JP5669210B2 - Display device - Google Patents

Description

  The present invention relates to a display device that performs full-color display by focusing color light of a corresponding color on a picture element obtained by color-coding pixels of a transmissive display panel (image modulation element), and more particularly to a transmissive display device. Is.

  In recent years, a liquid crystal display device including a transmissive liquid crystal display panel has been generalized as a transmissive display device capable of performing full color display. The pixel is divided into three picture elements, and red (R), green (G), and blue (B) color filters are pasted on these three picture elements, respectively, and white light is emitted from the backlight to the white picture elements. Full-color display is realized by controlling the transmittance when light passes through the picture element for each picture element by a voltage signal applied to the liquid crystal layer.

  However, since the color filter transmits light in the wavelength band corresponding to each color of RGB and absorbs other light, in a liquid crystal display device using such a color filter, about 2 of light from the backlight. / 3 is a light absorption loss, and there is a problem that the light utilization efficiency is very poor.

  As a method for improving such a problem, a microlens array (hereinafter abbreviated as MLA) is bonded to the backlight side of the liquid crystal display panel, and a light source for each RGB is used as a light source disposed immediately below the liquid crystal display panel. There is a method in which pixels are color-separated with colored light from a light source using a light emitter to form RGB-specific picture elements.

  However, in such a system, although the light utilization efficiency can be improved, the size of the light source is reduced to the pixel size by the MLA and is condensed on the liquid crystal display panel. Problems arise when the thickness of the panel increases.

  Therefore, Patent Document 1 proposes a method in which each of the RGB light sources is disposed not at the bottom of the liquid crystal display panel but at the end of the light guide to reduce the thickness of the backlight.

  FIG. 15 is a diagram showing a schematic configuration of a conventional liquid crystal display device described in Patent Document 1. In FIG.

  As illustrated, the transmissive liquid crystal display device 116 includes a liquid crystal display panel unit and a backlight unit.

  The backlight unit includes light transmissive light guide plates 101, 102, and 103 and light sources 104, 105, and 106, and the light source 104 that emits red light is incident on the first light transmissive light guide plate 101. The light source 105 that makes red light incident on the surface and emits green light enters the light from the incident surface of the second light-transmissive light guide plate 102 and emits blue light. The light source 106 allows blue light to enter from the incident surface of the third light-transmissive light guide plate 103.

  The light incident on the light transmissive light guide plates 101, 102, and 103 from the light sources 104, 105, and 106 is parallel light, and is incident on the light incident surfaces of the light transmissive light guide plates 101, 102, and 103. The light enters perpendicularly and travels in a direction parallel to the main surface portion of each light-transmissive light guide plate 101, 102, 103.

  Then, each light transmissive light guide plate 101, 102, 103 has a plurality of reflecting surfaces 107, which change the traveling direction of light traveling inside each light transmissive light guide plate 101, 102, 103 and emit the light to the front side. 108 and 109 are provided.

  The reflective surfaces 107, 108, and 109 are formed by inclining predetermined portions of the rear portions of the light transmissive light guide plates 101, 102, and 103, and the light transmissive light guide plates 101, 102, and 103 are reflected by internal reflection. The traveling direction of the light traveling inside is changed.

  On the other hand, in the liquid crystal display panel unit, red light emitted from the first light-transmissive light guide plate 101 is incident on the MLA 114, the polarizing filter 111, the glass substrate 112, and the pixel electrode 113R corresponding to red, and the second Green light emitted from the light transmissive light guide plate 102 is incident on the MLA 114, the polarizing filter 111, the glass substrate 112, and the pixel electrode 113G corresponding to green, and emitted from the third light transmissive light guide plate 103. Blue light is incident on the MLA 114, the polarizing filter 111, the glass substrate 112, and the pixel electrode 113B corresponding to blue.

  According to such a liquid crystal display device 116, it is described in Patent Document 1 that the backlight portion can be thinned.

JP 2008-243386 (released October 9, 2008) WO2010 / 061699 (released on June 3, 2010) WO2011 / 024530 (released March 3, 2011) JP 2008-258076 A (released on October 23, 2008)

  According to the liquid crystal display device 116 described in Patent Document 1, a comparison is made with a configuration in which MLA is bonded to the backlight side of the liquid crystal display panel, and RGB light emitters are disposed immediately below the liquid crystal display panel. Then, it is possible to reduce the thickness of the backlight portion. However, as shown in FIG. 15, the light transmissive light guide plates 101, 102, and 103 are laminated in three layers, so that the backlight portion is thin. It cannot be realized to the extent that it is satisfactory.

  Further, as shown in FIG. 15, the positions of the plurality of reflecting surfaces 107, 108, and 109 provided in the light transmissive light guide plates 101, 102, and 103 are different. The light emitted from each of the light sources 104, 105, and 106 is transmitted to the MLA 114 between the light reflected on the front side (left side in the figure) of 102 and 103 and the light reflected on the tip side (right side in the figure). The distance to the incident is greatly different.

  In this way, when the distance from the light source to the MLA is different, the condensing pitch and the imaging position change. Therefore, it is possible to separate and focus the light on the picture elements of the same size provided in the liquid crystal display panel at all locations. It becomes difficult.

  In such a case, color light other than the color light corresponding to the picture element is mixed, resulting in color unevenness of the display image, leading to a deterioration in the image quality of the display image.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a display device that maintains high light utilization efficiency and has a thin thickness and a high display image quality.

  In order to solve the above problems, the display device of the present invention has a display panel in which pixels composed of a plurality of picture elements are provided in a matrix and a plurality of points having peak values of light emission amounts in different wavelength regions. A display device comprising: a light source; and an illumination optical system that guides light emitted from the plurality of point light sources and irradiates the light from an opposite surface side of the display surface of the display panel. The light source is formed along the light incident position of the illumination optical system, and a pixel provided in the display panel is disposed between the illumination optical system and the surface opposite to the display surface of the display panel. A plurality of imaging optical lenses are provided corresponding to the pitch, and the illumination optical system has a plurality of inclined surfaces for deflecting the light emitted from the point light source in the direction of the display panel. From the plurality of point light sources Each of the emitted light in different wavelength regions is guided to a different picture element in each pixel of the display panel via the inclined surface and the imaging optical lens, and from one of the point light sources. The plurality of inclined surfaces and the point-like shapes so that the shortest distance between each of the plurality of inclined surfaces and the imaging optical lens located immediately above each of the inclined surfaces is within a predetermined range. The light source is provided at a predetermined interval.

  According to the above configuration, each shortest distance from one of the point light sources through each of the plurality of inclined surfaces to the imaging optical lens located immediately above each of the inclined surfaces is Each of light in different wavelength regions incident from a plurality of point light sources is guided to different picture elements in each pixel of the display panel via the inclined surface and the imaging optical lens, and within a predetermined range. The plurality of inclined surfaces and the point light source are provided at predetermined intervals so that

  Therefore, since color light other than color light corresponding to the picture elements provided in the display panel is not mixed, color unevenness of the display image can be suppressed, and a display device with high display image quality can be realized. Can do.

  Further, according to the above configuration, the plurality of point light sources are formed along the light incident position of the illumination optical system, and each light from the plurality of point light sources is the inclined surface and the image forming unit. A thin display device can be realized because it is guided to different picture elements in each pixel of the display panel via the optical lens.

  In the illumination optical system of the display device of the present invention, the light emitted from the point light source is guided to the opposite surface side of the display surface side of the display panel by reflection or total reflection, and each pixel has the same wavelength region. The imaging optical lens for condensing light in a region including the center of the picture element to which light is guided is provided, and is arranged in the center of the region where the plurality of inclined surfaces are formed from one of the point light sources. The shortest distance a from the imaging optical lens to the pixel of the display panel via the reference inclined surface, the shortest distance a from the imaging optical lens to the pixel of the display panel, and the connection. The focal length f of the image optical lens satisfies the relationship of 1 / a + 1 / b = 1 / f, and the number of picture elements provided in each pixel is M, and for one imaging optical lens. , Emitted from one or more of the above point light sources The one or more point light sources are horizontally moved to a region immediately below the one imaging optical lens, and the horizontal including the perpendicular passing through the center of the imaging optical lens is included. Dividing the surface formed along the moving direction into a reference, and counting the number, when the number of point light sources that are equal or larger is X, the point light source from one of the point light sources to the plurality of The shortest distance L between each of the inclined surfaces and the imaging optical lens positioned immediately above each of the inclined surfaces is {2 × X × M / (2 × X × M + 1)} × a <. It is preferable that the relationship of L <{2 × X × M / (2 × X × M−1)} × a is satisfied.

  In the illumination optical system of the display device of the present invention, the light emitted from the point light source is guided to the opposite surface side of the display surface side of the display panel by reflection or total reflection, and each pixel has the same wavelength region. The imaging optical lens for condensing light in a region including the center of the picture element to which light is guided is provided, and is arranged in the center of the region where the plurality of inclined surfaces are formed from one of the point light sources. The shortest distance a from the imaging optical lens to the pixel of the display panel via the reference inclined surface, the shortest distance a from the imaging optical lens to the pixel of the display panel, and the connection. The focal length f of the image optical lens satisfies the relationship 1 / a + 1 / b = 1 / f, and the number of picture elements provided in each pixel is M, and for one imaging optical lens, The light emitted from less than two point light sources When the light is projected, each shortest distance L from one of the point light sources through each of the plurality of inclined surfaces to the imaging optical lens positioned immediately above each of the inclined surfaces is { 2M / (2M + 1)} × a <L <{2M / (2M−1)} × a is preferably satisfied.

  According to the above configuration, the imaging optical lens passes through the reference inclined surface disposed in the center of the region where the plurality of inclined surfaces are formed from one of the point light sources, and the reference inclined surface. Even when it is designed based on the shortest distance a to the imaging optical lens located directly above, color light other than color light corresponding to the picture element provided in the display panel does not mix, Color unevenness of the display image can be suppressed, and a display device with high display image quality can be realized.

  In the illumination optical system of the display device of the present invention, the light emitted from the point light source is guided to the opposite surface side of the display surface side of the display panel by reflection or total reflection, and each pixel has the same wavelength region. The imaging optical lens for condensing light in a region including the center of a picture element through which light is guided is provided, and an inclined surface closest to one of the point light sources is a reference inclined surface, and the reference inclined surface is Via, the shortest distance a to the imaging optical lens located immediately above the reference inclined surface, the shortest distance b from the imaging optical lens to the pixel of the display panel, and the focal length of the imaging optical lens f satisfies the relationship of 1 / a + 1 / b = 1 / f, and the number of picture elements provided in each pixel is M, and one or more of the above-described imaging optical lenses is used. When light emitted from a point light source is incident The one or more point light sources are horizontally moved to a region immediately below the one imaging optical lens and formed along the horizontal movement direction including a perpendicular passing through the center of the imaging optical lens. If the number of equal or larger number of point light sources is X, the number of the surface is divided into a reference, and if the number of equal or larger point light sources is X, then one of the point light sources passes through each of the plurality of inclined surfaces. Each shortest distance L to the imaging optical lens located immediately above each inclined surface is a ≦ L <{(2 × X × M) / (2 × X × M−1)} ×. It is preferable that the relationship a is satisfied.

  According to the above configuration, the imaging optical lens has the inclined surface closest to one of the point light sources as a reference inclined surface, passes through the reference inclined surface, and is positioned immediately above the reference inclined surface. Even when designed based on the shortest distance a to the imaging optical lens, color light other than the color light corresponding to the picture element provided in the display panel does not mix, so color unevenness of the display image is prevented. It is possible to realize a display device that can be suppressed and display image quality is high.

  In the illumination optical system of the display device of the present invention, the light emitted from the point light source is guided to the opposite surface side of the display surface side of the display panel by reflection or total reflection, and each pixel has the same wavelength region. The imaging optical lens for condensing light in a region including the center of a picture element through which light is guided is provided, and an inclined surface farthest from one of the point light sources is a reference inclined surface, and the reference inclined surface is Via, the shortest distance a to the imaging optical lens located immediately above the reference inclined surface, the shortest distance b from the imaging optical lens to the pixel of the display panel, and the focal length of the imaging optical lens f satisfies the relationship of 1 / a + 1 / b = 1 / f, and the number of picture elements provided in each pixel is M, and one or more of the above-described imaging optical lenses is used. When light emitted from a point light source is incident The one or more point light sources are horizontally moved to a region immediately below the one imaging optical lens and formed along the horizontal movement direction including a perpendicular passing through the center of the imaging optical lens. If the number of equal or larger number of point light sources is X, the number of the surface is divided into a reference, and if the number of equal or larger point light sources is X, then one of the point light sources passes through each of the plurality of inclined surfaces. Each shortest distance L to the imaging optical lens located immediately above each inclined surface is {(2 × X × M) / (2 × X × M + 1)} × a <L ≦ a. It is preferable that the relationship is satisfied.

  According to the above configuration, the imaging optical lens has the inclined surface furthest from one of the point light sources as a reference inclined surface, passes through the reference inclined surface, and is located immediately above the reference inclined surface. Even when designed based on the shortest distance a to the imaging optical lens, color light other than the color light corresponding to the picture element provided in the display panel does not mix, so color unevenness of the display image is prevented. It is possible to realize a display device that can be suppressed and display image quality is high.

  In the display device of the present invention, the illumination optical system includes an incident surface on which light emitted from the point light source is incident, a running region that guides the light incident from the incident surface to an extraction region that extracts the light to the outside, and It is preferable that it is a light guide plate provided with the said extraction area | region provided with the some inclined surface.

  According to the above configuration, since the light guide plate is used as the illumination optical system, the illumination optical system can be designed relatively easily.

  In the light guide plate of the display device of the present invention, it is preferable that the extraction region is formed such that the thickness thereof decreases stepwise as the distance from the incident surface increases.

  According to the said structure, light can be efficiently taken out from the said light-guide plate.

  In the light guide plate of the display device of the present invention, the run-up area and the take-out area are provided so as to overlap in a plan view, and the run-up area and the take-out area are connected portions including a bent reflection surface. It is preferable that it is connected by.

  According to the above configuration, since the run-up area can be secured for a relatively long time, it is possible to realize a good light collection state by the picture elements provided in the display panel.

  The said light guide plate of the display apparatus of this invention consists of two or more, and two adjacent light guide plates are arrange | positioned so that the taking-out area | region of one light guide plate may run on the run area of the other light guide plate. preferable.

  According to the said structure, the said illumination optical system can be enlarged comparatively easily.

  The illumination optical system in the display device of the present invention is provided so that a plurality of substrates whose mirror surfaces are both partially overlapped in plan view, and a region where two adjacent substrates overlap in the plurality of substrates is , A run-out region that guides the light emitted from the point light source to a take-out region for taking out to the outside, and in the plurality of substrates, the region where two adjacent substrates do not overlap is on the region that does not overlap, It is preferable that a prism sheet provided with a triangular prism including the plurality of inclined surfaces is provided and is the extraction region.

  According to the above configuration, since a refractive index medium (such as a light guide plate) is not used, the display device can be significantly reduced in weight. In addition, since most of the light emitted from the point light source travels through the air layer, the optical distance from the point light source to the imaging optical lens is determined when a refractive index medium is used. As a result, the optical change ratio as a whole can be reduced.

  In the illumination optical system in the display device of the present invention, it is preferable that a layer in which a plurality of lenticular lenses are formed is disposed between the prism sheet and the plurality of imaging optical lenses.

  According to the above configuration, local luminance unevenness in the prism sheet can be eliminated.

  In the illumination optical system of the display device according to the present invention, an incident surface for allowing light emitted from the point light source to enter an area where two adjacent substrates do not overlap among the plurality of substrates, and the incident surface. It is preferable that a light guide plate for adjusting an optical path provided with an emission surface formed such that the thickness thereof decreases as the distance from the light source increases.

  According to the above configuration, by inserting the optical path adjusting light guide plate, the difference in optical distance from the virtual image positions of the plurality of point light sources generated on the prism sheet to the imaging optical lens is relatively determined. The shortest distance from one of the point light sources to each of the imaging optical lenses via each of the inclined surfaces of the triangular prism can be relatively easily within the predetermined range. can do.

  The illumination optical system in the display device of the present invention reflects the light of different wavelength regions emitted from the plurality of point light sources, and includes the plurality of inclined surfaces provided on the prism sheet. A reflector having a plurality of mirror surfaces to be led in steps, and the prism sheet provided with the triangular prism. In the reflector, each of the point light sources It is preferable that the optical path lengths until the light is emitted, reflected by each of the mirror surfaces, and guided to the prism sheet are substantially equal.

  According to the above configuration, the distance from each virtual image point of the light reflected by each mirror surface of the reflector to the imaging optical lens is approximately equal by the reflector, and the point light source is provided. Each shortest distance from one to the imaging optical lens can be relatively easily within the predetermined range.

  In the illumination optical system in the display device of the present invention, it is preferable that a layer in which a plurality of lenticular lenses are formed is disposed between the prism sheet and the plurality of imaging optical lenses.

  According to the above configuration, local luminance unevenness in the prism sheet can be eliminated.

  The display panel in the display device of the present invention may be a liquid crystal display panel including a liquid crystal layer.

  According to the above configuration, it is possible to realize a display device including a liquid crystal display panel having a thin thickness and a high display image quality.

  As described above, in the display device of the present invention, the plurality of point light sources are formed along the light incident position of the illumination optical system, and are opposite to the display surface side of the illumination optical system and the display panel. Between the surface side, a plurality of imaging optical lenses are provided corresponding to the pitch of the pixels provided in the display panel, and the illumination optical system includes light emitted from the point light source. Are provided with a plurality of inclined surfaces for deflecting the light in the direction of the display panel, and light of different wavelength regions incident from the plurality of point-like light sources is provided on the inclined surface and the imaging optical lens. Through each of the plurality of inclined surfaces from one of the point light sources through the plurality of inclined surfaces, and directly above each of the inclined surfaces. Each shortest to imaging optical lens Away is a configuration in which the plurality of inclined surfaces and the point light source to be within a predetermined range is provided at a predetermined interval.

  Therefore, it is possible to realize a display device that maintains high light utilization efficiency and has a thin thickness and high display image quality.

It is a figure which shows schematic structure of the liquid crystal display device of one embodiment of this invention. It is a figure which shows the shortest distance from the virtual image point corresponding to each inclined surface for light extraction with which the liquid crystal display device of one embodiment of this invention was provided to MLA. It is the schematic which shows the change of the light ray which passes the inside of the pixel of a liquid crystal layer when the shortest distance from a light source to MLA changes. It is a figure for demonstrating the change of the space | interval (imaging pitch) of the imaging position when the shortest distance from a light source to MLA changes. It is a figure which shows schematic structure of the liquid crystal display device of other one Embodiment of this invention, and the shortest distance from the virtual image point corresponding to each inclined surface for light extraction with which this liquid crystal display device was equipped to MLA. It is a figure which shows schematic structure of the liquid crystal display device of other one Embodiment of this invention provided with the light-guide plate of another shape. It is a figure which shows schematic structure of the liquid crystal display device of further another embodiment of this invention provided with the backlight which consists of a some light-guide plate. It is a figure which shows schematic structure of the liquid crystal display device of further another embodiment of this invention provided with the backlight which has a light guide member and a prism sheet if it consists of several board | substrates in which both surfaces are mirror surfaces. It is a figure which shows the optical effect | action in the prism sheet with which the liquid crystal display device of further another embodiment of this invention was equipped. It is a figure which shows schematic structure of the liquid crystal display device of further another embodiment of this invention provided with the backlight which has a light-guide member, a prism sheet, and a lenticular lens if it consists of a several board | substrate with which both surfaces are mirror surfaces. . It is a figure which shows schematic structure of the liquid crystal display device of further another embodiment of this invention by which the light-guide plate for optical path adjustments was added to the structure shown in FIG. It is a figure which shows schematic structure of the liquid crystal display device of further another embodiment of this invention by which the light-guide plate for optical path adjustment was added to the structure shown in FIG. Still another aspect of the present invention includes a backlight having a reflector in which a plurality of mirror surfaces for reflecting each of light in different wavelength regions emitted from a light source and guiding the light to a prism sheet are formed in a step shape. It is a figure which shows schematic structure of the liquid crystal display device of embodiment. FIG. 14 is a diagram illustrating a schematic configuration of a liquid crystal display device according to still another embodiment of the present invention in which the configuration illustrated in FIG. 13 is further provided with a lenticular lens, and an optical action in this configuration. It is a figure which shows schematic structure of the conventional liquid crystal display device described in patent document 1. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the component parts described in this embodiment are merely one embodiment, and the scope of the present invention should not be construed as being limited thereto.

  In each of the following embodiments, a transmissive liquid crystal display device that performs full-color display by condensing color light of the corresponding color from the back of the pixel of the transmissive liquid crystal display panel that is color-coded is taken as an example. However, the present invention is not limited to this, and the present invention includes an image modulation element that displays an image by changing the light transmittance, and the back surface of the pixel of the image modulation element is color-coded. The display device is applicable to any display device that collects the color light of the corresponding color and performs full color display.

[Embodiment 1]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a diagram showing a schematic configuration of a liquid crystal display device 1 according to an embodiment of the present invention.

  As shown in the figure, the liquid crystal display device 1 includes a backlight 2 as a lighting device and a liquid crystal display panel 3 as a transmissive image modulation element.

  The backlight 2 includes a light source 4 and a light guide plate 5.

  The light guide plate 5 has an incident surface 5a for allowing the light emitted from the light source 4 to enter, and a plurality of inclined surfaces 5b for deflecting the light emitted from the light source 4 in the direction of the liquid crystal display panel 3. The light exit surface 5c is provided.

  On the other hand, the liquid crystal display panel 3 includes a counter substrate 6 and an active matrix substrate 7, and a liquid crystal layer 8 is sandwiched between the substrates 6 and 7.

  Since the liquid crystal display device 1 performs full-color display by condensing color light of the corresponding color from the back of the pixels of the liquid crystal display panel 3 that are color-coded, it is not necessary to provide a color filter on the liquid crystal display panel 3.

  In the liquid crystal display panel 3, an imaging optical lens is provided on the surface of the light guide plate 5 facing the emission surface 5 c, that is, on the surface opposite to the surface in contact with the liquid crystal layer 8 in the active matrix substrate 7. A plurality of microlens arrays 9 (hereinafter referred to as MLA) are provided.

  In the present embodiment, the microlens array 9 is formed on the surface of the active matrix substrate 7 opposite to the surface in contact with the liquid crystal layer 8. However, the present invention is not limited to this, and the light exit surface 5c of the light guide plate 5 is used. As long as it is formed on the path of light that is emitted from and incident on the liquid crystal display panel 3.

  In the present embodiment, the microlens array 9 formed of a single layer is used as the imaging optical lens. However, the present invention is not limited to this, and a plurality of lenticular lenses are used in an orthogonal arrangement. Alternatively, a plurality of microlens arrays may be stacked and used.

(Backlight 2)
Hereinafter, the configuration of the backlight 2 will be described in more detail with reference to FIG.

  As shown in the drawing, in the present embodiment, the light source 4 is a light source (red light emitting diode 4R (R-LED) emitting different main wavelengths along the depth direction on the incident surface 5a side of the light guide plate 5. ) · Green light emitting diode 4G (G-LED) · Blue light emitting diode 4B (B-LED)) is used in a repeated arrangement in one row, but is not limited to this. The number of light sources arranged with respect to the light guide plate 5 is one red light emitting diode 4R (R-LED), one green light emitting diode 4G (G-LED), and one blue light emitting diode 4B (B-LED). There may be.

  Also, the color of the light source to be used is not limited to three colors of red, green and blue, and the full color is obtained by condensing the corresponding color light from the back to the picture element in which the pixels of the liquid crystal display panel 3 are color-coded. As long as display can be performed, a light source of another color can be used.

  In the light guide plate 5 used in the present embodiment, as shown in the drawing, the left end surface of the light guide plate 5 is an incident surface 5a on which light emitted from the light source 4 is incident. Is provided with a plurality of inclined surfaces 5b for light extraction on the back side of the light guide plate 5 facing the emission surface 5c so that light can be emitted from the emission surface 5c. ing.

  The light extraction inclined surface 5b is formed in a uniform shape in the depth direction (not shown), and can be formed in a planar or lenticular lens surface shape.

  In the present embodiment, five inclined surfaces 5b for extracting light are formed at a predetermined interval, but the corresponding color light can be condensed from the back of the pixels of the liquid crystal display panel 3 color-coded. If it is, it will not be limited to this.

  As shown in the figure, a distance from the incident surface 5a of the light guide plate 5 to the light extraction inclined surface 5b closest to the incident surface 5a is formed as a running region and a plurality of light extraction inclined surfaces 5b. The area from which the area is taken out and the distance from the exit surface 5c of the light guide plate 5 to the MLA 9 will be referred to as a backlight gap distance.

  As shown in the drawing, when attention is focused on the light extracted from the light extraction inclined surface 5b closest to the incident surface 5a of the light guide plate 5, the light reflected by the light extraction inclined surface 5b is: Since it is deflected almost directly above, a virtual image point exists in the direction directly below MLA 9.

  The same applies to the other inclined surfaces 5b for extracting light that can be provided in the light guide plate 5.

  FIG. 2 is a diagram showing the shortest distance from the virtual image point 4R ′ to the MLA 9 corresponding to each light extraction inclined surface 5b provided in the liquid crystal display device 1. FIG.

  As shown in the figure, the shortest distance from the virtual image point 4R ′ corresponding to the light extraction inclined surface 5b closest to the incident surface 5a of the light guide plate 5 to the MLA 9 is the distance between the running region and the backlight gap distance. Equal to the sum.

  On the other hand, paying attention to the light extracted from the light-extracting inclined surface 5b farthest from the incident surface 5a of the light guide plate 5, the shortest distance from the virtual image point 4R 'to the MLA 9 is the distance of the running region and the backlight gap distance. And the distance of the extraction area.

  From the above, the shortest distances from the virtual image point 4R 'to the MLA 9 of the light emitted from a certain light source 4R and extracted from each inclined surface 5b for light extraction are different from each other.

  In the liquid crystal display panel 3, the influence of the change in the shortest distance from each virtual image point 4R 'to the MLA 9 on the light condensing state on the liquid crystal layer 8 provided in the liquid crystal display panel 3 will be described later.

(Liquid crystal display panel 3)
Hereinafter, the configuration of the liquid crystal display panel 3 will be described in more detail with reference to FIG.

  The MLA 9 provided in the liquid crystal display panel 3 has a light extraction inclined surface 5b (in the direction of the incident surface 5a of the light guide plate 5) whose curvature characteristic and lens pitch correspond to the center of the extraction region shown in FIG. Is designed and arranged so that the light reflected by the third light extraction inclined surface 5b) counted from the above is condensed in the picture element of the liquid crystal layer 8 provided in the liquid crystal display panel 3. ing.

  That is, the third light extraction inclined surface 5b corresponding to the third incident surface 5a of the light guide plate 5 is the reference inclined surface, and is emitted from one light source 4R as shown in FIG. The shortest distance from the virtual image point 4R ′ of the light extracted from the reference inclined surface 5b to the MLA 9 is a.

  Note that the picture element of the liquid crystal layer 8 refers to a region where the light transmittance can be independently controlled in the liquid crystal layer 8.

  Then, the light emitted from the light source 4 enters the light guide plate 5 from the incident surface 5a of the light guide plate 5 and then is reflected by each inclined surface 5b for extracting light while repeating total reflection. Through the liquid crystal display panel 3.

  Then, the light irradiated to the liquid crystal display panel 3 side passes through the MLA 9 corresponding to the pixel pitch of the liquid crystal layer 8 so that the light from the corresponding light sources 4R, 4G, and 4B is applied to each pixel in the pixel. Focused.

  In the present embodiment, it is assumed that one pixel is composed of three picture elements colored in red, green, and blue.

  In a display device that does not include a color filter layer, what is important for performing full color display is that only the colored light corresponding to each picture element passes through each picture element in which the pixels of the liquid crystal display panel 3 are color-coded. That is.

  Then, the amount of transmitted color light passing through each picture element is adjusted by finely adjusting the voltage applied to a predetermined region of the liquid crystal layer 8 provided in the liquid crystal display panel 3, without using a color filter layer. Full color display can be realized.

  However, in reality, due to manufacturing variations, optical components cannot be manufactured as designed, or optical components cannot be assembled, or optical components that are slightly out of design must be manufactured in consideration of manufacturing costs. Due to such problems, it may be difficult to focus only the corresponding light on the sub-pixels forming the pixel array with the liquid crystal layer.

  In such a case, the display quality may be deteriorated depending on circumstances. In order to avoid such a situation, in this embodiment, a color filter layer can be provided as necessary. However, in the case where the color filter layer is provided, in the color filter layer that transmits light of a predetermined wavelength, the transmittance of the light of the predetermined wavelength is also about 90%. From the viewpoint of the light utilization efficiency, it is preferable not to provide them.

  Although not shown in FIG. 1, a diffusing element for expanding viewing angle characteristics may be disposed on the upper surface side of the liquid crystal display panel 3.

  Moreover, in order to suppress the backscattering of the external light which generate | occur | produces in the said diffusion element, you may arrange | position a circularly-polarizing plate above and below the said diffusion element, for example. And the said circularly-polarizing plate is comprised from a linear polarizer and a quarter wavelength plate, but when arrange | positioning the said circularly-polarizing plate on the upper and lower sides of the said diffusion element, it is each 4 minutes in a circularly-polarizing plate. It is preferable to arrange the single wavelength plate on the diffusing element side.

  In addition, the structure which provides the said diffusing element or the said diffusing element, and the said circularly-polarizing plate is applicable not only to this Embodiment but to each embodiment mentioned later, and suppresses backscattering of external light. The method is not limited to the above.

  Hereinafter, based on FIG. 3 and FIG. 4, in the liquid crystal display panel 3, the change in the shortest distance from each virtual image point 4 </ b> R ′ to the MLA 9 changes to the light condensing state on the liquid crystal layer 8 provided in the liquid crystal display panel 3. The effect will be described.

  FIG. 3 is a schematic diagram showing changes in light rays passing through the picture elements of the liquid crystal layer 8 when the shortest distance from the light source 4 to the MLA 9 changes.

  Note that the positions of the virtual image points 4R ′ of the light extracted from the respective light extraction inclined surfaces 5b shown in FIG. 2 correspond to the positions of the light sources 4G shown on the left and right sides of FIG. doing.

  3 shows that the light emitted from the light emitting point 4G ′ corresponding to one light source 4G corresponds to the third light counted from the direction of the incident surface 5a of the light guide plate 5 inside the light guide plate 5. FIG. A state where the light is taken out from the take-out inclined surface 5b (reference inclined surface) and condensed in the picture element of the liquid crystal layer 8 through the MLA 9 is shown. That is, the diagram on the left side of FIG. 3 shows a light condensing state in a case where the light emitting point 4G ′ corresponding to the light source 4G is at a position used as a reference for designing the MLA 9.

  On the other hand, the diagram on the right side of FIG. 3 shows an example in which the light emitting point 4G ″ corresponding to the light source 4G is deviated from the position used as the reference for designing the MLA 9, and the position of the light emitting point 4G ″ is the reference. The light condensing state in the case where it is further away from the MLA 9 is shown.

  It should be noted that the lens conditions of the MLA 9 are the same, and when the light emitting point 4G ′ corresponding to the light source 4G is disposed at the position of the left side of FIG. Assume that it is designed to collect light.

  Then, it is assumed that the distance from the MLA 9 to the liquid crystal layer 8 is always constant in the two cases shown in FIG.

  Here, in the two cases shown in FIG. 3, the width when the light beam passes through the liquid crystal layer 8 is expressed as the light width.

  In FIG. 3, for the sake of clarity, only three of the light emitting points 4G ′ and 4G ″ corresponding to the plurality of light sources 4G are illustrated, and only light from one point is illustrated. Show.

  In FIG. 3, only the light emission points 4G ′ and 4G ″ corresponding to the green light source 4G are illustrated, but the light emission points corresponding to the other light sources 4R and 4B are light emission corresponding to the green light source 4G. It is arranged between the points 4G ′ and 4G ″.

  Here, assuming that the size of the light source 4 is small enough to be ignored, the light emitted from the position of the light emitting point 4G ′ corresponding to the light source 4G in the left diagram of FIG. Light is collected at intervals of P. This is because the lens condition of MLA 9 is matched with the case of the left side of FIG.

  At this time, the focal length f of the MLA 9 is expressed by the following (formula 1).

1 / a + 1 / b = 1 / f (Formula 1)
Here, a in (Expression 1) indicates the shortest distance from one of the light sources 4 to the MLA 9 located directly above the reference inclined surface 5b via the reference inclined surface 5b. The shortest distance to the liquid crystal layer 8 is shown, and the above a and b show the length when converted to the refractive index of air.

Further, the lens pitch P _{0 of the} MLA 9 is expressed by the following (formula 2).

P ₀ = (n / n + 1) × P (Formula 2)
Here, n is a reduction magnification and is expressed by n = a / b. Thus, in the diagram on the left side of FIG. 3, since the position of the light emitting point 4G ′ corresponding to the light source 4G exists at the design reference position of the MLA 9, each corresponding picture element is spaced at the pixel pitch P interval of the liquid crystal layer 8. Can be condensed. In this case, the light transmission width is as small as possible.

Next, consider the diagram on the right side of FIG. In the right diagram, the position of the light emitting point 4G ″ corresponding to the light source 4G is moved to a distance a ′ far from the MLA 9 as compared to the left diagram. Other lens conditions of the MLA 9 (focal length f and lens pitch P ₀ ), the shortest distance b from the MLA 9 to the liquid crystal layer 8, and the size of the light source are the same as those on the left side.

  In the diagram on the right side of FIG. 3, since the distance from the position of the light emitting point 4G ″ corresponding to the light source 4G to the MLA 9 is a ′ and the focal length of the MLA 9 is f, the following (Equation 3) holds. .

1 / f = 1 / a ′ + 1 / b ′ = 1 / a + 1 / b (Formula 3)
And when expanding (Equation 3) above,
1 / a + 1 / b = 1 / a ′ + 1 / b ′
1 / a-1 / a '= 1 / b'-1 / b
When a ′> a, 1 / a−1 / a ′> 0, so 1 / b′−1 / b> 0, and b ′ <b is derived.

  That is, the light emitted from the position of the light emitting point 4G ″ corresponding to the light source 4G in the right side of FIG. 3 passes through the MLA 9 and forms an image with the imaging pitch P ′ at the height position b ′. Thus, the height is imaged between the MLA 9 and the liquid crystal layer 8.

  As shown in the drawing, once imaged light diverges thereafter, the light transmission width when passing through the liquid crystal layer 8 becomes wider than that on the left side.

  If this light transmission width is wider than the picture element width of the liquid crystal layer 8, it passes through adjacent picture elements of other colors, thereby causing a change in display color.

  In the case of the diagram on the right side of FIG. 3, the light from the green light source 4G passes through the adjacent red and blue picture elements, leading to a reduction in display quality.

  As described above, it has been described that when the position of the light emitting point corresponding to the light source is changed from the reference height, the light passing width in the liquid crystal layer 8 is increased because the height of the imaging surface is changed.

  On the other hand, as shown in FIG. 3, when the position of the light emitting point corresponding to the light source is changed from the reference height, the interval between the imaging positions after passing through the MLA 9 also changes (the liquid crystal pixel pitch). P to imaging pitch P ′). Considering the actual reduction ratio of the MLA 9, it is the change in the interval between the imaging positions that has a great influence on the light transmission width in the liquid crystal layer 8, and the change amount will be described in detail below.

  FIG. 4 is a diagram for explaining a change in the interval between the imaging positions (imaging pitch) when the shortest distance from the light source 4 to the MLA 9 changes.

  In FIG. 4, the light (G light) from the green light source 4G to the green picture element (G picture element) passes through the center of the MLA in order to mathematically analyze the imaging relationship shown in FIG. Only the chief ray path is shown, and the R and B light paths are not shown. The refraction phenomenon due to the difference in refractive index at the MLA interface is also omitted.

Here, the positions of the green light source 4G in FIG. 4 are respectively G1, G2, G1 ′, G2 ′, the center of the MLA lens is L1, and the positions where the light is condensed by the MLA lens are P1, P2, P1 ′. , P2 ′. Also, the position interval for condensing at MLA lenses assuming respectively [Delta] P, and [Delta] P ', the distance between the G picture elements of the liquid crystal layer is assumed to be P _LC.

  First, (a) of FIG. 4 will be described. This figure corresponds to the figure on the left side of FIG. 3, and shows a case where the green light source 4G is arranged at the position of the MLA design condition.

  Of the light emitted from the G1 and G2 light sources corresponding to the green light source 4G, the light that has passed through the lens centered on L1 is condensed on P1 and P2, respectively. At this time, the illustrated triangles G1, G2, and L1 and the triangle P1P2L1 are similar to each other, the heights of the triangle G1G2L1 and the triangle P1P2L1 are a and b, respectively, (line G1G2) = ΔG, (line Since (P1P2) = ΔP, the following (formula 4) is established.

a / ΔG = b / ΔP (Formula 4)
Here, a and b have a relationship of n = a / b. n is a reduction magnification, and from this relational expression, from a = nb, the condensing position interval ΔP after passing through the lens of L1 is expressed by the following (formula 5).

ΔP = ΔG / n (Formula 5)
Here, when [Delta] P is equal to _{P LC,} i.e., from _{ΔG / n = ΔP = P LC} , if .DELTA.G satisfies the following equation (6), under the condition of FIG. 4 (a), the light passing width Ideally Thus, an ideal condensing state is realized.

ΔG = n × P _LC (Formula 6)
The ideal condensing state is that the positions P1 and P2 where the light emitted from G1 and G2 corresponding to the position of the green light source 4G is collected are the green picture elements (G picture elements) in the pixels of the liquid crystal layer. ) Refers to the state that matches the center.

  On the other hand, FIG. 4B shows a case where only the positions of G1 and G2 are changed under the condition of FIG. This figure corresponds to the figure on the right side of FIG. 3 and shows a case where the green light source 4G is arranged at a position away from the design condition position of the MLA.

  Of the light emitted from the green light source 4G at the positions G1 'and G2', the light that has passed through the lens centered on L1 is condensed on P1 'and P2', respectively. At this time, the illustrated triangles G1 ′, G2 ′, and L1 and the triangles P1 ′, P2 ′, and L1 are similar to each other, and the triangles G1 ′, G2 ′, and L1 and the triangles P1 ′, P2 ′, and L1 Are (line G1′G2 ′) = ΔG and (line P′1P2 ′) = ΔP ′, and the following (formula 7) is established.

a ′ / ΔG = b ′ / ΔP (Formula 7)
Here, from a ′ = n′b ′, the interval ΔP ′ of the condensing position after passing through the lens L1 is expressed by the following (formula 8).

ΔP ′ = ΔG / n ′ (Formula 8)
Here, the magnitudes of ΔP and ΔP ′ are compared. The difference between ΔP and ΔP ′ is expressed by the following equation (Equation 9).

ΔP−ΔP ′ = (1 / n−1 / n ′) × ΔG (Formula 9)
On the other hand, from the above (Equation 3), when a ′> a, b ′ <b.
Since b / a> b ′ / a ′ holds, b / a−b ′ / a ′ = 1 / n−1 / n ′> 0, and when applied to the above (Equation 9), ΔP−ΔP ′> 0 Therefore, ΔP> ΔP ′.

  From the above, when the position of the green light source 4G moves away from the reference height, the interval between the condensing positions after passing through the lens of the MLA becomes narrower than that at the reference height.

  On the other hand, although not shown, when the position of the green light source 4G is closer to the MLA side than the reference height, the same result is derived by developing the above expression under the condition of a> a ′. The condensing position interval after passing through the lens becomes wider than that at the reference height.

  The change in the light transmission width of the liquid crystal layer 8 when the distance from the light source 4 to the MLA 9 is changed has been described above.

  There are two optical characteristics that affect the light transmission width of the liquid crystal layer 8: a change in height of the condensing position of the MLA 9 and a change in interval of the condensing position of the MLA 9; Considering this, a change in the interval between the condensing positions of the MLA 9 has a greater influence. From this, the light transmission width of the liquid crystal layer is expressed by the following formula (Formula 10).

| (Interval of MLA focusing position when light source is at reference height) − (Interval of MLA focusing position when light source is changed from reference height) | ≈ (Transmission width of liquid crystal layer) (Formula 10)
In the above (Expression 10), || represents an absolute value.

  In the liquid crystal layer, if the condensed light passes between adjacent different picture elements, an appropriate color display cannot be performed. Therefore, the light transmission width of the liquid crystal layer is as shown below (Formula 11). ) Must be satisfied.

| (Transmission width of liquid crystal surface) | <P _LC / (2 × M) (Formula 11)
In the above (Equation 11), || is the absolute value, the P _LC of the pixel pitch of the liquid crystal layer, M represents the number of picture elements constituting the pixel, respectively.

  In the liquid crystal display device 1 of the present embodiment, one pixel is composed of RGB three-color picture elements, and in this case, M = 3.

  In the case of FIG. 4B, when the above condition is applied, the following (Expression 12) can be derived from (Expression 9), (Expression 10), and (Expression 11).

| ΔP−ΔP ′ | <P _LC / (2 × M)
| (1 / n−1 / n ′) × ΔG | <P _LC / (2 × M)
ΔG × | (1 / n−1 / n ′) | <P _LC / (2 × M) (Formula 12)
Here, the following (Formula 13) can be derived from the above (Formula 6).

P _LC = (1 / n) × ΔG (Formula 13)
And when the above (Formula 13) is substituted into the above (Formula 12),
ΔG × | (1 / n−1 / n ′) | <(1 / n) × ΔG / (2 × M)
| (1 / n−1 / n ′) | <1 / (2 × M) × (1 / n)
| (N′−n) | <n ′ / (2 × M)
Here, n = a / b, n ′ = a ′ / b ′,
| (A ′ / b′−a / b) | <1 / (2 × M) × (a ′ / b ′),
The following (Expression 14) can be derived from b≈b ′.

| (A′−a) | <a ′ / (2 × M) (Formula 14)
When a ′> a, the following (Expression 15) can be derived from the above (Expression 14).

(A′−a) <a ′ / (2 × M)
{(2 × M−1) / (2 × M)} × a ′ <a
a ′ <{(2 × M) / (2 × M−1)} × a (Formula 15)
On the other hand, when a ′ <a, the following (Expression 16) can be derived from the above (Expression 14).

− (A′−a) <a ′ / (2 × M)
{(2 × M + 1) / (2 × M)} × a ′> a
a ′> {(2 × M) / (2 × M + 1)} × a (Formula 16)
Here, the above (Expression 15) is an allowable conditional expression of the reduction magnification of the lens of the MLA when a ′> a, and the distance a from the position of the light source to the MLA within the range where the above (Expression 15) is satisfied. When 'becomes longer, it indicates that light does not leak into the adjacent other color elements.

  Similarly, (Expression 16) is an allowable condition expression for the reduction magnification of the lens of the MLA when a ′ <a, and the distance a ′ from the position of the light source to the MLA is within the range in which (Expression 16) is satisfied. Indicates that light does not leak into the adjacent other color picture elements.

  Furthermore, when the ratio between the above (Formula 15) and the above (Formula 16) is expressed by the formula, the following (Formula 17) is obtained.

{(2 × M) / (2 × M−1)} / {(2 × M) / (2 × M + 1)} = (2 × M + 1) / (2 × M−1) (Equation 17)
As described above, it can be seen that the maximum and minimum ratio in the allowable condition of the distance a ′ from the position of the light source to the MLA is determined by the constant of M as in (Expression 17).

  Further, from the above (Expression 15) and (Expression 16), it can be seen that the allowable change range of the distance L from the position of the light source to the MLA varies depending on the position of the inclined surface that is the design reference of the imaging optical system.

  That is, in FIG. 1, when the MLA lens design is performed using the light extraction inclined surface 5b closest to the incident surface 5a of the light guide plate 5 as a reference inclined surface, a change allowable range of the distance L from the position of the light source to the MLA. Is (2 × M) / (2 × M−1) times the distance a from the position of the light source passing through the reference inclined surface at this time to the MLA.

  In the case of the liquid crystal display device 1 of the present embodiment, since one pixel is composed of RGB three-color picture elements, since M = 3, the allowable range of change in the height of the position of the light source is the above (formula 15), (2 × 3) / (2 × 3-1) = 1.2, and the MLA lens design is made with the inclined surface 5b for light extraction closest to the incident surface 5a of the light guide plate 5 as the reference inclined surface. If the height change of the position of the light source is suppressed to less than 1.2 of the distance a from the light source position to the MLA at this time, it is possible to ensure a good light collection state in all display areas. Become.

  A change in distance from the position of the light source to the MLA will be further described with reference to FIGS.

  In the liquid crystal display device 1 illustrated in FIG. 1, light extracted through the light extraction inclined surface 5 b closest to the incident surface 5 a of the light guide plate 5 and light extraction farthest from the incident surface 5 a of the light guide plate 5. When compared with the light extracted through the inclined surface 5b, the optical distance from the position of one of the light sources 4R, 4G, and 4B in the light source 4 to the MLA 9 changes substantially. .

  This is because the liquid crystal display device 1 has no optical element for diffusing light between the light source 4 and the MLA 9.

  The refraction at the incident surface 5a of the light guide plate 5, the reflection at the inclined surface 5b for extracting light, the refraction at the upper surface of the light guide plate 5, etc. all change the direction of the light. It plays a role of condensing light from the light source 4 on the liquid crystal layer 8.

  On the other hand, when an optical element that randomly changes the direction of light, such as a diffusion plate, is present in the middle of the optical path from the light source 4 to the MLA 9, light is once diffused in a random direction at the position of the diffusion plate. MLA 9 behaves as if the light source 4 is present at the position of the diffusion plate, and MLA 9 plays a role of condensing the light of the diffusion plate on the liquid crystal layer 8.

  Therefore, the liquid crystal display device 1 does not include an optical element that diffuses light such as a diffusion plate in the middle of the optical path from the light source 4 to the MLA 9.

  As shown in FIG. 2, the light extraction inclined surface 5b corresponding to the center of the extraction region (the light extraction inclined surface corresponding to the third counted from the incident surface 5a direction of the light guide plate 5). When the lens design of MLA9 is performed using 5b) as the reference inclined surface, the shortest distance from the virtual image point 4R 'of the light extracted from the reference inclined surface 5b to MLA9 is a.

  In such a case, the allowable change range D1 and D2 of the distance L from the position of the light source 4 to the MLA 9 can be obtained using the above (Formula 15) and the above (Formula 16).

  That is, the light extraction inclined surface 5b may be provided so as to be within the allowable change range D1 and D2 of the distance L from the position of the light source 4 to the MLA 9.

  On the other hand, in the case where the lens design of the MLA 9 is performed using the light extraction inclined surface 5b closest to the incident surface 5a of the light guide plate 5 as a reference inclined surface, the above-described (Equation 15) is used. The light extraction inclined surface 5b farthest from the incident surface 5a of the light guide plate 5 may be provided within a range of (2 × M) / (2 × M−1) times the distance a from the position to the MLA. .

  Further, when the lens design of the MLA 9 is performed using the inclined surface 5b for extracting light farthest from the incident surface 5a of the light guide plate 5 as a reference inclined surface, the above equation (16) is used to determine the light source at this time. The light extraction inclined surface 5b closest to the incident surface 5a of the light guide plate 5 may be provided within a range of (2 × M) / (2 × M + 1) times the distance a from the position to the MLA.

  As described above, if the distance from the light source 4 to the MLA 9 can be controlled, the light can be condensed in each picture element of the liquid crystal layer 8 in all display regions, without using a color filter. Good full color display can be realized.

  In FIG. 3 and FIG. 4, the calculation is performed for the case where light emitted from a plurality of positions is irradiated on one lens of the MLA 9. However, when one lens of the MLA 9 is irradiated with light emitted from one position, it can be assumed that only one of the emission points G1 and G2 in FIG. 4 emits light. By calculating the above, the constraint condition can be obtained.

  That is, when the light from one light source is irradiated on one lens of the MLA 9 or when the light from a plurality of light sources is irradiated, the inclined surface 5b for extracting light within the above-described fixed range. If it is provided, it becomes possible to realize a satisfactory full color display without using a color filter.

  More specifically, when a single lens of the MLA 9 is irradiated with light emitted from a plurality of three or more positions, conditions more severe than the above (Equation 17) are required. This can be easily imagined by considering the case where the G light source positions G3 and G3 'are present on the right side of the positions G2 and G2' in FIGS.

  At this time, the maximum / minimum ratio of change in the distance from the light source to the MLA (the same condition as that of the equation 17) is expressed by the following (equation 18).

{(2 × xx × M) / (2 × xx × (M−1))} / {(2 × xx × M) / (2 × xx × (M + 1))} = (2 × xx × (M + 1) ) / (2 × x × (M−1)) (Formula 18)
Here, x is divided into right and left from right under one lens of MLA9 among the number of light sources irradiated to one lens of MLA9 in the direction in which light sources 4R, 4G, and 4B of each color are arranged. It is the number of the more frequent cases.

  When light from one light source is irradiated to one lens of MLA9, since the number of light sources is 1 and 0 when divided right and left from one lens of MLA9, x = 1. The above (Formula 18) is the same condition as the above (Formula 17).

  In addition, when light from two light sources is irradiated to one lens of MLA9, as can be seen from FIG. 4, the number of light sources in the case of dividing right and left from directly under one lens of MLA9 is respectively Since x = 1, x = 1, and the above (Formula 18) has the same condition as the above (Formula 17).

  Then, in FIGS. 4A and 4B, when there is a G light source position of G3 or G3 ′ on the right side of the position of G2 or G2 ′, it is divided into right and left from right under one lens of MLA9. In this case, since the number of the light sources is 2 and 1, x = 2, and the above (Expression 18) becomes (4M + 1) / (4M-1).

  From these facts, the above (Formula 18) is a conditional expression in which the number of light sources irradiated to one lens of the MLA 9 is established under all conditions, and is a comprehensive constraint including the above (Formula 17). I understand that there is.

  In the above description, when the lens design of the MLA 9 is performed using the light extraction inclined surface 5b closest to the incident surface 5a of the light guide plate 5 as a reference inclined surface, three or more plural lenses are provided for one lens of the MLA 9. Although the case where the light emitted from the position of the light is irradiated is described, the case where the lens design of the MLA 9 is designed with the light extraction inclined surface 5b corresponding to the center of the extraction region as the reference inclined surface, The present invention can also be applied to the case where the lens design of the MLA 9 is performed using the inclined surface 5b for extracting light farthest from the incident surface 5a of the optical plate 5 as a reference inclined surface.

  According to the above configuration, the light emitted from the light sources 4R, 4G, and 4B of each color is irradiated into the RGB picture elements constituting the pixels of the liquid crystal layer 8 of the liquid crystal display panel 3 after passing through the MLA 9. Therefore, full color display can be performed without using a color filter, and the use efficiency of light corresponding to the amount absorbed by the color filter can be improved. Moreover, since light is guided in the horizontal direction using the light guide plate 5, the thickness of the backlight 2 can be drastically reduced.

  The effect of thinning the backlight 2 provided in the liquid crystal display device 1 of the present embodiment will be described by taking specific numbers as an example.

  The distance from the point light source (LED) to the MLA is a parameter relatively determined by the same color interval of the point light source, the pixel pitch of the liquid crystal layer, and the distance from the MLA to the liquid crystal layer.

  For example, when the same color interval of the point light source is 60 mm, the pixel pitch of the liquid crystal layer is 0.6 mm, and the distance from the MLA to the liquid crystal layer is 3 mm, the distance from the point light source to the MLA is 60 × 3 / 0.6. = 300 mm. In such a case, when the point light source is disposed immediately below the liquid crystal display panel, the thickness of the backlight portion is 300 mm, which is about the same as the distance from the point light source to the MLA, and becomes very thick.

  On the other hand, according to the backlight 2 provided in the liquid crystal display device 1 of the present embodiment, light is guided in the parallel direction of the liquid crystal display panel 3, and the thickness of the backlight 2 is substantially 10 mm to 60 mm. It becomes possible to suppress to the extent.

[Embodiment 2]
Next, a second embodiment of the present invention will be described based on FIG. 5 and FIG. In the present embodiment, the shape of the light guide plate 12 provided in the backlight 11 is different from that of the first embodiment. Other configurations are as described in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 5 is a diagram showing a schematic configuration of the liquid crystal display device 1a and the shortest distance from the virtual image point 4R 'to the MLA 9 corresponding to each of the inclined surfaces 12b for light extraction provided in the liquid crystal display device 1a.

  As shown in FIG. 5A, the shape of the light guide plate 12 provided in the backlight 11 is different from the shape of the light guide plate 5 used in the first embodiment.

  The left end surface of the light guide plate 12 is an incident surface 12a on which light emitted from the light source 4 is incident, and a bending reflection surface 12d is provided at the right end portion of the light guide plate 12. A plurality of inclined surfaces 12b for extracting light are provided at predetermined positions so that the light reflected by the reflecting surface 12d for bending is emitted to the liquid crystal display panel 3 side.

  The reflecting surface 12d for bending and the inclined surface 12b for extracting light have a uniform shape in the depth direction, and can be formed as a flat surface or a lenticular lens surface.

  In the light guide plate 12, the surface facing the emission surface 12 c, that is, the surface on which the light extraction inclined surface 12 b is provided has a structure in which the light guide plate 12 becomes thinner by the height of each inclined surface 12 b. (Staircase structure).

  In the present embodiment, the number of inclined surfaces 12b for extracting light is eight.

  As shown in FIG. 5B, the shortest distances from the virtual image point 4R ′ to the MLA 9 of the light extracted from the respective light extraction inclined surfaces 12b are different from each other, and the virtual image point 4R. Since the influence of the change in the shortest distance from 'to MLA 9 on the light condensing state on the liquid crystal layer 8 is the same as described above, it is omitted here.

  The curvature characteristics and lens pitch of the MLA 9 are based on the virtual reference point based on the shortest distance a from the virtual image point 4R ′ of light extracted from the virtual reference inclined surface corresponding to the center of the extraction region to the MLA 9. The light reflected by the inclined surface is designed and arranged so as to be condensed in the pixels of the liquid crystal layer 8.

  In such a case, the allowable change range D1 and D2 of the distance L from the position of the light source 4 to the MLA 9 can be obtained using the above (Formula 15) and the above (Formula 16).

  That is, the light extraction inclined surface 12b may be provided so as to be within the allowable change range D1 and D2 of the distance L from the position of the light source 4 to the MLA 9.

  On the other hand, when the lens design of the MLA 9 is performed using the light extraction inclined surface 12b closest to the incident surface 12a of the light guide plate 12 as a reference inclined surface, the above-described (Equation 15) is used. The light extraction inclined surface 12b farthest from the incident surface 12a of the light guide plate 12 may be provided within a range of (2 × M) / (2 × M−1) times the distance a from the position to the MLA. .

  Further, when the lens design of the MLA 9 is performed using the inclined surface 12b for extracting light farthest from the incident surface 12a of the light guide plate 12 as a reference inclined surface, the above formula (16) is used to determine the light source at this time. The inclined surface 12b for light extraction closest to the incident surface 12a of the light guide plate 12 may be provided within a range of (2 × M) / (2 × M + 1) times the distance a from the position to the MLA.

  When the distance L from the position of the light source 4 to the MLA 9 satisfies the conditions in each of the above cases, the light irradiated to the liquid crystal display panel 3 side corresponds to each by passing through the MLA 9 corresponding to the pixel pitch of the liquid crystal layer 8. The light from the light sources 4R, 4G, and 4B of each color is condensed on each pixel in the pixel. By finely adjusting the amount of light transmitted through each pixel by the voltage applied to the liquid crystal layer 8, full color display can be realized without using a color filter.

  FIG. 6 shows a schematic configuration of a liquid crystal display device 1b including a light guide plate 14 of another shape.

  As shown in the drawing, the left end surface of the light guide plate 14 is an incident surface 14 a for allowing the light emitted from the light source 4 to enter, and a bending reflection surface 14 d is provided at the right end portion of the light guide plate 14. . A plurality of inclined surfaces 14b for extracting light are provided at predetermined positions so that the light reflected by the reflecting surface 14d for bending is emitted to the liquid crystal display panel 3 side.

  The reflecting surface 14d for bending and the inclined surface 14b for extracting light have a uniform shape in the depth direction, and can be formed as a flat surface or a lenticular lens surface.

  In the light guide plate 14, the surface facing the emission surface 14 c, that is, the surface on which the light extraction inclined surface 14 b is provided, even when the height of each inclined surface 14 b is changed. Although the thickness is constant, even in such a case, it is possible to realize the same light extraction characteristics as the configuration shown in FIG.

  In the light guide plate 14, the number of inclined surfaces 14b for extracting light is seven.

[Embodiment 3]
Next, a third embodiment of the present invention will be described with reference to FIG. The present embodiment is different from the first and second embodiments in that the backlight 15 includes a plurality of light guide plates 16 and 16 '. Other configurations are as described in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 7 is a diagram showing a schematic configuration of a liquid crystal display device 1c having a backlight 15 composed of a plurality of light guide plates 16 and 16 '.

  As shown in the figure, the backlight 15 is arranged such that the take-out area of one light guide plate 16 ′ rides on the run area of the other light guide plate 16 in the adjacent two light guide plates 16, 16 ′. A plurality of light guide plates 16, 16 'are provided.

  In each of the light guide plates 16 and 16 ′, the left end surface is an incident surface 16a and 16′a on which light emitted from the light source 4 is incident, and on the upper surface side of each of the light guide plates 16 and 16 ′. The exit surfaces 16c and 16'c are provided, and light is emitted on the back side of the light guide plates 16 and 16 'facing the exit surfaces 16c and 16'c so that light can be emitted from the exit surfaces 16c and 16'c. A plurality of inclined surfaces 16b and 16'b for taking out are provided.

  In the present embodiment, the number of inclined surfaces 16b and 16'b for light extraction is five.

  The distance from the virtual image point of the light extracted from the inclined surfaces 16b and 16'b for each light extraction to the MLA 9 is different, and the change in the distance from the virtual image point to the MLA 9 becomes a condensing state on the liquid crystal layer 8. The effect is the same as described above, and is omitted here.

  As for the curvature characteristics and lens pitch of the MLA 9, as described above, a reference inclined surface is set, and based on the shortest distance a from the virtual image point of the light extracted from the reference inclined surface to the MLA 9, The light reflected by the reference inclined surface is designed and arranged so as to be condensed in the pixels of the liquid crystal layer 8.

  When the distance L from the position of the light source 4 to the MLA 9 satisfies the predetermined condition described above, the light irradiated to the liquid crystal display panel 3 side corresponds to each by passing through the MLA 9 corresponding to the pixel pitch of the liquid crystal layer 8. The light from the light sources 4R, 4G, and 4B of each color is condensed on each pixel in the pixel. By finely adjusting the amount of light transmitted through each pixel by the voltage applied to the liquid crystal layer 8, full color display can be realized without using a color filter.

  In the present embodiment, the run area of each of the light guide plates 16 and 16 'is extended from the run area of the light guide plate 5 used in the first embodiment. As a result, the relative ratio between the maximum length and the minimum length from the virtual image point generated on the inclined surfaces 16b and 16'b for each light extraction to the MLA 9 can be reduced, and a better condensing state can be realized. It becomes.

  At the same time, by providing a running area of the light guide plate 16 on the back side of the take-out area of the adjacent light guide plate 16 ', the light emitted from the adjacent light guide plates 16 and 16' is partially overlapped to irradiate the MLA 9 It becomes possible. As a result, the effect of suppressing the luminance unevenness at the boundary between the light guide plate 16 and the light guide plate 16 'and the effect of smoothing the luminance shift and chromaticity shift between the light guide plates 16 and 16' are produced. Can achieve uniform brightness and reduction of color unevenness.

[Embodiment 4]
Next, a fourth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the configurations of the backlights 17 and 20 provided in the liquid crystal display device are different from those in the first to third embodiments. Other configurations are as described in the first embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of the first embodiment are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 8 is a diagram showing a schematic configuration of a liquid crystal display device 1d including a backlight 17 including a light guide member composed of a plurality of substrates 18 whose both surfaces are mirror surfaces and a prism sheet 19. As shown in FIG.

As shown in the drawing, the light sources 4R, 4G, and 4B that emit different dominant wavelengths are light incident surfaces in a plane vertical between two adjacent substrates among a plurality of substrates 18 whose both surfaces are mirror surfaces. Are repeatedly arranged in a row along the depth direction.
Note that the arrangement method of the light sources 4R, 4G, and 4B is not limited to this, and only one light source 4R, 4G, and 4B may be arranged for each color.

  The plurality of substrates 18 whose both surfaces are mirror surfaces are arranged above and below the light sources 4R, 4G, and 4B for each color, and each substrate 18 extends to the prism sheet 19, so that the light sources 4R, 4G, and 4B for each color On the other hand, the length of the substrate 18 disposed on the lower surface in the light traveling direction is longer than that of the substrate 18 disposed on the upper surface.

  That is, the plurality of substrates 18 whose both surfaces are mirror surfaces are provided so as to partially overlap in a plan view, and among the plurality of substrates 18, the region R1 where two adjacent substrates 18 overlap is the light source 4R. A region R2 where the light emitted from 4G and 4B is guided to the extraction region for extraction to the outside, where the two adjacent substrates 18 do not overlap includes a plurality of inclined surfaces on the region R2 where they do not overlap A prism sheet 19 provided with a triangular prism is provided and serves as an extraction area.

  On the surface of the prism sheet 19 facing the substrate 18, triangular prisms having an acute apex angle are continuously arranged in the left-right direction in the same shape, and are also formed in a uniform shape in the depth direction.

  The curvature characteristic and lens pitch of the MLA 9 are determined based on the shortest distance a from the virtual image point of the light extracted from the virtual reference inclined surface corresponding to the center portion of the extraction area to the MLA 9, and the virtual reference inclined surface. Designed and arranged so that the light reflected by the light is condensed in the pixels of the liquid crystal layer 8.

  The light emitted from the light source 4 is applied to the prism sheet 19 while being repeatedly reflected between the two adjacent substrates 18.

  FIG. 9 is a diagram showing an optical action in the prism sheet 19.

  As shown in the drawing, in the prism sheet 19, when focusing on a reference triangular prism that includes a reference inclined surface that corresponds to the center of the extraction region, that is, the center of the prism sheet 19, the one closer to the light source 4. The light refracted by the inclined surface 19a and proceeding into the prism sheet 19 is largely deflected by total reflection at the opposite inclined surface 19b (an inclined surface far from the light source 4).

  After being deflected, the light emitted from the upper surface side of the prism sheet 19 to the liquid crystal display panel 3 side passes through the MLA 9 corresponding to the pixel pitch of the liquid crystal layer 8, so that the light sources 4R, 4G, and 4B of the corresponding colors, respectively. Is condensed on each pixel in the pixel. Then, the transmitted light amount of each picture element can be finely adjusted by the voltage applied to the liquid crystal layer 8, and full color display can be realized without using a color filter.

  In such a case, the allowable change range of the distance L from the position of the light source 4 to the MLA 9 can be obtained using (Expression 15) and (Expression 16).

  That is, if a triangular prism composed of an inclined surface 19a closer to the light source 4 and an inclined surface 19b farther from the light source 4 is provided so as to be within a change allowable range of the distance L from the position of the light source 4 to the MLA 9. Good.

  On the other hand, when the lens design of the MLA 9 is performed using the triangular prism including the inclined surfaces 19a and 19b existing at the leftmost end portion of the prism sheet 19 as a reference triangular prism, the above equation (15) is used. A triangular prism including inclined surfaces 19a and 19b existing at the rightmost end of the prism sheet 19 within a range of (2 × M) / (2 × M−1) times the distance a from the light source position to the MLA. What is necessary is just to provide.

  Further, when the lens design of the MLA 9 is performed by using the triangular prism including the inclined surfaces 19a and 19b existing at the rightmost end portion of the prism sheet 19 as a reference triangular prism, the above equation (16) is used. A triangular prism including inclined surfaces 19a and 19b existing at the leftmost end of the prism sheet 19 is provided within a range of (2 × M) / (2 × M + 1) times the distance a from the light source position to the MLA. That's fine.

  In the present embodiment, unlike the first to third embodiments described above, since a refractive index medium (light guide plate) is not used, a significant reduction in weight can be achieved. Furthermore, since most of the light emitted from the light source 4 travels through the air layer, the optical distance from the light source 4 to the MLA 9 is relatively longer than when a refractive index medium is used. It becomes possible to reduce the optical change ratio as a whole.

  In the present embodiment, the triangular prism of the prism sheet 19 is used as an optical member corresponding to the inclined surface for light extraction used in the above-described first to third embodiments. Therefore, it is possible to realize full color display without using a color filter when virtual image points are generated by the number of triangular prisms and the distance from each virtual image point to the MLA satisfies each condition in each case described above. Become.

  FIG. 10 is a diagram showing a schematic configuration of a liquid crystal display device 1e including a backlight 20 including a light guide member, a prism sheet 19, and a lenticular lens 21 from a plurality of substrates 18 whose both surfaces are mirror surfaces.

  As shown in the figure, by arranging a plurality of lenticular lenses 21 in the direction shown in the figure on the surface of the prism sheet 19 that faces the liquid crystal display panel 3, local luminance unevenness in the prism sheet 19 is reduced. It becomes possible to cancel.

  When the light from the light source 4 is deflected to the liquid crystal display panel 3 side by total reflection on the triangular prism surface of the prism sheet 19, the prism sheet 19 is not irradiated from the portion other than the total reflection surface to the liquid crystal display panel 3 side. 19, a locally bright part (area irradiated to the liquid crystal display panel 3 side) and a dark part (area not irradiated to the liquid crystal display panel 3 side) are generated. In order to solve this problem, the lenticular lens 21 is arranged as shown in the figure, and the light emission direction is expanded in the arrangement direction of the triangular prisms (the left and right direction in the figure), whereby the local in the prism sheet 19 is obtained. Uneven brightness can be eliminated. In this case, in order to effectively reduce local luminance unevenness, the arrangement pitch of the lenticular lenses 21 is preferably several times smaller than the arrangement pitch of the triangular prisms in the prism sheet 19.

[Embodiment 5]
Next, a fifth embodiment of the present invention will be described based on FIG. 11 and FIG. The present embodiment is different from the fourth embodiment in that an optical path adjusting light guide plate 23 is added to the configuration of the fourth embodiment described above. Other configurations are as described in the fourth embodiment. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiment 4 are given the same reference numerals, and explanation thereof is omitted.

  FIG. 11 is a diagram showing a schematic configuration of a liquid crystal display device 1f in which an optical path adjusting light guide plate 23 is added to the configuration shown in FIG.

  As shown in the drawing, the light path adjusting light guide plate 23 is inserted between the substrate 18 and the prism sheet 19 in the backlight 22 provided in the liquid crystal display device 1 f.

  By inserting the light path adjusting light guide plate 23, it is possible to relatively reduce the difference in optical distance from each virtual image position generated in the prism sheet 19 to the MLA 9, and from the position of the light source 4 to the MLA 9. The distance L can easily realize the predetermined condition described above.

  That is, in the liquid crystal display device 1f, an effect of improving the light condensing state in the liquid crystal layer 8 can be expected as compared with the configuration shown in FIG.

  As shown in the drawing, the light path adjusting light guide plate 23 is provided with a plurality of incident surfaces 23a and stepwise formed emission surfaces 23b.

  FIG. 12 is a diagram showing a schematic configuration of a liquid crystal display device 1g in which an optical path adjusting light guide plate 23 is added to the configuration shown in FIG.

  As shown in the drawing, a lenticular lens 21 is arranged in the liquid crystal display device 1g, and the light emission direction is expanded in the arrangement direction of the triangular prisms (left and right direction in the figure), whereby the local luminance in the prism sheet 19 is increased. Unevenness can be eliminated. In this case, in order to effectively reduce local luminance unevenness, the arrangement pitch of the lenticular lenses 21 is preferably several times smaller than the arrangement pitch of the triangular prisms in the prism sheet 19.

[Embodiment 6]
Next, based on FIG. 13 and FIG. 14, a sixth embodiment of the present invention will be described. In the backlights 25 and 27 of the present embodiment, a plurality of mirror surfaces 26a for reflecting each of the lights in the different wavelength regions emitted from the light source 4 and guiding them to the prism sheet 19 are formed in a step shape. The point from which the reflector 26 is provided differs from Embodiment 1-5. Other configurations are as described in the first to fifth embodiments. For convenience of explanation, members having the same functions as those shown in the drawings of Embodiments 1 to 5 are given the same reference numerals, and descriptions thereof are omitted.

  FIG. 13 shows a backlight 25 having a reflector 26 in which a plurality of mirror surfaces 26 a for reflecting each of light in different wavelength regions emitted from the light source 4 and guiding it to the prism sheet 19 are formed in a stepped shape. It is a figure which shows schematic structure of the liquid crystal display device 1h provided.

  As shown in the drawing, the light sources 4R, 4G, and 4B emitting different principal wavelengths are arranged along the depth direction of the mirror surface 26a of the reflector 26 for guiding the light emitted from the light source 4 to the prism sheet 19. It is repeatedly arranged in one row. However, the number of light sources irradiated to one reflector 26 is not limited to this, and one for each color may be used.

  Each mirror surface 26a of the reflector 26 is arranged in a horizontal position with respect to the light sources 4 arranged in a line in the depth direction in the figure, and the reflector 26 includes a plurality of reflectors 26 as shown in the figure. The mirror surfaces 26a are arranged step by step, each mirror surface 26a has a uniform shape in the depth direction, and at least in the region irradiated with the light source 4, the mirror surface 26a is arranged. .

  On the surface of the prism sheet 19 facing the reflector 26, triangular prisms having acute apex angles are continuously arranged in the left-right direction with the same shape, and formed in a uniform shape in the depth direction. Has been.

  Then, the curvature characteristics and lens pitch of the MLA 9 are designed and arranged so that the light reflected by each mirror surface 26a of the reflector 26 is condensed in the pixels of the liquid crystal layer 8 after passing through the prism sheet 19. Has been.

  The light emitted from the light source 4 is reflected on each mirror surface 26 a of the reflector 26 and then irradiated onto the prism sheet 19. When attention is paid to the reference triangular prism including the reference inclined surface corresponding to the central portion of the prism sheet 19, the light emitted from the light source 4 is refracted by the incident inclined surface 19 a and proceeds into the prism sheet 19. Is largely deflected by total reflection at the other inclined surface 19b facing each other.

  After being deflected, the light emitted from the upper surface side of the prism sheet 19 to the liquid crystal display panel 3 side passes through the MLA 9 corresponding to the pixel pitch of the liquid crystal layer 8, so that the light sources 4R, 4G, and 4B of the corresponding colors, respectively. Is condensed on each pixel in the pixel. Then, the transmitted light amount of each picture element can be finely adjusted by the voltage applied to the liquid crystal layer 8, and full color display can be realized without using a color filter.

  In the present embodiment, unlike the first to third embodiments described above, since a refractive index medium (light guide plate) is not used, a significant reduction in weight can be achieved. Furthermore, since most of the light emitted from the light source 4 travels through the air layer, the optical distance from the light source 4 to the MLA 9 is relatively longer than when a refractive index medium is used. It becomes possible to reduce the optical change ratio as a whole.

  In the present embodiment, the triangular prism of the prism sheet 19 is used as an optical member corresponding to the inclined surface for light extraction used in the first to third embodiments, and each of the triangular prisms. Therefore, if the number of triangular prisms is the number of virtual image points and the distance from each virtual image point to the MLA satisfies the above conditions, the full color display can be realized without using a color filter. It becomes possible.

  In such a configuration, the distance from each virtual image point of the light reflected by each mirror surface 26a of the reflector 26 to the MLA 9 is substantially equal, and the conditions in each case described above are easily satisfied. Thus, a color filter-less liquid crystal display device can be realized.

  Factors that cause the distances from the virtual image points to the MLA 9 by the mirror surfaces 26a of the reflectors 26 to be approximately equal are the positions of the mirror surfaces 26a of the reflectors 26 and the irradiation position of the prism sheet 19 after reflection. Is related.

  Below, based on FIG. 14, the factor that the distance from each virtual image point by each mirror surface 26a of the reflector 26 to the MLA 9 becomes substantially equal will be described in more detail.

  FIG. 14 is a diagram showing a schematic configuration of a liquid crystal display device 1 i in which the liquid crystal display device 1 h shown in FIG. 13 is further provided with a lenticular lens 21, and the light emitted from the light source 4 is reflected by the reflector 26. Since it is the same that the prism sheet 19 is irradiated after being reflected by each mirror surface 26a, it will be described with reference to FIG.

  As shown in the figure, according to the reflector 26, the light reflected by the mirror surface 26 a closest to the light source 4 is irradiated to the MLA 9 side by the triangular prism disposed at a position far from the light source 4. The light reflected by the mirror surface 26 a farthest from the light source 4 is irradiated to the MLA 9 side by a triangular prism disposed at a position near the light source 4.

  The distance from the light source 4 to the MLA 9 is substantially expressed by the following (formula 19).

(Distance from light source 4 to MLA 9) = (Distance from light source 4 to mirror surface 26a) + (Distance from mirror surface 26a to prism sheet 19) + (Distance from prism sheet 19 to MLA 9) (Equation 19)
In the mirror surface 26a closest to the light source 4, the first term on the right side is small and the second term on the right side is large. In the mirror surface 26a farthest from the light source 4, the first term on the right side is large and the second term on the right side is small. Accordingly, when considered as the distance from the light source 4 to the MLA 9, the light reflected by the nearest mirror surface 26a and the light reflected by the farthest mirror surface 26a are substantially equal distances.

  Here, only the light reflected by the mirror surfaces arranged at both ends of each mirror surface 26a of the reflector 26 is taken up, but the light reflected by the other mirror surfaces is also expressed by the above (formula 19). When applied, the distance from the light source 4 to the MLA 9 is substantially equal.

  In the present embodiment, the reflector 26 in which a plurality of mirror surfaces 26a are formed in a step shape is used. However, the light is emitted from each light source 4 and reflected by each mirror surface 26a. The shape of the reflector is not limited to this as long as the optical path lengths until being guided to can be made substantially equal.

  Further, in the liquid crystal display device 1i shown in FIG. 14, a plurality of lenticular lenses 21 are arranged in the direction shown in the figure on the surface of the prism sheet 19 facing the liquid crystal display panel 3 as shown in the figure. Thus, local brightness unevenness in the prism sheet 19 can be eliminated.

  When the light from the light source 4 is deflected to the liquid crystal display panel 3 side by total reflection on the triangular prism surface of the prism sheet 19, the prism sheet 19 is not irradiated from the portion other than the total reflection surface to the liquid crystal display panel 3 side. 19, a locally bright part (area irradiated to the liquid crystal display panel 3 side) and a dark part (area not irradiated to the liquid crystal display panel 3 side) are generated. In order to solve this problem, the lenticular lens 21 is arranged as shown in the figure, and the light emission direction is expanded in the arrangement direction of the triangular prisms (the left and right direction in the figure), whereby the local in the prism sheet 19 is obtained. Uneven brightness can be eliminated. In this case, in order to effectively reduce local luminance unevenness, the arrangement pitch of the lenticular lenses 21 is preferably several times smaller than the arrangement pitch of the triangular prisms in the prism sheet 19.

  The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope shown in the claims, and the present invention can be obtained by appropriately combining technical means disclosed in different embodiments. Embodiments are also included in the technical scope of the present invention.

  The present invention can be suitably used in the field of display devices such as liquid crystal display devices.

1, 1a, 1b, 1c Liquid crystal display device (display device)
1d, 1e, 1f, 1g Liquid crystal display device (display device)
1h, 1i Liquid crystal display device (display device)
2, 11, 13 Backlight (illumination optical system)
3 Liquid crystal display panel (display panel)
4 Light source 5, 12, 14 Light guide plate 5a, 12a, 14a Incident surface 5b, 12b, 14b Inclined surface 5c, 12c, 14c Outgoing surface 6 Opposing substrate 7 Active matrix substrate 8 Liquid crystal layer 9 MLA (imaging optical lens)
14d Reflecting surface for bending 15 Backlight (illumination optical system)
16, 16 'Light guide plate 16a, 16'a Incident surface 16b, 16'b Inclined surface 16c, 16'c Output surface 17 Backlight (illumination optical system)
18 Substrate whose both surfaces are mirror surfaces 19 Prism sheet 19a, 19b Inclined surface of prism sheet 20 Backlight (illumination optical system)
21 Lenticular lens 22 Backlight (illumination optical system)
23 Light path adjusting light guide plate 23a Incident surface 23b Output surface 24, 25, 27 Backlight (illumination optical system)
26 Reflector 26a Mirror surface R1 Region where two adjacent substrates overlap R2 Region where two adjacent substrates do not overlap

Claims (14)

A display panel in which pixels composed of a plurality of picture elements are provided in a matrix,
A plurality of point light sources having light emission peak values in different wavelength regions;
An illumination optical system for guiding light emitted from the plurality of point light sources and irradiating from the opposite surface side of the display surface of the display panel, and a display device comprising:
The plurality of point light sources are formed in a line in a direction along a light incident position of the illumination optical system,
Between the illumination optical system and the opposite surface side of the display surface of the display panel, a plurality of imaging optical lenses are provided corresponding to the pitch of the pixels provided in the display panel,
The imaging optical lens guides light emitted from the point light source to the opposite side of the display surface of the display panel by reflection or total reflection, and guides light in the same wavelength region in each pixel. Condensing in the area including the center of
The illumination optical system includes a plurality of inclined surfaces for deflecting light emitted from the point light source in the direction of the display panel,
Each of the plurality of inclined surfaces is formed at a predetermined interval in a uniform shape in a direction along the light incident position,
Via the reference inclined plane, which is one in the plurality of inclined surfaces arranged in the center of the region where the plurality of inclined surfaces from the point-shaped light source is formed, directly above the reference inclined plane The shortest distance a to the imaging optical lens, the shortest distance b from the imaging optical lens to the pixel of the display panel, and the focal length f of the imaging optical lens are:
1 / a + 1 / b = 1 / f
Satisfy the relationship
Let M be the number of picture elements provided in each pixel,
A light emitted from one or more point light sources is incident on each of the imaging optical lenses,
The number of the point light sources that make light incident on each of the imaging optical lenses is counted by dividing by the center in the direction along the light incident position of each of the imaging optical lenses. If the number of point light sources on the other side is X,
Each shortest distance L from the point light source via each of the plurality of inclined surfaces to the imaging optical lens located immediately above each inclined surface is:
{2 * X * M / (2 * X * M + 1)} * a <L <{2 * X * M / (2 * X * M-1)} * a
A display device characterized by satisfying the above relationship . A display panel in which pixels composed of a plurality of picture elements are provided in a matrix,
A plurality of point light sources having light emission peak values in different wavelength regions;
An illumination optical system for guiding light emitted from the plurality of point light sources and irradiating from the opposite surface side of the display surface of the display panel, and a display device comprising:
The plurality of point light sources are formed in a line in a direction along a light incident position of the illumination optical system,
Between the illumination optical system and the opposite surface side of the display surface of the display panel, a plurality of imaging optical lenses are provided corresponding to the pitch of the pixels provided in the display panel,
The imaging optical lens guides light emitted from the point light source to the opposite side of the display surface of the display panel by reflection or total reflection, and guides light in the same wavelength region in each pixel. Condensing in the area including the center of
The illumination optical system includes a plurality of inclined surfaces for deflecting light emitted from the point light source in the direction of the display panel,
Each of the plurality of inclined surfaces is formed at a predetermined interval in a uniform shape in a direction along the light incident position,
The reference point is located immediately above the reference inclined surface via a reference inclined surface that is one of the plurality of inclined surfaces arranged in the center of the region where the plurality of inclined surfaces are formed from the point light source. The shortest distance a to the imaging optical lens, the shortest distance b from the imaging optical lens to the pixel of the display panel, and the focal length f of the imaging optical lens are:
1 / a + 1 / b = 1 / f
Satisfy the relationship
Let M be the number of picture elements provided in each pixel,
When light emitted from two or less point light sources is incident on each imaging optical lens,
Each shortest distance L from the point light source via each of the plurality of inclined surfaces to the imaging optical lens located immediately above each inclined surface is:
{2M / (2M + 1)} × a <L <{2M / (2M−1)} × a
A display device characterized by satisfying the above relationship . A display panel in which pixels composed of a plurality of picture elements are provided in a matrix,
A plurality of point light sources having light emission peak values in different wavelength regions;
An illumination optical system for guiding light emitted from the plurality of point light sources and irradiating from the opposite surface side of the display surface of the display panel, and a display device comprising:
The plurality of point light sources are formed in a line in a direction along a light incident position of the illumination optical system,
Between the illumination optical system and the opposite surface side of the display surface of the display panel, a plurality of imaging optical lenses are provided corresponding to the pitch of the pixels provided in the display panel,
The imaging optical lens guides light emitted from the point light source to the opposite side of the display surface of the display panel by reflection or total reflection, and guides light in the same wavelength region in each pixel. Condensing in the area including the center of
The illumination optical system includes a plurality of inclined surfaces for deflecting light emitted from the point light source in the direction of the display panel,
Each of the plurality of inclined surfaces is formed at a predetermined interval in a uniform shape in a direction along the light incident position,
The inclined surface closest to the point light source is set as a reference inclined surface, and the shortest distance a to the imaging optical lens located immediately above the reference inclined surface via the reference inclined surface, and from the imaging optical lens The shortest distance b to the pixel of the display panel and the focal length f of the imaging optical lens are:
1 / a + 1 / b = 1 / f
Satisfy the relationship
Let M be the number of picture elements provided in each pixel,
A light emitted from one or more point light sources is incident on each of the imaging optical lenses,
The number of the point light sources that make light incident on each of the imaging optical lenses is counted by dividing by the center in the direction along the light incident position of each of the imaging optical lenses. If the number of point light sources on the other side is X,
Each shortest distance L from the point light source via each of the plurality of inclined surfaces to the imaging optical lens located immediately above each inclined surface is:
a ≦ L <{(2 × X × M) / (2 × X × M−1)} × a
A display device characterized by satisfying the above relationship . A display panel in which pixels composed of a plurality of picture elements are provided in a matrix,
A plurality of point light sources having light emission peak values in different wavelength regions;
An illumination optical system for guiding light emitted from the plurality of point light sources and irradiating from the opposite surface side of the display surface of the display panel, and a display device comprising:
The plurality of point light sources are formed in a line in a direction along a light incident position of the illumination optical system,
Between the illumination optical system and the opposite surface side of the display surface of the display panel, a plurality of imaging optical lenses are provided corresponding to the pitch of the pixels provided in the display panel,
The imaging optical lens guides light emitted from the point light source to the opposite side of the display surface of the display panel by reflection or total reflection, and guides light in the same wavelength region in each pixel. Condensing in the area including the center of
The illumination optical system includes a plurality of inclined surfaces for deflecting light emitted from the point light source in the direction of the display panel,
Each of the plurality of inclined surfaces is formed at a predetermined interval in a uniform shape in a direction along the light incident position,
The inclined surface furthest from the point light source is defined as a reference inclined surface, the shortest distance a to the imaging optical lens located immediately above the reference inclined surface via the reference inclined surface, and the imaging optical lens The shortest distance b to the pixel of the display panel and the focal length f of the imaging optical lens are:
1 / a + 1 / b = 1 / f
Satisfy the relationship
Let M be the number of picture elements provided in each pixel,
A light emitted from one or more point light sources is incident on each of the imaging optical lenses,
The number of the point light sources that make light incident on each of the imaging optical lenses is counted by dividing by the center in the direction along the light incident position of each of the imaging optical lenses. If the number of point light sources on the other side is X,
Each shortest distance L from the point light source via each of the plurality of inclined surfaces to the imaging optical lens located immediately above each inclined surface is:
{(2 × X × M) / (2 × X × M + 1)} × a <L ≦ a
A display device characterized by satisfying the above relationship . The illumination optical system includes an incident surface on which light emitted from the point light source is incident, a running region that leads to an extraction region that extracts light incident from the incident surface to the outside, and the plurality of inclined surfaces. 5. The display device according to claim 1 , wherein the display device is a light guide plate provided with the extraction region . 6. The light extraction plate according to claim 5 , wherein the extraction region of the light guide plate is formed such that the thickness thereof decreases stepwise through the inclined surfaces as the distance from the incident surface increases. The display device described. The run-up area and the take-out area are provided so as to overlap in plan view,
The display device according to claim 5 , wherein the run-up area and the take-out area are connected by a connection portion including a bent reflection surface . The light guide plate comprises a plurality of
The display device according to claim 5, wherein the two adjacent light guide plates are arranged such that an extraction region of one light guide plate rides on a running region of the other light guide plate . The illumination optical system is
In plan view, the two substrates having mirror surfaces on both sides are provided so as to partially overlap, and the region where the two substrates overlap is an extraction region for extracting the light emitted from the point light source to the outside Is a run-up area that leads to
The area where the two substrates do not overlap is the take-out area,
5. The prism sheet according to claim 1, wherein a prism sheet provided with a triangular prism including the plurality of inclined surfaces is provided on a region where the two substrates do not overlap . Display device. The display device according to claim 9 , wherein a layer in which a plurality of lenticular lenses are formed is disposed between the prism sheet and the plurality of imaging optical lenses . In the region where the two substrates do not overlap, an incident surface on which the light emitted from the point light source is incident, an emission surface formed such that its thickness decreases as the distance from the incident surface increases, The display device according to claim 9, further comprising an optical path adjusting light guide plate provided with an optical path . In the illumination optical system,
A plurality of mirror surfaces are formed in a staircase shape for reflecting each of the light in different wavelength regions emitted from the plurality of point light sources and guiding them to the triangular prism including the plurality of inclined surfaces provided in the prism sheet. A reflector,
The prism sheet provided with the triangular prism, and
2. The reflector according to claim 1, wherein the optical path lengths from the respective point light sources, reflected by the respective mirror surfaces, and guided to the prism sheet are substantially equal. 2. The display device according to 2 . The display device according to claim 12 , wherein a layer in which a plurality of lenticular lenses is formed is disposed between the prism sheet and the plurality of imaging optical lenses . The display device according to claim 1, wherein the display panel is a liquid crystal display panel including a liquid crystal layer .

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