JP4844443B2 - Lighting device and display device - Google Patents

Description

  The present invention relates to a surface light source device, a light guide plate used in the surface light source device, and a display device using the surface light source device, and more particularly to a surface light source device using a point light source such as an LED.

  2. Description of the Related Art Conventionally, display devices configured to display an image by illuminating a spatial light modulation element such as a liquid crystal display element with an illumination device have been proposed.

  FIG. 7 is a perspective view showing a configuration of a display device using a conventional transmissive TFT-LCD (liquid crystal display element).

  FIG. 8 is a cross-sectional view showing a configuration of a display device using a conventional transmissive TFT-LCD (liquid crystal display element).

  In a display device using a non-light emitting spatial light modulation element typified by a liquid crystal display element, the spatial light modulation element 101 is illuminated on the back side of the spatial light modulation element 101 as shown in FIGS. A lighting device (backlight unit) 102 is provided. The white illumination light emitted from the illumination device 102 enters the red pixel electrode (transparent electrode), the green pixel electrode, and the blue pixel electrodes 103R, 103G, and 103B. The illumination light that has passed through the pixels for each color passes through the red, green, and blue color filters 104R, 104G, and 104B to become red light, green light, and blue light. These color lights are combined to display a color image.

  As a lighting device in such a display device, for example, a so-called “directly-type” lighting device having a light source and a light guide plate arranged with the back surface facing the light source is known. In this illuminating device, the illumination light emitted from the light source is incident on the light guide plate from the back surface portion, is emitted from the front surface portion of the light guide plate, and is incident on the spatial light modulation element.

  In addition, as an illumination device in such a display device, a so-called “edge light type” illumination device having a light source and a light guide plate disposed with a side surface facing the light source is known. In this illumination device, the illumination light emitted from the light source is incident on the light guide plate from the side surface portion, is emitted from the surface portion of the light guide plate, and is incident on the spatial light modulation element. The illumination light that has passed through the back surface of the light guide plate is reflected by the reflection sheet disposed on the back side of the light guide plate and returned to the light guide plate.

  Further, in these illumination devices, the surface portion (exit surface) of the light guide plate is a prism lens sheet for condensing illumination light emitted from the surface portion within the viewing angle to improve the luminance, You may provide the diffusion plate and diffusion sheet for making it uniform.

  And as a light source in such an illuminating device, light emitting elements, such as a cold cathode fluorescent lamp used as a linear light source, and a light emitting diode (henceforth "LED") used as a point light source, are used. When a light emitting element is used as a light source, for example, as described in Patent Document 1 and Patent Document 2, a plurality of light emitting elements are arranged in a state of being separated from each other, and the incident surface (back surface portion) of the light guide plate is arranged. Or a side surface portion).

  Note that, in the illumination devices described in Patent Document 1 and Patent Document 2, in order to facilitate positioning of the light emitting element with respect to the light guide plate, the light guide plate is provided with a recess for fitting the light emitting element. The light emitting element is positioned with respect to the light guide plate by being fitted into a recess provided in the light guide plate.

Utility Model Registration No. 2578529 JP-A-10-82915

  By the way, in the illumination device of the display device as described above, when a plurality of light emitting elements are arranged and used as a light source, the luminance unevenness corresponding to the distance from the light emitting element occurs in the illumination light emitted from the light guide plate. In particular, when the interval between the light emitting elements is wide, the luminance unevenness becomes remarkable. Therefore, in such a lighting device, the interval between the light emitting elements cannot be widened, so that it is difficult to reduce the number of light emitting elements to facilitate manufacturing and reduce manufacturing costs.

  And when using the element which emits red light, the element which emits green light, and the element which emits blue light as a light emitting element, in order to synthesize these color lights into white illumination light, It is necessary to use a light guide plate having a sufficient thickness or to provide a light mixing chamber so that each color light is sufficiently mixed. Use of such a sufficiently thick light guide plate and light mixing chamber hinders downsizing of the display device.

  Moreover, even if white illumination light with less luminance unevenness is obtained by using a sufficiently thick light guide plate or light mixing chamber, the illumination light is converted into a red component, a green component, or a blue component by a color filter. Only is selected and transparent. At this time, since 2/3 of the illumination light is absorbed by the color filter, the illumination light used for image display is 1/3 or less of the component. Due to such a loss of illumination light, more light emitting elements are required to obtain a display image with a necessary luminance, and the number of light emitting elements is reduced to facilitate manufacturing and reduce manufacturing costs. It is difficult to plan.

  Therefore, the present invention has been proposed in view of the above circumstances, and in a lighting device using a light emitting element that emits red light, a light emitting element that emits green light, and a light emitting element that emits blue light as a light source, Loss of illumination light due to the use of a filter can be prevented, and the required illumination brightness can be obtained, while the number of light-emitting elements can be reduced to facilitate manufacturing and reduce manufacturing costs. An object of the present invention is to provide a lighting device that can be miniaturized by reducing the thickness.

  Further, according to the present invention, by using such an illuminating device, a display image with sufficient luminance can be obtained, but a good color reproducibility can be obtained by not using a color filter, and miniaturization can be achieved. An object is to provide a display device.

  In order to solve the above-described problems, an illumination device according to the present invention has the following configuration.

[Configuration 1]
A plurality of light transmissive light guide plates stacked in at least three layers, a plurality of cylindrical lenses disposed on the side surface portions of each light transmissive light guide plate, and a side surface portion of each light transmissive light guide plate. The plurality of cylindrical lenses convert a light beam emitted from the plurality of light emitting elements into a parallel light beam, and enters the light transmissive light guide plate. Light beams of different colors for each transmissive light guide plate are incident on the corresponding light transmissive light guide plate through a cylindrical lens, and each light transmissive light guide plate has a traveling direction of the light beam that travels inside each light transmissive light guide plate. A plurality of reflecting surfaces that change the direction of light are emitted on the back side, and light beams whose traveling direction has been changed by these reflecting surfaces are emitted to the front side, and the plurality of reflecting surfaces allow parallel light beams to enter the corresponding predetermined pixels, respectively. It is installed in the position And it is characterized in and.

  The display device according to the present invention has the following configuration.

[Configuration 2 ]
A plurality of light transmissive light guide plates stacked in at least three layers, a plurality of cylindrical lenses disposed on the side surface portions of each light transmissive light guide plate, and a side surface portion of each light transmissive light guide plate. A plurality of light-emitting elements and each light-transmitting light guide plate are formed on the back side of each light-transmitting light guide plate. A plurality of cylindrical lenses are emitted from a plurality of light emitting elements , each having a plurality of reflecting surfaces to be emitted to the front side of the light transmissive light guide plate and a spatial light modulation element disposed on the front side of each light transmissive light guide plate. The converted light flux is converted into a parallel light flux and incident into the light transmissive light guide plate, and the plurality of light emitting elements emit light beams of different one of the three primary colors through the cylindrical lens for each light transmissive light guide plate. , Enter into the corresponding light transmissive light guide plate, The light beam of the first color among the three primary colors emitted from the light transmissive light guide plate is incident on the pixel corresponding to the first color in the spatial light modulator and is emitted from the second light transmissive light guide plate. Of the three primary colors, the light flux of the second color is incident on the pixel corresponding to the second color in the spatial light modulator, and the third color of the three primary colors emitted from the third light-transmissive light guide plate. the light beam, is incident on the pixels corresponding to the third color in the spatial light modulator, have rows display of a color image, a plurality of reflecting surfaces, the position entering the predetermined pixel corresponding parallel light fluxes respectively It is characterized by being installed

  In the illuminating device according to the present invention, having the configuration 1, the plurality of light transmissive light guide plates stacked in at least three layers change the traveling direction of the light beam traveling inside each light transmissive light guide plate. Since the light beam whose traveling direction is changed by the reflecting surface is emitted to the front side, the light beams of different colors for each light transmissive light guide plate incident on each light transmissive light guide plate are not mixed with each other, The light is emitted at different positions according to the positions of the plurality of reflecting surfaces.

  Therefore, in this illumination device, illumination light of a predetermined color can be incident on a predetermined pixel of the spatial light modulation element without using a color filter. In this lighting device, there is no loss of illumination light due to the use of a color filter, so that it is possible to facilitate manufacturing and reduce manufacturing cost by reducing the number of light emitting elements while obtaining necessary illumination brightness. In addition, power saving is possible. Furthermore, it is possible to reduce the size by reducing the thickness of the light guide plate.

And in the display apparatus which concerns on this invention, by having the structure 2 , the light beam of the 1st color of the three primary colors inject | emitted from the 1st light transmissive light guide plate is 1st in a spatial light modulation element. A light beam of the second color of the three primary colors that is incident on the pixel corresponding to the color and is emitted from the second light-transmissive light guide plate is incident on the pixel corresponding to the second color in the spatial light modulator, Since the light beam of the third color among the three primary colors emitted from the third light-transmissive light guide plate is incident on the pixel corresponding to the third color in the spatial light modulator, and displays a color image. There is no loss of illumination light due to the use of a color filter, and it is possible to reduce the number of light emitting elements while simplifying manufacturing and reducing manufacturing costs while obtaining a display image with the required brightness. It is also possible. Furthermore, it is possible to reduce the size by reducing the thickness of the light guide plate.

  That is, the present invention prevents a loss of illumination light due to the use of a color filter in a lighting device using a light emitting element that emits red light, a light emitting element that emits green light, and a light emitting element that emits blue light as a light source. While reducing the number of light-emitting elements, it is possible to facilitate manufacturing and reduce manufacturing costs and reduce power consumption while reducing the number of light-emitting elements, and reducing the thickness of the light guide plate. Accordingly, it is possible to provide a lighting device that can be downsized.

  In addition, according to the present invention, by using such an illuminating device, a display image with sufficient luminance can be obtained, but good color reproducibility can be obtained by not using a color filter. It is possible to provide a display device that can be downsized.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

[Embodiment of Lighting Device]
FIG. 1 is a perspective view showing configurations of a lighting device and a display device according to the present invention.

  As shown in FIG. 1, the lighting device according to the present invention includes a plurality of light transmissive light guide plates 1, 2, and 3 stacked in at least three layers. In this embodiment, first to third light transmissive light guide plates 1, 2, 3 are stacked, and a second light transmissive light guide plate is provided on the front side of the first light transmissive light guide plate 1. 2 is disposed, and the third light transmissive light guide plate 3 is disposed on the front side of the second light transmissive light guide plate 2.

  The 1st thru | or 3rd light transmissive light-guide plates 1,2,3 are formed in flat form with the transparent material, and are laminated | stacked in parallel. These light transmissive light guide plates 1, 2, and 3 are main surface portions having a size and shape substantially equal to the display surface of the spatial light modulation element in the case where a display device is configured using the illumination device and the spatial light modulation element. It is formed.

  And this illuminating device has the some light source 4,5,6 installed facing the side part (incident surface) of each light transmissive light-guide plate 1,2,3. Each of the first to third light sources 4, 5, and 6 includes a plurality of light emitting elements. In other words, each of the light sources 4, 5, and 6 is a light emitting element that is a point light source, for example, an LED array light source configured by arranging a plurality of LED chips on a substrate in a separated state. Note that a semiconductor laser may be used as the light emitting element.

  FIG. 2 is a side view showing the configuration of the illumination device and the display device according to the present invention.

  As shown in FIG. 2, these light sources 4, 5, 6 are light transmissive light guide plates 1, 2, 3 that correspond to different light fluxes (illumination light) for each light transmissive light guide plate 1, 2, 3. Incidently enter. In other words, the first light source 4 transmits a first color, for example, a red light beam into the first light transmissive light guide plate 1 from the side surface (incident surface) of the first light transmissive light guide plate 1. Make it incident. The second light source 5 transmits a second color, for example, a green light beam into the second light transmissive light guide plate 2 from the side surface (incident surface) of the second light transmissive light guide plate 2. Make it incident. Then, the third light source 6 transmits a third color, for example, a blue light beam into the third light transmissive light guide plate 3 from the side surface (incident surface) of the third light transmissive light guide plate 3. Make it incident.

  The light beams incident on the light transmissive light guide plates 1, 2, 3 from the light sources 4, 5, 6 are parallel light beams and are incident on the side surfaces (incident surfaces) of the light transmissive light guide plates 1, 2, 3. On the other hand, the light is incident perpendicularly and travels in the light transmissive light guide plates 1, 2, 3 in a direction parallel to the main surface portions of the light transmissive light guide plates 1, 2, 3.

  Except for the side surfaces (incident surfaces) from the light sources 4, 5, 6 to the light transmissive light guide plates 1, 2, 3, high reflection such as a reflector (not shown) or a silver or white tape member. It is desirable to cover it with a member.

  The light transmissive light guide plates 1, 2, and 3 each have a plurality of reflecting surfaces 7, 8, and 9 that change the traveling direction of the light beams traveling inside the light transmissive light guide plates 1, 2, and 3. Have. The light transmissive light guide plates 1, 2, 3 change the traveling direction by reflecting the light beams incident from the light sources 4, 5, 6 and traveling inside by the reflecting surfaces 7, 8, 9, respectively. Inject to the side. These reflective surfaces 7, 8, 9 are formed by inclining predetermined portions of the back portions of the light transmissive light guide plates 1, 2, 3. That is, the light beam traveling inside each light transmissive light guide plate 1, 2, 3 is deflected in the traveling direction by internal reflection at each reflection surface 7, 8, 9. Accordingly, each light transmissive light guide plate 1, 2, 3 is thickest on the incident surface side of the light beam from each light source 4, 5, 6, and passes through each reflecting surface 7, 8, 9 along the traveling direction of this light beam. As the thickness gradually decreases.

  FIG. 3 is a side view showing the shape of the reflecting surface, which is the main part of the light transmissive light guide plate of the lighting device according to the present invention.

  As shown in FIG. 3, the plurality of reflecting surfaces 7, 8, 9 in each light transmissive light guide plate 1, 2, 3 has a shape in which a plurality of inclined surfaces 10 are arranged on a predetermined inclined surface. . Each inclined surface 10 is an inclined surface of 45 ° with respect to the main surface portion of each light transmissive light guide plate 1, 2, 3. A space between one inclined surface 10 and the other inclined surface 10 is parallel to the main surface portion of each light transmissive light guide plate 1, 2, 3, that is, parallel to the traveling direction of the light beam. The light beams incident on the light transmissive light guide plates 1, 2, 3 from the light sources 4, 5, 6 are reflected by the inclined surfaces 10 in the reflection surfaces 7, 8, 9, and the traveling direction is deflected by 90 °, The light transmissive light guide plates 1, 2, 3 are emitted perpendicularly to the front-side main surface portion (exit surface).

  In each of the reflecting surfaces 7, 8, 9, the reflecting surfaces 7, 8, 8 having a projected area nb (n is the number of the inclined surfaces 10 in each reflecting surface 7, 8, 9) in the light exit direction of each inclined surface 10 The ratio (nb / a) (area occupancy) to the projected area a in the emission direction of the entire luminous flux 9 is, for example, about 15%.

  As shown in FIG. 2, the light beam that has entered the first light-transmissive light guide plate 1 from the first light source 4 and has traveled straight through the first light-transmissive light guide plate 1 without entering the reflecting surface 7 is The light enters the other reflection surface 7 and is deflected by 90 ° in the traveling direction. In this way, the light beam incident from the first light source 4 sequentially enters the plurality of reflecting surfaces 7 and is deflected in the traveling direction by 90 °.

  Similarly, a light beam that is incident on the second light-transmissive light guide plate 2 from the second light source 5 and travels straight through the second light-transmissive light guide plate 2 without entering the reflective surface 8 is transmitted to another reflective surface. 8 is deflected by 90 ° in the traveling direction. In this way, the light beam incident from the second light source 5 sequentially enters the plurality of reflecting surfaces 8 and is deflected by 90 ° in the traveling direction.

  Further, the light beam that has entered the third light-transmissive light guide plate 3 from the third light source 6 and has traveled straight through the third light-transmissive light guide plate 3 without entering the reflective surface 9 is transmitted to the other reflective surface 9. And the direction of travel is deflected by 90 °. In this way, the light beam incident from the third light source 6 sequentially enters the plurality of reflecting surfaces 9 and is deflected by 90 ° in the traveling direction.

  The light beam whose traveling direction is deflected by 90 ° in the first light-transmissive light guide plate 1 is emitted from the front-side main surface portion (exit surface) of the first light-transmissive light guide plate 1, and the second and third light beams are emitted. The light is transmitted through the transmissive light guide plates 2 and 3 and is emitted to the front side of the third light transmissive light guide plate 3. On the optical path of the light beam emitted from the first light transmissive light guide plate 1, the reflection surface 8 in the second light transmissive light guide plate 2 and the reflection surface 9 in the third light transmissive light guide plate 3 do not exist. It is like that. That is, the plurality of reflecting surfaces 7, 8, and 9 in the light transmissive light guide plates 1, 2, and 3 have different distances from the side surfaces (incident surfaces) of the light transmissive light guide plates 1, 2, and 3, respectively. Is formed.

  In addition, the light beam whose traveling direction is deflected by 90 ° in the second light transmissive light guide plate 2 is emitted from the front-side main surface portion (exit surface) of the second light transmissive light guide plate 2, and is third light transmissive. The light is transmitted through the transmissive light guide plate 3 and emitted to the front side of the third light transmissive light guide plate 3. The reflection surface 9 of the third light transmissive light guide plate 3 does not exist on the optical path of the light beam emitted from the second light transmissive light guide plate 2.

  Then, the light beam whose traveling direction is deflected by 90 ° in the third light transmissive light guide plate 3 is emitted from the front side main surface portion (exit surface) of the third light transmissive light guide plate 3 to the front side. In this way, on the front side of the third light transmissive light guide plate 3, light beams whose traveling directions are deflected by 90 ° in the light transmissive light guide plates 1, 2, 3 are emitted from different positions. .

  By the way, each of the transmissive light guide plates 1, 2, 3 in this lighting device can be easily formed by extrusion molding, pressure molding, or injection molding using a thermoplastic resin. That is, the reflecting surfaces 7, 8, 9 including the plurality of inclined surfaces 10 can be integrally and easily formed by a general molding process using a mold. In this case, in each of the light transmissive light guide plates 1, 2, 3, the plurality of reflection surfaces 7, 8, 9 are respectively from the side surfaces (incident surfaces) of the light transmissive light guide plates 1, 2, 3. The distance is formed differently. The lighting device as described above can be configured by laminating the light transmissive light guide plates 1, 2, 3 formed in this way with the side surfaces aligned.

Embodiment of display device
In the display device according to the present invention configured using the illumination device described above, the light beam emitted to the front side of the third light-transmissive light guide plate 3 of the illumination device is as shown in FIGS. 1 and 2. Then, the light is incident on a liquid crystal display element (transmission type TFT-LCD) 16 which is a spatial light modulation element. 1 and 2, only the incident side polarizing filter 11 of the liquid crystal display element 16, the sealing glass 12 on the light beam incident side (back side), and the pixel electrodes (transparent electrodes) 13R, 13G, and 13B are shown. However, in the liquid crystal display element 16, a liquid crystal layer (not shown) is formed on the front side of the pixel electrodes 13R, 13G, and 13B. The liquid crystal layer is sealed with a sealing glass on the light beam incident side and a sealing glass on the light beam emission side (front side) (not shown) on the front side of the liquid crystal layer.

  In order to perform color display in this display device, the light beam emitted from the first light source 4 in the illumination device is set to the first color of the three primary colors, for example, red, and the light beam emitted from the second light source 5 is set to the one of the three primary colors. The second color, for example, green, is used, and the light beam emitted from the third light source 6 is the third of the three primary colors, for example, blue.

  The first color light beam emitted from the first light transmissive light guide plate 1 passes through the polarizing filter 11 and the sealing glass 12 on the light beam incident side, and then the pixel electrode corresponding to the first color in the liquid crystal display element 16. (Transparent electrode) Enters 13R. The second color light beam emitted from the second light-transmissive light guide plate 2 corresponds to the second color in the liquid crystal display element 16 through the polarizing filter 11 and the sealing glass 12 on the light beam incident side. The light enters the pixel electrode 13G. The light beam of the third color emitted from the third light-transmissive light guide plate 3 corresponds to the third color in the liquid crystal display element 16 through the polarizing filter 11 and the sealing glass 12 on the light beam incident side. The light enters the pixel electrode 13B.

  In this way, the light beams of the respective colors are incident on the pixel electrodes 13R, 13G, and 13B corresponding to the respective colors, and are polarized and modulated for each pixel by passing through the liquid crystal layers corresponding to the pixel electrodes 13R, 13G, and 13B. Thus, the light is emitted from the sealing glass on the light emission side to the front side. The light beam emitted to the front side passes through an emission side polarizing filter whose optical axis direction is orthogonal to the incident side polarizing filter 11, and is emitted after intensity modulation. A color display is performed by intensity-modulating the luminous flux of each color for each pixel.

  As shown in FIG. 2, it is desirable to form a cylindrical lens (or microlens) array 14 on the incident side polarization filter 11 on the incident surface of the light beam from the illumination device. The cylindrical lens (or microlens) array 14 is configured by arranging a plurality of cylindrical lenses (or microlenses), and the bus of each cylindrical lens (or microlens) is connected to each light source 4, 5, 6. The direction is orthogonal to the direction of incidence of the light flux on each light transmissive light guide plate 1, 2, 3. With this cylindrical lens (or microlens) array 14, the light beam incident from the illumination device is once converged in the incident direction of the light beam to each light transmissive light guide plate 1, 2, 3 and then diffused in the same direction. However, it enters the corresponding pixel electrodes 13R, 13G, and 13B. Since the light flux after passing through the pixel electrodes 13R, 13G, and 13B is further diffused, the viewing angle (the range in which the display image can be seen) in the display device can be expanded.

  The cylindrical lens (or microlens) array may be provided on the front surface (exit side) of the third light transmissive light guide plate 3 without being provided on the incident side polarizing filter 11, or on the incident side polarizing filter 11. And you may provide in both the 3rd light transmissive light-guide plates 3. FIG.

  FIG. 4 is a front view showing the configuration of the display device according to the present invention.

  In this display device, when the display screen (the display surface of the spatial light modulation element (liquid crystal display element 16)) is rectangular, as shown in FIG. It is desirable to provide along either one of the short sides of the screen. This is because if the light sources 4, 5 and 6 are provided along the long sides, the number of light emitting elements forming the light sources 4, 5 and 6 must be increased.

  FIG. 5 is a side view showing another example of the configuration of the display device according to the present invention.

  Further, in this display device, the light sources 4, 5, and 6 in the illumination device may be provided along both sides of the display screen as shown in FIG. In this case, since each light transmissive light guide plate 1, 2, 3 receives a light beam from both side surfaces, two sets of each light transmissive light guide plate 1, 2, 3 in the above-described lighting device are arranged in parallel. It becomes the composition which did.

  In this display device, the light sources 4, 5, and 6 do not always have to turn on all the light emitting elements. For example, when the number of light emitting elements forming each of the light sources 4, 5, and 6 is n, the driving signal of each light emitting element is controlled, and each of the three light emitting elements in the period obtained by dividing one frame time of the display image by n. A straight line illuminated by this lighting device by sequentially turning on (one for each light source 4, 5, 6) and turning on all [n × 3] light emitting elements within one frame time. Can be scanned.

  Then, the linear region illuminated by the illumination device is synchronized with the writing line of the image data written line-sequentially into the liquid crystal display element 16 by the pixel circuit of the liquid crystal display element 16, thereby performing image display by line scanning. be able to.

[Other Embodiments of Lighting Device]
FIG. 6 is a side view showing a configuration of a main part in another embodiment of the lighting device according to the present invention.

  In the illumination device according to the present invention, as shown in FIG. A cylindrical lens (or microlens) 15 may be formed. With this cylindrical lens (or microlens) 15, the light beam from each of the light sources 4, 5, 6 can be converted into a highly accurate parallel light beam in each of the light transmissive light guide plates 1, 2, 3. , 5 and 6 can be improved, and the light intensity distribution of the light beam emitted to the front side of the illumination device can be made uniform to reduce unevenness in the emitted light illuminance.

  The cylindrical lens (or microlens) 15 is preferably an aspherical cylindrical lens (or microlens) that is optimized according to the light distribution angle from the light emitting elements of the light sources 4, 5, and 6. The light transmissive light guide plates 1, 2, and 3 including the cylindrical lens (or microlens) 15 are integrally and easily formed by a general molding process using a mold. be able to.

(Example of display device)
The above-described display device according to the present invention was configured using an LED array light source as each of the light sources 4, 5, and 6. The light distribution angle emitted from the LED chip of the LED array light source was about 80 ° (± 40 °) in the horizontal direction (LED chip arrangement direction), and 40 ° (± 20 °) in the vertical direction. A cylindrical lens (or microlens) 15 was formed on the side surface of each light transmissive light guide plate 1, 2, 3.

  When 40 lm (lumen) red, green, and blue light beams are emitted from the light sources 4, 5, and 6, the total light flux incident on the spatial light modulator (liquid crystal display element 16) is 79.28 lm. Met. That is, the maximum light utilization efficiency [total amount of light incident on the liquid crystal display element / total amount of light emitted from the light source] = 79.28 / (40 × 3) = 0.661, which is 66.1%. The light use efficiency in the illumination device (backlight) for the display element was almost the same. In this display device, since there is no absorption by the color filter as in the conventional lighting device, as a result, the maximum light utilization efficiency is three times that of the conventional lighting device.

  Therefore, in the case of illuminating a transmissive liquid crystal display element (TFT-LCD) using the illumination device according to the present invention, the number of light-emitting elements necessary for obtaining a predetermined illuminance is the same as that of the conventional illumination device. It becomes possible to reduce to 1/3. In addition, the power consumption can be reduced to one-third that of the conventional lighting device. Furthermore, the thickness of each light transmissive light guide plate 1, 2, 3 can be made thinner than that of a conventional lighting device.

It is a perspective view which shows the structure of the illuminating device and display apparatus which concern on this invention. It is a side view which shows the structure of the illuminating device and display apparatus which concern on this invention. It is a side view which shows the shape of the reflective surface which is the principal part of the light transmissive light-guide plate of the illuminating device which concerns on this invention. It is a front view which shows the structure of the display apparatus which concerns on this invention. It is a side view which shows the other example of a structure of the display apparatus which concerns on this invention. It is a side view which shows the structure of the principal part in other embodiment of the illuminating device which concerns on this invention. It is a perspective view which shows the structure of the display apparatus using the conventional transmissive | pervious TFT-LCD (liquid crystal display element). It is sectional drawing which shows the structure of the display apparatus using the conventional transmissive | pervious TFT-LCD (liquid crystal display element).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st light transmissive light guide plate 2 2nd light transmissive light guide plate 3 3rd light transmissive light guide plate 4 1st light source 5 2nd light source 6 3rd light source 7 Reflective surface 8 Reflective surface 9 Reflection Surface 10 Inclined surface 13R Red pixel electrode 13G Green pixel electrode 13B Blue pixel electrode 14 Cylindrical lens (or microlens) array 15 Cylindrical lens (or microlens)
16 Liquid crystal display elements

Claims (2)

A plurality of light transmissive light guide plates laminated in at least three layers;
A plurality of cylindrical lenses disposed on a side surface of each light transmissive light guide plate;
A plurality of light emitting elements installed facing the side surface of each light transmissive light guide plate,
The plurality of cylindrical lenses convert a light beam emitted from the plurality of light emitting elements into a parallel light beam and enter the light transmissive light guide plate,
The plurality of light emitting elements make light beams of different colors for each light transmissive light guide plate enter the corresponding light transmissive light guide plates through the cylindrical lenses,
Each of the light transmissive light guide plates has a plurality of reflection surfaces on the back side that change the traveling direction of the light beam traveling inside each light transmissive light guide plate. Inject to the front side ,
The illuminating device according to claim 1, wherein the plurality of reflecting surfaces are installed at positions where the parallel light beams are incident on predetermined corresponding pixels . A plurality of light transmissive light guide plates laminated in at least three layers;
A plurality of cylindrical lenses disposed on a side surface of each light transmissive light guide plate;
A plurality of light emitting elements installed facing the side surface of each light transmissive light guide plate;
Each light transmissive light guide plate is formed inside each light transmissive light guide plate and is positioned on the back side of each light transmissive light guide plate, and changes the traveling direction of the light beam traveling inside these light transmissive light guide plates. A plurality of reflecting surfaces to be emitted to the front side of the
A spatial light modulator disposed on the front side of each light transmissive light guide plate,
The plurality of cylindrical lenses convert a light beam emitted from the plurality of light emitting elements into a parallel light beam and enter the light transmissive light guide plate,
The plurality of light-emitting elements make light beams of different one of the three primary colors enter the corresponding light-transmissive light guide plate through the cylindrical lens for each light-transmissive light guide plate,
The light beam of the first color among the three primary colors emitted from the first light-transmissive light guide plate is incident on the pixel corresponding to the first color in the spatial light modulator,
The light flux of the second color among the three primary colors emitted from the second light transmissive light guide plate is incident on the pixel corresponding to the second color in the spatial light modulator,
The light beam of the third color among the three primary colors emitted from the third light transmissive light guide plate is incident on the pixel corresponding to the third color in the spatial light modulator,
There line the display of the color image,
The display device according to claim 1, wherein the plurality of reflecting surfaces are disposed at positions where the parallel light beams are incident on predetermined corresponding pixels .

Images