JP2013025034A - Illuminating device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an illuminating device capable of suppressing the decrease in uniformity of planar light beam due to an ambient temperature difference between light sources, and an image forming apparatus including the illuminating device.SOLUTION: An illuminating device 10A includes: light guide reflection members 16 and 17 that guides a plurality of light fluxes that are incident from a plurality of light sources 18to 18N; and a light guide plate 14. The light guide plate 14 has a first edge surface 14ea on which the plurality of light fluxes guided by the light guide reflection members 16 and 17 are incident, and converts the plurality of light fluxes that are incident on the inside from the edge surface 14ea, into planar light fluxes. Further, the light guide plate 14 has a second edge surface 14 ec that is formed on one end side in the extending direction of the first edge surface 14 ea. The light sources 18to 18are arranged to the second edge surface 14 ec side, and are arranged along the extending direction of the second edge surface 14 ec.

Description

  The present invention relates to an illuminating device that converts light beams emitted from a plurality of light sources into planar light and an image display device having the illuminating device, and more particularly, to illuminate a spatial light modulation element such as a liquid crystal display element. The present invention relates to an illumination device that converts a light beam emitted from a light source into planar light, and an image display device having the illumination device.

  In general, a liquid crystal display device includes a backlight unit having a light emitting surface that emits planar light, and a liquid crystal display element that is a spatial light modulation element that spatially modulates the intensity of the planar light to produce image light. Have. Since the liquid crystal display element does not emit light itself, a backlight unit is required to produce image light. 2. Description of the Related Art In recent years, edge-light backlight units have been widely used in order to reduce the thickness of liquid crystal display devices. The edge light system is a system in which a light beam is incident on the light guide plate from the end surface of a thin light guide plate to produce planar light. In the edge light system, the light beam is allowed to enter the light guide plate from any one of the side end surface, bottom end surface, and top end surface when the light emitting surface of the light guide plate is the front surface, but particularly from the side end surface of the light guide plate. A method of creating a planar light by making a light beam enter the light guide plate is called a sidelight method. In an edge light type backlight unit, the light source is often arranged at a position facing the light incident end face of the light guide plate.

  In recent years, a demand for a backlight unit using a light emitting diode (hereinafter referred to as an LED (Light Emitting Diode)) as a light source is rapidly increasing. There are roughly two types of LEDs used in the backlight unit. The first type uses only a single-color LED that emits light in a single-color (red, green, or blue) wavelength region as a light source, and the second type uses a single-color LED and the light of this single-color LED as excitation light. The combination with the fluorescent substance to be used is used. The second type includes, for example, a blue LED that emits light in the blue wavelength range (blue light), and a phosphor that emits light from the green wavelength range to the red wavelength range by absorbing and exciting blue light. The white LED light source which consists of a combination is mentioned. White LED light sources are widely used as light sources for backlight units because they have high luminous efficiency and are effective in reducing power consumption.

  For example, a display device disclosed in Japanese Unexamined Patent Application Publication No. 2010-164976 (Patent Document 1) includes a sidelight type backlight unit and a liquid crystal display panel as a liquid crystal display element. The backlight unit disclosed in Patent Document 1 includes a plurality of light guide plates arranged in parallel to each other and a plurality of white LEDs attached to the edges of the plurality of light guide plates. In this display device, these white LEDs are turned on in synchronization with the timing of rewriting the voltage of each pixel of the liquid crystal display panel. Thereby, blurring of a moving image displayed on the liquid crystal display panel can be improved. Note that one of the causes of such moving image blurring is liquid crystal responsiveness. Since it takes several tens of milliseconds from the time the voltage is applied to the pixel of the liquid crystal display panel until the light transmittance of the liquid crystal of the pixel changes to the target light transmittance, this light transmittance changes with time. The pixel state can cause blurring of moving images.

JP 2010-164976 A (for example, paragraphs 0063 to 0065, paragraphs 0073 to 0081, 0092 and FIGS. 1 and 13)

  In general, an image display apparatus is often used in a state where its display surface is set in a substantially vertical direction (gravity direction). In this state, since the light guide plate of the conventional sidelight type backlight unit is also used in a substantially vertical state, the plurality of white LED light sources attached to the edge of the light guide plate are arranged in the vertical direction. The Rukoto. In other words, the plurality of white LED light sources are arranged along the direction of gravity. In general, air has the property of rising when it gets warm and falling when it gets cold. Therefore, when these white LED light sources generate heat during light emission and warm the surrounding air, the warmed air rises against gravity. Thereby, a temperature difference arises between the white LED light source arranged below and the white LED light source arranged above. In general, the luminous efficiency of LEDs has a temperature dependency, and the higher the temperature, the lower the luminous efficiency. Therefore, the white LED light source between the white LED light sources due to the temperature difference between the upper part and the lower part in the backlight unit. There is a problem that a luminance difference or a light emission color difference is generated, thereby reducing the brightness of the planar light or the in-plane uniformity of the light emission color, thereby causing unevenness in the brightness or the emission color of the planar light.

  In view of the above, an object of the present invention is to provide an edge light type illumination device capable of suppressing a reduction in uniformity of planar light caused by a difference in ambient temperature between light sources such as an LED light source and a laser light source, and the illumination device. It is providing the image display apparatus which has.

  The illumination device according to the first aspect of the present invention includes a plurality of light sources, a light guide reflection member that guides a plurality of light beams incident from the plurality of light sources, and a plurality of light guides that are guided by the light guide reflection member. A light guide plate that has a first end surface on which a light beam is incident, and that converts a plurality of light beams incident inside from the first end surface into a planar light beam, wherein the light guide plate has the planar shape. A light emitting surface that emits a light beam, and a second end surface that is formed on one end side in the extending direction of the first end surface and extends in a direction intersecting the first end surface, wherein the plurality of light sources are: It is arrange | positioned along the extension direction of the said 2nd end surface, arrange | positioning at the said 2nd end surface side.

  An image display device according to a second aspect of the present invention spatially modulates the intensity of the planar light beam radiated from the illumination device, the illumination device according to the first aspect, and the illumination device as a backlight unit. A spatial light modulation element that generates image light, and a control unit that controls the operation of the spatial light modulation element in accordance with a video signal.

  In the illuminating device according to the present invention, the plurality of light sources are arranged on the second end surface side different from the first end surface of the light guide plate, and are arranged along the extending direction of the second end surface. Further, the light beams emitted from the plurality of light sources are guided by the light guide reflection member and are incident on the first end face of the light guide plate. When such an illuminating device is used in a state where the light incident end face (first end face) of the light guide plate is raised, the plurality of light sources are arranged either above or below the direction of gravity. Therefore, the ambient temperature difference between these light sources can be reduced. Thereby, since the variation in the light emission characteristic between light sources can be suppressed, planar light with no unevenness in brightness and emission color can be provided as illumination light. Therefore, it is possible to improve the image quality of an image display device having this illumination device as a backlight unit.

It is a functional block diagram which shows schematic structure of the liquid crystal display device of Embodiment 1 which concerns on this invention. 1 is a bottom view of a device schematically showing a main configuration of a liquid crystal display device according to a first embodiment; FIG. 3 is a schematic perspective view of the configuration of FIG. 2. FIG. 3 is a diagram schematically showing a back surface of the light guide member in the first embodiment. It is a figure which shows roughly the back surface structure of the light-guide diffusion plate of Embodiment 1. FIG. 1 is a schematic cross-sectional view of a micro optical element according to Embodiment 1. FIG. It is a figure which shows roughly the modification of the light guide diffusion plate of Embodiment 1. FIG. 4 is a perspective view schematically showing an example of an optical structure of a first optical sheet in Embodiment 1. FIG. It is a functional block diagram which shows schematic structure of the liquid crystal display device of Embodiment 2 which concerns on this invention. FIG. 6 is a bottom view of a device schematically showing a main configuration of a liquid crystal display device according to a second embodiment. It is a figure which shows roughly the back surface of the light guide member of Embodiment 2. FIG. It is a figure which shows roughly the back surface structure of the auxiliary | assistant light guide diffusion plate of Embodiment 2. FIG. 6 is a schematic cross-sectional view of a micro optical element according to Embodiment 2. FIG. It is a functional block diagram which shows schematic structure of the liquid crystal display device of Embodiment 3 which concerns on this invention. FIG. 10 is a device bottom view schematically showing a main configuration of a liquid crystal display device according to a third embodiment. It is a figure which shows roughly the back surface structure of the light-guide diffusion plate of Embodiment 3. FIG. 6 is a schematic cross-sectional view of a micro optical element according to Embodiment 3. FIG.

  Embodiments according to the present invention will be described below with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a functional block diagram showing a schematic configuration of a liquid crystal display device 1A according to the first embodiment of the present invention. As shown in FIG. 1, a liquid crystal display device 1A includes a backlight unit 10A, a transmissive liquid crystal display element 11, a liquid crystal display element driving unit 22 that drives the liquid crystal display element (liquid crystal display panel) 11, and a backlight. A light source driving unit 23A for individually driving the red laser group 18RG, the green laser group 18GG, and the blue laser group 18BG in the unit 10A, and a control unit 21 for controlling the operations of the liquid crystal display element driving unit 22 and the light source driving unit 23A. It has. As will be described later, the backlight unit 10A includes components other than the red laser group 18RG, the green laser group 18GG, and the blue laser group 18BG.

  When a digital or analog video signal is input, the control unit 21 performs image processing on the video signal to generate an element control signal MC, and supplies the element control signal MC to the liquid crystal display element driving unit 22. Further, the control unit 21 provides the light source control signal LC to the light source driving unit 23A in synchronization with the element control signal MC to cause the backlight unit 10A to emit light.

  As the liquid crystal display element 11, for example, a general liquid crystal display panel that operates in an active matrix system can be adopted. When the active matrix method is employed, the liquid crystal display element 11 has a plurality of horizontal scanning lines (gate lines) and a plurality of data lines formed on the substrate. Sub-pixels (sub-pixels) are formed in the vicinity of the intersection. Each subpixel includes a pair of pixel electrodes and a counter electrode, a liquid crystal layer sandwiched between the pixel electrodes and the counter electrode, a switching element such as a thin film transistor (TFT), and red, green and blue And a color filter that transmits monochromatic light in the visible light wavelength region. For example, one pixel (pixel) can be configured by a sub-pixel including a red color filter, a sub-pixel including a green color filter, and a sub-pixel including a blue color filter.

  The liquid crystal display element driving unit 22 has a function of sequentially scanning and selecting a plurality of horizontal scanning lines and supplying a control voltage pulse for turning on the switching element of the sub-pixel to the selected horizontal scanning line. In addition, the liquid crystal display element driving unit 22 supplies a gradation voltage to the pixel electrode of the subpixel through the data wiring and the switching element in the on state, thereby forming a liquid crystal layer between the pixel electrode and the counter electrode in the subpixel. It has a function of forming an electric field. The drive signal MD of the present embodiment includes such a control voltage pulse and a gradation voltage. Each sub-pixel can hold the supplied gradation voltage. The alignment state of the liquid crystal molecules in the liquid crystal layer is determined according to the gradation voltage, and light transmittance corresponding to the alignment state is formed.

  FIG. 2 is a bottom view of the apparatus schematically showing the configuration of the liquid crystal display device 1A excluding the control unit 21, the liquid crystal display element driving unit 22, and the light source driving unit 23A. FIG. 3 is a schematic perspective view of the configuration of the liquid crystal display device 1A of FIG. For convenience of explanation, FIGS. 2 and 3 show an X axis, a Y axis, and a Z axis forming a three-dimensional orthogonal coordinate system. The ± X axis direction coincides with the long side direction (horizontal pixel direction) of the liquid crystal display element 11 having a rectangular shape, and the ± Y axis direction coincides with the short side direction (vertical pixel direction) of the liquid crystal display element 11; The + Z axis direction coincides with the normal direction of the display surface 11 f of the liquid crystal display element 11. The + Y axis direction indicates the upper end side of the display surface 11f in the vertical pixel direction, and the −Y axis direction indicates the lower end side of the display surface 11f in the vertical pixel direction. FIG. 3 mainly shows a state in which the liquid crystal display device 1A is normally used when viewed from the back side, and the + Y-axis direction is opposite to the direction of gravity (the downward direction in FIG. 3). Shall mean. In the present specification, the X axis, the Y axis, and the Z axis are used only to indicate specific directions, and therefore the origin of the orthogonal coordinate system is not fixed.

  As shown in FIGS. 2 and 3, the liquid crystal display device 1A includes a liquid crystal display element 11, a first optical sheet 12, a second optical sheet 13, a light guide diffusion plate 14, and a light guide member 16 in the Z-axis direction. Are arranged and stacked.

  The light guide diffuser plate 14 has a function of converting a plurality of light beams incident on the inside from the side incident end face 14ea into planar light beams, that is, illumination lights DL,. The light guide diffuser plate 14 includes a front surface (light emitting surface) 14f that emits illumination light DL,..., DL, and an end surface 14ec that is formed on one end side in the extending direction of the side incident end surface 14ea and extends in the X-axis direction. have. A reflecting member 17 is disposed outside the side incident end face 14ea of the light guide diffuser plate 14. The light guide reflection member of the present invention can be composed of, for example, a light guide member 16 and a reflection member 17.

  A planar light beam emitted from the front surface of the backlight unit 10A in the + Z-axis direction (upward in FIG. 2), that is, illumination light DL,..., DL is incident on the liquid crystal display element 11 through the optical sheets 13 and 12. Is done. The liquid crystal display element 11 generates a color image by spatially modulating the intensity of illumination light incident on the back surface 11b in units of pixels or sub-pixels according to the drive signal MD. The light (image light) having this color image information is emitted forward from the display surface 11 f of the liquid crystal display element 11.

2, the light guide diffusion plate 14, the light reflection sheet 15, the laser light sources 18 ₁ to 18 _N , the light guide member 16, and the reflection member 17 constitute the backlight unit 10A that is the illumination device of the present embodiment. doing. The light guide member 16 is disposed adjacent to the light reflecting sheet 15 and behind the light reflecting sheet 15 as shown in FIGS. 2 and 3. The light guide member 16 has a plate shape and a triangular prism shape having a substantially triangular cross section in the XY plane. As a constituent material of the light guide member 16, for example, a light transmissive optical material such as a glass material or a light transmissive resin material (for example, acrylic resin (PMMA)) is used. When an acrylic resin is used, a plate-like light guide member 16 having a thickness of about 2 mm can be produced.

  FIG. 4 is a diagram schematically showing the back surface of the light guide member 16 of the first embodiment. As shown in FIG. 4, the light guide member 16 has an incident end face 16m to be disposed below the gravitational direction (−Y-axis direction) in a normal apparatus use state. It is formed along the longitudinal direction (X-axis direction) of the light guide diffusion plate 14. The incident end face 16m is substantially parallel to the XZ plane (a plane parallel to the X axis and the Z axis). The light guide member 16 has an inner surface reflecting surface 16r that forms an inclination angle of about 45 ° with respect to the incident end surface 16m, and an output end surface 16e that is substantially orthogonal to the incident end surface 16m. In the present specification, the emission means that light is emitted in a certain direction. The emission end face 16e is substantially parallel to the YZ plane (a plane parallel to the Y axis and the Z axis). Since the length in the longitudinal direction (X-axis direction) of the incident end face 16m is substantially equal to the length in the longitudinal direction (Y-axis direction) of the exit end face 16e, the light guide member 16 has an XY plane (X-axis and Y-axis). And a cross section in a plane parallel to the shape of a right angled isosceles triangle.

In the vicinity of the entrance end surface 16m of the light guide member 16, a plurality of laser light sources _{18 1, 18 2, ...,} 18 N are opposed with respect to the incident end face 16m. These laser light sources 18 ₁ , 18 ₂ ,..., 18 _N are along the extending direction of the end surface 14 ec on the −Y axis direction side of the light guide diffuser plate 14, that is, the longitudinal direction (X axis direction) of the light guide diffuser plate 14. Arranged in a row. These laser light sources 18 ₁ to 18 _N are composed of a plurality of types of point light sources (semiconductor laser elements) that respectively emit light beams having different wavelength ranges in order to produce white light. The diameter of the laser light emitted from each point light source is extremely small with respect to the size of the incident end face 16m of the light guide member 16 in the X-axis direction, but each laser light spreads as it propagates due to its divergence angle. As schematically shown in FIG. 4, the laser light sources 18 ₁ to 18 _{N according} to the present embodiment include a red laser light source 18R and a green laser light source that emit monochromatic light in the wavelength ranges of the three primary colors of red, green, and blue. A combination of 18G and blue laser light source 18R is arranged at equal intervals along the X-axis direction. The red laser group 18RG in FIG. 1 is a group composed of red laser light sources 18R,..., 18R, and the green laser group 18GG in FIG. 1 is a group composed of green laser light sources 18G,. The laser group 18BG is a group consisting of blue laser light sources 18B,.

As shown in FIG. 4, the light guide member 16 guides a plurality of light beams emitted from the laser light sources 18 ₁ ,..., 18 _N and incident inside from the incident end face 16 m, and reflects the light fluxes by the inner reflective surface 16 r. Then, it radiates in the direction of the reflecting member 17 from the emission end face 16e. Since the light guide member 16 has an isosceles right triangle cross section in the XY plane, the light beams emitted from the laser light sources 18 ₁ to 18 _N are guided from the incident end face 16 m to the outgoing end face 16 e. The inside of the member 16 propagates substantially the same optical distance (the product of the geometric distance through which light propagates and the refractive index of the light guide member 16).

In addition, since the light beam incident on the inside from the incident end face 16m is totally reflected at the interface between the light guide member 16 and the air layer, the light beam traveling inside the light guide member 16 is reflected on the front surface 16f and the back surface 16b of the light guide member 16. The light reaches the emission end face 16e while being totally reflected. Furthermore, the light diameter of the light beam (laser light) emitted from each of the laser light sources 18 ₁ to 18 _N is extremely small with respect to the size of the incident end face 16m of the light guide member 16 in the X-axis direction. Since it spreads as it propagates due to its own divergence angle, the plurality of light beams emitted from the laser light sources 18 ₁ to 18 _N spread to substantially the same extent until they reach the emission end face 16e and spatially overlap each other. The red laser beam, the green laser color beam, and the blue laser beam emitted from the red laser light source 18R, the green laser light source 18G, and the blue laser light source 18B also propagate through the light guide member 16 and reach the emission end surface 16e. Spatially overlap to form white light. Therefore, the exit end face 16e can emit a white light beam WL having a substantially uniform luminance distribution and spreading linearly.

Here, each of the laser light sources 18 ₁ to 18 _N emits a laser beam having a very high directivity, so that these laser beams are spatially overlapped by their divergence angles, and a linear white color with a uniform luminance distribution is obtained. In order to generate the light beam WL, it is necessary to secure a predetermined optical distance. The light guide member 16 is designed to have such an optical distance. Thus, a plurality of laser beams emitted from the laser light source 18 ₁ ~ 18 _N are formed a laser light source 18 ₁ ~ 18 _N white light beam WL arrangement direction spatially overlap one another by linear by their divergent angle can do. In the present embodiment, the laser light sources 18 ₁ to 18 _{N are} arranged in the order of emission colors of R (red), G (green), B (blue), R (red), G (green), B (blue),. Therefore, if the laser light sources 18 ₁ to 18 _N are arranged so that the laser beams of the same color are spatially overlapped, a good linear white light beam WL can be formed.

As described above, the light guide member 16 can be manufactured as a transparent member having a thickness of 2 mm, but is not limited thereto. The main function necessary for the light guide member 16 is a function of guiding the light beams emitted from the laser light sources 18 ₁ to 18 _N arranged in a horizontal row to the reflection member 17. If it has this function, it is good also considering the structure of the light guide member 16 as another structure. Further, from the viewpoint of realizing the thinning and weight reduction of the liquid crystal display device 1A, it is preferable to reduce the thickness of the light guide member 16, but if the thickness of the light guide member 16 is reduced, the rigidity of the light guide member 16 is increased. descend. For this reason, the thickness of the light guide member 16 may be determined in consideration of the function and rigidity (mechanical strength) required for the light guide member 16.

  As shown in FIG. 2, the light beam emitted from the emission end surface 16 e of the light guide member 16 is reflected by the reflection curved surface 17 r of the reflection member 17 and enters the side incident end surface 14 ea of the light guide diffuser plate 14. The light guide diffuser plate 14 converts the light beam incident inside from the side incident end face 14ea into illumination light DL,..., DL that travels in the thickness direction (+ Z-axis direction). These illumination lights DL,..., DL are radiated from the front surface (light emitting surface) 14f of the light guide diffusion plate 14 as planar uniform light.

  The reflection member 17 is a plate-like member having a thickness in the X-axis direction, which is disposed outside the side incident end face 14ea of the light guide diffuser plate 14 as shown in FIGS. The reflection curved surface 17 r of the reflection member 17 is disposed so as to face the emission end surface 16 e of the light guide member 16. The reflection curved surface 17r guides the light beam emitted from the light emitting end surface 16e of the light guide member 16 to the side incident end surface 14ea of the light guide diffusion plate 14 and changes the traveling direction of the light beam from the -X axis direction to the + X axis direction. It has a function. If it has this function, the shape of the reflection curved surface 17r of the reflection member 17 is not limited to the shape of FIG.

  The light guide diffusion plate 14 is a plate-like transparent member having a front surface 14f arranged in parallel to the display surface 11f of the liquid crystal display element 11 and a back surface structure on which the micro optical elements 14d,. is there. As shown in FIG. 2, the micro optical elements 14 d,..., 14 d are formed on the back surface opposite to the liquid crystal display element 11.

  Each of the micro optical elements 14d,..., 14d has a convex shape projecting to the back surface side (−Z axis direction). The light beam incident on the inside from the side incident end face 14ea of the light guide diffuser plate 14 travels in the + X-axis direction while being totally reflected at the interface between the light guide diffuser plate 14 and the air layer. The light beam that has reached the side end face 14eb is specularly reflected in the opposite direction by the side end face 14eb. The fine optical elements 14d,..., 14d have a function of converting the light beam reaching the back surface of the light guide diffuser plate 14 into the illumination light DL by totally reflecting the inner surface in the direction of the front surface 14f. That is, the light flux totally reflected by the micro optical elements 14d,..., 14d does not satisfy the total reflection condition between the front face 14f of the light guide diffuser plate 14 and the air layer, and the liquid crystal display element from the front face 14f. There is a light beam emitted in the direction of 11. The emitted light beam constitutes the illumination light DL.

  As a constituent material of such a light guide diffusion plate 14, for example, an optical material such as a glass material or a translucent resin material is used. When an acrylic resin is used, a plate-like light guide diffusion plate 14 having a thickness of about 4 mm can be produced. Examples of the light-transmitting resin material include acrylic resin (PMMA) and polycarbonate resin, but are not limited to these, and a light-transmitting resin material having high light transmittance and excellent moldability is used. do it. In order to reduce the thickness and weight of the liquid crystal display device 1A, the thickness of the light guide diffuser plate 14 should be reduced in consideration of the functions and rigidity (mechanical strength) required for the light guide diffuser plate 14. Is desirable.

  FIG. 5 is a diagram schematically showing the back surface structure of the light guide diffusion plate 14. As shown in FIG. 5, the arrangement density of the micro optical elements 14d,..., 14d (the number or size of the micro optical elements 14d per unit area) increases as the distance from the side incident end face 14ea increases. It is so low that it approaches 14ea. In other words, the fine optical elements 14d,..., 14d become denser as they move away from the side incident end face 14ea and become sparser as they approach the side incident end face 14ea. The reason for this is to make the in-plane luminance distribution (luminance distribution in the two-dimensional plane) of the illumination light DL uniform. That is, the closer to the side incident end face 14ea, the higher the light intensity. Therefore, the arrangement density of the micro optical elements 14d is lowered, and the proportion of the light totally reflected by the micro optical elements 14d,. However, as the distance from the side incident end face 14ea increases, the intensity of the light decreases. Therefore, the arrangement density of the fine optical elements 14d,..., 14d is increased, and the total internal reflection by the fine optical elements 14d,. The in-plane luminance distribution is made uniform by increasing the ratio of light to be emitted. The in-plane luminance distribution of the illumination light DL can be controlled by changing the arrangement density of the micro optical elements 14d,.

  FIG. 6 is a schematic cross-sectional view of the micro optical element 14d. The fine optical element 14d in FIG. 6 has a convex lens shape. The shape of the micro optical element 14d is a part of a spherical shape, and its surface has a certain curvature. For example, when the light guide diffuser plate 14 is manufactured using an acrylic resin having a refractive index of about 1.49, the surface curvature is about 0.15 mm and the maximum height Hmax is about 0.005 mm. The fine optical element 14d can be molded.

  The back surface structure of the light guide diffusion plate 14 is not limited to the structure shown in FIG. FIG. 7 is a view schematically showing a back surface structure of a light guide diffusion plate 14M which is a modification of the light guide diffusion plate 14. As shown in FIG. The back surface structure of the light guide diffusion plate 14M has micro optical elements 14Md,..., 14Md having a convex lens shape. The dimension of the micro optical element 14Md increases as it moves away from the side incident end face 14Mea, and decreases as it approaches the side incident end face 14Mea. Thereby, the in-plane luminance distribution of the illumination light DL can be made uniform.

  In place of the micro optical elements 14d and 14Md, a micro optical element having another convex or concave shape or a micro optical element having a cross-sectional prism shape may be employed. Further, the micro optical element does not necessarily have to be formed at regular positions, and may be formed at random positions.

  The light reflecting sheet 15 is a member that reflects light emitted backward (−Z-axis direction) from the back surface of the light guide diffusion plate 14 toward the liquid crystal display element 11. The light reflected by the light reflection sheet 15 passes through the light guide diffusion plate 14 and constitutes a part of the illumination light DL. As the light reflecting sheet 15, for example, a light reflecting sheet having a resin such as polyethylene terephthalate as a base material, or a light reflecting sheet in which a metal is deposited on the surface of the substrate can be used. The use efficiency of light can be improved by using such a light reflection sheet 15.

  On the other hand, the second optical sheet 13 has a structure that transmits the illumination light DL radiated from the front surface 14f of the light guide diffusion plate 14 and suppresses optical effects such as fine illumination unevenness.

  The first optical sheet 12 has an optical structure that adjusts the traveling direction of the illumination light DL transmitted through the second optical sheet 13 and directs the traveling direction toward the back surface 11 b of the liquid crystal display element 11. FIG. 8 is a perspective view schematically showing an example of the optical structure of the first optical sheet 12. As shown in FIG. 8, the surface of the first optical sheet 12 (the surface facing the back surface 11b of the liquid crystal display element 11) has a plurality of convex portions 12p,..., 12p parallel to the display surface 11f. Along the X-axis direction. Each convex part 12p has a triangular prism shape in cross section, the apex angle part of the convex part 12p protrudes toward the liquid crystal display element 11, and the ridge line forming the apex part extends in the Y-axis direction. The interval between the adjacent convex portions 12p, 12p is constant.

  Next, effects and advantages of the backlight unit 10A and the liquid crystal display device 1A according to Embodiment 1 described above will be described.

In the backlight unit 10A of the first embodiment, as shown in FIGS. 2 and 3, the laser light sources 18 ₁ to 18 _N are arranged in the extending direction of the end surface 14ec on the bottom surface side different from the side incident end surface 14ea. The light beams emitted from the laser light sources 18 ₁ to 18 _N are guided by the light guide member 16 and the reflection member 17 and are incident on the side incident end face 14ea. When such a backlight unit 10A is used in a state in which the side incident end face 14ea is upright (normal apparatus use state), the laser light sources 18 ₁ to 18 _N are laterally perpendicular to the gravity direction. Therefore, it is possible to reduce the ambient temperature difference between the laser light sources 18 ₁ to 18 _N and to suppress variations in light emission efficiency and light emission color (light emission wavelength).

In addition, since the laser light sources 18 ₁ to 18 _N are arranged below the gravitational direction in a normal apparatus use state, the heat generated by the laser light sources 18 ₁ to 18 _N warms the surrounding air, but the heated air Rises against gravity. Therefore, an increase in the ambient temperature of these laser light sources 18 ₁ to 18 _N is suppressed. Thus, it is possible to suppress a decrease in luminous efficiency has temperature dependence of the laser light source ₁₈ 1 ~ 18 _N, it is possible to extend the life of the laser light source ₁₈ 1 ~ 18 _N. The laser light sources 18 ₁ to 18 _N are arranged in a row so that heat generated by the laser light sources 18 ₁ to 18 _N can easily escape upward. Therefore, the backlight unit 10A of the present embodiment can provide uniform planar light with no unevenness in brightness and emission color as illumination light. Further, the image quality of the liquid crystal display device 1A can be improved.

Further, since the laser light sources 18 ₁ to 18 _N are arranged along a direction (X-axis direction) substantially perpendicular to the thickness direction (Z-axis direction) of the light guide diffuser plate 14, the backlight unit 10A is arranged. It can be easily reduced in thickness. In particular, as shown in FIG. 3, laser light sources 18 ₁ to 18 _N are arranged along the longitudinal direction of the light guide diffusion plate 14, and the longitudinal direction of the light guide diffusion plate 14 is a horizontal pixel of the liquid crystal display element 11. Since it coincides with the direction, it is possible to achieve both the arrangement of the laser light sources 18 ₁ to 18 _N below the gravitational direction and the thinning of the liquid crystal display device 1A.

Moreover, when using LED light sources (light-emitting diode light sources) instead of the laser light sources 18 ₁ to 18 _N , it is possible to suppress the ambient temperature difference between these LED light sources. However, in the case of a light source using a laser element, the electric / optical conversion efficiency is higher than in the case of an LED light source having a single emission color, so that the case where the laser light sources 18 ₁ to 18 _N are used is driven with low power consumption. There is an advantage that is possible. Furthermore, the light from the laser light source using the laser element has higher directivity than the light from the LED light source. For this reason, there is also an advantage that the optical coupling efficiency between the laser light sources 18 ₁ to 18 _N and the light guide member 16 is good. The optical coupling efficiency means the ratio of the amount of light coupled (incident) to the light guide member 16 with respect to the amount of light emitted from the light source.

Further, since the wavelength width (full width at half maximum of spectrum) of the emitted light of the laser light sources 18 ₁ to 18 _N is narrower than that of the LED light source, the use of the laser light sources 18 ₁ to 18 _N can increase the color purity of the display color. it can. Therefore, the liquid crystal display device 1A according to the present embodiment can realize brighter color expression than when a fluorescent lamp or a white LED light source is used.

  By the way, it is necessary to employ a light source that emits light with a narrow wavelength bandwidth in order to extend the color reproduction range while minimizing light loss due to the color filter. When a light source having a continuous spectrum with a wide wavelength bandwidth, such as a white LED light source, is used, the transmission band width (transmission wavelength region) of the color filter is set to a narrow one to widen the color reproduction range, and the display color It is necessary to increase the color purity. However, since the amount of unnecessary light increases by narrowing the transmission bandwidth of the color filter, there is a problem in that the light use efficiency is lowered, and the luminance of the display screen is reduced and the power consumption is increased. For example, a white LED light source or a fluorescent lamp having a phosphor has an emission spectrum having a peak intensity at a wavelength shifted to an orange color of about 615 nm in the red wavelength region due to the characteristics of the phosphor. For this reason, in particular, when trying to increase the color purity in the wavelength range of 630 to 640 nm, which is preferable as pure red in red, the amount of light transmitted through the color filter is extremely reduced, and the luminance is significantly reduced.

On the other hand, the laser light sources 18 ₁ to 18 _{N according} to the present embodiment are composed of the red laser group 18RG, the green laser light source 18GG, and the blue laser group 18BG that emit monochromatic light in the visible light wavelength range, and therefore are more than the LED light sources. , Excellent in monochromaticity. Therefore, the transmission bandwidth of the color filter of the liquid crystal display element 11 can be selected in accordance with the emission wavelength range of the laser light sources 18 ₁ to 18 _N. That is, it is possible to narrow the transmission bandwidth of the color filter while suppressing a reduction in the amount of transmitted light of the color filter. Thereby, it is possible to increase the color purity of the display color and widen the color reproduction range. Therefore, the image quality of the liquid crystal display device 1A can be improved.

Further, since the laser light sources 18 ₁ to 18 _N are configured by the red laser group 18RG, the green laser group 18GG, and the blue laser group 18BG, the control unit 21 in FIG. 1 controls the light emission amount of the red laser group 18RG and the green laser group. It is easy to individually control the light emission amount of 18GG and the light emission amount of the blue laser group 18BG. For this reason, the control part 21 is a ratio of the luminance of the red laser group 18RG, the luminance of the green laser group 18GG, and the luminance of the blue laser group 18BG so as to reduce the power consumption of the liquid crystal display device 1A according to the video signal. Can be optimized.

  Further, the control unit 21 individually controls the light emission amount of the red laser group 18RG, the light emission amount of the green laser group 18GG, and the light emission amount of the blue laser group 18BG. Stray light that is not necessary for the generation of can be reduced. Thereby, the contrast of a display image can be improved.

Conventionally, when a laser light source is employed as a light source incorporated in an edge light type backlight unit, luminance unevenness (decrease in luminance in-plane uniformity) of the display surface of the liquid crystal display panel has been a problem. One of the causes of this luminance unevenness is that the laser light source is a point light source that emits light with high directivity. On the other hand, in the backlight unit 10A according to the present embodiment, by using the light guide member 16, light beams with high directivity emitted from laser light sources arranged close to each other among the laser light sources 18 ₁ to 18 _N are obtained. A sufficient optical distance for spatially overlapping each other can be ensured by their divergence angles, so that the light guide member 16 can emit a uniform linear light beam WL (FIG. 4) from the emission end face 16e. Therefore, the backlight unit 10A can generate illumination lights DL,..., DL having a uniform in-plane distribution of luminance and emission color. Therefore, it is possible to suppress a decrease in the in-plane uniformity of luminance and emission color on the display surface 11f of the liquid crystal display element 11.

In addition, as described above, the backlight unit of the conventional display device described in Patent Document 1 includes a plurality of light guide plates arranged in parallel to each other, and a plurality of white LEDs attached to the edges of the plurality of light guide plates. A light source. These white LED light sources are turned on in synchronization with the timing of rewriting the voltage held in the pixels or sub-pixels of the liquid crystal display panel. That is, it is necessary to turn on the backlight in accordance with the timing of rewriting the voltage every predetermined number of horizontal pixel lines. In order to realize such a configuration, it is necessary to arrange a plurality of white LED light sources along the vertical pixel direction. On the other hand, in the backlight unit 10A of the present embodiment, the laser light sources 18 ₁ to 18 _N are arranged on one end side in the vertical pixel direction of the liquid crystal display element 11, and the horizontal pixel direction of the liquid crystal display element 11, that is, horizontal They are arranged along the extending direction of the scanning wiring. When the control unit 21 executes the lighting control in which the light source driving unit 23 sequentially turns on the laser light sources 18 ₁ to 18 _N in synchronization with the scanning with respect to the horizontal scanning wiring, the light guide member 16 and the reflection member 17 have the laser light source 18. ₁ to 18 _N guides a light beam emitted in the vertical pixel direction (+ Y-axis direction) from _N and enters the side incident end face 14ea of the light guide diffusion plate 14 from the horizontal pixel direction side (−X-axis direction side). Can be made. Therefore, even if the laser light sources 18 ₁ to 18 _N are sequentially turned on in synchronization with the timing of rewriting the gradation voltages of the sub-pixels for each predetermined number of horizontal pixel lines of the liquid crystal display element 11, these laser light sources 18 ₁ to 18 _N It is possible to guide the light flux and make it incident on the side incident end face 14ea of the light guide diffusion plate 14.

Embodiment 2. FIG.
Next, a second embodiment according to the present invention will be described. FIG. 9 is a functional block diagram showing a schematic configuration of the liquid crystal display device 1B of the second embodiment. As shown in FIG. 9, the liquid crystal display device 1B includes a backlight unit 10B, a transmissive liquid crystal display element 11, a liquid crystal display element driving unit 22 that drives the liquid crystal display element (liquid crystal display panel) 11, and a backlight. Control for controlling each operation of the light source driving unit 23B for individually driving the red laser group 18RG and the blue-green LED group (blue-green light emitting diode group) 20G in the unit 10B, and the liquid crystal display element driving unit 22 and the light source driving unit 23B. Part 21.

  The liquid crystal display device 1B according to the present embodiment has the same configuration as the liquid crystal display device 1A according to the first embodiment except for a part of the configuration of the backlight unit 10B and the light source driving unit 23B. In addition, the same code | symbol is attached | subjected to the component same as the component of Embodiment 1, and the detailed description is abbreviate | omitted.

  FIG. 10 is a bottom view of the apparatus schematically showing the configuration of the liquid crystal display device 1B, excluding the control unit 21, the liquid crystal display element driving unit 22, and the light source driving unit 23B. In FIG. 10, an X axis, a Y axis, and a Z axis forming a three-dimensional orthogonal coordinate system are shown. The ± X axis direction coincides with the long side direction (horizontal pixel direction) of the liquid crystal display element 11 having a rectangular shape, and the ± Y axis direction coincides with the short side direction (vertical pixel direction) of the liquid crystal display element 11; The + Z axis direction coincides with the normal direction of the display surface 11 f of the liquid crystal display element 11. The + Y axis direction indicates the upper end side of the display surface 11f in the vertical pixel direction, and the −Y axis direction indicates the lower end side of the display surface 11f in the vertical pixel direction. The + Y axis direction means the direction opposite to the gravity direction.

  As shown in FIG. 10, the liquid crystal display device 1B includes a liquid crystal display element 11, a first optical sheet 12, a second optical sheet 13, an auxiliary light guide diffusion plate 19, a light guide diffusion plate 14, and a light guide member 16. Are arranged along the Z-axis direction and stacked. 10, blue-green LED light source (auxiliary light source) 20, auxiliary light guide diffusion plate 19, light guide diffusion plate 14, light reflection sheet 15, red laser light sources 18R,..., 18R, light guide member 16 and reflection. The member 17 comprises the backlight unit 10B which is the illuminating device of this Embodiment. The configuration of the backlight unit 10B is the same as the configuration of the backlight unit 10A of Embodiment 1 except for the auxiliary light guide diffuser plate 19, the blue-green LED light source 20, and the red laser light sources 18R,. .

  FIG. 11 is a diagram schematically showing the back surface of the light guide member 16 according to the second embodiment. As shown in FIG. 11, the light guide member 16 has an incident end face 16m that should be disposed below the gravitational direction (−Y-axis direction) in a normal apparatus use state. It is formed along the longitudinal direction (X-axis direction) of the light guide diffusion plate 14. In the vicinity of the incident end face 16m, a plurality of red laser light sources 18R, 18R,..., 18R, which are point light sources having semiconductor laser elements, are arranged to face the incident end face 16m. The red laser light sources 18R, 18R,..., 18R are arranged in a line along the extending direction of the end surface 14ec of the light guide diffusion plate 14 on the −Y axis direction side, that is, the longitudinal direction (X axis direction) of the light guide diffusion plate 14. It is arranged. The red laser group 18RG in FIG. 9 is a group composed of these red laser light sources 18R, 18R,.

  As shown in FIG. 11, the light guide member 16 guides a plurality of light beams emitted from the red laser light sources 18R, 18R,..., 18R and incident inside from the incident end face 16m, and is reflected by the inner reflective surface 16r. Then, the light is emitted in the direction of the reflecting member 17 from the emission end face 16e. Since the light guide member 16 has a right isosceles triangular cross section in the XY plane, the light beam emitted from the red laser light sources 18R, 18R,..., 18R reaches the emission end face 16e from the incident end face 16m. The light guide member 16 propagates substantially the same optical distance (the product of the geometric distance through which light propagates and the refractive index of the light guide member 16).

  Since the light beam entering from the incident end face 16m is totally reflected at the interface between the light guide member 16 and the air layer, the light beam traveling inside the light guide member 16 is reflected between the front surface 16f and the back surface 16b of the light guide member 16. The light reaches the emission end face 16e while being totally reflected. Further, the light diameter of the light beam (laser light) emitted from each of the red laser light sources 18R, 18R,..., 18R is extremely small with respect to the size of the incident end face 16m of the light guide member 16 in the X-axis direction. Since the luminous flux spreads as it propagates due to its own divergence angle, a plurality of luminous fluxes emitted from the red laser light sources arranged close to each other among the red laser light sources 18R, 18R,. They spread about the same extent and overlap each other spatially. Therefore, the emission end face 16e can emit a red light beam RL having a substantially uniform luminance distribution and spreading linearly.

  As the red laser light source 18R, for example, a semiconductor laser element that outputs monochromatic light of an emission spectrum having a peak intensity formed in the vicinity of about 640 nm and a wavelength width of about 1 nm (spectrum full width at half maximum) may be used. It is not limited to this. The divergence angle of the emitted light beam of the red laser light source 18R is, for example, about 40 degrees at the full width at half maximum in the fast axis direction and about 10 degrees at the full width at half maximum in the slow axis direction.

  The red laser light source 18R is arranged so that the slow axis direction thereof is parallel to the short side direction (Z-axis direction) of the incident end face 16m of the light guide member 16. The short side direction of the incident end face 16m is a direction in which the distance between the opposing faces 16f and 16b of the light guide member 16 is the smallest. Although the arrangement direction of the red laser light source 18R is not limited to this, the red laser light source 18R is arranged so that the slow axis direction is parallel to the short side direction of the incident end face 16m, thereby guiding the light. The reflection on the inner surface 16r of the member 16 is efficiently performed. When the divergence angle of the laser beam in the short side direction of the incident end face 16m is large, the incident angle of a part of the laser beam to the incident end face 16m may be larger than the critical angle and may not reach the inner reflection surface 16r. is there.

  The light beam emitted from the emission end face 16e of the light guide member 16 is reflected by the reflection curved surface 17r of the reflection member 17 and enters the side incidence end face 14ea of the light guide diffuser plate 14 as shown in FIG. The light guide diffuser plate 14 converts the light beam incident inside from the side incident end face 14ea into illumination lights DL1, ..., DL1 that travel in the thickness direction (+ Z-axis direction). These illumination lights DL1,..., DL1 are radiated from the front surface (light emitting surface) 14f of the light guide diffuser plate 14 as planar uniform light.

  FIG. 12 is a diagram schematically showing the back surface structure of the auxiliary light guide diffusion plate 19. As shown in FIGS. 10 and 12, the auxiliary light guide diffusion plate 19 includes a front surface 19f, a side incident end surface 19ea, a side end surface (which is disposed in parallel with the display surface 11f of the liquid crystal display element 11). A light-reflecting surface) 19eb and a plate-like transparent member having a back surface structure on which fine optical elements 19d,. The auxiliary light guide diffusion plate 19 is made of a material that transmits the illumination lights DL1,..., DL1 emitted from the front surface 14f of the light guide diffusion plate 14. Each of the micro optical elements 19d,..., 19d has a convex shape protruding toward the back surface side (−Z axis direction).

  As shown in FIG. 12, a plurality of blue-green LED light sources 20,..., 20 are disposed at positions facing the side incident end face 19ea of the auxiliary light guide diffuser plate 19, and these blue-green LED light sources 20,. Are arranged at equal intervals along the Y-axis direction. The blue-green LED light sources 20,... 20 emit light beams toward the side incident end face 19 ea of the auxiliary light guide diffuser plate 19. The light beam incident on the inside of the auxiliary light guide diffusion plate 19 from the side incident end face 19ea travels in the + X-axis direction while being totally reflected at the interface between the auxiliary light guide diffusion plate 19 and the air layer. The fine optical elements 19d,..., 19d have a function of converting the light beam reaching the back surface of the auxiliary light guide diffuser plate 19 into the illumination light (auxiliary light beam) DL2 by total internal reflection in the direction of the front surface 19f. That is, among the light beams totally reflected by the micro optical elements 19d,..., 19d, the liquid crystal display is made from the front surface 19f without satisfying the total reflection condition between the front surface 19f of the auxiliary light guide diffusion plate 19 and the air layer. There is a light beam emitted in the direction of the element 11. The emitted light beam constitutes the illumination light DL2.

  As a constituent material of such an auxiliary light guide diffusion plate 19, for example, an optical material such as a glass material or a translucent resin material is used. When an acrylic resin is used, a plate-shaped auxiliary light guide diffusion plate 19 having a thickness of about 4 mm can be produced. Examples of the light-transmitting resin material include acrylic resin (PMMA) and polycarbonate resin, but are not limited to these, and a light-transmitting resin material having high light transmittance and excellent moldability is used. do it. In order to reduce the thickness and weight of the liquid crystal display device 1B, the thickness of the auxiliary light guide diffusion plate 19 is reduced in consideration of the functions and rigidity (mechanical strength) necessary for the auxiliary light guide diffusion plate 19. It is desirable to do.

  The arrangement density of the micro optical elements 19d,..., 19d (the number or size of the micro optical elements 19d per unit area) increases as the distance from the side incident end face 19ea increases, and decreases toward the side incident end face 19ea. In other words, the fine optical elements 19d, ..., 19d become denser as they move away from the side incident end face 19ea and become sparser as they approach the side incident end face 19ea. The reason for this is to make the in-plane luminance distribution of the illumination light DL2 uniform. It is possible to control the in-plane luminance distribution of the illumination light DL2 by changing the arrangement density of the micro optical elements 19d,.

  FIG. 13 is a schematic cross-sectional view showing an example of the micro optical element 19d. The fine optical element 19d in FIG. 13 has a convex lens shape. The shape of the micro optical element 19d is a part of a spherical shape, and its surface has a certain curvature. For example, when the auxiliary light guide diffusion plate 19 is manufactured using an acrylic resin having a refractive index of about 1.49, the curvature of the surface is about 0.15 mm and the maximum height Dmax is about 0.005 mm. The fine optical element 19d can be molded.

  The back surface structure of the auxiliary light guide diffusion plate 19 is not limited to the structure shown in FIG. Instead of the structure shown in FIG. 12, similarly to the back surface structure of FIG. 7, the size of the micro optical element may be increased as it is farther from the side incident end face, and may be decreased as it is closer to the side incident end face. Thereby, the in-plane luminance distribution of the illumination light DL2 can be made uniform. Moreover, you may employ | adopt the micro optical element which has another convex shape or a concave shape, and the micro optical element which has a cross-sectional prism shape. Furthermore, the micro optical element does not necessarily have to be formed at regular positions, and may be formed at random positions.

  The emission color of the blue-green LED light source 20 is complementary to the emission color of the red laser light source 18R. As the blue-green LED light source 20, for example, a light source that emits light of an emission spectrum having peak intensities near 450 nm and 530 nm may be used. Specifically, a blue LED light source that emits light in the blue wavelength region (blue light) and green fluorescence that emits light in the green wavelength region (green light) by absorbing the emitted light from the blue laser light source as excitation light A light source consisting of a combination with the body can be used. Such a light source outputs blue-green light (light in which blue light and green light are mixed) having a continuous spectrum in a wavelength range of about 420 nm to about 580 nm. Further, since each blue-green LED light source 20 emits blue-green light having a wide divergence angle, the light beams emitted from the blue-green LED light sources 20,..., 20 are mutually in the arrangement direction of the blue-green LED light sources 20,. Overlapping to form linear light.

  The backlight unit 10B of the present embodiment uses a blue-green LED light source 20 that outputs blue light and green light. For the green light, a single-color LED light source or a single-color laser light source that emits green light. It is also possible to use. However, among simple and small light sources applicable to displays, such monochromatic LED light sources and monochromatic laser light sources are inferior in terms of low power consumption and high output as compared to so-called multicolor LED light sources that use phosphors. . Therefore, the backlight unit 10B of the present embodiment uses a blue-green LED light source 20 including a green phosphor in order to simplify the device configuration, reduce the size, and reduce power consumption.

  A blue LED light source is used as a light source for exciting the green phosphor of the blue-green LED light source 20, but a blue laser light source is employed instead of the blue LED light source from the viewpoint of further expanding the color reproduction range. It is also effective. However, it is preferable to use an LED light source rather than a laser light source as a light source for exciting the phosphor from the viewpoint of reducing power consumption and suppressing a decrease in internal conversion efficiency of the phosphor. The reason is as follows.

  A laser light source is a high current drive and a high output with respect to a low current drive and a low output LED light source. For this reason, the amount of heat generated from the laser light source during driving is very large. In addition, light emitted from the LED light source has a wide divergence angle, whereas light emitted from the laser light source has a very narrow divergence angle. For this reason, in the case of a laser light source, the intensity density of the excitation light incident on the phosphor (the intensity of the light incident per unit volume of the phosphor) is very high. Part of the light that is incident on and absorbed by the phosphor is converted into light of another wavelength and emitted to the outside, and the other light mainly becomes thermal energy. Generally, the internal conversion efficiency (the amount of light converted into light of other wavelengths with respect to the amount of light absorbed) of the phosphor is about 40% to 80%. That is, the thermal energy generated at the same time ranges from 20% to 60% of the incident light energy. Therefore, when a laser beam having a high output and a high light intensity density is incident, the calorific value of the phosphor becomes very large.

  As the amount of heat generated by the laser light source for exciting the phosphor increases, the temperature of the phosphor also increases. Moreover, even if the calorific value of the phosphor itself increases, the temperature of the phosphor rises. When the temperature of the phosphor rises in this way, the internal conversion efficiency of the phosphor is greatly lowered, causing a decrease in luminance and an increase in power consumption. For the above reason, in the blue-green LED light sources 20,..., 20 in the second embodiment, a blue LED light source is employed as a light source for exciting the green phosphor.

  The auxiliary light guide diffuser plate 19 converts the light beam incident inside from the side incident end face 19ea into illumination lights DL2, ..., DL2 that travel in the thickness direction (+ Z-axis direction). These illumination lights DL2,..., DL2 form a planar uniform light. The auxiliary light guide diffusion plate 19 mixes the illumination light DL2,..., DL2 with the illumination light DL1,..., DL1 incident from the front surface 14f of the rear light guide diffusion plate 14 and radiates it in the direction of the liquid crystal display element 11. . The red illumination light DL1 and the blue-green illumination light DL2 radiated from the front surface 19f of the auxiliary light guide diffusion plate 19 become white light and enter the liquid crystal display element 11 through the optical sheets 13 and 12. The auxiliary light guide diffuser plate 19 is made of a transparent material that minimizes optical influences such as reflection and absorption on the illumination light DL1. Therefore, the loss of the illumination light DL1 is suppressed, and the illumination light DL1 can be efficiently used to illuminate the liquid crystal display element 11.

  The illumination lights DL1 and DL2 emitted in the direction of the liquid crystal display element 11 include light that is reflected by the optical sheets 12 and 13 and travels in the −Z-axis direction. Such light is reflected in the direction of the liquid crystal display element 11 (+ Z-axis direction). For this reason, the loss of illumination light DL1, DL2 can be suppressed, and illumination light DL1, DL2 can be utilized efficiently.

  Next, effects and advantages of the backlight unit 10B and the liquid crystal display device 1B according to Embodiment 2 described above will be described.

  In the backlight unit 10B of the second embodiment, the laser light sources 18R,..., 18R are along the extending direction of the end surface 14ec on the bottom surface side of the light guide diffusion plate 14, as shown in FIGS. The light beams emitted from the laser light sources 18R,..., 18R are guided by the light guide member 16 and the reflection member 17 and are incident on the side incident end face 14ea. When such a backlight unit 10B is used in a state in which the side incident end face 14ea is upright (normal apparatus use state), the laser light sources 18R,. Therefore, it is possible to reduce the ambient temperature difference between the laser light sources 18R,..., 18R, and to suppress variations in light emission efficiency and light emission color (light emission wavelength).

  Moreover, since the red laser light sources 18R,..., 18R are arranged below in the gravity direction, the heat generated by the red laser light sources 18R,..., 18R warms the surrounding air, but the warmed air is against gravity. To rise. Therefore, an increase in the ambient temperature of these red laser light sources 18R, ..., 18R is suppressed. Accordingly, it is possible to suppress a decrease in light emission efficiency having temperature dependence of the red laser light sources 18R,..., 18R, and to extend the lifetime of the red laser light sources 18R,. The red laser light sources 18R,..., 18R are arranged in a row so that heat generated by the red laser light sources 18R,. Therefore, the backlight unit 10B of the present embodiment can provide uniform planar light with no unevenness in brightness and emission color as illumination light. In addition, the image quality of the liquid crystal display device 1B can be improved.

  Further, two types of light sources of red laser light sources 18R,..., 18R and blue-green LED light sources 20,. Thereby, the rise in ambient temperature due to the heat generated by these two types of light sources can be mitigated. Therefore, it is possible to suppress a decrease in light emission efficiency due to an increase in ambient temperature, and it is possible to extend the lifetime of each of the red laser light source 18R and the blue-green LED light source 20.

  As in the case of the first embodiment, the red laser light sources 18R,..., 18R are along a direction (X-axis direction) substantially perpendicular to the thickness direction (Z-axis direction) of the light guide diffuser plate 14. Therefore, the backlight unit 10B can be easily thinned. In particular, red laser light sources 18R,..., 18R are arranged along the longitudinal direction of the light guide diffuser plate 14, and the longitudinal direction of the light guide diffuser plate 14 matches the horizontal pixel direction of the liquid crystal display element 11. The arrangement of the laser light sources 18R,..., 18R below the gravitational direction and the thinning of the liquid crystal display device 1B can be made compatible.

  Further, the use of the red laser light sources 18R,..., 18R can improve the color purity of red as compared with the case of using a fluorescent lamp or a white LED light source. In addition, the improvement in red color purity enables the liquid crystal display device 1B to reduce light loss due to the color filter. For this reason, the liquid crystal display device 1B of the present embodiment can realize a high color and a wide color gamut simultaneously with low power consumption.

  In the case of using an LED light source instead of the red laser light source 18R, ..., 18R, it is possible to suppress the ambient temperature difference between these LED light sources, but in the case of a laser light source using a laser element, Since the electric / light conversion efficiency is higher than that of the single light emitting LED light source, the use of the red laser light sources 18R,. Furthermore, the light from the laser light source using the laser element has higher directivity than the light from the LED light source. Therefore, there is an advantage that the optical coupling efficiency between the red laser light sources 18R,..., 18R and the light guide member 16 is good.

  By the way, red is a color with high human sensitivity to color difference. The red wavelength bandwidth of a typical monochromatic LED light source that emits red light is about several tens of nanometers, but the red wavelength bandwidth of a red laser light source is only a few nanometers, so the difference between these wavelength bandwidths Is more noticeable in human vision. Human vision perceives differences in wavelength bandwidth as differences in color purity. In the case of a white LED light source (for example, a combination of a blue LED light source and a yellow phosphor) widely used in a conventional backlight unit, the amount of light energy in the red wavelength region is relatively small. The ratio of light in the wavelength range of 630 nm to 640 nm, which is preferable as pure red, is very small. For this reason, when it is attempted to increase the color purity in this wavelength range, the amount of transmitted light is extremely reduced, and the luminance may be significantly reduced.

  On the other hand, the backlight unit 10B of the present embodiment uses the red laser light sources 18R,..., 18R that emit red light among the three primary colors of red, green, and blue. Compared to the case of using a (green or blue) laser light source, there is an advantage that the effect of reducing power consumption and improving color purity is high. Also, since the red wavelength bandwidth of the red laser light sources 18R,..., 18R is very narrow, the backlight unit 10B of the present embodiment is more than a backlight unit that uses a monochromatic LED light source that emits red light. It is possible to increase the color purity of red. Further, the transmission bandwidth (transmission wavelength region) of the red color filter of the liquid crystal display element 11 can be optimized in accordance with the wavelength bandwidth of the red laser light source 18R. Specifically, it is possible to narrow the transmission bandwidth of the red color filter while suppressing a reduction in the amount of transmitted light of the red color filter. Thereby, it is possible to increase the color reproduction range by increasing the color purity of red. Therefore, the liquid crystal display device 1B according to the present embodiment can realize a vivid color expression and provide a good image quality.

  Further, in the case of a backlight unit using a white LED light source having a continuous spectrum from the blue wavelength range to the red wavelength range or a red single color LED light source having a wide wavelength bandwidth, it cannot be shielded by a green color filter. Wavelength light may be generated. In this case, since the green color filter transmits unnecessary light, there is a problem that the color purity of the green color is lowered. On the other hand, since the backlight unit 10B of the present embodiment uses the red laser light sources 18R,..., 18R that emit red light with a narrow wavelength bandwidth, a white LED light source or a red monochromatic LED light source is used. Compared with the backlight unit to be used, the color purity of green can be improved.

  Further, as described above, conventionally, when a laser light source is employed in an edge light type backlight unit, luminance unevenness (decrease in luminance in-plane uniformity) of the display surface of the liquid crystal display panel has been a problem. It was. On the other hand, since the backlight unit 10B of the present embodiment employs the light guide member 16, directivity emitted from laser light sources arranged close to each other among the red laser light sources 18R,. It is possible to secure a sufficient optical distance for spatially superimposing high luminous fluxes on the basis of their divergence angles. Thereby, the light guide member 16 can emit a uniform linear light beam from the emission end face 16e. Therefore, the backlight unit 10B of the present embodiment can generate illumination lights DL1,..., DL1 having a uniform in-plane luminance distribution. Therefore, it is possible to suppress a reduction in in-plane uniformity of luminance and emission color on the display surface 11f of the liquid crystal display element 11.

  The control unit 21 of the present embodiment reduces the brightness of the red laser light sources 18R,..., 18R and the blue-green LED light sources 20,..., 20 so as to reduce the power consumption of the liquid crystal display device 1B according to the video signal. It is possible to optimize the ratio with luminance. Furthermore, the control unit 21 can reduce stray light unnecessary for generating image light by individually controlling the light emission amount of the red laser group 18RG and the light emission amount of the blue-green LED group 20G. Thereby, the contrast of a display image can be improved.

Embodiment 3 FIG.
Next, a third embodiment according to the present invention will be described. FIG. 14 is a functional block diagram showing a schematic configuration of the liquid crystal display device 1C according to the third embodiment. As shown in FIG. 14, the liquid crystal display device 1 </ b> C includes a backlight unit 10 </ b> C, a transmissive liquid crystal display element 11, a liquid crystal display element driving unit 22 that drives the liquid crystal display element (liquid crystal display panel) 11, and a backlight. Control for controlling each operation of the light source driving unit 23C for individually driving the red laser group 18RG and the blue-green LED group (blue-green light emitting diode group) 20G in the unit 10C, and the liquid crystal display element driving unit 22 and the light source driving unit 23C. Part 21.

  The liquid crystal display device 1C of the present embodiment has the same configuration as the liquid crystal display device 1A of the first embodiment except for a part of the configuration of the backlight unit 10C and the light source driving unit 23C. In addition, the same code | symbol is attached | subjected to the component same as the component of Embodiment 1, 2, and the detailed description is abbreviate | omitted.

  FIG. 15 is a device bottom view schematically showing the configuration of the liquid crystal display device 1 </ b> C except for the control unit 21, the liquid crystal display element driving unit 22, and the light source driving unit 23 </ b> C. In FIG. 15, an X axis, a Y axis, and a Z axis forming a three-dimensional orthogonal coordinate system are shown. The ± X axis direction coincides with the long side direction (horizontal pixel direction) of the liquid crystal display element 11 having a rectangular shape, and the ± Y axis direction coincides with the short side direction (vertical pixel direction) of the liquid crystal display element 11; The + Z axis direction coincides with the normal direction of the display surface 11 f of the liquid crystal display element 11. The + Y axis direction indicates the upper end side of the display surface 11f in the vertical pixel direction, and the −Y axis direction indicates the lower end side of the display surface 11f in the vertical pixel direction. The + Y axis direction means the direction opposite to the gravity direction.

  As shown in FIG. 15, the liquid crystal display device 1 </ b> C includes a liquid crystal display element 11, a first optical sheet 12, a second optical sheet 13, a light guide diffusion plate 30, and a light guide member 16 along the Z-axis direction. It has an arrayed and stacked structure. FIG. 16 is a diagram schematically showing the back surface structure of the light guide diffusion plate 30. 15, the blue-green LED light source (auxiliary light source) 20, the light guide diffuser plate 30, the light reflection sheet 15, the red laser light sources 18R,..., 18R, the light guide member 16, and the reflection member 31 are the present embodiment. The backlight unit 10 </ b> C that is the illumination device is configured.

  The light guide diffuser plate 30 has a function of converting a plurality of light beams incident inside from the side incident end face 30ea into planar light beams, that is, illumination lights DL,. The light guide diffusion plate 30 includes a front surface (light emitting surface) 30f that emits illumination light DL,..., DL, and an end surface 30ec that is formed on one end side in the extending direction of the side incident end surface 30ea and extends in the X-axis direction. have. A reflecting member 31 is disposed outside the side incident end face 30ea of the light guide diffuser plate 30. The light guide reflection member of the present invention can be composed of the light guide member 16 and the reflection member 31, for example.

  As in the case of the second embodiment, the light guide member 16 guides a plurality of light beams emitted from the red laser light sources 18R, 18R,... Radiates in the direction of the reflecting member 31 from 16e. Since the light beam incident inside from the incident end face 16m of the light guide member 16 is totally reflected at the interface between the light guide member 16 and the air layer, the light beam traveling inside the light guide member 16 is reflected on the front surface 16f of the light guide member 16. And the back surface 16b are totally reflected to reach the emission end face 16e.

  Further, the laser light beams emitted from each of the red laser light sources 18R, 18R,..., 18R spread as they propagate according to their own divergence angles, and thus are arranged close to each other among the red laser light sources 18R, 18R,. The plurality of light beams emitted from the red laser light source spread to substantially the same extent before reaching the emission end face 16e and spatially overlap each other. Therefore, the emission end face 16e can emit a red light beam having a substantially uniform luminance distribution and spreading linearly.

  As shown in FIG. 15, the light beam emitted from the emission end face 16 e of the light guide member 16 is reflected by the reflection curved surface 31 r of the reflection member 31 and enters the side incidence end face 30 ea of the light guide diffusion plate 30. The reflecting member 31 is a plate-like member having a thickness in the X-axis direction and disposed outside the side incident end face 30ea of the light guide diffuser plate 30. The reflection curved surface 31 r of the reflection member 31 is disposed so as to face the emission end surface 16 e of the light guide member 16. The reflection curved surface 31r guides the light beam emitted from the light emitting end surface 16e of the light guide member 16 to the side incident end surface 30ea of the light guide diffusion plate 30, and changes the traveling direction of the light beam from the −X axis direction to the + X axis direction. It has a function. If it has this function, the shape of the reflection curved surface 31r of the reflection member 31 is not limited to the shape of FIG.

  Light beams are incident on the side incident end face 30ea of the light guide diffuser plate 30 from the blue-green LED light sources 20,..., 20 and the reflection curved surface 31r of the reflection member 31, respectively. The light guide diffuser plate 30 converts the light beam incident inside from the side incident end face 30ea into illumination light DL,..., DL that travels in the thickness direction (+ Z-axis direction). These illumination lights DL,..., DL are radiated from the front surface (light emitting surface) 30f of the light guide diffusion plate 30 as planar uniform light.

  As shown in FIG. 16, a plurality of blue-green LED light sources 20,..., 20 are arranged at positions facing the side incident end face 30ea of the light guide diffuser plate 30, and these blue-green LED light sources 20,. They are arranged at equal intervals along the Y-axis direction. These blue-green LED light sources 20,..., 20 emit light beams toward the side incident end face 30 ea of the light guide diffusion plate 30. As the blue-green LED light source 20 of the present embodiment, the same one as the blue-green LED light source 20 of the first embodiment may be used. As in the case of the second embodiment, each blue-green LED light source 20 emits blue-green light having a wide divergence angle. Therefore, the light emitted from the blue-green LED light sources 20,. ,..., 20 overlap each other in the arrangement direction to form linear light.

  As shown in FIGS. 15 and 16, the light guide diffuser plate 30 includes a front surface 30 f, a side incident end surface 30 ea, and a side end surface (light beam) arranged in parallel to the display surface 11 f of the liquid crystal display element 11. This is a plate-like transparent member having a (reflective surface) 30eb and a back surface structure on which fine optical elements 30d, ..., 30d are formed. Each of the micro optical elements 30d,..., 30d has a convex shape protruding toward the back surface side (−Z axis direction).

  The light beam that has entered the light guide diffuser plate 30 from the side incident end face 30ea of the light guide diffuser plate 30 travels in the + X-axis direction while being totally reflected at the interface between the light guide diffuser plate 30 and the air layer. The fine optical elements 30d,..., 30d have a function of converting the light beam reaching the back surface of the light guide diffuser plate 30 into the illumination light DL by totally reflecting the inner surface in the direction of the front surface 30f. That is, the light flux totally reflected by the micro optical elements 30d, ..., 30d does not satisfy the total reflection condition between the front surface 30f of the light guide diffuser plate 30 and the air layer, and the liquid crystal display element from the front surface 30f. There is a light beam emitted in the direction of 11. The emitted light beam constitutes the illumination light DL.

  As a constituent material of such a light guide diffuser plate 30, for example, an optical material such as a glass material or a translucent resin material is used. When an acrylic resin is used, a plate-shaped light guide diffusion plate 30 having a thickness of about 4 mm can be produced. Examples of the light-transmitting resin material include acrylic resin (PMMA) and polycarbonate resin, but are not limited to these, and a light-transmitting resin material having high light transmittance and excellent moldability is used. do it. In order to reduce the thickness and weight of the liquid crystal display device 1C, the thickness of the light guide diffusion plate 30 should be reduced in consideration of the functions and rigidity (mechanical strength) required for the light guide diffusion plate 30. Is desirable.

  The arrangement density of the micro optical elements 30d,..., 30d (the number or size of the micro optical elements 30d per unit area) increases as the distance from the side incident end face 30ea increases, and decreases toward the side incident end face 30ea. In other words, the fine optical elements 30d, ..., 30d become denser as they move away from the side incident end face 30ea and become sparser as they approach the side incident end face 30ea. The reason for this is to make the in-plane luminance distribution of the illumination light DL uniform. By changing the arrangement density of the micro optical elements 30d,..., 30d, the in-plane luminance distribution of the illumination light DL can be controlled.

  FIG. 17 is a schematic cross-sectional view showing an example of the micro optical element 30d. The micro optical element 30d in FIG. 17 has a convex lens shape. The shape of the micro optical element 30d is a part of a spherical shape, and its surface has a certain curvature. For example, when the light guide diffuser plate 30 is manufactured using an acrylic resin having a refractive index of about 1.49, the surface curvature is about 0.15 mm and the maximum height Emax is about 0.005 mm. The micro optical element 30d can be molded.

  The back surface structure of the light guide diffusion plate 30 is not limited to the structure shown in FIG. In place of the structure shown in FIG. 16, similarly to the back surface structure of FIG. 7, the dimension of the micro optical element may be increased as it is farther from the side incident end surface, and may be decreased as it is closer to the side incident end surface. Thereby, the in-plane luminance distribution of the illumination light DL can be made uniform. Moreover, you may employ | adopt the micro optical element which has another convex shape or a concave shape, and the micro optical element which has a cross-sectional prism shape. Furthermore, the micro optical element does not necessarily have to be formed at regular positions, and may be formed at random positions.

  White illumination light DL radiated from the front surface 30 f of the light guide diffusion plate 30 enters the liquid crystal display element 11 through the optical sheets 13 and 12. The illumination light DL radiated in the direction of the liquid crystal display element 11 includes light that is reflected by the optical sheets 12 and 13 and travels in the −Z-axis direction. The light is reflected in the direction of the liquid crystal display element 11 (+ Z axis direction). For this reason, the loss of the illumination light DL can be suppressed, and the illumination light DL can be used efficiently.

  Next, effects and advantages of the backlight unit 10C and the liquid crystal display device 1C according to Embodiment 3 described above will be described.

  In the backlight unit 10C of the third embodiment, the laser light sources 18R,..., 18R are arranged along the extending direction of the end surface 30ec on the bottom surface side of the light guide diffusion plate 30, as shown in FIG. The light beams emitted from the laser light sources 18R,..., 18R are guided by the light guide member 16 and the reflection member 31 and are incident on the side incident end face 30ea. When such a backlight unit 10C is used in a state where the side incident end face 30ea is upright (normal apparatus use state), the laser light sources 18R,. Therefore, it is possible to reduce the ambient temperature difference between the laser light sources 18R,..., 18R, and to suppress variations in light emission efficiency and light emission color (light emission wavelength).

  Moreover, since the red laser light sources 18R,..., 18R are arranged below the gravitational direction as in the case of the second embodiment, an increase in the ambient temperature of the red laser light sources 18R,. Accordingly, it is possible to suppress a decrease in light emission efficiency having temperature dependence of the red laser light sources 18R,..., 18R, and to extend the lifetime of the red laser light sources 18R,. Therefore, the backlight unit 10C of the present embodiment can provide uniform planar light with no unevenness in brightness and emission color as the illumination light DL. Further, it is possible to improve the image quality of the liquid crystal display device 1C.

  Further, since the backlight unit 10C of the present embodiment uses a single light guide diffuser plate 30, the backlight unit 10C is thinner and lighter than the backlight unit 10B of the second embodiment. Can be realized. Therefore, the liquid crystal display device 1C can be reduced in thickness and weight.

  Further, two types of light sources of red laser light sources 18R,..., 18R and blue-green LED light sources 20,. Thereby, the rise in ambient temperature due to the heat generated by these two types of light sources can be mitigated. Therefore, it is possible to suppress a decrease in light emission efficiency due to an increase in ambient temperature, and it is possible to extend the lifetime of each of the red laser light source 18R and the blue-green LED light source 20.

  Further, since the red laser light sources 18R,..., 18R are arranged along a direction (X-axis direction) substantially perpendicular to the thickness direction (Z-axis direction) of the light guide diffuser plate 30, the backlight unit 10B. Can be easily reduced in thickness. In particular, red laser light sources 18R,..., 18R are arranged along the longitudinal direction of the light guide diffuser plate 30, and the longitudinal direction of the light guide diffuser plate 30 coincides with the horizontal pixel direction of the liquid crystal display element 11, so that red The arrangement of the laser light sources 18R,..., 18R below the gravitational direction can be compatible with the thinning of the liquid crystal display device 1C.

  Further, as in the case of the second embodiment, the red color light purity can be improved by using the red laser light sources 18R,..., 18R as compared with the case of using a fluorescent lamp or a white LED light source. In addition, the improvement in red color purity enables the liquid crystal display device 1C to reduce light loss due to the color filter. Furthermore, compared with the case where an LED light source is used, there is an advantage that the electric / light conversion efficiency is high and the optical coupling efficiency between the red laser light sources 18R,. Therefore, the liquid crystal display device 1C of the present embodiment can realize a high color and a wide color gamut simultaneously with low power consumption. Further, as in the case of the second embodiment, green color purity can be improved as compared with a backlight unit using a white LED light source or a red single color LED light source.

  Further, as described above, conventionally, when a laser light source is employed in an edge light type backlight unit, uneven luminance in the surface of the display surface of the liquid crystal display panel has been a problem. Since the backlight unit 10C employs the light guide member 16, the light beams having high directivity emitted from the laser light sources arranged close to each other among the red laser light sources 18R,. Thus, a sufficient optical distance for spatially overlapping each other can be secured. Therefore, the backlight unit 10C of the present embodiment can generate illumination lights DL,..., DL having a uniform in-plane distribution of luminance and emission color. Therefore, it is possible to suppress a decrease in the in-plane uniformity of luminance and emission color on the display surface 11f of the liquid crystal display element 11.

  The controller 21 of the present embodiment reduces the luminance of the red laser light sources 18R,..., 18R and the blue-green LED light sources 20,..., 20 so as to reduce the power consumption of the liquid crystal display device 1C according to the video signal. It is possible to optimize the ratio with luminance. Furthermore, the control unit 21 can reduce stray light unnecessary for generating image light by individually controlling the light emission amount of the red laser group 18RG and the light emission amount of the blue-green LED group 20G. Thereby, the contrast of a display image can be improved.

Modifications of the first to third embodiments.
Although various embodiments according to the present invention have been described above with reference to the drawings, these are examples of the present invention, and various forms other than the above can be adopted. For example, the backlight units 10A, 10B, and 10C are preferably applied to a liquid crystal display device, but are not limited thereto. The backlight units 10A, 10B, and 10C can be applied to indoor lighting devices and outdoor street lamps.

  In the first and second embodiments, the light guide member 16 and the reflection member 17 are separate optical members independent of each other. However, the present invention is not limited to this, and the light guide member 16 and the reflection member 17 are not limited thereto. And may be integrally formed. Similarly, in the third embodiment, the light guide member 16 and the reflection member 31 may be integrally formed.

In the _first to third embodiments, the laser light sources 18 ₁ to 18 _N and 18R are disposed below the gravitational direction in a normal apparatus use state, but are not limited thereto. There may be a form in which the laser light sources 18 ₁ to 18 _N and 18R are arranged above the direction of gravity in a normal apparatus use state. However, from the viewpoint of suppressing an increase in the ambient temperature of the laser light sources 18 ₁ to 18 _N and 18R and suppressing a decrease in light emission efficiency thereof, the laser light sources 18 ₁ to 18 _N and 18R are more than arranged above. It is preferable to arrange it below.

  In the first to third embodiments, terms indicating the positional relationship between components or the shape of the components such as “parallel” and “vertical” may be used. In some cases, expressions using the term “almost” such as “substantially triangular” or “substantially parallel” are used. These represent that a range that takes into account manufacturing tolerances and assembly variations is included. For this reason, even if a term that does not have "substantially" is described in the claims, the term includes a range that takes into account manufacturing tolerances, assembly variations, and the like.

1A, 1B, 1C liquid crystal display device, 10A, 10B, 10C backlight unit, 11 liquid crystal display element (spatial light modulation element), 12 first optical sheet, 12p prismatic convex part, 13 second optical sheet 14, 14M light guide diffuser plate, 14ea side incident end face, 14eb side end face, 14ec bottom face side end face, 14d, 14Md micro optical element, 15 light reflecting sheet, 16 light guiding member, 17 reflecting member, 18 ₁ to 18 _N laser light source, 18R red laser light source, 18G green laser light source, 18B blue laser light source, WL white light, RL red light, 19 auxiliary light guide diffuser plate, 19d fine optical element, 20 blue green LED light source (auxiliary light source), 21 Control part, 22 liquid crystal display element drive part, 23A, 23B, 23C light source drive part, 30 light guide diffuser plate, 30ea side Itanmen, 30Ec bottom end face, 30d microscopic optical element 31 reflecting member.

Claims (21)

Multiple light sources;
A light guide reflection member for guiding a plurality of light beams incident from the plurality of light sources;
A light guide plate having a first end surface on which a plurality of light beams guided by the light guide reflection member are incident, and converting the plurality of light beams incident on the inside from the first end surface into a planar light beam; With
The light guide plate is
A light emitting surface that emits the planar luminous flux;
A second end surface formed on one end side of the first end surface in the extending direction and extending in a direction intersecting the first end surface;
The illuminating device, wherein the plurality of light sources are arranged on the second end face side and arranged along an extending direction of the second end face.   2. The illumination device according to claim 1, wherein the light guide reflection member reflects the plurality of light beams incident from the plurality of light sources and approaches a traveling direction of the plurality of light beams to the first end surface. A lighting device having a first reflecting surface that changes direction. The lighting device according to claim 2,
The light guide reflection member has a second reflection surface arranged outside the first end surface,
The lighting device according to claim 2, wherein the second reflecting surface reflects a plurality of light beams incident from the first reflecting surface and enters the first end surface. The lighting device according to claim 3,
The light guide plate has a back surface facing the light emitting surface,
The light guide reflection member is
A light guide member disposed on the back side and having the first reflective surface;
A lighting device comprising: a reflecting member having the second reflecting surface.   5. The lighting device according to claim 4, wherein the light guide member is opposed to each other in a thickness direction of the light guide plate, and internally reflects the plurality of light beams incident on the inside from the plurality of light sources. An illumination device having a reflective surface. It is an illuminating device of any one of Claims 1-5, Comprising:
The light emitting surface of the light guide plate has a rectangular shape,
The lighting device, wherein the plurality of light sources are arranged along a longitudinal direction of the light emitting surface.   7. The illumination device according to claim 4, wherein the plurality of light sources are arranged along a direction perpendicular to a thickness direction of the light guide plate. Lighting device.   8. The illumination device according to claim 1, wherein the light guide reflection member spatially overlaps the plurality of light beams incident inside from the plurality of light sources. An illuminating device having an optical distance of   9. The illuminating device according to claim 8, wherein the plurality of light sources include a red laser light source, a green laser light source, and a blue laser light source that emit light beams in wavelength regions of three primary colors. The illumination device according to any one of claims 1 to 8,
An auxiliary light source;
An auxiliary light guide plate having an incident end face on which a light beam propagated from the auxiliary light source is incident, and transmitting the planar light beam;
The auxiliary light guide plate converts a light beam incident inside from an incident end face of the auxiliary light guide plate into a planar auxiliary light beam, and radiates the planar auxiliary light beam mixed with the planar light beam. A lighting device. The illumination device according to any one of claims 1 to 8,
An auxiliary light source,
The illumination device according to claim 1, wherein a light beam propagated from the auxiliary light source is incident on the first end face of the light guide plate.   12. The illuminating device according to claim 10, wherein the plurality of light sources are composed of a plurality of laser light sources that emit light beams having a wavelength region of the same color.   13. The illumination device according to claim 12, wherein the laser light source is a red laser light source that emits a light beam in a red wavelength region.   14. The lighting device according to claim 10, wherein a light emission color of the auxiliary light source is different from a light emission color of the plurality of light sources.   15. The lighting device according to claim 14, wherein the auxiliary light source is a light emitting diode light source. The lighting device according to any one of claims 1 to 15,
The light guide plate has a back surface structure in which a plurality of micro optical elements are formed,
The illuminating device, wherein the plurality of micro optical elements generate the planar light beam by totally reflecting the light beam incident from the first end surface into the light guide plate. The lighting device according to any one of claims 1 to 16,
A spatial light modulation element that generates image light by spatially modulating the intensity of the planar light beam emitted from the illumination device, wherein the illumination device is a backlight unit;
An image display device comprising: a control unit that controls the operation of the spatial light modulator in accordance with a video signal.   18. The image display device according to claim 17, wherein the plurality of light sources are arranged on one end side in the vertical pixel direction of the display surface of the spatial light modulator.   19. The image display device according to claim 18, wherein the plurality of light sources are arranged along a horizontal pixel direction of the display surface.   20. The image display device according to claim 19, wherein one end side in the vertical pixel direction of the display surface is a lower end side in the vertical pixel direction.   21. The image display device according to claim 17, wherein the spatial light modulation element is a liquid crystal display element.

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