direction.

According to the present invention, the surface light source device and the liquid crystal display device can have a wider color reproduction range than the liquid crystal display device using the conventional white LED light source, and can use a monochrome LED light source only by using the above configuration. The liquid crystal display device of the monochrome laser light source has low power consumption to achieve the same brightness as the liquid crystal display device using only the conventional white LED light source.

1‧‧‧LCD panel

1a‧‧‧ display surface

1b‧‧‧back

2, 3‧‧‧ optical film

4, 5‧‧‧ face light guide plate

6, 60, 600‧‧‧ optical path change components

8‧‧‧Light reflection sheet

9‧‧‧LED light source

9a~9e‧‧‧LED light source group

10‧‧‧Laser light source

10a~10e‧‧‧Laser light source group

31‧‧‧Control Department

32‧‧‧Liquid display device driver

33‧‧‧Light source drive department

33a, 330a‧‧‧LED light source drive unit

33b, 330b‧‧‧Laser light source drive

34‧‧‧Image signal

35‧‧‧Liquid crystal display element control signal

36‧‧‧Light source control signal

36a‧‧‧LED light source control signal

36b‧‧‧Laser light source control signal

41a, 51a‧‧‧ light exit surface

41b, 51b‧‧‧ back

41c, 51c‧‧‧light incident surface

41d, 51d‧‧‧ end face

41e‧‧‧Mixed Department

41f‧‧‧Light Guide

42, 52‧‧‧ tiny optical components

60a~60e, 600a~600e‧‧‧ optical path change component components

61, 601, 6001‧‧‧ light incident surface

62, 602‧‧ ‧Light Guide

63, 603‧‧‧Light Path Change Department

63a, 63b, 603a, 603b‧‧‧ reflecting surface

64‧‧‧Light exit surface

100, 101‧‧‧ liquid crystal display device

200, 201‧‧‧ surface light source device

510c‧‧‧Light Diffusion Department

L9‧‧‧LED light

L10, L110‧‧ ‧ laser light

L90‧‧‧LED lighting

L111‧‧‧Laser illumination

L120‧‧‧ illumination light

Fig. 1 is a cross-sectional view schematically showing an example of a structure of a liquid crystal display device (including a surface light source device) according to a first embodiment of the present invention.

Figs. 2(a) and 2(b) are a perspective view and a side view schematically showing an optical path changing element of the surface light source device shown in Fig. 1.

The third (a) and third (b) diagrams schematically show a perspective view and a side view of the optical path changing element of the surface light source device shown in Fig. 1 and the first surface emitting light guide plate.

Fig. 4 is a schematic plan view of the first surface light-emitting light guide of the surface light source device shown in Fig. 1 as seen from the back side.

Fig. 5 is a schematic plan view of the second surface light-emitting light guide of the surface light source device shown in Fig. 1 as seen from the back side.

Fig. 6 is a schematic plan view showing another example of the first surface light-emitting light guide plate of the surface light source device shown in Fig. 1 as viewed from the back side.

Fig. 7 is a schematic plan view showing another example of the second surface light-emitting light guide plate of the surface light source device shown in Fig. 1 as seen from the back side.

Fig. 8 is a block diagram schematically showing the structure of a control system of the liquid crystal display device shown in Fig. 1.

Fig. 9 is a block diagram schematically showing another example of the control system architecture of the liquid crystal display device shown in Fig. 1.

Fig. 10 is a cross-sectional view schematically showing another example of the structure of a liquid crystal display device (including a surface light source device) according to Embodiment 1 of the present invention.

Fig. 11 is a cross-sectional view schematically showing an example of a structure of a liquid crystal display device (including a surface light source device) of the second embodiment.

Fig. 12 is a block diagram showing the architecture of a control system of the liquid crystal display device of Embodiment 2.

Fig. 13 is a schematic plan view showing the surface light source device shown in Fig. 12, that is, the liquid crystal display device, viewed from the back side.

Fig. 14 is a schematic plan view of the surface light source device shown in Fig. 12 as seen from the liquid crystal panel side.

Fig. 15 is a plan view schematically showing another example of the optical path changing element member of the second embodiment viewed from the back side.

Fig. 16 is a schematic plan view of the liquid crystal display device including the optical path changing element member shown in Fig. 15 as seen from the back side.

Example 1:

Hereinafter, the surface light source device 200 and the liquid crystal display device 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 9. The first picture shows the outline A cross-sectional view showing an example of the structure of the liquid crystal display device 100 (including the surface light source device 200) of the first embodiment of the invention. The second (a) and second (b) diagrams schematically show a perspective view and a side view of the optical path changing element 6 of the surface light source device 200 shown in Fig. 1 . 3(a) and 3(b) are a perspective view and a side view showing the optical path changing element 6 and the first surface emitting light guide plate 5 of the surface light source device 200 shown in Fig. 1 . Fig. 4 is a schematic plan view of the first surface light-emitting light guide plate 5 of the surface light source device 200 shown in Fig. 1 as seen from the back side. Fig. 5 is a schematic plan view of the second surface light-emitting light guide plate 4 of the surface light source device 200 shown in Fig. 1 as viewed from the back side. Fig. 6 is a schematic plan view showing another example of the first surface light-emitting light guide plate 5 of the surface light source device 200 shown in Fig. 1 as viewed from the back side. Fig. 7 is a schematic plan view showing another example of the second surface light-emitting light guide plate 4 of the surface light source device 200 shown in Fig. 1 as viewed from the back side. Fig. 8 is a block diagram schematically showing the control system architecture of the liquid crystal display device 100 shown in Fig. 1. Fig. 9 is a block diagram schematically showing another example of the control system architecture of the liquid crystal display device 100 shown in Fig. 1.

In the first embodiment, the liquid crystal display device 100 includes a transmissive liquid crystal panel 1 having a liquid crystal display element and a surface light source device 200. The liquid crystal display device 100 can include an optical sheet (first optical sheet) 2 and an optical sheet (second optical sheet) 3. Here, the "surface light source device" refers to a surface light source device that illuminates the back surface 1b (described later) of the liquid crystal panel 1 with light. The surface light source device 200 irradiates light to the back surface 1b (described later) of the liquid crystal panel 1 via the optical sheets 3 and 2. Although not shown in FIG. 1, the liquid crystal display device 100 can include the control unit 31, the liquid crystal display element drive unit 32, and the light source drive unit 33 as shown in FIG. As shown in FIG. 9, the light source driving unit 33 may include an LED light source driving unit (first light source driving unit) 33a that drives the LED light source 9 (described later) and a laser light source driving unit that drives the laser light source 10 (described later) ( 2nd Light source driving unit) 33b.

Here, for ease of explanation, the xyz rectangular coordinate system is defined as follows, and the coordinate axes of the XYZ rectangular coordinate system are shown in each of the drawings. It is assumed that the longitudinal direction of the display surface 1a of the liquid crystal panel 1 is the x-axis direction (the horizontal direction in FIG. 1), and the short-side direction of the display surface 1a of the liquid crystal panel 1 is the y-axis direction (the vertical paper surface in FIG. 1) The direction is perpendicular to the xy plane including the x-axis and the y-axis in the z-axis direction (up and down direction in FIG. 1). In Fig. 1, it is assumed that the direction in which the LED light source 9 emits the LED light L9 (the direction of the center ray of the LED ray, the direction of the paper surface from left to right in Fig. 1) is the positive direction of the x-axis (+x-axis direction), The opposite direction is the negative direction of the x-axis (--axis direction). It is also assumed that the direction from the front side of the paper surface toward the back surface of the first drawing is the positive direction of the y-axis (+y-axis direction), and the opposite direction is the negative direction of the y-axis (-y-axis direction). In the first drawing, it is assumed that the direction from the surface-emitting light-guide plate 5 toward the liquid crystal panel 1 (the direction from the bottom to the top in the first drawing) is the positive direction of the z-axis, and the opposite direction is the negative direction of the z-axis (-z). Axis direction).

As shown in FIG. 1, the liquid crystal display device 100 includes a liquid crystal panel 1, an optical sheet 2, an optical sheet 3, and a surface light source device 200 which are disposed in the negative direction from the positive z-axis direction. Here, "arrangement" means that it is set to an individual position, and is also set to a predetermined position. The optical sheet 2 has a function of directing the LED illumination light L90 (described later) and the laser illumination light L111 (described later) transmitted through the optical sheet 2 toward the back surface 1b of the liquid crystal panel 1. The optical plate 3 has a function of suppressing optical influences such as uneven illumination caused by the LED illumination light L90 and the laser illumination light L111.

The liquid crystal panel 1 has a display surface 1a on the surface on the +z axis side, a back surface 1b on the surface on the -z axis side, and a liquid crystal layer (not shown) between the display surface 1a and the back surface 1b. The display surface 1a of the liquid crystal panel 1 is a surface parallel to the x-y plane. LCD surface The liquid crystal layer of the board 1 has a planar configuration developed in a direction parallel to the x-y plane. The display surface 1a of the liquid crystal panel 1 is generally rectangular, and the adjacent sides (the long sides along the x-axis direction and the short sides along the y-axis direction) of the display surface 1a are perpendicular to each other. In the first embodiment, the display surface 1a of the liquid crystal panel 1 is rectangular, but the shape of the display surface 1a of the liquid crystal panel 1 is not limited, and may be another shape.

As shown in Fig. 1, the surface light source device 200 includes a thin-plate surface emitting light guide plate 4 (second surface light-emitting light guide plate), another thin plate-shaped surface light-emitting light guide plate 5 (first surface light-emitting light guide plate), and optical path change. Element 6, LED light source 9 and laser source 10. The surface light source device 200 may be provided with a light reflection sheet 8 as needed. On the surface light source device 200, the surface emitting light guide plate 4, the surface emitting light guide plate 5, the light reflecting sheet 8, and the optical path changing element 6 are arranged in this order from the positive side to the negative side of the z-axis. In the surface light source device 200, the LED light source 9 is disposed on the -x axis side of the surface emitting light guide plate 4. In the surface light source device 200, the laser light source 10 is disposed on the back side (-z axis side) of the light reflection sheet 8 and on the +x axis side of the optical path changing element 6. That is, the laser light source 10 is disposed on one side of the face-to-surface light-emitting light guide plate 4 of the surface-emitting light guide plate 5.

The LED light source 9 is a light source having a blue LED and a phosphor. The laser source 10 is a light source having a laser emitting element that emits red laser light. The LED light source 9 is more specifically a light source using a cyan LED, which is filled with a green phosphor that absorbs the blue light and emits green light in a package having a blue monochromatic LED chip that emits blue light. The blue-green LED has a smaller power consumption and higher output than a single-color LED that emits green light, and has a smaller consumption than a green-emitting laser. Power with higher output. Therefore, combining the LED light source 9 having a blue LED and a green phosphor and the laser light source 10 emitting red laser light can achieve a wider range of techniques than the prior art. A liquid crystal display device having a color reproduction range and low power consumption characteristics. The LED light source 9 may be a light source having, for example, a blue LED chip that emits blue light and a green LED chip that emits green light. However, when these LEDs are used as the LED light source 9, the power saving effect is inferior in the case where the blue-green LED is used as the LED light source 9.

In general, humans are more sensitive to the chromatic aberration of red. Therefore, human vision will perceive that the difference in the wavelength band of red is more significant than the difference in the wavelength band of other colors. Here, the "difference in the wavelength band" means the difference in color purity. The white LED used as a light source in the conventional liquid crystal display device has less energy in the red spectrum of the band of 600 nm to 700 nm. In other words, in order to increase the color purity to a wavelength range of 630 to 640 nm which is close to pure red and use a color filter having a narrow wavelength band, the amount of transmitted light is reduced, and the light use efficiency is lowered, and the luminance is lowered. here. "Band" indicates the range of wavelengths. "Pure red" means pure red.

In this regard, the wavelength band of the laser light-emitting element is narrower than that of the white LED, and light having a high color purity can be obtained with almost no loss of light amount. The liquid crystal display device 100 of the first embodiment and the surface light source device 200 emit red light in a laser light source 10 having a high monochromaticity among the three primary colors of light. Thereby, compared with the use of a laser light source to emit light other than red, a remarkable effect of a reduction in power consumption and an increase in color purity can be achieved.

In a conventional liquid crystal display device using a white LED light source, the wavelength band of red light emitted from the white LED is wider than the wavelength band of the red light of the laser light emitting element. Therefore, in the conventional liquid crystal display device, a part of the red light passes through the green filter to lower the color purity of the green color. Through the green filter The spectrum of the light of the slice will abut the spectrum of the red light. In the liquid crystal display device 100 and the surface light source device 200 of the first embodiment, by using the red laser light source 10, the color purity of red is increased. By using the red laser light source 10, the amount of red light passing through the green filter is reduced, so that the green color purity can also be improved.

Here, the LED light source 9 will be described as an LED light source that emits blue-green light, and the laser light source 10 will be described as a laser light source that emits red light. However, the configuration of the present invention is not limited to this. For example, it is also possible to constitute the LED light source 9 with an LED element that emits green light, and to constitute a laser light source 10 by emitting a red light-emitting laser light-emitting element and a blue light-emitting laser light-emitting element. Alternatively, for example, the LED light source 9 is configured by a red light emitting LED element and a green light emitting LED element, and the blue light emitting laser light emitting element is used to constitute the laser light source 10. When a red laser light-emitting element is used as the laser light source 10, it can be displayed and conventionally compared with the use of the blue laser light-emitting element in terms of reduction in power consumption and improvement in color purity. The apparent difference in the liquid crystal display device.

The angular intensity distribution of the light emitted by both the LED element and the laser emitting element is different. When light sources of different angular intensity distributions are used, the spatial intensity distribution of each color is uneven, and thus color unevenness occurs on the display surface 1a of the liquid crystal display element. That is to say, the uneven light intensity of each color will exhibit color unevenness when white light of these colors is mixed. Uneven light intensity is also called uneven brightness. The "angle intensity distribution" refers to the distribution of the intensity of light with respect to the angle of incidence of light.

To prevent color unevenness, it is necessary to increase the uniformity of the spatial intensity distribution on the plane. In the case where the light-emitting principle of the light source or the material properties of the light-emitting elements are different, the light emitted by these light sources may have different luminous efficiencies in addition to the angular intensity distribution. Therefore, it is necessary to adjust the number of each light source to be configured or the configuration method. Place The term "on-plane" refers to the display surface 1a of the liquid crystal panel 1. In the first embodiment, means for uniformizing the spatial intensity distribution is provided on the plane corresponding to the LED light source 9 and the laser light source 10, respectively.

First, the LED light source 9 will be described. The LED light source 9 is composed of a plurality of LED elements arranged in a line in the y-axis direction. The light-emitting portion of the LED light source 9 (the end surface of each of the LED elements emitting the LED light L9) faces the light incident surface 41c of the surface-emitting light-guide plate 4. "Orientation" means facing each other. The LED light source 9 has a plurality of LED elements that emit LED light L9 generated by each of the plurality of LED elements.

The LED light source 9 emits a blue-green LED light L9. This cyan LED light L9 has a peak in the vicinity of, for example, around 450 nm and around 530 nm, and has a continuous spectrum of light in a band of 420 nm to 580 nm. The LED light source 9 has an angular intensity distribution of a Lambertian distribution with a half-valued full-angle of 120 degrees in the x-y plane and the z-x plane. Here, the "half value angle" means an angle in which the light intensity is a direction in which the light intensity is a peak, and the light intensity is 50% of the peak value. "Lambertian distribution" means that the brightness of the light-emitting surface is not affected by the viewing direction and is distributed. That is, the light distribution in the case of complete diffusion.

Next, the laser light source 10 will be described. The laser light source 10 is composed of a plurality of laser light emitting elements arranged in a line in the y-axis direction. These laser light emitting elements respectively emit a red laser light source L10. This red laser light L10 is light having a peak of light intensity near, for example, a wavelength of 640 nm. The half-value width of the laser light L10 is 1 nm, and the spectral width is extremely narrow compared to the spectrum of light emitted from a single-color LED element or an LED element using a phosphor. Here, the "half value width" means a wavelength width when the light intensity is 50% of the highest intensity with respect to the wavelength at which the light intensity is the highest.

The divergence angle of the laser light L10 is, for example, in the fast axis direction (divergence angle) The half value angle on the large direction is 40 degrees. The divergence angle of the laser beam L10 is the slow axis direction (the direction in which the divergence angle is small) and the upper half angle is 10 degrees. Here, the "divergence angle" refers to the angle at which the light is unfolded. The "fast axis direction" is a direction in which the divergence angle is large, and the "slow axis direction" is a direction in which the divergence angle is small. The "half value angle" refers to an angle in which the light intensity is a direction in which the light intensity is a peak, and the light intensity is 50% of the peak value.

The laser light emitting elements of the laser light source 10 of the surface light source device 200 are arranged such that the fast axis direction is parallel to the arrangement direction (y-axis direction) of the laser light emitting elements. The laser light emitting element of the laser light source 10 is disposed such that the slow axis direction is parallel to the thickness direction (z-axis direction) of the optical path changing element 6. The light-emitting portion of the laser light source 10 (the end surface of the laser beam L10 that emits each of the laser light-emitting elements) faces the light incident surface 61 (described later) of the optical path changing element 6. The laser light source 10 has a plurality of laser light emitting elements that emit laser light L10 generated by each of the plurality of laser light emitting elements. The laser light source 10 is disposed on one side of the surface-emitting light guide plate 5 of the surface-emitting light guide plate 5.

Next, the optical path changing element 6 will be described with reference to the first, second (a), second (b), third (a), and third (b) drawings. The optical path changing element 6 is made of a transparent material. For example, the material of the optical path changing element 6 may be polymethyl methacrylate (PMMA), polycarbonate (PC), cycloolefin polymer (COP), glass or the like. The optical path changing element 6 has a light incident surface 61 on which the laser beam 10 emitted from the laser light source 10 enters, a light guiding portion 62, an optical path changing portion 63, and a light emitting surface 64. The optical path changing unit 63 has a reflecting surface 63a (first reflecting surface) and a reflecting surface 63b (second reflecting surface). The light exit surface 64 of the optical path changing element 6 is a surface parallel to the y-z plane of Fig. 1 . As shown in Fig. 1 and Fig. 3(a) and Fig. 3(b), the light exit surface 64 of the optical path changing element 6 faces the light incident surface 51c of the surface emitting light guide plate 5 (post Said) configuration. The length of the optical path changing element 6 in the longitudinal direction (y-axis direction) is equal to the length of the light incident surface 51c of the surface emitting light guide plate 5 in the y-axis direction or shorter than the length of the light incident surface 51c in the y-axis direction. In addition, as described above, the longitudinal direction of the display surface 1a of the liquid crystal panel 1 is the x-axis direction (the horizontal direction in the first drawing).

The reflecting surfaces 63a and 63b of the optical path changing element 6 are all reflecting surfaces having a difference in refractive index of the interface. The reflecting surface 63a has a function of causing the laser beam L10 that has passed through the light guiding portion 62 of the optical path changing element 6 to travel toward the optical path changing portion 63 to face the +z-axis direction. The reflecting surface 63b has a function of causing the laser beam L10 that has passed through the optical path changing portion 63 of the optical path changing element 6 to travel in the +z-axis direction to face the +x-axis direction.

The thickness (the width of the z-x plane) of the light guiding portion 62 of the optical path changing element 6 is thicker as it approaches the optical path changing portion 63 from the light incident surface 61. That is, the light guiding portion 62 has a wedge shape. By such a wedge shape, the divergence angle of the z-x plane of the laser beam L10 incident from the light incident surface 61 can be reduced. For example, the divergence angle of the laser beam L10 can be converted into parallel light. By converting the laser beam L10 into parallel light, it is easy to design the reflecting surfaces 63a and 63b of the optical path changing portion 63 to have a higher reflectance. In this manner, the shape of the z-x plane of the light guiding portion 62 of the optical path changing element 6 is formed into a wedge shape thickened in the -x-axis direction, and is particularly effective when the divergence angle of the laser z-x plane is large. The reflecting surfaces 63a and 63b may be formed by a method such as aluminum vapor deposition. In this case, the manufacturing procedure of the optical path changing element 6 becomes complicated, but the light can be reflected more reliably than the reflecting surface using total reflection.

The beam diameter of the laser beam L10 just emitted by the laser light source 10 is extremely small with respect to the y-axis direction of the light incident surface 61 of the optical path changing element 6. That is to say, the laser light source 10 can be treated as a point light source. The laser light L10 is spread toward the arrangement direction (y-axis direction) due to its own divergence angle. Therefore, laser light The laser light emitted from each of the laser light-emitting elements of the source 10 overlaps with the laser light of the adjacent other laser light-emitting elements during the propagation of the optical path changing element 6 in space. On the other hand, each of the laser beams forms a linear laser beam having a uniform brightness distribution in the direction in which the laser light emitting elements are arranged (y-axis direction). The "arrangement direction" refers to a direction perpendicular to the traveling direction of the laser light. The "point light source" refers to a light source whose size of the light-emitting portion is smaller than that of the light-receiving portion (here, the light incident surface) and can be regarded as a point. "Communication" means the meaning of transmission. Here, it means that light travels in the optical path changing element 6 or the surface emitting light guide plates 4, 5, and the like.

By extending the length of the light guiding portion 62 of the optical path changing element 6 in the x-axis direction, the uniformity of the spatial light intensity distribution in the arrangement direction (y-axis direction) of the laser light emitting element can be improved. Further, by lengthening the length of the light guiding portion 62 in the x-axis direction, the spatial light intensity distribution in the arrangement direction (y-axis direction) of the laser light emitting elements is uniform, so that the number of required laser light emitting elements can be reduced. The optical path changing element 6 adjusts the laser beam emitted from the laser light source 10 and incident on the light incident surface 61 in a first plane perpendicular to the traveling direction of the laser beam (in the second (a) and second (b) views. The spatial intensity distribution on the plane of the yz plane or the plane substantially parallel to the yz plane changes the laser beam incident on the incident light incident surface 61 to a laser beam having a linear cross-sectional shape of the laser beam on the first plane. This linear laser beam L110 is then emitted from the light exit surface 64. Here, the "substantially parallel plane" is described because the light guiding portion 62 of the optical path changing element 6 is inclined by 3 to 8 degrees with respect to the x-y plane as shown in Fig. 1 . The light guiding portion 62 is inclined so as to secure a space for arranging the driving substrate for the laser light source 10, the heat releasing member, and the like at the position of the laser light source 10. When these members can be downsized, it is not necessary to tilt the light guiding portion 62. In the second (a) diagram, the cross-sectional shape of the linear laser beam L110 is at the plane 64. A strip-shaped (or linear) dot area having a narrow z-axis direction in the y-axis direction is displayed. The adjustment of the spatial intensity distribution of the linear laser beam on the first plane by the optical path changing element 6 is the uniformity of the spatial intensity distribution on the first plane. Here, the "line shape" is shown in FIG. 2(a) as a schematic view, and the linear laser beam L110 has a long length in the z-axis direction compared to the length in the y-axis direction. However, in reality, the length in the z-axis direction is much smaller than the length in the y-axis direction, so there is no problem even if it is called "linear". That is, the optical path changing element 6 changes the laser beam L10 emitted from the laser light source 10 into a laser beam having a uniform spatial intensity distribution in a direction perpendicular to the traveling direction of the laser beam L10, and then emits it. In the first embodiment, the optical path changing element 6 changes the laser beam into a linear laser beam having a uniform spatial intensity distribution in a direction parallel to the arrangement direction of the laser light emitting elements of the laser light source 10, and then emits the light. The optical path changing element 6 includes a light guiding unit 62, and has an optical path length of a laser beam that is emitted from the laser beam 10 emitted from the laser light source 10, and an optical path changing unit 63 that guides the light guided by the light guiding unit 62. The traveling direction of the laser light is emitted toward the surface emitting light guide plate 5. The light guiding portion 62 has a wedge shape which is formed from the end surface 61 of the laser beam 10 emitted from the laser light source 10 toward the optical path changing portion 63 in a direction perpendicular to the linear laser beam and perpendicular to the line shape. The direction in which the laser rays travel in the direction of travel.

Next, the surface emitting light guide plate 4 will be described with reference to the first, fifth, and seventh drawings. The surface emitting light guide plate 4 has a light emitting surface 41a, a back surface 41b, a light incident surface 41c, an end surface 41d, a mixing portion 41e, and a light guiding portion 41f. The light exit surface 41a is a surface on the liquid crystal panel 1 side (+z axis side). The light exit surface 41a is a plane parallel to the x-y plane. The back surface 41b is a surface on the -z axis side, and is a surface provided in a direction opposite to the light exit surface 41a. The back surface 41b is a surface parallel to the x-y plane. The light incident surface 41c is disposed at the end on the -x axis side surface. The LED light L9 emitted from the LED light source 9 is incident on the surface light-emitting light guide plate 4 from the light incident surface 41c. The end surface 41d is provided on the end surface on the +x axis side. The end surface 41d is provided on a surface opposite to the light incident surface 41c of the surface emitting light guide plate 4. The mixing portion 41e is a field (mixing field) for mixing the LED light rays L9 incident from the light incident surface 41c. Adjacent LED rays L9 are superimposed and mixed in the mixing portion 41e. The light guiding portion 41f is a field in which the surface emitting light guide plate 4 removes the mixing portion 41e.

The surface-emitting light guide plate 4 is made of a transparent material. For example, the material of the surface-emitting light guide plate 4 is polymethyl methacrylate (for example, PMMA), polycarbonate (PC), cycloolefin polymer (COP), glass, or the like. The surface-emitting light guide plate 4 is a plate-like member. The surface emitting light guide plate 4 is, for example, a plate member having a thickness of 3 mm. The surface emitting light guide plate 4 is laminated between the optical sheet 3 and the surface emitting light guiding plate 5, and is disposed in parallel with respect to the display surface 1a of the liquid crystal panel 1. The term "layered" refers to a layered arrangement, and does not require the connection of components. Here, each constituent element is parallel to the x-y plane and arranged in the z-axis direction. The mixing portion 41e has a predetermined length from the light incident surface 41c toward the center of the surface emitting light guide plate 4 (in the +x-axis direction). Here, the "predetermined length of the mixing portion 41e" means the length determined by the divergence angle and the arrangement interval of the LED elements used for the LED light source 9. In the mixing portion 41e, both of the light-emitting surface 41a and the back surface 41b of the surface-emitting light-guiding plate 4 have no optical structure and face the air layer. In other words, the LED light beam L9 is totally reflected by the light exit surface 41a and the back surface 41b of the mixing portion 41e, and proceeds toward the light guiding portion 41f.

A microscopic optical element 42 is provided in a portion corresponding to the light guiding portion 41f of the back surface 41b of the surface emitting light guide plate 4. That is, the microscopic optical element 42 is provided on the back surface 41b of the light guiding portion 41f. The microscopic optical element 42 has a hemispherical convex shape that protrudes in the -z axis direction. The micro optical element 42 illuminates the back of the light guide plate 4 in response to the surface The positions on the face 41b (on the x-y plane) are arranged at different arrangement densities. Here, the "arrangement density" means the number of unit areas of the microscopic optical elements 42 or the size of the unit area of the microscopic optical elements 42. That is, for example, when the sizes of the microscopic optical elements 42 are equal, the number of unit areas of the microscopic optical elements 42 may be different, and in the case where the number of unit areas of the microscopic optical elements 42 is equal, the size of the minute optical elements 42 may be different. Of course, the case where the size of the minute optical element 42 and the number of unit areas of the minute optical element 42 are different are also included. The in-plane luminance distribution of the LED illumination light L90 (described later) can be controlled by the change in the arrangement density of the microscopic optical elements 42. That is to say, the arrangement of the minute optical elements 42 causes the spatial intensity distribution of the LED illumination light L90 emitted from the light exit surface 41a to be uniform. Here, "in-plane" means the inside of the display surface 1a of the liquid crystal panel 1. "In-plane luminance distribution" refers to the distribution of luminance in any plane on a 2-dimensional position. "Brightness" refers to the physical quantity of brightness.

The microscopic optical element 42 changes its position in accordance with the traveling direction of the LED light beam L9 (the +x-axis direction of the x-y plane) as shown in Fig. 7, for example. In the example of Fig. 7, the arrangement density is continuously narrowed from the vicinity of the light incident surface 41c toward the end surface 41d. By appropriately setting the arrangement density of the microscopic optical elements 42, it is possible to obtain the LED illumination light L90 having a uniform spatial intensity distribution. Fig. 7 is an example of the arrangement of the microscopic optical elements 42, and other configurations may be used as long as they have the same function. The surface-emitting light-guiding plate 4 and the surface-emitting light-guiding plate 5 are laminated in parallel, and the LED light L9 emitted from the LED light source 9 is converted into a planar LED illumination light having uniform spatial intensity distribution on a plane perpendicular to the emission direction of the laser illumination light L111. L90 emits LED illumination light L90 in the same direction as the emission direction of the laser illumination light L111.

Next, the surface emitting light guide plate 5 will be described with reference to the first, third, fourth, and sixth drawings. The surface emitting light guide plate 5 has a light emitting surface 51a, a back surface 51b, a light incident surface 51c, and an end surface 51d. The light exit surface 51a is a surface on the liquid crystal panel 1 side (+z axis side). The light exit surface 51a is a surface parallel to the x-y plane. The back surface 51b is a surface on the -z axis side, and is a surface provided in a direction opposite to the light exit surface 51a. The back surface 51b is a surface parallel to the x-y plane. The light incident surface 51c is provided on the end surface on the -x axis side. The laser beam L10 emitted from the light exit surface 64 of the optical path conversion element 6 is incident on the surface emitting light guide plate 5 from the light incident surface 51c. The end surface 51d is provided on the end surface on the +x-axis side opposite to the light incident surface 51c of the surface-emitting light-guide plate 5.

The surface-emitting light guide plate 5 is made of a transparent material. For example, the material of the surface-emitting light guide plate 5 is polymethyl methacrylate (for example, PMMA), polycarbonate (PC), cycloolefin polymer (COP), glass, or the like. The surface emitting light guide plate 5 is a plate member. The surface emitting light guide plate 5 is, for example, a plate member having a thickness of 3 mm. The surface emitting light guide plate 5 is laminated between the surface emitting light guide plate 4 and the light reflecting sheet 8, and is disposed in parallel with respect to the display surface 1a of the liquid crystal panel 1. The light incident surface 51c of the surface emitting light guide plate 5 has a diffusing portion 510c having a light diffusing structure. The surface-emitting light-guiding plate 5 has a microscopic optical element 52 on the back surface 51b from the vicinity of the light incident surface 51c to the end surface 51d.

The light diffusion structure of the light incident surface 51c is, for example, a structure in which a plurality of fine convex lenses are formed in the z-axis direction. The light diffusion structure of the light incident surface 51c may be a structure in which, for example, a plurality of fine concave lenses are formed. The light-diffusing structure of the light incident surface 51c may be a structure in which a plurality of fine pyramids are formed. The light-diffusing structure of the light incident surface 51c may be a structure in which a fine random uneven shape is formed by sandblasting or the like. The light diffusing structure of the light incident surface 51c may be folded in a coating manner A structure in which particles having different irradiance and surrounding materials adhere to each other. Further, the light diffusing structure of the light incident surface 51c may be replaced with a light diffusing element. That is, the light diffusing structure of the light incident surface 51c can be replaced with a light diffusing element. That is to say, a light diffusing element which is a member different from the surface emitting light guide plate 5 can be provided. In other words, the diffusion portion 510 can be formed in a manner different from the member that illuminates the light guide plate 5 . The light diffusing element can be formed on the light incident surface 51c of the surface emitting light guide plate 5. The light diffusing element can have the light diffusing structure described above. For example, the light diffusing element may comprise particles having a refractive index different from that of the surrounding material. When the light diffusing element is used, the light diffusing structure of the light incident surface 51c can be removed. The light diffusing element may be disposed in front of the light incident surface 51c (on the -x axis direction side). The light diffusing element may have a gap even if it is connected to the light incident surface 51c. Further, the light diffusing element may be disposed behind the light emitting surface 64 (on the +x axis direction side). The light diffusing element may have a gap even if it is connected to the light exit surface 64. The light diffusing element can be disposed between the light exit surface 64 and the light incident surface 51c. The light diffusing members of different members may be attached to the light incident surface 51c of the surface emitting light guide plate 5 to be integrated. The light diffusing elements of different members may be attached to the light exit surface 64 of the optical path changing element 6 to be integrated.

As a result, by providing the light diffusion structure on the light incident surface 51c of the surface emitting light guide plate 5, it is possible to obtain the laser light ray L110 in which the angular intensity distribution on the z-x plane is effectively expanded. As described above, for example, a light diffusion structure can be provided on the light exit surface 64 of the optical path changing element 6. However, in this configuration, since the current angular intensity distribution of the laser beam L110 emitted from the optical path changing element 6 is widened, light leakage occurs on the light incident surface 51c of the surface emitting light guide plate 5, and the efficiency is lowered. Therefore, it is possible to suppress a decrease in light efficiency by providing the light diffusion structure on the incident surface 51c. Alternatively, the light diffusing element is disposed in the vicinity of the incident surface 51c to suppress light efficiency. drop.

The laser light L10 in front of the incident surface light-emitting light guide plate 5 is a very straight-through light. Therefore, in the case where the light-diffusing structure is not provided on the light incident surface 51c, a large portion of the laser light L10 will be totally reflected after the incident surface is illuminated by the light guide plate 5, and is not directly reflected at the interface between the surface-emitting light-guide plate 5 and the air layer. End face 51d. The laser beam L110 incident from the light incident surface 51c advances in the +x-axis direction. Thereafter, the laser light L110 is totally totally reflected and propagates inside the surface emitting light guide plate 5. The light incident on the minute optical element 52 among the laser light rays L110 changes the traveling direction by the minute optical element 52, and is emitted from the light exit surface 51a. As described above, when the light diffusing structure is not provided on the light incident surface 51c, a large portion of the light of the incident surface emitting light guide plate 5 reaches the end surface 51d. In this case, the light incident on the minute optical element 52 is reduced, the light emitted from the light exit surface 51a is reduced, and the light use efficiency is lowered. Here, the "light use efficiency" means the ratio of the amount of light emitted to the liquid crystal panel 1 to the amount of light of the light-emitting light guide plate 5 on the incident surface. The surface-emitting light-guiding plate 5 converts the linear laser beam emitted from the optical path changing element 6 into planar laser illumination light having a uniform spatial intensity distribution on a plane (the dot in the 3(a) diagram represents Plane (laser illumination light), the direction of travel of the laser illumination light L111 is indicated by a white thick arrow pointing in the z-axis direction) parallel to the line of laser light (the laser light L110 in the second (a) diagram) The cross-sectional shape is represented by a strip-shaped (or linear) dot field that is long in the y-axis direction on the surface 64 and narrow in the z-axis direction) and the traveling direction of the linear laser ray (the laser in the second (a)) A plane in which the traveling direction of the light ray L110 is indicated by a thick arrow in the +x-axis direction (the xy plane in the third (a) way). The surface-emitting light guide plate 5 further directs the laser illumination light L111 to a plane perpendicular to the traveling direction of the linear laser light and the linear laser light. The direction is shot. The end surface of the surface of the surface of the laser beam on the incident side of the laser beam has a diffusing portion 510c, which is perpendicular to the direction of the linear laser beam and perpendicular to the angle of the linear laser beam in the traveling direction of the linear laser beam. Intensity distribution.

As described above, the light-diffusing structure for expanding the angular intensity distribution of the z-x plane of the laser beam L10 is suitably disposed on the light incident surface 51c of the surface-emitting light guide plate 5 as in the first embodiment. Alternatively, the light diffusion structure is suitably disposed in the vicinity of the light incident surface 51c.

The microscopic optical element 52 has a hemispherical convex shape that protrudes in the -z axis direction. The micro-optical elements 52 are arranged at different arrangement densities depending on the positions on the back surface 51b of the surface-emitting light-guide plate 5 (on the x-y plane). Here, the "arrangement density" means the number of unit areas of the microscopic optical element 52 or the size per unit area of the microscopic optical element 52 (the outer dimension of the x-y plane of the microscopic optical element 52). That is, for example, in the case where the sizes of the microscopic optical elements 52 are equal, the number of unit areas of the microscopic optical elements 52 may be different, and in the case where the number of unit areas of the microscopic optical elements 52 is equal, the size of the minute optical elements 52 may be different. Of course, the case where the size of the microscopic optical element 52 and the number of unit areas of the microscopic optical element 52 are different are also included. The in-plane luminance distribution of the laser illumination light L111 (described later) can be controlled by the change in the arrangement density of the microscopic optical elements 52. That is to say, the arrangement of the minute optical elements 52 causes the spatial intensity distribution of the laser illumination light L111 emitted from the light exit surface 51a to be uniform. Here, "in-plane" means the inside of the display surface 1a of the liquid crystal panel 1.

The microscopic optical element 52 changes its position in accordance with the traveling direction of the laser beam L110 (the +x-axis direction of the x-y plane) as shown in Fig. 6, for example. In the example of Fig. 6, the arrangement density is from the vicinity of the light incident surface 51c toward the end surface 51d. Continuously changed by sparse. By appropriately setting the arrangement density of the microscopic optical elements 52, it is possible to obtain the laser illumination light L111 having a uniform spatial intensity distribution. Fig. 6 is an example of the arrangement of the microscopic optical elements 52, and other configurations may be used as long as they have the same function.

Here, the microscopic optical element 52 has a convex lens shape, but is not limited thereto. The microscopic optical element 52 may have another shape as long as it has a function of reflecting the laser beam L110 in the +z-axis direction and emitting the laser illumination light L111 toward the back surface 1b of the liquid crystal panel 1. For example, a 稜鏡 shape or a random emboss pattern or the like can be used as the other shape of the microscopic optical element 52.

The surface-emitting light guide plates 4, 5 are generally stretched and contracted by the influence of temperature or humidity. The surface-emitting light guide plates 4 and 5 may differ in size per sheet due to workmanship during processing. The "size" refers to the size of the surface-emitting light guide plates 4, 5. That is to say, the size of the surface-emitting light guide plates 4, 5 may be deviated. In the first embodiment, a sufficient gap is provided between the light exit surface 64 of the optical path changing element 6 and the light incident surface 51c of the surface emitting light guide plate 5 in consideration of such expansion and contraction and dimensional difference. The laser beam L10 emitted from the light exit surface 64 of the optical path changing element 6 has a strong straightness in the x-z plane. Therefore, even if a gap is provided between the light exit surface 64 of the optical path changing element 6 and the light incident surface 51c of the surface emitting light guide plate 5, the laser beam L10 can efficiently reach the light incident surface 51c of the surface emitting light guide plate 5.

Next, the light reflection sheet 8 will be described. The light reflection sheet 8 is disposed at a position facing the back surface 51b of the surface emitting light guide plate 5. The light reflection sheet 8 is disposed in parallel to the display surface 1a of the liquid crystal panel 1. The light reflection sheet 8 is, for example, a sheet in which a resin such as polyethylene terephthalate is used as a base material to form reflected light. The light reflection sheet 8 may be a sheet in which metal is vapor-deposited on the surface of the substrate to reflect light.

In the liquid crystal display device 100 of the first embodiment, the light incident surface 51c of the surface emitting light-guide plate 5 is not used for displaying an image, except that the -x-axis side is outside the range (effective range) in which the liquid crystal panel 1 displays an image. A portion of the liquid crystal panel 1 outside the display image range is a margin portion. That is to say, all the constituent components of the field are disposed at the forefront portion of the periphery of the screen. The surface-emitting light-guide plate 4 is laminated on the liquid crystal panel 1 side (+z-axis side) of the surface-emitting light-guide plate 5. Thereby, the arrangement of the surface emitting light guide plate 4 can be extended to the field of the liquid crystal panel 1 side (+z axis direction side) of the optical path changing part 63. A portion of the optical path changing portion 63 of the optical path changing element 6 is disposed on the fore edge portion. Therefore, by arranging the mixing portion 41e of the surface emitting light-guide plate 4 on the +z-axis direction side of the optical path changing portion 63, uniform LED light L9 can be generated in the field (mixing portion 41e) that does not affect image display. In other words, the LED light source 9 and the optical path changing portion 63 are disposed at the same position of the forehead portion, and the other forehead portions can be narrowed. On the other hand, the LED light source 9 and the optical path changing unit 63 are disposed at positions overlapping the z-axis direction, and the length of the mixing portion 41e can be lengthened, and the mixing of the LED light L9 can be easily realized. The "frontal edge" refers to a frame surrounding the liquid crystal panel. It is helpful to arrange the LED light source 9 and the optical path changing unit 63 on the lower side of the liquid crystal display device 100 in consideration of increasing the front edge portion of one side of the display surface 1a. Generally, a switch or a speaker or the like is disposed on the lower side of the liquid crystal display device 100. Therefore, even if the margin portion is increased, there are few problems in design. In this case, unlike the xyz rectangular coordinate system originally explained, the +-axis direction becomes the upper side, and the +y-axis direction becomes the left side toward the display surface 1a.

Here, an operation until the liquid crystal panel 1 is displayed on the liquid crystal display device 100 will be described. As shown in FIG. 8, the video signal 34 is input to the control unit 31 provided in the liquid crystal display device 100. In other words, image signal 34 input control unit. The control unit 31 generates a liquid crystal display element control signal 35, and sends the liquid crystal display element control signal 35 to the liquid crystal display element drive unit 32. Further, the control unit 31 generates a light source control signal 36 and sends the light source control signal 36 to the light source driving unit 33. The light source control signal 36 generated by the control unit 31 is generated in accordance with the ratio of the light intensities of the respective colors required to display the image of the input image signal 34 on the liquid crystal display element 1.

After receiving the liquid crystal display element control signal 35, the liquid crystal display element drive unit 32 drives the liquid crystal display element 1 in response to a signal. In other words, the liquid crystal display element driving unit 32 transmits an electric signal corresponding to the liquid crystal display element control signal 35 to the liquid crystal display element 1, and changes the light transmittance of each pixel. Specifically, the liquid crystal display element drive unit 32 changes the alignment of the liquid crystal by changing the voltage applied to the liquid crystal layer, and rotates the polarization direction of the light transmitted through the liquid crystal layer at the position. The light that is rotated in the polarization direction is controlled by the amount of light transmitted through the polarizing plate disposed behind the liquid crystal layer. The brightness or color of the image is changed by the change in the transmittance of the light. After receiving the light source control signal 36, the light source driving unit 33 drives the LED light source 9 and the laser light source 10 in response to the signal.

Further, as shown in FIG. 9, the LED light source driving unit 33a and the laser light source driving unit 33b can be provided instead of the light source driving unit 33. When the video signal 34 is input to the control unit 31, the control unit 31 generates a liquid crystal display element control signal 35, and sends the liquid crystal display element control signal 35 to the liquid crystal display element drive unit 32. The control unit 31 also generates an LED light source control signal 36a, and sends the LED light source control signal 36a to the LED light source driving unit 33a. The control unit 31 also generates a laser light source control signal 36b and sends the laser light source control signal 36b to the laser light source driving unit 33b. The LED light source control signal 36a is responsive to the image of the input image signal 34. The light intensity ratio of each color required when displayed on the liquid crystal display element 1 is generated. The laser light source control signal 36b is generated in accordance with the light intensity ratio of each color required for displaying the image of the input image signal 34 on the liquid crystal display element 1.

When the LED light source driving unit 33a receives the LED light source control signal 36a, the LED light source 9 is driven in response to this signal. Similarly, after receiving the laser light source control signal 36b, the laser light source driving unit 33b drives the laser light source 10 in response to this signal.

The control unit 31 individually controls the LED light source driving unit 33a and the laser light source driving unit 33b. In this case, the control unit 31 can easily adjust the ratio of the amount of blue-green light emitted from the LED light source 9 and the amount of red light emitted from the laser light source 10. In other words, the control unit 31 adjusts the amount of light emitted from the LED light source 9 and the amount of light emitted from the laser light source 10 in accordance with the ratio of the light intensity of each color required for displaying the video signal 34 on the liquid crystal display element 1. Thereby, the liquid crystal display device 100 and the surface light source device 200 can reduce power consumption.

The laser beam L10 enters the inside of the optical path changing element 6 from the light incident surface 61, and proceeds toward the optical path changing unit 63 in the light guiding unit 62. The laser beam L10 is emitted from the light emitting portion of the laser light source 10. The light guiding portion 62 constitutes a thin plate-shaped portion that connects the light incident surface to the optical path changing portion, and the thin plate-shaped portion has a wedge shape that is thicker toward the optical path changing portion 63. The laser beam L10 that has reached the optical path changing unit 63 is reflected by the reflecting surface 63a in the +z-axis direction. Thereafter, the laser beam L10 is reflected by the reflecting surface 63b in the +x-axis direction.

The laser beam L10 reflected by the reflecting surface 63b is emitted from the light emitting surface 64 of the optical path changing element 6. The laser beam L10 emitted from the light exit surface 64 of the optical path changing element 6 is caused by the light diffusing structure of the light incident surface 51c of the surface emitting light guide plate 5. The angular intensity distribution on the z-x plane is developed, and the incident surface illuminates the inside of the light guide plate 5. The angular intensity distribution on the x-y plane of the laser beam L10 is uniformized in the optical path changing element 6 due to the overlapping of light. However, the angular distribution on the z-x plane of the laser ray L10 remains unchanged. Therefore, it is necessary to expand the angular intensity distribution of the laser light L10 by the light diffusion structure of the light incident surface 51c.

A large portion of the laser beam L110 inside the incident surface emitting light guide plate 5 is totally reflected at the interface between the surface emitting light guide plate 5 and the air layer, and proceeds toward the inside of the surface emitting light guide plate 5 toward the +x axis direction. A part of the laser beam L110 enters the micro-optical element 52 during the process of total reflection, and is reflected by the curved surface of the micro-optical element 52 to change the traveling direction. The laser beam L110 that changes the traveling direction includes light that does not satisfy the condition of total reflection at the interface between the surface of the surface emitting light guide plate 5 and the air layer. Light that does not satisfy the total reflection condition (light that travels in the +z axis direction) is used as the laser illumination light L111, and the surface light is emitted from the light exit surface 51a of the surface light-emitting light guide plate 5 toward the liquid crystal in the +z-axis direction. The back surface 1b of the panel 1 is emitted. At this time, the laser illumination light L111 is planar light having a uniform spatial intensity distribution on the x-y plane. The x-y plane is a plane perpendicular to the emission direction of the laser illumination light L111.

The LED light L9 emitted from the LED light source 9 enters the inside of the surface emitting light guide plate 4 from the incident surface 41c of the surface emitting light guide plate 4. The LED light beam L9 incident from the light incident surface 41c is totally reflected at the interface between the surface emitting light-guide plate 4 and the air layer, and proceeds in the +x-axis direction in the mixing portion 41e. The "interface between the surface-emitting light-guide plate 4 and the air layer" means the surface on the light-emitting surface 41a side of the mixing portion 41e and the surface on the back surface 41b side of the mixing portion 41e. After the LED light L9 is incident from the light incident surface 41c to the inside of the surface emitting light guide plate 4, the LED light beam L9 is adjacent to each other while the mixing portion 41e is propagating. LED light L9 will overlap in space. The "adjacent LED light L9" refers to light emitted by one LED element included in the LED light source 9 and light emitted by the LED element adjacent to the LED element. On the other hand, the luminance distribution of the LED light rays 9 superimposed in the space in the arrangement direction (y-axis direction) of the LED elements becomes uniform linear light, and proceeds toward the light guiding portion 41f.

A large part of the LED light beam L9 that has proceeded toward the light guiding portion 41f is totally reflected at the interface between the surface emitting light-guide plate 4 and the air layer, and proceeds in the +x-axis direction inside the surface-emitting light-guide plate 4. A part of the LED light beam L9 that has proceeded toward the light guiding portion 41f enters the microscopic optical element 42 during the total reflection, and is reflected by the curved surface of the microscopic optical element 42 to change the traveling direction. The LED light ray L9 that changes the traveling direction contains light that does not satisfy the condition of total reflection at the interface between the surface of the surface-emitting light-guide plate 4 and the air layer. Light that does not satisfy the total reflection condition (light that travels in the +z-axis direction) is used as the LED illumination light L90, and is emitted from the light-emitting surface 41a of the surface-emitting light-guide plate 4 toward the back surface 1b of the liquid crystal panel 1 in the +z-axis direction. . At this time, the LED illumination light L90 is planar light having a uniform spatial intensity distribution on the x-y plane. The x-y plane is a plane perpendicular to the emission direction of the LED illumination light L90.

Here, light emitted from the back surface 41b of the surface emitting light guide plate 4 toward the -z-axis direction is reflected by the light reflecting sheet 8 in the LED light beam L9 traveling inside the surface emitting light-guide plate 4, and is converted to the +z-axis direction. Forward light (LED illumination light L90). Similarly, in the laser beam L110 traveling inside the surface-emitting light-guide plate 5, light traveling from the back surface 51b of the surface-emitting light-guide plate 5 toward the -z-axis direction is reflected by the light-reflecting sheet 8 and is converted to the +z-axis direction. Forward light (laser illumination L111). The LED light L9 and the laser light L110 reflected by the light reflection sheet 8 illuminate the back surface 1b of the liquid crystal panel 1.

Both the LED illumination light L90 and the laser illumination light L111 illuminate the back surface 1b of the liquid crystal panel 1 through the optical sheet 3 and the optical sheet 2. Both of the LED illumination light L90 and the laser illumination light L111 are mixed and transmitted to the white illumination light L120 while the optical sheet 3 and the optical sheet 2 reach the back surface 1b of the liquid crystal panel 1.

The white illumination light L120 is generated by mixing the LED illumination light L90 and the laser illumination light L111. Both the LED illumination light L90 and the laser illumination light L111 are light having a uniform spatial intensity distribution on the x-y plane. Therefore, the generated illumination light L120 is also white planar light having a high uniformity in spatial intensity distribution on the x-y plane.

The LED light source 9 is a light source including an LED element having a relatively wide divergence angle. Therefore, even if an optical element is not particularly provided between the LED light source 9 and the surface-emitting light-guiding plate 4, the arrangement direction of the LED elements (y-axis direction) can be improved by the LED light L9 propagating in the mixing portion 41e of the surface-emitting light-guiding plate 4 The uniformity of the spatial intensity distribution.

On the other hand, the laser light source 10 is a light source including a laser light emitting element having a relatively narrow divergence angle. Therefore, it is difficult to improve the uniformity of the spatial intensity distribution in the arrangement direction (y-axis direction) of the laser light-emitting elements. In the first embodiment, the optical path changing element 6 is provided in the thickness direction (-z-axis direction) of the liquid crystal display device 100. Therefore, it is possible to ensure that the light guiding portion 62 of the optical path changing element 6 has a sufficient optical distance without increasing the frontal area of the liquid crystal display device 100. Therefore, the uniformity of the spatial intensity distribution in the arrangement direction (y-axis direction) of the laser light emitting elements can be improved.

Fig. 10 is a cross-sectional view schematically showing another example of the structure of a liquid crystal display device (including a surface light source device) according to Embodiment 1 of the present invention. Said above In the description, the light incident surface 41c of the surface emitting light guide plate 4 and the light incident surface 51c of the surface emitting light guide plate 5 are the end faces on the same direction side (the -x axis direction side). However, the positional relationship between the light incident surface 41c and the light incident surface 51c is not limited thereto. For example, as shown in Fig. 10, the light incident surface 51c of the surface emitting light-guide plate 5 is provided on the end surface on the -x-axis direction side, and the light incident surface 41c of the surface-emitting light-guide plate 4 is provided on the end surface on the -y-axis direction side. Therefore, the light incident surfaces 41c and 51c can be arranged as shown in Fig. 10. In this case, the LED light source 9 arranges the LED elements in one dimension in the x-axis direction. Further, when the surface of the light incident surface 41c is changed, the arrangement of the microscopic optical elements 42 of the surface emitting light guide plate 4 is also changed to an appropriate position. Specifically, the arrangement of the microscopic optical elements 42 as shown in FIG. 7 is rotated to the left by 90°. In addition, the surface of the light incident surface 51c of the surface emitting light guide plate 5 may be changed without changing the surface of the light incident surface 41c of the surface emitting light guide plate 4. In this case, the arrangement of the microscopic optical elements 52 is changed to an appropriate position as in the case of changing the surface of the surface light incident surface 41c.

Further, not only the light incident surface 41c of the surface light-emitting plate 4 but also the end surface 41d can be used as the light incident surface. The light incident surface 41c is an end surface on the −x-axis direction side of the surface-emitting light-guide plate 4, and the end surface 41d is an end surface on the +x-axis direction side of the surface-emitting light-guide plate 4. In other words, the LED light source 9 is disposed facing the light incident surface 41c on the −x-axis direction side of the surface-emitting light-guide plate 4, and the LED light source 9 may be disposed to face the end surface 41d on the +x-axis direction side of the surface-emitting light-guide plate 4. When the light incident surface 41c is provided on the end surface on the -y-axis direction side, or when the light incident surface 41c is provided on the end surface on the -y-axis direction side and the end surface on the +y-axis direction side, the optical path is considered to be changed. The portion 63 is disposed on the lower side of the liquid crystal display device 100. This is because the length of the diffusing portion 510c is made shorter than the length of the optical path changing portion 63 in the x-axis direction. Easy, the narrow portion of the forehead can be easily realized on the side of the diffusing portion 510c. In other words, in this case, the laser beam L110 is incident on the light-emitting light guide plate 5 from the lower side of the liquid crystal display device 100, and the LED light beam L9 is incident on the light-emitting plate 4 from the left and right side of the liquid crystal display device 100.

Further, not only the light incident surface 51c of the surface light-emitting plate 5 but also the end surface 51d may be used as the light incident surface. The light incident surface 51c is an end surface on the −x-axis direction side of the surface-emitting light-guide plate 5, and the end surface 51d is an end surface on the +x-axis direction side of the surface-emitting light-guide plate 5. In other words, the optical path changing element 6 and the laser light source 10 are disposed facing the light incident surface 51c on the −x-axis direction side of the surface-emitting light-guide plate 5, and may also face the end surface 51d on the +x-axis direction side of the surface-emitting light-guide plate 5. Configuration. In this way, at least one of the surface emitting light guide plates 4 and 5 can increase the amount of light by increasing the number of light sources by making the opposite two end faces a light incident surface. Thereby, for example, in a case where it is necessary to increase the screen size of the liquid crystal panel 1 and more and more illumination light is required, a sufficient amount of light can be obtained. However, these configurations are relatively difficult to obtain the effect of narrowing the other marginal portions by arranging the LED light source 9 and the optical path changing portion 63 at the same position of the forehead portion as described above, and it is also difficult to borrow. By arranging the LED light source 9 and the optical path changing portion 63 at positions overlapping in the z-axis direction, the length of the elongated mixing portion 41e is obtained to easily achieve mixing of the LED light beams L9.

According to the first embodiment, the surface light source device 200 includes the laser light source 10, the optical path changing element 6, the surface emitting light guide plate 5, the LED light source 9, and the surface emitting light guide plate 4. The laser light source 10 has a plurality of laser light emitting elements that emit laser light L10. The optical path changing element 6 converts the laser beam L10 into a linear laser beam L10 having a uniform spatial intensity distribution in the y-axis direction and emits it. The y-axis direction is a direction perpendicular to the traveling direction of the laser beam L10. The y-axis direction is the side of the arrangement of the laser light-emitting elements to. The surface emitting light guide plate 5 converts the linear laser beam L10 emitted from the optical path changing element 6 into a planar laser illumination light L111 having a uniform spatial intensity distribution on the x-y plane. The x-y plane is a plane including the direction in which the laser light emitting elements are arranged (y-axis direction) and the traveling direction (+x-axis direction) of the linear laser beam L10. The laser illumination light L111 is emitted from the surface emitting light guide plate 5 in the +z-axis direction. The LED light source 9 has a plurality of LED elements that emit LED light L9. The surface emitting light guide plate 4 is disposed in parallel with the surface emitting light guide plate 5. The surface-emitting light-guiding plate 4 converts the LED light L9 emitted from the LED light source 9 into planar LED illumination light L90 having a uniform spatial intensity distribution on the x-y plane. The x-y plane is a plane perpendicular to the emission direction (+z-axis direction) of the laser illumination light L111. The x-y plane is a plane parallel to the light exit surface 41a. The direction in which the LED illumination light L90 is emitted is the same as the emission direction (+z-axis direction) of the laser illumination light L111.

The surface light source device 200 has a wider color reproduction range than the surface light source device of the conventional white LED light source. The surface light source device 200 is capable of achieving the same brightness as the conventional surface light source device using only the LED light source, with lower power consumption than a surface light source device using only a single-color LED light source or a laser light source. That is to say, the surface light source device 200 can have a wide color reproduction range, and the surface light source device 200 can also reduce power consumption.

Since the liquid crystal display device 100 has the above-described surface light source device 200, it is possible to have a wider color reproduction range than a liquid crystal display device using only an LED light source. The liquid crystal display device 100 can also reduce power consumption. In the surface light source device 200, the diffusing portion 510c that expands the divergence angle of the linear laser beam L10 in the z-axis direction in the vicinity of the light incident surface 51c or the light incident surface 51c can improve the light use efficiency of the laser beam.

The liquid crystal display device 100 and the surface light source device 200 change the optical path Most of the element 6 is disposed in the thickness direction of the liquid crystal display device 100. Therefore, it is possible to ensure a sufficient optical distance so that the laser light diverge at its own divergence angle and the adjacent laser rays overlap each other, and the spatial intensity distribution in the arrangement direction (y-axis direction) of the laser light-emitting element can also be improved. Uniformity. The laser light source 10 is disposed in the thickness direction of the liquid crystal display device 100 (that is, in the -z axis side direction), and most of the optical path changing element 6 is disposed in the thickness direction of the liquid crystal display device 100 (that is, the -z axis side). Direction) can narrow the marginal part. The "narrowing of the forehead portion" means narrowing the width of the forehead portion when the display surface 1a is viewed from the front. The so-called "front" refers to the direction in which the image is displayed. Further, by improving the uniformity of the spatial intensity distribution of the laser light L10, the light use efficiency can be improved. It is possible to obtain planar illumination light L120 having high uniformity in spatial light intensity distribution.

In the liquid crystal display device 100 including the surface light source device 200, since the planar illumination light L120 having high spatial light intensity distribution is obtained, it is possible to provide a high-quality image having a wide color reproduction range and suppressing uneven brightness. The liquid crystal display device 100 emits red light from the laser light emitting element by the laser light source 10 and emits blue-green light from the LED element by the LED light source 9, and this configuration can simultaneously achieve a color reproduction range wider than that of the conventional liquid crystal display device. With a low power consumption, and a high-productivity liquid crystal display device can be obtained.

Example 2:

The surface light source device 201 and the liquid crystal display device 101 according to the second embodiment of the present invention will be described with reference to Figs. 11 to 16 . The surface light source device 201 shown in Fig. 11 is a surface light source device corresponding to local dimming. Area dimming is a dimming control method that independently controls a complex light-emitting element. By the area dimming, it is possible to suppress the light source of the region corresponding to the black portion of the image in the screen, The light source corresponding to the bright portion of the image in the screen is illuminated. With such control, for example, even in the case where the entire screen is a gray image, the light source in the region corresponding to a particularly dark position in the corresponding screen can be darkened to improve the contrast.

Fig. 11 is a cross-sectional view schematically showing an example of a structure of a liquid crystal display device 101 (including a surface light source device 201) of the second embodiment. Fig. 12 is a block diagram showing the architecture of a control system of the liquid crystal display device 101 of the second embodiment. In the eleventh and twelfth drawings, the same or corresponding components as those in the first embodiment of the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

Among the components shown in Fig. 11, the liquid crystal panel 1, the optical sheets 2, 3, the surface-emitting light-guide plates 4, 5, the light-reflecting sheet 8, and the LED light source 9 are the same as those of the first embodiment (first drawing). And the laser source 10. Among the components shown in FIG. 12, the liquid crystal display element drive unit 32, the video signal 34, and the liquid crystal display element control signal 35 are the same as those of the first embodiment (the eighth and ninth drawings). Further, similarly to the first embodiment, the +x axis direction can be regarded as the upper side of the liquid crystal display device 101. However, in this case, the areas separated by the area dimming (the fields A, B, C, D, and E described later) are vertically arranged in the left-right direction on the display surface 1a.

The optical path changing element 60 of the liquid crystal display device 101 has any number (any number is plural, for example, five) of light guiding elements. The LED light source driving unit 330a groups (separates) the plurality of LED elements included in the LED light source 9 into an arbitrary number (any number is plural, for example, five) to perform drive control. Similarly, the laser light source driving unit 330b groups (distinguishes) the plurality of laser light-emitting elements included in the laser light source 10 into an arbitrary number (any number is plural, for example, five). Drive control. The liquid crystal display device 101 of the second embodiment differs from the liquid crystal display device 100 of the first embodiment only in these points.

Fig. 13 is a schematic plan view of the surface light source device 201 shown in Fig. 12, that is, the liquid crystal display device 101, viewed from the -z-axis direction side (back side). The optical path changing element 60 has five optical path changing element members 60a, 60b, 60c, 60d, and 60e. The optical path changing element members 60a, 60b, 60c, 60d, and 60e have the same shape as the optical path changing element 6 of the first embodiment divided into five equal parts in the y-axis direction. That is, in the second embodiment, the optical path changing element members 60a, 60b, 60c, 60d, 60e have the same shape as each other.

The optical path changing element members 60a, 60b, 60c, 60d, and 60e are arranged at equal intervals in the y-axis direction. The positions of the optical path changing element members 60a, 60b, 60c, 60d, and 60e in the x-axis direction and the positions in the z-axis direction are identical to each other.

The optical path changing element 60 having the optical path changing element members 60a, 60b, 60c, 60d, and 60e has a total length in the y-axis direction equal to or shorter than the surface emitting light guide plate 5. The optical path changing element members 60a, 60b, 60c, 60d, 60e are made of a transparent material. The material of the optical path changing element members 60a, 60b, 60c, 60d, 60e is, for example, polymethyl methacrylate (for example, PMMA), polycarbonate (PC), cycloolefin polymer (COP), glass, or the like.

Similarly to the first embodiment, the LED light source 9 includes a plurality of LED elements arranged in one-dimensional direction in the y-axis direction. These plural LED elements are divided into (divided into) complex arrays having the same number. These complex arrays are arranged in a column in the y-axis direction. For example, in Fig. 13, a group including four LED elements is arranged in five groups. However, the number of groups including the LED elements and the number of LED elements included in one set are not limited thereto, and can be arbitrarily changed.

Fig. 14 is a schematic plan view of the surface light source device 201 (viewing the liquid crystal display device 101 from the +z-axis direction side) shown in Fig. 12 as viewed from the liquid crystal panel 1 side. The display surface 1a of the liquid crystal panel 1 is divided into (divided into) five fields A, B, C, D, and E. The number of fields corresponds to the number of optical path changing element members constituting the optical path changing element 60, the number of groups constituting the LED light source 9, and the number of groups constituting the laser light source 10. The fields A, B, C, D, and E correspond to the positions of the optical path changing element members 60a, 60b, 60c, 60d, and 60e. The LED light source 9 is composed of five groups 9a, 9b, 9c, 9d, and 9e. These LED light source groups 9a, 9b, 9c, 9d, 9e mainly illuminate respective fields A, B, C, D, E. As shown in Fig. 12, each of the five LED light source groups constituting the LED light source 9 is driven and controlled.

Similarly to the first embodiment, the laser light source 10 includes a plurality of laser light-emitting elements arranged in one-dimensional direction in the y-axis direction. The plurality of laser light-emitting elements included in the laser light source 10 are divided into groups having the same number in the y-axis direction. The number of groups is an arbitrary number. For example, in Fig. 13, the number of laser light emitting elements included in one group is two. The laser light source groups 10a, 10b, 10c, 10d, 10e mainly illuminate respective fields A, B, C, D, E. That is to say, the laser light source group 10a mainly illuminates the field A. The laser source set 10b is primarily in the field of illumination B. The laser source set 10c is primarily illuminated in the field C. The laser light source group 10d is mainly in the field of illumination D. The laser source group 10e is mainly in the field of illumination E. As shown in Fig. 12, each of the five laser light source groups constituting the laser light source 10 is driven and controlled. Therefore, it is possible to control the brightness of each field of the picture in the area. The so-called "regional control" refers to regional dimming.

The light emitted from the laser light source 10a of the field A is incident on the optical path changing element member 60a. Light emitted from the laser light sources 10b, 10c, 10d, and 10e of the fields B, C, D, and E enters the optical path changing element members 60b, 60c, 60d, and 60e, respectively. Also In other words, the light emitted from the laser light source 10b of the field B enters the optical path changing element member 60b. The light emitted from the laser light source 10c of the field C enters the optical path changing element member 60c. The light emitted from the laser light source 10d of the field D is incident on the optical path changing element member 60d. The light emitted from the laser light source 10e of the field E is incident on the optical path changing element member 60e. In other words, the number of optical path changing element members constituting the optical path changing element 60 is equal to the number of LED light source groups constituting the LED light source 9. The number of optical path changing element members constituting the optical path changing element 60 is equal to the number of groups of the laser light emitting elements constituting the laser light source 10.

By the area control, the brightness of the LED light source groups 9a, 9b, 9c, 9d, 9e in the corresponding field can be individually lowered for the dark portions in the screen. By the area control, the brightness of the laser light source groups 10a, 10b, 10c, 10d, 10e in the corresponding field can be individually lowered for the dark portions in the screen. Therefore, the liquid crystal display device 101 can enhance the contrast within the screen. On the other hand, the liquid crystal display device 101 can also reduce power consumption by the above configuration. When the screen is switched by the area control, both the LED light source group and the laser light source group corresponding to the field can be turned off. The term "screen switching" refers to the blanking period. The "masking period" refers to a period in which one scanning line of the television screen is moved to the next scanning line. The image is not displayed during this blanking period. The liquid crystal display device 101 can reduce the influence of the afterimage by turning off the LED light source group and the laser light source group in the corresponding field.

According to the second embodiment, the optical path changing element 60 is divided into the optical path changing element members 60a, 60b, 60c, 60d, and 60e, and each of the corresponding optical path changing element members 60a, 60b, 60c, 60d, and 60e can be realized in a more detailed manner. Brightness control. Each of the optical path changing element members 60a, 60b, 60c, 60d, and 60e is disposed corresponding to each of the laser light source groups 10a, 10b, 10c, 10d, and 10e. From laser light The light emitted from the source group 10a enters the corresponding optical path changing element member 60a, and propagates in the -x-axis direction while the optical path changing element member 60a and the interface of the air layer are totally reflected.

At this time, the laser beams adjacent to each other among the laser beams emitted from the laser light source group 10a overlap each other while traveling in the optical path changing element member 60a. That is, the laser beam constituting one laser light-emitting element of the laser light source group 10a and the laser beam portion of another laser light-emitting element constituting the same laser light source group 10a and adjacent to the laser light-emitting element Overlap. The superimposed laser light is uniform in the y-axis direction luminance distribution of the optical path changing element member 60a, and linear light having uniform (or substantially uniform) luminance distribution in the y-axis direction is formed. Similarly, the light beams emitted from the other laser light source groups 10b, 10c, 10d, and 10e are also uniform in the y-axis direction of the corresponding optical path changing element members 60b, 60c, 60d, and 60e, and the y-axis direction luminance distribution is formed. Uniform (or roughly uniform) linear light. In other words, the light emitted from the laser light source 10b forms linear light having a uniform luminance distribution in the y-axis direction in the optical path changing element member 60b. The light emitted from the laser light source 10c forms linear light having a uniform luminance distribution in the y-axis direction in the optical path changing element member 60c. The light beam emitted from the laser light source 10d forms linear light having a uniform luminance distribution in the y-axis direction in the optical path changing element member 60d. The light emitted from the laser light source 10e forms linear light having a uniform luminance distribution in the y-axis direction in the optical path changing element member 60e.

The optical path changing element members 60a, 60b, 60c, 60d, and 60e correspond to the fields A, B, C, D, and E of the liquid crystal panel 1. Linear light having uniform luminance distribution in the y-axis direction is formed in each of the optical path changing element members 60a, 60b, 60c, 60d, and 60e, whereby the linear light having a uniform luminance distribution for each field of the liquid crystal panel 1 is obtained by the laser beam. The incident surface illuminates the light guide plate 5. Therefore, lighting the laser light for each field When the source groups 10a, 10b, 10c, 10d, and 10e are not leaked to the adjacent other areas A, B, C, D, and E, precise area control can be performed.

The optical path changing element members 60a, 60b, 60c, 60d, and 60e are the same shape as the optical path changing element 6 of the first embodiment divided into five equal parts in the y-axis direction. In other words, the light incident surface 601 shown in Fig. 11 is different from the light incident surface 61 shown in Fig. 1 only in the y-axis direction, and other shapes and functions are completely the same. Similarly, the light guiding portion 602 is different from the light guiding portion 62 only in the y-axis direction, and other shapes and functions are completely the same. The optical path changing unit 603 (reflecting surfaces 603a and 603b) is different from the optical path changing unit 63 (reflecting surfaces 63a and 63b) only in the y-axis direction, and other shapes and functions are completely the same. The light exit surface 604 is different from the light exit surface 64 only in the y-axis direction, and other shapes and functions are completely the same. That is, the optical path changing element members 60a, 60b, 60c, 60d, 60e have the same shape as each other. Therefore, the structure and function of the optical path changing element members 60a, 60b, 60c, 60d, and 60e are the same as those of the optical path changing element 6 of the first embodiment, and thus detailed description thereof will be omitted.

Here, the light incident surface 601 of the optical path changing element 60 will be described in a plane, but the light incident surface 601 may be provided with a light diffusing structure. Fig. 15 is a plan view schematically showing the optical path changing element member 600a (another example of the optical path changing element member) constituting the optical path changing element 600 viewed from the -z axis side direction side (back side). As shown in Fig. 15, the light-diffusing structure of the light incident surface 6001 has a structure in which, for example, a small concave cylindrical lens is arranged in a plurality of y-axis directions. By providing a light diffusion structure on the light incident surface 6001, the divergence angle of the laser light source in the y-axis direction (fast axis direction) can be developed. The light diffusion structure of the light incident surface 6001 may be a structure in which a crucible structure or a mesa shape is arranged. That is, as long as there is hold The divergence angle in the z-axis direction may be a structure in which only the divergence angle in the y-axis direction is developed.

Therefore, the laser light incident from the light incident surface 6001 easily overlaps with the light of the adjacent laser light emitting element. In this way, the uniformity of the spatial light intensity distribution in the arrangement direction (y-axis direction) of the laser light emitting elements can be improved. The distance required for the uniformity of the spatial light intensity distribution in the direction in which the laser light emitting elements are arranged is shortened. Therefore, the length of the optical path changing element 600 in the x-axis direction can be shortened.

Fig. 16 is a schematic plan view of the liquid crystal display device 101 including the optical path changing element members 600a to 600e of the optical path changing element 600 shown in Fig. 15 viewed from the -z axis direction side (back side). The optical path changing elements 600 provided with the light-diffusing structure on the light incident surface are arranged in an arbitrary number in the y-axis direction, and the same effects as those in the thirteenth aspect can be obtained.

Although the entire light incident surface 6001 of the light guiding element 600 has been described as a light diffusing structure, the second embodiment is not limited thereto. It is also possible to make only a portion through which the laser light of the light incident surface 6001 passes through a light diffusion structure. In this way, the light diffusion structure is provided only in a necessary portion, and the structure of the light guiding element can be simplified as compared with the case where the light incident surface is entirely formed into a light diffusion structure. The same structure as the light diffusion structure of the light incident surface 6001 described above can be provided on the light incident surface 61 of the optical path changing element 6 of the first embodiment.

In the second embodiment, the number of the optical path changing element members 60a, 60b, 60c, 60d, and 60e constituting the optical path changing element 60 has been described as five. However, the number of optical path changing element members of the present invention is not limited thereto. The number of optical path changing element members can be determined in accordance with the number of individually lit areas. The number of optical path changing element members is equal to the number of divisions of the optical path changing elements 60.

The surface light source device 201 and the liquid crystal display device 101 of the second embodiment have the same configuration as that of the first embodiment, and the effects described in the first embodiment can be obtained. That is, the surface light source device 201 and the liquid crystal display device 101 have a wide color reproduction range. The surface light source device 201 and the liquid crystal display device 101 can realize image display with low power consumption. The surface light source device 201 and the liquid crystal display device 101 can further improve the light use efficiency of the laser light. The surface light source device 201 and the liquid crystal display device 101 can also improve the uniformity of the spatial intensity distribution in the arrangement direction (y-axis direction) of the laser light emitting elements. The surface light source device 201 and the liquid crystal display device 101 can narrow the front edge portion. The surface light source device 201 and the liquid crystal display device 101 can provide high-quality images that suppress uneven brightness. A liquid crystal display device having high mass productivity can be obtained by the surface light source device 201 and the liquid crystal display device 101. Further, the surface light source device 201 can improve the contrast of the image and reduce the power consumption by the structure of the area dimming (area control). The liquid crystal display device 101 can reduce the influence of the afterimage by turning off the LED light source group or the laser light source group in the field corresponding to the blanking period.

In the first and second embodiments described above, terms such as "parallel" and "vertical" may be used when indicating the positional relationship between the components or the shape of the components. These terms include ranges that take into account manufacturing tolerances or assembly variations.

Although the embodiments of the present invention have been described above, the present invention is not limited to the embodiments.

1‧‧‧LCD panel

1a‧‧‧ display surface

1b‧‧‧back

2, 3‧‧‧ optical film

4, 5‧‧‧ face light guide plate

6‧‧‧Light path changing components

8‧‧‧Light reflection sheet

9‧‧‧LED light source

10‧‧‧Laser light source

41a, 51a‧‧‧ light exit surface

41b, 51b‧‧‧ back

41c, 51c‧‧‧light incident surface

41d, 51d‧‧‧ end face

41e‧‧‧Mixed Department

41f‧‧‧Light Guide

42, 52‧‧‧ tiny optical components

61‧‧‧Light incident surface

62‧‧‧Light Guide

63‧‧‧Light Path Change Department

63a, 63b‧‧‧reflecting surface

64‧‧‧Light exit surface

100‧‧‧Liquid crystal display device

200‧‧‧ surface light source device

510c‧‧‧Light Diffusion Department

L9‧‧‧LED light

L10, L110‧‧ ‧ laser light

L90‧‧‧LED lighting

L111‧‧‧Laser illumination

L120‧‧‧ illumination light

Claims (12)

A surface light source device comprising: a laser light source having a plurality of laser light emitting elements and emitting laser light generated by the plurality of laser light emitting elements; and an optical path changing element having the laser light emitted by the laser light source a light incident surface incident on the light, and a light exiting surface, wherein the optical path changing element adjusts a first plane of the laser light emitted by the laser light source and incident on the light incident surface perpendicular to a traveling direction of the laser light a spatial intensity distribution, and the laser beam emitted from the laser light source and incident on the light incident surface is changed to a linear laser beam having a linear cross-sectional shape of the laser beam on the first plane And emitting the linear laser beam from the light exit surface; and the first surface light-emitting light guide plate is adjusted to be parallel to the second plane including the linear laser light and the plane of the linear laser light traveling direction a spatial intensity distribution, the linear laser beam emitted from the optical path changing element is converted into a planar laser illumination light, and the laser illumination light is emitted in a direction perpendicular to the second plane; an LED light a plurality of LED elements and emitting LED light generated by the plurality of LED elements; and a second surface light-emitting light guide plate disposed parallel to the first surface light-emitting light guide layer, and adjusting the LED light emitted by the LED light source in parallel The spatial intensity distribution on the third plane of the second plane converts the LED light emitted by the LED light source into planar LED illumination light, and causes the LED illumination light to be emitted in the same direction as the laser illumination light emission direction. . The surface light source device of claim 1, wherein the optical path is changed The adjustment of the spatial intensity distribution of the linear laser ray on the first plane by the element means the uniformity of the spatial intensity distribution on the first plane. The surface light source device according to claim 2, wherein the adjustment of the spatial intensity distribution of the laser illumination light on the second plane by the first surface light-emitting light guide means the second plane The uniformity of this spatial intensity distribution. The surface light source device according to any one of claims 1 to 3, wherein the adjustment of the spatial intensity distribution of the LED illumination light on the third plane by the second surface light-emitting light guide means The spatial intensity distribution on the third plane is uniform. The surface light source device according to claim 1, wherein the first surface light-emitting light guide plate is divided into a plurality of laser light emission regions, and the optical path changing element includes a plurality of optical path changing element members respectively corresponding to the plurality of In the field of laser light emission, the adjustment of the spatial intensity distribution of the linear laser beam on the first plane is a homogenization of the spatial intensity distribution of the plurality of laser light emission fields on the first plane. . The surface light source device of claim 5, wherein the spatial intensity distribution of the laser illumination light on the second plane is adjusted by the pointer to each of the plurality of laser light emission fields on the second plane The uniformity of the spatial intensity distribution. The surface light source device according to any one of claims 1, 5, and 6, wherein The second surface light-emitting light guide plate is divided into a plurality of LED light-emitting areas, and the spatial intensity distribution of the planar LED illumination light on the third plane is adjusted by the pointer to each of the plurality of LED light-emitting areas. The uniformity of the spatial intensity distribution on the 3 plane. The surface light source device according to claim 1, wherein the first surface light-emitting light guide plate has a diffusion portion on an end surface of the linear laser light incident side for changing the first surface light-emitting light guide plate. The angular intensity distribution of the linear laser ray in the thickness direction. The surface light source device of claim 1, wherein the light path changing element comprises: a light guiding portion, wherein the laser light emitted by the laser light source is converted into an optical path length of the linear laser light And an optical path changing unit that converts a traveling direction of the linear laser beam that guides the light guiding portion to be emitted toward the first surface emitting light guide plate. The surface light source device according to claim 9, wherein the light guiding portion has a thin plate-shaped portion that is in contact with the light incident surface and the optical path changing portion, and the thin plate portion has a thickness that is thicker toward the optical path changing portion. Wedge shape. The surface light source device according to any one of claims 1 to 9, wherein the laser light source is disposed on a side of the first surface light-emitting light guide plate opposite to the second surface light-emitting light guide plate. A liquid crystal display device comprising: a liquid crystal panel; and the surface light source device according to any one of claims 1 to 11 The laser illumination light and the LED illumination light are irradiated onto the liquid crystal panel.