WO2011118563A1 - Plaque de guidage de lumière à déviation, appareil d'éclairage et appareil d'affichage du type projection - Google Patents

Plaque de guidage de lumière à déviation, appareil d'éclairage et appareil d'affichage du type projection Download PDF

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Publication number
WO2011118563A1
WO2011118563A1 PCT/JP2011/056760 JP2011056760W WO2011118563A1 WO 2011118563 A1 WO2011118563 A1 WO 2011118563A1 JP 2011056760 W JP2011056760 W JP 2011056760W WO 2011118563 A1 WO2011118563 A1 WO 2011118563A1
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Prior art keywords
light
light guide
refracting
polarized light
incident
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PCT/JP2011/056760
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English (en)
Japanese (ja)
Inventor
悟郎 齋藤
雅雄 今井
慎 冨永
昌尚 棗田
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日本電気株式会社
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Priority to JP2012507001A priority Critical patent/JPWO2011118563A1/ja
Publication of WO2011118563A1 publication Critical patent/WO2011118563A1/fr

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
    • G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining

Definitions

  • the present invention relates to a polarizing light guide plate from which polarized light is emitted, and more particularly, to a polarizing light guide plate of a projection display device represented by a display device such as a mobile phone or a liquid crystal projector.
  • Patent Document 1 discloses an illumination device that emits light having polarization.
  • the illumination device includes an isotropic waveguide, a lamp provided on an end face of the waveguide, a reflector provided on an end face opposite to the side provided with the lamp of the waveguide, and a waveguide. And an anisotropic layer provided on the road through an adhesive layer.
  • the waveguide-side surface is the first prism surface, and the opposite surface is the second prism surface.
  • the first prism surface is formed by periodically forming a microstructure having a triangular wave cross section along the first direction.
  • the second prism surface is an exit surface of the illumination device, and a fine structure whose cross section is a triangular wave shape is periodically formed along a second direction orthogonal to the first direction.
  • the first polarized light out of the light traveling from the waveguide toward the anisotropic layer is refracted by the first prism surface, but the polarization state is different from that of the first polarized light.
  • the second polarized light passes through the first prism surface as it is. That is, the first prism surface has an action of separating incident light (unpolarized light) into first and second polarized light.
  • the first polarized light refracted by the first prism surface is emitted from the second prism surface.
  • the second prism surface has a function of collimating the emitted first polarized light in a predetermined direction.
  • the second polarized light transmitted through the first prism surface is reflected by the second prism surface toward the waveguide side.
  • the illumination device described in Patent Document 1 not only collimated light (emitted light near the front surface) but also divergent light is emitted from the second prism surface (emitted surface).
  • the emitted light is divergent light having a horizontal angle of 60 ° to 70 ° and a vertical angle of 20 ° to 40 °, and a horizontal angle of ⁇ 60 °.
  • the divergent light is shown with ⁇ 70 ° and a vertical angle of 20 ° to 40 °.
  • the illumination device described in Patent Document 1 has the following problems because the angular spread (outgoing angle) of outgoing light due to divergent light is large.
  • a projection display device that irradiates a display element with light from a light source and projects an image formed by the display element by a projection optical system
  • an etendue determined by the light emission cross-sectional area of the light source and the divergence angle of the emitted light Design that takes into account the constraints imposed by That is, in order to use all of the light emitted from the light source as projection light, the product value of the light emission cross-sectional area of the light source and the divergence angle of the emitted light is expressed by the display area of the display element and the F number of the projection optical system. It is necessary to make the value less than the product of the determined capture angle (solid angle). If this condition is not satisfied, part of the light from the light source is not used as projection light.
  • the divergent light emitted from the illumination device becomes stray light and leaks out of the device, or the stray light enters the projection optical system, thereby degrading the image quality of the projected image. For this reason, it is necessary to provide a member that absorbs or blocks such stray light in the projection display device, and the cost of the device increases accordingly.
  • the object of the present invention is to solve the above-mentioned problems due to etendue restrictions and the problem of viewing angle dependence, and to suppress the spread of the emission angle, a polarizing light guide plate using the same, an illumination device using the same, and a projection type It is to provide a display device.
  • the polarizing light guide plate of the present invention comprises: A light guide through which light incident from the end face propagates, A quarter wave plate formed on one surface of the light guide; A reflective layer provided on the other surface facing the one surface of the light guide; A plurality of refractive indexes with respect to a first polarized light that is larger than a refractive index of the light guide, and a refractive index with respect to a second polarized light having a polarization state different from that of the first polarized light is the same as the refractive index of the light guide.
  • a first refracting portion of A plurality of second refracting sections having a refractive index with respect to the first polarized light smaller than a refractive index of the light guide and a refractive index with respect to the second polarized light being the same as the refractive index of the light guide;
  • the plurality of first and second refracting portions are provided in the light guide so as to face the one surface, and at least in a first direction intersecting a direction perpendicular to the end surface, The first refracting portions and the second refracting portions are alternately arranged.
  • the lighting device of the present invention is The polarizing light guide plate, And at least one light source provided on an end surface of the polarizing light guide plate.
  • the projection display device of the present invention is The above lighting device; A display element irradiated with light emitted from the illumination device; A projection optical system for projecting an image formed by the display element.
  • Another projection display device of the present invention is A lighting device of each color of red, green, and blue composed of the lighting device described above, A first display element irradiated with red light emitted from the red illumination device; A second display element irradiated with green light emitted from the green illumination device; A third display element irradiated with blue light emitted from the blue illumination device; A projection optical system for projecting each color image displayed on the first to third display elements.
  • FIG. 1 It is a schematic diagram which shows the structure of the polarizing light-guide plate which is the 1st Embodiment of this invention. It is a schematic diagram which shows an example of the two-dimensional arrangement
  • FIG. 8A It is a schematic diagram which shows an example of a structure of the refractive part which satisfy
  • FIG. 1 It is a schematic diagram which shows one Example of arrangement
  • FIG. 14B It is a schematic diagram which shows the cross-sectional shape of the prism sheet of the polarizing light guide plate shown to FIG. 14B. It is a schematic diagram which shows another modification of the polarizing light-guide plate shown in FIG. It is a schematic diagram which shows the structure of the polarizing light-guide plate which is the 2nd Embodiment of this invention. It is a schematic diagram for demonstrating the emission conditions with respect to the 1st polarized light in the 1st refractive part of the polarizing light-guide plate shown in FIG. It is a schematic diagram for demonstrating the 1st light guide condition with respect to the 1st polarized light in the 1st refractive part of the polarizing light guide plate shown in FIG.
  • FIG. 1 is a schematic diagram showing a configuration of a polarizing light guide plate according to the first embodiment of the present invention.
  • the polarization light guide plate is used in a projection display device typified by a liquid crystal projector, and is provided with a light guide 10 and a quarter provided so as to sandwich the light guide 10.
  • Refraction part The cross section shown in FIG. 1 is a surface obtained by cutting the polarizing light guide plate along the first direction.
  • the first direction is a direction intersecting or orthogonal to a direction perpendicular to a predetermined end surface of the light guide 10 (an end surface on the side where the light source is disposed).
  • the light guide 10 is plate-shaped and made of a material having an isotropic refractive index.
  • Refractive index isotropic means that the refractive indexes for the first and second polarized lights (P-polarized light and S-polarized light) having different polarization states are the same.
  • the refractive index of the light guide 10 is n0.
  • the light guide 10 has a plurality of end faces (usually four end faces), and light from the light source is incident on at least one of the end faces.
  • the light source is, for example, a semiconductor light source such as a light emitting diode (LED) or a semiconductor laser (LD), or a light source called a solid light source.
  • the refractive index of the quarter wave plate 11 is substantially equal to the refractive index n0 of the light guide 10.
  • the surface of the quarter-wave plate 11 opposite to the light guide 10 is an emission surface 11a.
  • the refracting portions 13 and 14 are made of a material having refractive index anisotropy, and the cross-sectional shape thereof is a rectangular shape.
  • the refractive index anisotropy indicates that the refractive indexes for the first and second polarized lights are different.
  • the refractive index for the first polarized light in the refracting section 13 is n1
  • the refractive index for the second polarized light is n2.
  • the refractive index for the first polarized light is n1 '
  • the refractive index for the second polarized light is n2'.
  • the refracting portions 13 and the refracting portions 14 are provided periodically and alternately in at least the first direction.
  • the arrangement of the refracting portions 13 and 14 may be a one-dimensional arrangement or a two-dimensional arrangement.
  • FIG. 2 schematically shows a two-dimensional arrangement of the refracting portions 13 and 14.
  • the refracting portions 13 and 14 are alternately arranged in the first direction described in FIG. 1 and are alternately arranged in a second direction intersecting or orthogonal to the first direction.
  • the refracting portions 13 and 14 may be alternately arranged only in the first direction.
  • the size (height, length and width) of the refracting portions 13 and 14 and the interval between the refracting portions 13 and 14 are appropriately set in consideration of light guide conditions and emission conditions.
  • the height is a thickness in a direction perpendicular to the surface 10a on the side where the quarter wavelength plate 11 is provided.
  • the length and width are the lengths of two intersecting sides when the refracted portion is viewed from a direction perpendicular to the surface 10a.
  • a part of the light (non-polarized light) incident on the first end face of the light guide 10 from the light source is emitted from the output surface 11a of the quarter wavelength plate 11 and the reflection layer 12. And propagates in the light guide 10 toward the second end face facing the first end face. In this propagation process, a part of the light enters the refracting parts 13 and 14.
  • the refracting units 13 and 14 are the first and second polarized light between the emission condition for emitting the first polarized light from the emission surface 11a and between the emission surface 11a of the quarter-wave plate 11 and the reflective layer 12. Although it is configured to satisfy the light guide condition for guiding light, the conditions are different from each other.
  • FIG. 3A is a diagram for explaining the emission conditions of the refracting unit 13 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG. 2 is a schematic diagram of a cross section cut along a plane perpendicular to the emission surface 11a of the quarter-wave plate 11).
  • the first polarized light incident at an angle ⁇ 0 formed with the surface 13a with respect to the surface 13a located on the quarter wavelength plate 11 side is refracted at an angle ⁇ 1 and faces the surface 13a. 13b is reached.
  • the incident angle of the first polarized light with respect to the surface 13a is given by “90 ° ⁇ 0”, which is larger than the angle ⁇ 1.
  • the surface 13 b is an interface between the refracting portion 14 and the reflective layer 12.
  • the first polarized light incident from the surface 13a and reaching the surface 13b is reflected by the surface 13b.
  • the first polarized light reflected by the surface 13b reaches the side surface 13c.
  • the refractive index of the 1 ⁇ 4 wavelength plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the side surface 13c passes through the surface 10a without being refracted and is 1 ⁇ 4 wavelength. It reaches the exit surface 11a of the plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 1) of the circularly polarized light incident on the emission surface 11a is smaller than the critical angle, the circularly polarized light is emitted from the emission surface 11a at the emission angle ⁇ .
  • the first polarized light that satisfies the condition of being incident from the surface 13 a and emitted from the side surface 13 c (outgoing condition) is converted into circularly polarized light by the quarter wavelength plate 11. Then, the light is emitted from the emission surface 11a.
  • the quarter-wave plate 11 is The condition of passing through and exiting from the exit surface 11a is also established as the exit condition.
  • FIG. 3B is a diagram for explaining the first light guide condition of the refracting unit 13 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident at an angle ⁇ 0 formed with the surface 13a with respect to the surface 13a is refracted at an angle ⁇ 1 and reaches the surface 13b.
  • the first polarized light incident from the surface 13a and reaching the surface 13b is reflected by the surface 13b.
  • the first polarized light reflected by the surface 13b reaches the surface 13a.
  • the incident angle (same as ⁇ 1) of the first polarized light reflected by the surface 13b with respect to the surface 13a is smaller than the critical angle. For this reason, the first polarized light incident on the surface 13 a from the surface 13 b is refracted and reaches the surface 10 a of the light guide 10.
  • the angle between the first polarized light emitted from the surface 13a and the surface 13a is ⁇ 0.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 13a passes through the surface 10a without being refracted and is 1 ⁇ 4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the first light guide condition that is incident from the surface 13a, reflected by the surface 13b, and emitted from the surface 13a is emitted from the emission surface 11a. Instead, after being converted into the second polarized light by the quarter wavelength plate 11, the light propagates through the light guide 10.
  • FIG. 3C is a diagram for explaining the second light guide condition of the refracting unit 13 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident at the incident angle ⁇ 0 with respect to the side surface 13d is refracted at the angle ⁇ 1 and reaches the surface 13b.
  • the first polarized light incident from the side surface 13d and reaching the surface 13b is reflected by the surface 13b.
  • the first polarized light reflected by the surface 13b reaches the surface 13a.
  • the incident angle ⁇ 2 of the first polarized light reflected by the surface 13b with respect to the surface 13a is smaller than the critical angle. For this reason, the first polarized light incident on the surface 13 a from the surface 13 b is refracted and reaches the surface 10 a of the light guide 10.
  • the angle between the first polarized light emitted from the surface 13a and the surface 13a is ⁇ 1.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 13a passes through the surface 10a without being refracted and is 1 ⁇ 4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° - ⁇ 1) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the second light guiding condition that is incident from the side surface 13d, reflected by the surface 13b, and emitted from the surface 13a is emitted from the emission surface 11a.
  • the light propagates through the light guide 10.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident at the incident angle ⁇ 0 with respect to the side surface 13d is refracted at the angle ⁇ 1 and reaches the surface 13b.
  • the first polarized light incident from the side surface 13d and reaching the surface 13b is reflected by the surface 13b.
  • the first polarized light reflected by the surface 13b reaches the side surface 13c.
  • the incident angle (same as ⁇ 1) of the first polarized light reflected by the surface 13b with respect to the side surface 13c is smaller than the critical angle. For this reason, the first polarized light incident on the side surface 13 c from the surface 13 b is refracted and reaches the surface 10 a of the light guide 10.
  • the angle between the first polarized light emitted from the side surface 13c and the side surface 13c is ⁇ 0.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the side surface 13c passes through the surface 10a without being refracted, and becomes 1/4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a has passed through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the exit surface 11a passes through the quarter-wave plate 11, the light incident on the light guide 10 from the exit surface 11a is second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the third light guiding condition which is incident from the side surface 13d, reflected by the surface 13b, and emitted from the side surface 13c, is emitted from the emission surface 11a.
  • the light propagates through the light guide 10.
  • FIG. 4A is a diagram for explaining the emission condition of the refraction unit 14 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end surface provided with) and the emission surface 11a.
  • the first polarized light incident on the side surface 14d located on the first end surface side at the incident angle ⁇ 0 is refracted at the angle ⁇ 1 ′ (> ⁇ 0) and reaches the surface 14b.
  • the surface 14 b is an interface between the refracting portion 14 and the reflective layer 12.
  • the first polarized light incident from the surface 14d and reaching the surface 14b is reflected by the surface 14b.
  • the first polarized light reflected by the surface 14b reaches the surface 14a (the surface located on the quarter wavelength plate 11 side).
  • the relationship between the incident angle ⁇ 2 ′ and the angle ⁇ 1 ′ is given by “ ⁇ 2 ′> 90 ° ⁇ 1 ′”.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 14a passes through the surface 10a without being refracted and is 1 ⁇ 4 wavelength. It reaches the exit surface 11a of the plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 1 ′) of the circularly polarized light incident on the emission surface 11a is smaller than the critical angle, the circularly polarized light is emitted from the emission surface 11a at the emission angle ⁇ .
  • the first polarized light that satisfies the condition (outgoing condition) that is incident from the side surface 14 d and is emitted from the surface 14 a is converted into circularly polarized light by the quarter-wave plate 11. Then, the light is emitted from the emission surface 11a.
  • the first polarized light that enters the refracting portion 14 from the side surface 14d and exits from the surface 14a passes through the quarter-wave plate 11 and exits from the exit surface 11a.
  • the above condition is also established as the emission condition.
  • FIG. 4B is a diagram for explaining the first light guide condition of the refracting unit 14 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident at the incident angle ⁇ 0 with respect to the side surface 14d is refracted at the angle ⁇ 1 ′ and reaches the surface 14b.
  • the first polarized light incident from the side surface 14d and reaching the surface 14b is reflected by the surface 14b.
  • the first polarized light reflected by the surface 14b reaches the side surface 14c.
  • the incident angle (same as ⁇ 1 ′) of the first polarized light reflected by the surface 14b with respect to the side surface 14c is smaller than the critical angle. Therefore, the first polarized light incident on the side surface 14c from the surface 14b is refracted at an angle ⁇ 0 and reaches the surface 10a of the light guide 10.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the side surface 14c passes through the surface 10a without being refracted, and becomes 1/4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the exit surface 11a passes through the quarter-wave plate 11 again, the light incident on the surface 10a from the exit surface 11a is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the first light guiding condition which is incident from the side surface 14d, reflected by the surface 14b, and output from the side surface 14c, is output from the output surface 11a. Instead, after being converted into the second polarized light by the quarter wavelength plate 11, the light propagates through the light guide 10.
  • FIG. 4C is a diagram for explaining the second light guide condition of the refracting unit 14 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11a of the quarter-wave plate 11.
  • the first polarized light incident on the surface 14a at an angle ⁇ 0 with the surface 14a is refracted at an angle ⁇ 1 ′ and reaches the surface 14b.
  • the first polarized light incident from the surface 14a and reaching the surface 14b is reflected by the surface 14b.
  • the first polarized light reflected by the surface 14b is incident on the side surface 14c at an incident angle ⁇ 2 ′.
  • the incident angle ⁇ 2 ′ is smaller than the critical angle. Therefore, the first polarized light incident on the side surface 14c from the surface 14b is refracted at the angle ⁇ 1 'and reaches the surface 10a.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the side surface 14c passes through the surface 10a without being refracted and is 1 ⁇ 4 wavelength. It reaches the exit surface 11a of the plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° - ⁇ 1 ') of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the second light guiding condition that is incident from the surface 14a, reflected by the surface 14b, and emitted from the side surface 14c is emitted from the emission surface 11a.
  • the light propagates through the light guide 10.
  • FIG. 4D is a diagram for explaining a third light guide condition of the refracting unit 14 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident on the surface 14a at an angle ⁇ 0 with the surface 14a is refracted at an angle ⁇ 1 ′ and reaches the surface 14b.
  • the first polarized light incident from the surface 14a and reaching the surface 14b is reflected by the surface 14b.
  • the first polarized light reflected by the surface 14b reaches the surface 14a.
  • the incident angle (same as ⁇ 1 ′) of the first polarized light reflected by the surface 14b with respect to the surface 14a is smaller than the critical angle. For this reason, the first polarized light incident on the surface 14 a from the surface 14 b is refracted and reaches the surface 10 a of the light guide 10.
  • the angle between the first polarized light emitted from the surface 14a and the surface 14a is ⁇ 0.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 14a passes through the surface 10a without being refracted, and becomes 1/4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the third light guide condition that is incident from the surface 14a, reflected by the surface 14b, and output from the surface 14a is output from the output surface 11a. Instead, after being converted into the second polarized light by the quarter-wave plate 11, the light propagates through the light guide 10.
  • FIG. 4E is a diagram for explaining the fourth light guide condition of the refracting unit 14 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11a of the quarter-wave plate 11.
  • the first polarized light that is incident on the surface 14a at an angle ⁇ with the surface 14a is reflected by the surface 14a.
  • the first polarized light reflected by the surface 14 a reaches the surface 10 a of the light guide 10. Since the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 14a passes through the surface 10a without being refracted, and becomes 1/4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° - ⁇ ) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the fourth light guide condition of being reflected by the surface 14a is not emitted from the emission surface 11a, but is secondly emitted by the quarter wavelength plate 11. After being converted into the polarized light, the light propagates through the light guide 10.
  • the emission angle ⁇ is controlled within a possible range.
  • the emission angle ⁇ is taken in the in-plane direction of the first plane intersecting (or orthogonal to) each of the first end face (end face on the side where the light source is disposed) of the light guide 10 and the emission face 11a. The first emission angle to be obtained.
  • the emission angle ⁇ is 67.3 °.
  • the emission angle ⁇ is 80.5 °.
  • the emission angle ⁇ is 89.8 °.
  • the exit angle width is 22.5 °.
  • the emission angle width is an angle width given by the maximum angle and the minimum angle of the emission angle ⁇ , and is an angular spread of the first emission angle of the outgoing light of the polarizing light guide plate of the present embodiment.
  • the polarization light guide plate of the present embodiment light is circulated between the 1 ⁇ 4 wavelength plate 11 and the reflection layer 12, and in the circulation process, polarization separation by the refracting portions 13 and 14 and a 1 ⁇ 4 wavelength plate are performed.
  • the light can be reused by performing the polarization conversion according to 11. Thereby, the light utilization efficiency can be further improved.
  • FIG. 5 schematically shows the operation of the S-polarized light and the P-polarized light with respect to the light in the polarizing light guide plate having the matrix arrangement shown in FIG.
  • the dashed arrow indicates S-polarized light
  • the solid arrow indicates P-polarized light.
  • the refracting portion 14 a solid-line rectangular portion and a broken-line rectangular portion are described, but the broken-line rectangular portion is located on the back side of the refracting portion 13 toward the drawing, and the solid-line rectangular portion faces the drawing. And located in front of the refracting portion 13.
  • the refractive index for P-polarized light is n1
  • the refractive index for S-polarized light is n2
  • the refractive index for P-polarized light is n1 '
  • the refractive index for S-polarized light is n2'
  • the S-polarized light is transmitted as it is without being refracted by the refraction portions 13 and 14.
  • a part of the S-polarized light is reflected by the reflective layer 12, and the reflected S-polarized light enters the quarter-wave plate 11 from the surface 10 a of the light guide 10.
  • the light that has entered the quarter-wave plate 11 is reflected by the exit surface 11a, and the reflected light is incident on the surface 10a of the light guide 10 again.
  • the light incident on the quarter wavelength plate 11 from the light guide 10 passes through the quarter wavelength plate 11 twice. That is, the S-polarized light incident on the quarter-wave plate 11 from the surface 10a of the light guide 10 passes through the quarter-wave plate 11 twice, and thus is converted into P-polarized light.
  • the P-polarized light that does not satisfy the emission condition in the refracting portions 13 and 14 propagates through the light guide 10 while being reflected by the emission surface 11 a of the quarter-wave plate 11 and the reflection layer 12. To do. In this propagation process, the P-polarized light incident on the quarter-wave plate 11 from the surface 10a of the light guide 10 passes through the quarter-wave plate 11 twice, and thus is converted into S-polarized light.
  • a part of the light guided through the light guide 10 is subjected to angle conversion.
  • the first polarized light is emitted from the emission surface 11a. It is emitted from.
  • the angle ⁇ 1 is larger than the angle ⁇ 0
  • the incident angle (90 ⁇ 1) is equal to or larger than the critical angle
  • the first polarized light is reflected by the emission surface 11a and is guided to the light guide 10. Guide the light inside.
  • the angle ⁇ is gradually increased.
  • the incident angle (90 ⁇ 1) is smaller than the critical angle, and the guided light is emitted from the emission surface 11a. Is done.
  • the angle ⁇ 0 is increased in such a light guide process, and the light propagating through the light guide 10 while being reflected by the output surface 11 a of the quarter-wave plate 11 and the reflection layer 12. Among them, the first polarized light satisfying the emission condition can be obtained.
  • the refractive index for S-polarized light may be n1, n1 ', and the refractive index for P-polarized light may be n2, n2'.
  • the refractive index for S-polarized light may be n1, n1 ', and the refractive index for P-polarized light may be n2, n2'.
  • only S-polarized light satisfying the emission condition is emitted from the emission surface 11 a of the quarter-wave plate 11.
  • the polarizing light guide plate of the present embodiment not only the first emission angle described above is controlled, but also the first plane described above (the first end surface of the light guide 10 and each of the emission surfaces 11a). It is also possible to control the second emission angle that can be taken in the in-plane direction of the second plane intersecting or orthogonal to each of the intersecting or orthogonal surfaces and the exit surface 11a.
  • FIG. 6 is a schematic diagram showing how the second emission angle is limited.
  • FIG. 6 shows a state in which adjacent refracting portions 13 and 14 are viewed from a direction perpendicular to the emission surface 11 a of the quarter-wave plate 11.
  • the refraction part 13 has four side surfaces 13c to 13f.
  • the side surfaces 13c and 13d are parallel, and the side surfaces 13e and 13f are parallel.
  • the refracting portion 14 has four side surfaces 14c to 14f.
  • the side surfaces 14c and 14d are parallel, and the side surfaces 14e and 14f are parallel.
  • the side surface 13e of the refracting portion 13 is parallel to the side surface 14f of the refracting portion 14.
  • the first polarized light enters from the side surface 13d and exits from the side surface 13e.
  • the angle ⁇ 1 between the first polarized light emitted from the side surface 13e and the perpendicular drawn with respect to the side surface 13d (or the side surface 13c) is the perpendicular of the first polarized light incident on the side surface 13d. Is smaller than the angle ⁇ 0.
  • a part of the first polarized light emitted from the side surface 13e of the refracting portion 13 is incident from the side surface 14f of the refracting portion 14 and is emitted from the side surface 14c of the refracting portion 14.
  • the angle ⁇ 1 ′ formed between the first polarized light emitted from the side surface 14c and the perpendicular line is smaller than the angle ⁇ 1 formed between the first polarized light emitted from the side face 13e and the perpendicular line described above.
  • the first polarized light is incident from the side surface 13d of the refracting portion 13 and is emitted from the side surface 13e, and the emitted first polarized light is incident from the side surface 14f of the refracting portion 14 and the side surface.
  • the angle conversion condition of being emitted from 14c is satisfied, the second emission angle can be narrowed.
  • the angle ⁇ 1 ′ is 40.4 °. If the angle ⁇ 0 is 30.0 ° and the angle ⁇ 1 is 25.3 °, the angle ⁇ 1 ′ is 20.0 °. If the angle ⁇ 0 is 20.0 ° and the angle ⁇ 1 is 12.8 °, the angle ⁇ 1 ′ is 12.8 °. As described above, when the maximum incident angle ⁇ 0 of the light incident on the end surface of the light guide 10 from the light source to the side surfaces of the refractive portions 13 and 14 is 48.1 °, the light is incident on a predetermined surface of the refractive portion 13.
  • the angle can be narrowed by about 4 °. Subsequently, when the light from the refracting portion 13 enters the predetermined surface of the refracting portion 14, the angle can be further narrowed by about 4 °. Accordingly, the refraction portions 13 and 14 can be narrowed by about 8 degrees.
  • the refracting portions 13 and 14 can each narrow the angle by about 5 °. Therefore, the refracting portions 13 and 14 can be narrowed by about 10 degrees.
  • the effect of narrowing the angular spread of the second emission angle varies depending on the number of times of passing through a predetermined surface of the refracting portions 13 and 14.
  • FIG. 7 shows an example of the sizes and intervals of the refraction parts 13 and 14 that satisfy the angle conversion condition shown in FIG.
  • FIG. 7 shows a state in which the adjacent refracting portions 13 and 14 are viewed from a direction perpendicular to the exit surface 11a of the quarter-wave plate 11.
  • the symbol A indicates the length of the short side (side surfaces 13 c and 13 d) of the refracting portion 13
  • the symbol B indicates the length of the long side (side surfaces 13 e and 13 f) of the refracting portion 13.
  • the symbol b indicates the length of the side (side surfaces 14e, 14f) of the refracting unit 14 parallel to the long side of the refracting unit 13
  • the symbol a indicates the side (side surface) of the refracting unit 14 parallel to the short side of the refracting unit 13. 14c, 14d).
  • Reference sign D indicates a distance between a plane including the side surface 13d of the refracting portion 13 and a plane including the side surface 13d of the refracting portion 14.
  • the symbol P indicates the distance between the side surface 13e of the refracting portion 13 and the side surface 14f of the refracting portion 14.
  • the second emission angle described above is widened.
  • such an angular spread is suppressed by increasing the long side of the refracting portion 13 so that the first polarized light incident from the side surface 13e is emitted from the side surface 13f. be able to.
  • FIG. 8B shows an example of the conditions for suppressing the angular spread.
  • the first polarized light enters from the side surface 13e and exits from the side surface 13f.
  • the first polarized light is refracted when passing through each of the side surfaces 13e and 13f.
  • the angle of the first polarized light incident on the side surface 13e with respect to the side surface 13e is ⁇ 0.
  • the angle between the first polarized light passing through the side surface 13e and the perpendicular to the side surface 13e is defined as ⁇ 3.
  • the side portions 13c and 13d of the refracting portion 14 are increased in the length of the side portions and the interval between the refracting portions 13 is increased.
  • second technique There is a technique (second technique).
  • the first polarized light is prevented from entering from the side surface 14d of the refracting unit 14 and exiting from the side surface 14f.
  • the conditions for this suppression will be described with reference to FIG. 9B.
  • the first polarized light is incident from the side surface 14d and emitted from the side surface 14c.
  • the first polarized light is refracted when passing through each of the side surfaces 14c and 14d.
  • the angle of the first polarized light incident on the side surface 14d with respect to the perpendicular of the side surface 14d is ⁇ 1.
  • the angle of the first polarized light that has passed through the side surface 14d with respect to the side surface 14d is defined as ⁇ 1 '.
  • the amount of light emitted from the exit surface 11a of the quarter-wave plate 11 varies depending on the spacing and size (length and height) of the refracting portions 13 and 14. .
  • the size of the refracting portion 13 for increasing the amount of emitted light will be described with reference to FIG. 10A.
  • the symbol B indicates the length of the long side of the refracting portion 13 (the length of the surfaces 13a and 13b), and the symbol H indicates the thickness of the refracting portion 13 (the length of the side surfaces 13c and 13d). .
  • the first polarized light is incident from the surface 13a and reflected by the surface 13b, and the reflected light is emitted from the side surface 13c.
  • the first polarized light is refracted when passing through the surface 13a and the side surface 13c.
  • the angle of the first polarized light incident from the surface 13a with respect to the surface 13b is ⁇ 2
  • the angle between the first polarized light emitted from the side surface 13c and the perpendicular of the side surface 13c is ⁇ 1.
  • the amount of light emitted from the exit surface 11a of the quarter-wave plate 11 can be increased by setting the length B of the refracting portion 13 to satisfy the following formula (6).
  • symbols B and H indicate the length and thickness of the refracting portion 13 as described in FIG. 10A.
  • the symbol Q indicates the distance between the refracting portion 13 and the refracting portion (refractive portion 13 or refracting portion 14) adjacent thereto.
  • the first polarized light emitted from the side surface 13 c of the refracting unit 13 is reflected by the reflective layer 12.
  • the angle between the first polarized light emitted from the side surface 13c and the perpendicular of the side surface 13c is ⁇ 1.
  • the amount of light emitted from the emission surface 11a of the quarter-wave plate 11 can be increased by setting the interval Q so as to satisfy the following expression (7).
  • the size of the refracting portion 14 for increasing the amount of emitted light will be described with reference to FIG. 11A.
  • the symbol b indicates the length of the refracting portion 14 (the length of the surfaces 14a and 14b), and the symbol h indicates the thickness of the refracting portion 14 (the length of the side surfaces 14c and 14d).
  • the first polarized light is incident from the side surface 14d and reflected by the surface 14b, and the reflected light is emitted from the surface 14a.
  • the first polarized light is refracted when passing through each of the surface 14a and the side surface 14d.
  • the angle of the first polarized light incident from the side surface 14d with respect to the surface 14b is ⁇ 2 ′.
  • the amount of light emitted from the exit surface 11a of the quarter-wave plate 11 can be increased by setting the length b of the refracting portion 14 to satisfy the following formula (8).
  • FIG. 11B An interval between the refracting portion 14 for increasing the amount of emitted light and the refracting portion adjacent thereto will be described with reference to FIG. 11B.
  • symbols b and h indicate the length and thickness of the refracting portion 14 as described in FIG. 11A.
  • the symbol q indicates the distance between the refracting part 14 and the refracting part (refractive part 13 or refracting part 14) adjacent thereto.
  • the first polarized light is reflected by the reflective layer 12, and the reflected light enters the side surface 14d of the refracting section 14.
  • the angle of the first polarized light incident on the reflective layer 12 with respect to the surface of the reflective layer 12 is ⁇ 0.
  • the amount of light emitted from the emission surface 11a of the quarter-wave plate 11 can be increased by setting the interval q so as to satisfy the following expression (9).
  • the lengths B and b and the intervals Q and q are set in the range of 30 to 100 ⁇ m, respectively. Is preferable from the viewpoint of making the emitted light uniform and practical.
  • Example 1 In FIG. 12, an example of arrangement
  • the upper part is a top view and the lower part is a cross-sectional view.
  • Symbols A, B, and H respectively indicate the length, width, and height of the refracting portion 13, and symbols a, b, and h indicate the length, width, and height of the refracting portion 14, respectively.
  • the symbol Q indicates the distance between the refracting portion 13 and the refracting portion 13 adjacent thereto.
  • Reference symbol P indicates the distance between the refracting portion 13 and the refracting portion 14.
  • Reference sign D indicates the length between the end faces located on the side where the light source is disposed, among the side surfaces of the refraction portions 13 and 14.
  • the refractive index n0 of the light guide 10 is 1.50.
  • the refractive indexes n1 and n2 of the refracting portion 13 are 1.55 and 1.50, respectively.
  • the refractive indices n1 'and n2' of the refracting section 14 are 1.45 and 1.50, respectively.
  • the length D between the side surfaces of the refracting portions 13 and 14 is 10.2 ⁇ m.
  • the interval P is 10.0 ⁇ m, and the interval Q is 46.1 ⁇ m.
  • the width A, length B, and height H of the refracting portion 13 are 36.4 ⁇ m, 50.0 ⁇ m, and 29.5 ⁇ m, respectively.
  • the width a, length b, and height h of the refracting portion 14 are 20.0 ⁇ m, 22.1 ⁇ m, and 19.5 ⁇ m, respectively.
  • the angle of light incident on the light guide 10 from the light source with respect to the plane parallel to the exit surface 11a of the quarter-wave plate 11 is 48.1 ° or less.
  • the angular spread of the first emission angle emitted from the emission surface 11a of the quarter wavelength plate 11 is 22.7 °.
  • the angular spread of the second emission angle emitted from the emission surface 11a of the quarter-wave plate 11 is set to about 7 ° to 18 ° with respect to the angular spread of the light incident into the light guide 10 from the light source.
  • the first emission angle is taken in the in-plane direction of the first plane that intersects (or is orthogonal to) the end surface of the light guide 10 on the side where the light source is disposed and the emission surface 11a of the quarter-wave plate 11.
  • the second emission angle is an emission angle that can be taken in the in-plane direction of the second plane parallel to the emission surface 11a of the quarter-wave plate 11 and intersecting the first plane.
  • Example 2 The polarizing light guide plate of this embodiment also has the arrangement shown in FIG.
  • the refractive index n0 of the light guide 10 is 1.50.
  • the refractive indexes n1 and n2 of the refracting portion 13 are 1.55 and 1.50, respectively.
  • the refractive indices n1 'and n2' of the refracting section 14 are 1.45 and 1.50, respectively.
  • the length D between the side surfaces of the refracting portions 13 and 14 is 10.2 ⁇ m.
  • the interval P is 10.0 ⁇ m, and the interval Q is 75.1 ⁇ m.
  • the width A, length B, and height H of the refracting portion 13 are 50.0 ⁇ m, 67.6 ⁇ m, and 37.0 ⁇ m, respectively.
  • the width a, length b, and height h of the refracting portion 14 are 20.0 ⁇ m, 22.1 ⁇ m, and 13.3 ⁇ m, respectively.
  • the angle of light incident on the light guide 10 from the light source with respect to the plane parallel to the exit surface 11a of the quarter-wave plate 11 is 48.1 ° or less.
  • the polarized light guide plate of the present embodiment has a first polarized light on the light source side end face of the refracting portion 13 by an amount corresponding to the width A of the refracting portion 13 larger than that of the polarizing light guide plate of the first embodiment. More light can be incident.
  • the length D between the side surfaces of the refracting portions 13 and 14, the length B and height H of the refracting portion 13, and the length b and height h of the refracting portion 14 can be suppressed.
  • the angular spread of the first emission angle emitted from the emission surface 11a of the quarter-wave plate 11 is 22.7 °.
  • the angular spread of the second emission angle emitted from the emission surface 11a of the quarter wavelength plate 11 can be set to about 7 to 18 °.
  • the polarizing light guide plate of this embodiment also has the arrangement shown in FIG.
  • the refractive index n0 of the light guide 10 is 1.50.
  • the refractive indexes n1 and n2 of the refracting portion 13 are 1.55 and 1.50, respectively.
  • the refractive indices n1 'and n2' of the refracting section 14 are 1.45 and 1.50, respectively.
  • the length D between the side surfaces of the refracting portions 13 and 14 is 16.0 ⁇ m.
  • the interval P is 10.0 ⁇ m
  • the interval Q is 101.0 ⁇ m.
  • the width A, length B, and height H of the refracting portion 13 are 40.0 ⁇ m, 83.5 ⁇ m, and 49.1 ⁇ m, respectively.
  • the width a, length b, and height h of the refracting portion 14 are 20.0 ⁇ m, 48.0 ⁇ m, and 29.5 ⁇ m, respectively.
  • the angle of light incident on the light guide 10 from the light source with respect to the plane parallel to the exit surface 11a of the quarter-wave plate 11 is 48.1 ° or less.
  • the angular spread of the first emission angle emitted from the emission surface 11a of the quarter-wave plate 11 is 22.7 °.
  • the angular spread of the second emission angle emitted from the emission surface 11a of the quarter-wave plate 11 is 7 ° to 18 ° with respect to the angular spread of the light incident into the light guide 10 from the light source. It can be fitted to the extent.
  • Example 4 The polarizing light guide plate of this embodiment also has the arrangement shown in FIG.
  • the refractive index n0 of the light guide 10 is 1.50.
  • the refractive indexes n1 and n2 of the refracting portion 13 are 1.60 and 1.50, respectively.
  • the refractive indexes n1 'and n2' of the refracting section 14 are 1.40 and 1.50, respectively.
  • the length D between the side surfaces of the refracting portions 13 and 14 is 11.8 ⁇ m.
  • the interval P is 10.0 ⁇ m
  • the interval Q is 74.0 ⁇ m.
  • the width A, length B, and height H of the refracting portion 13 are 36.3 ⁇ m, 50.0 ⁇ m, and 32.0 ⁇ m, respectively.
  • the width a, length b, and height h of the refracting portion 14 are 20.0 ⁇ m, 28.5 ⁇ m, and 18.8 ⁇ m, respectively.
  • the angle of light incident on the light guide 10 from the light source with respect to the plane parallel to the exit surface 11a of the quarter-wave plate 11 is 48.1 ° or less.
  • the angular spread of the first emission angle emitted from the emission surface 11a of the quarter wavelength plate 11 is 33.6 °. Further, the angular spread of the second emission angle emitted from the emission surface 11a of the quarter-wave plate 11 is set to about 12 to 26 ° with respect to the angular spread of the light incident into the light guide 10 from the light source. be able to.
  • the polarizing light guide plate of the present embodiment described above it is possible to reduce the angular spread of the first emission angle and to reduce the angular spread of the second emission angle. Therefore, the spread of the emission angle of the light emitted from the polarizing light guide plate can be kept within the light usable range based on the etendue constraint.
  • the light propagating in the light guide 10 can be used by circulating light between the quarter-wave plate 11 and the reflection layer 12, the light use efficiency can be improved.
  • the refracting parts 13 and 14 may be arranged at equal intervals.
  • the interval between the refracting portions 13 and 14 may be gradually increased.
  • the luminance distribution in the in-plane direction of the exit surface 11a of the quarter wavelength plate 11 can be made uniform as compared with the case where the refracting portions 13 and 14 are arranged at equal intervals.
  • FIG. 13A schematically shows the luminance distribution of the emitted light when the refracting portions 13 are arranged at equal intervals
  • FIG. 13B shows the emitted light when the interval between the refracting portions 13 is gradually increased as the distance from the end face increases.
  • the luminance distribution of is schematically shown. 13A and 13B, a part of the polarizing light guide plate is cut along a plane perpendicular to the first end face of the light guide 10 (end face provided with the light source) and the exit face 11a of the quarter-wave plate 11.
  • a first end face (not shown) is arranged on the right side of the drawing.
  • the interval between the refracting portions 13 is small on the first end surface side.
  • the reflected light 102 from the reflective layer 12 in the configuration of FIG. 13A, the reflected light 102 becomes outgoing light
  • the light is emitted from the surface on the emission surface 11 a side of the quarter-wave plate 11.
  • the light emitted from the refracting unit 13 then becomes the light guide light 101, is reflected by the emission surface 11 a of the quarter-wave plate 11 and the reflection layer 12, and propagates through the light guide 10.
  • the distance between the refracting portions 13 increases as the distance from the first end surface increases, the amount of reflected light 102 incident on the side surface (side surface on the first end surface side) of the refracting portion 13 also moves away from the first end surface. It becomes small according to. As a result, the luminance distribution of the light emitted from the emission surface 11a is more uniform than the configuration of FIG. 13A.
  • the refracting portions 13 are arranged in one direction.
  • the refracting portions 14 are arranged in one direction, or the refracting portions 13 and 14 are alternately arranged in one direction.
  • the luminance distribution of the emitted light can be made uniform as described above.
  • the luminance distribution of the emitted light can be made uniform by gradually increasing the refracting portions 13 and 14 as they move away from the first end face.
  • the size of the refracting portions 13 and 14 is defined by one or more of the length, width, and height of the refracting portions.
  • the luminance distribution of the emitted light can be made more uniform.
  • the light emitted from the emission surface 11a of the quarter-wave plate 11 has an inclination with respect to the normal of the emission surface 11a.
  • a prism sheet may be used to emit light in a direction perpendicular to the emission surface 11a.
  • FIG. 14A shows a configuration using a prism sheet. As shown in FIG. 14A, the plurality of vertices of the prism sheet 15 are provided so as to face the emission surface 11 a of the quarter-wave plate 11.
  • the prism sheet 15 is a two-dimensional arrangement of prism surfaces 15a having a triangular cross-sectional shape.
  • the apex angle of the prism surface 15a is determined based on the angle of light emitted from the emission surface 11a (for example, the emission angle ⁇ shown in FIGS. 3A and 4A).
  • the refractive index n0 of the light guide 10 is 1.50
  • the refractive indexes n1 and n2 of the refracting part 13 are 1.55 and 1.50, respectively
  • the refractive indices n1 ′ and n2 ′ of the refracting part 14 are When they are 1.45 and 1.50, respectively, the emission angle ⁇ is larger than 67 ° and smaller than 90 °.
  • the refractive index of the prism sheet 15 is 1.50
  • the apex angle of the prism surface 15a is 70 °.
  • the prism sheet 15 having a prism surface 15a having an apex angle of 70 ° has an angle ⁇ formed by a surface parallel to a surface forming one side of the prism surface 15a and the emission surface 11a. It arrange
  • the light emitted from the emission surface 11a of the quarter wavelength plate 11 is circularly polarized light.
  • the first or second polarized light specifically, S-polarized light or P-polarized light
  • the light emitted from the outgoing surface 11a of the quarter-wave plate 11 Another quarter wave plate may be arranged in the traveling direction.
  • FIG. 15 shows a configuration including another quarter wavelength plate.
  • the quarter wavelength plate 16 is provided so as to face the surface of the prism sheet 15 opposite to the surface on the quarter wavelength plate 11 side.
  • the circularly polarized light emitted from the quarter wavelength plate 11 passes through the quarter wavelength plate 16 after passing through the prism sheet 15.
  • the polarization light guide plate is configured so that the first polarized light passes through the quarter wavelength plate 11, the second polarized light is emitted from the quarter wavelength plate 16.
  • the first polarized light is emitted from the quarter wavelength plate 16.
  • the first or second polarized light can be obtained as the emitted light from the polarization light guide plate.
  • a light guide having a concave portion in a region to be the refractive portions 13 and 14 is created.
  • the light guide can be created for mold forming, cutting and the like.
  • an alignment film is applied to the surface of the light guide where the concave portion is formed and one surface of the reflective layer (reflecting plate), and an alignment treatment is performed.
  • a UV curable liquid crystal monomer is embedded in the recess by screen printing. Thereafter, the surface of the light guide body on which the concave portion is formed and one surface of the reflective layer are bonded together.
  • the bonded light guide and reflective layer are heated and then cooled to align the UV curable liquid crystal monomer. Finally, UV light is irradiated to cure the aligned UV curable liquid crystal monomer, and then a quarter-wave plate is attached to the surface of the light guide opposite to the reflective layer. Thereby, the polarization light guide plate of the first embodiment is obtained.
  • FIG. 16 is a schematic diagram showing a configuration of a polarizing light guide plate according to the second embodiment of the present invention.
  • a plurality of refracting portions 13 and 14 are provided inside the light guide 10, and the other configuration is the same as that of the first embodiment.
  • the refracting parts 13 and 14 are periodically arranged inside the light guide 10 so as to face the quarter-wave plate 11, and the refracting parts 13 and 14 are alternately arranged in at least one direction. .
  • the arrangement of the refracting portions 13 and 14 is as described in the first embodiment.
  • a part of the light (unpolarized light) incident on the first end surface of the light guide 10 from the light source is a quarter wavelength plate 11 as in the first embodiment.
  • the light is reflected between the light exit surface 11a and the reflective layer 12, and propagates in the light guide 10 toward the second end surface facing the first end surface. In this propagation process, a part of the light enters the refracting parts 13 and 14.
  • the refracting units 13 and 14 are the first and second polarized light between the emission condition for emitting the first polarized light from the emission surface 11a and the emission surface 11a of the quarter-wave plate 11 and the reflective layer 12. Although it is configured to satisfy the light guide condition for guiding light, the conditions are different from each other.
  • FIG. 17A is a diagram for explaining the emission conditions of the refraction unit 13 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG. 2 is a schematic diagram of a cross section cut along a plane perpendicular to the emission surface 11a of the quarter-wave plate 11).
  • the first polarized light incident at an angle ⁇ 0 formed with the surface 13a with respect to the surface 13a located on the quarter wavelength plate 11 side is refracted at an angle ⁇ 1 and faces the surface 13a. It is emitted from 13b.
  • the incident angle of the first polarized light with respect to the surface 13a is given by “90 ° ⁇ 0”.
  • the incident angle of the first polarized light with respect to the surface 13b is given by “90 ° ⁇ 1”.
  • the first polarized light emitted from the surface 13b is reflected by the reflective layer 12, and enters the light guide 10 again from the surface 13b.
  • the incident angle of the first polarized light reflected by the reflective layer 12 with respect to the surface 13b is smaller than the critical angle.
  • the first polarized light entering the light guide 10 from the surface 13b reaches the side surface 13c.
  • the incident angle ⁇ 2 of the first polarized light incident from the surface 13b with respect to the side surface 13c is smaller than the critical angle. Therefore, the first polarized light incident on the side surface 13 c is refracted at an angle ⁇ 1 and reaches the surface 10 a of the light guide 10.
  • the refractive index of the 1 ⁇ 4 wavelength plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the side surface 13c passes through the surface 10a without being refracted and is 1 ⁇ 4 wavelength. It reaches the exit surface 11a of the plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 1) of the circularly polarized light incident on the emission surface 11a is smaller than the critical angle, the circularly polarized light is emitted from the emission surface 11a at the emission angle ⁇ .
  • the first polarized light that satisfies the condition (exit condition) that enters from the surface 13a and exits from the surface 13b, and then enters from the surface 13b and exits from the side surface 13c, After being converted into circularly polarized light by the quarter-wave plate 11, the light is emitted from the emission surface 11a.
  • the quarter-wave plate 11 is The condition of passing through and exiting from the exit surface 11a is also established as the exit condition.
  • FIG. 17B is a diagram for explaining the first light guide condition of the refracting unit 13 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light that is incident on the surface 13a at an angle ⁇ 0 with the surface 13a is refracted at an angle ⁇ 1 and is emitted from the surface 13b.
  • the first polarized light emitted from the surface 13 b is reflected by the reflective layer 12 and then reaches the surface 10 a of the light guide 10.
  • the angle of the first polarized light reflected by the reflective layer 12 with respect to the reflective layer 12 is the same as the angle ⁇ 0.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the reflective layer 12 passes through the surface 10a without being refracted, and 1 / It reaches the emission surface 11a of the four-wavelength plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first light guide condition is satisfied that the light enters the surface 13 a, exits from the surface 13 b, is reflected by the reflective layer 12, and then reaches the surface 10 a of the light guide 10.
  • the first polarized light is not emitted from the emission surface 11 a, and is propagated through the light guide 10 after being converted into second polarized light by the quarter-wave plate 11.
  • FIG. 17C is a diagram for explaining the second light guide condition of the refracting unit 13 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light that is incident on the surface 13a at an angle ⁇ 0 with the surface 13a is refracted at an angle ⁇ 1 and emitted from the surface 13b.
  • emitted from the surface 13b is reflected in the reflection layer 12, and injects into the light guide 10 again from the surface 13b.
  • the first polarized light entering the light guide 10 from the surface 13b reaches the surface 13a.
  • the incident angle (same as ⁇ 1) of the first polarized light incident from the surface 13b with respect to the surface 13a is smaller than the critical angle. Therefore, the first polarized light incident on the surface 13a is refracted at an angle ⁇ 0 and reaches the surface 10a of the light guide 10.
  • the angle between the first polarized light emitted from the surface 13a and the surface 13a is ⁇ 0.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 13a passes through the surface 10a without being refracted and is 1 ⁇ 4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the second light guide condition of entering from the surface 13a and exiting from the surface 13b and then entering from the surface 13b and exiting from the surface 13a is obtained.
  • the light is not emitted from the emission surface 11 a but is converted into the second polarized light by the quarter-wave plate 11 and then propagates through the light guide 10.
  • FIG. 17D is a diagram for explaining a third light guide condition of the refracting unit 13 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident at the incident angle ⁇ 0 with respect to the side surface 13d is refracted at the angle ⁇ 1 and is emitted from the surface 13b.
  • the incident angle of the first polarized light with respect to the surface 13b is given by “90 ° ⁇ 1”.
  • the first polarized light emitted from the surface 13b is reflected by the reflective layer 12, and enters the light guide 10 again from the surface 13b.
  • the first polarized light entering the light guide 10 from the surface 13b reaches the surface 13a.
  • the incident angle (same as ⁇ 1) of the first polarized light incident from the surface 13b with respect to the surface 13a is smaller than the critical angle. Therefore, the first polarized light incident on the surface 13a is refracted at an angle ⁇ 0 and reaches the surface 10a of the light guide 10.
  • the angle between the first polarized light emitted from the surface 13a and the surface 13a is ⁇ 0.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 13a passes through the surface 10a without being refracted and is 1 ⁇ 4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the third light guide condition of entering from the side surface 13d and exiting from the surface 13b and then entering from the surface 13b and exiting from the surface 13a is obtained.
  • the light is not emitted from the emission surface 11 a but is converted into the second polarized light by the quarter-wave plate 11 and then propagates through the light guide 10.
  • FIG. 17E is a diagram for explaining the fourth light guide condition of the refracting unit 13 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident at the incident angle ⁇ 0 with respect to the side surface 13d is refracted at the angle ⁇ 1 and is emitted from the surface 13b.
  • the incident angle of the first polarized light with respect to the surface 13b is given by “90 ° ⁇ 1”.
  • the first polarized light emitted from the surface 13 b is reflected by the reflective layer 12 and then reaches the surface 10 a of the light guide 10.
  • the angle of the first polarized light reflected by the reflective layer 12 with respect to the reflective layer 12 is ⁇ 1.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the reflective layer 12 passes through the surface 10a without being refracted, and 1 / It reaches the emission surface 11a of the four-wavelength plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° - ⁇ 1) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light is not emitted from the emission surface 11 a, and is propagated through the light guide 10 after being converted into second polarized light by the quarter-wave plate 11.
  • FIG. 17F is a diagram for explaining the fifth light guide condition of the refracting unit 13 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident at the incident angle ⁇ 0 with respect to the side surface 13d is refracted at the angle ⁇ 1 and is emitted from the surface 13b.
  • emitted from the surface 13b is reflected in the reflection layer 12, and injects into the light guide 10 again from the surface 13b.
  • the first polarized light entering the light guide 10 from the surface 13b reaches the side surface 13c.
  • the incident angle (same as ⁇ 1) of the first polarized light incident from the surface 13b with respect to the side surface 13c is smaller than the critical angle. Therefore, the first polarized light incident on the side surface 13 c is refracted at an angle ⁇ 0 and reaches the surface 10 a of the light guide 10.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the side surface 13c passes through the surface 10a without being refracted, and becomes 1/4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a has passed through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the exit surface 11a passes through the quarter-wave plate 11, the light incident on the light guide 10 from the exit surface 11a is second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the fifth light guiding condition is incident from the side surface 13d and emitted from the surface 13b, and then incident from the surface 13b and emitted from the side surface 13c.
  • the light is not emitted from the emission surface 11 a but is converted into the second polarized light by the quarter-wave plate 11 and then propagates through the light guide 10.
  • FIG. 18A is a diagram for explaining the first emission condition of the refracting unit 14 for the first polarized light, and a part of the polarization light guide plate shown in FIG. It is a schematic diagram of the cross section cut
  • the first polarized light incident on the side surface 14d at the incident angle ⁇ 0 is refracted at the angle ⁇ 1 ′ and emitted from the surface 14b.
  • the incident angle of the first polarized light with respect to the surface 14b is given by “90 ° ⁇ 1 ′”.
  • the first polarized light emitted from the surface 14b is reflected by the reflection layer 12, and then enters the refraction part 14 again from the surface 14b and reaches the surface 14a.
  • the incident angle ⁇ 2 ′ of the first polarized light incident from the surface 14b with respect to the surface 14a is smaller than the critical angle. For this reason, the first polarized light is refracted at an angle ⁇ 1 ', exits from the surface 14a, and then reaches the surface 10a.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 14a passes through the surface 10a without being refracted and is 1 ⁇ 4 wavelength. It reaches the exit surface 11a of the plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 1 ′) of the circularly polarized light incident on the emission surface 11a is smaller than the critical angle, the circularly polarized light is emitted from the emission surface 11a at the emission angle ⁇ .
  • the first polarized light that satisfies the first emission condition of entering from the side surface 14d and exiting from the surface 14b, and then entering from the surface 14b and exiting from the surface 14a is: After being converted into circularly polarized light by the quarter-wave plate 11, the light is emitted from the emission surface 11a.
  • the first polarized light that enters the refracting portion 14 from the side surface 14d and exits from the surface 14a passes through the quarter-wave plate 11 and exits from the exit surface 11a.
  • the above condition is also established as the emission condition.
  • 18B is a diagram for explaining the second emission condition of the refracting unit 14 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG. It is a schematic diagram of the cross section cut
  • the first polarized light incident at the incident angle ⁇ 0 with respect to the side surface 14d is refracted at the angle ⁇ 1 ′ and emitted from the surface 14b.
  • the incident angle of the first polarized light with respect to the surface 14b is given by “90 ° ⁇ 1 ′”.
  • the first polarized light emitted from the surface 14 b is reflected by the reflective layer 12 and then reaches the surface 10 a of the light guide 10.
  • the angle of the first polarized light reflected by the reflective layer 12 with respect to the reflective layer 12 is ⁇ 1 ′.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the reflective layer 12 passes through the surface 10a without being refracted and is 1 ⁇ 4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 1 ′) of the circularly polarized light incident on the emission surface 11a is smaller than the critical angle, the circularly polarized light is emitted from the emission surface 11a at the emission angle ⁇ .
  • the first polarized light that satisfies the second emission condition of entering from the side surface 14d and exiting from the surface 14b and then reflected by the reflective layer 12 and reaching the surface 10a is After being converted into circularly polarized light by the quarter-wave plate 11, the light is emitted from the emission surface 11a.
  • FIG. 18C is a diagram for explaining the first light guide condition of the refracting unit 14 with respect to the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident on the side surface 14d at the incident angle ⁇ 0 is refracted at the angle ⁇ 1 ′ and emitted from the surface 14b.
  • the incident angle of the first polarized light with respect to the surface 14b is given by “90 ° ⁇ 1 ′”.
  • the first polarized light emitted from the surface 14b is reflected by the reflection layer 12, and then enters the refracting portion 14 from the surface 14b again.
  • the first polarized light incident from the surface 14b reaches the side surface 14c.
  • the incident angle (same as ⁇ 1 ′) of the first polarized light with respect to the side surface 14c is smaller than the critical angle. Therefore, the first polarized light exits from the side surface 14c and is refracted at an angle ⁇ 0.
  • the first polarized light emitted from the side surface 14 c reaches the surface 10 a of the light guide 10.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the side surface 14c passes through the surface 10a without being refracted, and becomes 1/4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the exit surface 11a passes through the quarter-wave plate 11 again, the light incident on the surface 10a from the exit surface 11a is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the first light guide condition of entering from the side surface 14d and exiting from the surface 14b and then entering from the surface 14b and exiting from the side surface 14c is obtained.
  • the light is not emitted from the emission surface 11 a but is converted into the second polarized light by the quarter-wave plate 11 and then propagates through the light guide 10.
  • FIG. 18D is a diagram for explaining the second light guide condition of the refracting unit 14 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident on the surface 14a at an angle ⁇ 0 with the surface 14a is refracted at an angle ⁇ 1 ′ and emitted from the surface 14b.
  • the incident angle of the first polarized light with respect to the surface 14a is given by “90 ° ⁇ 0”.
  • the first polarized light emitted from the surface 14 b is reflected by the reflective layer 12.
  • the first polarized light reflected by the reflective layer 12 is incident on the refraction part 14 again from the surface 14b.
  • the first polarized light incident from the surface 14b is incident on the side surface 14c at an incident angle ⁇ 2 ′.
  • the incident angle ⁇ 2 ′ is smaller than the critical angle. For this reason, the first polarized light incident on the side surface 14c is emitted from the side surface 14c and refracted at an angle ⁇ 1 'to reach the surface 10a.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the side surface 14c passes through the surface 10a without being refracted and is 1 ⁇ 4 wavelength. It reaches the exit surface 11a of the plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° - ⁇ 1 ') of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the second light guiding condition that is incident from the surface 14a, reflected by the surface 14b, and emitted from the side surface 14c is emitted from the emission surface 11a.
  • the light propagates through the light guide 10.
  • FIG. 18E is a diagram for explaining the third light guide condition of the refracting unit 14 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident on the surface 14a at an angle ⁇ 0 with the surface 14a is refracted at an angle ⁇ 1 ′ and emitted from the surface 14b.
  • the incident angle of the first polarized light with respect to the surface 14a is given by “90 ° ⁇ 0”.
  • the first polarized light emitted from the surface 14 b is reflected by the reflective layer 12 and then reaches the surface 10 a of the light guide 10.
  • the angle of the first polarized light reflected by the reflective layer 12 with respect to the reflective layer 12 is ⁇ 0.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the reflective layer 12 passes through the surface 10a without being refracted and is 1 ⁇ 4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the first polarized light that satisfies the second light guiding condition that is incident from the surface 14a, reflected by the surface 14b, and emitted from the side surface 14c is emitted from the emission surface 11a.
  • the light propagates through the light guide 10.
  • FIG. 18F is a diagram for explaining the fourth light guide condition of the refracting unit 14 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light incident on the surface 14a at an angle ⁇ 0 with the surface 14a is refracted at an angle ⁇ 1 ′ and emitted from the surface 14b.
  • the incident angle of the first polarized light with respect to the surface 14a is given by “90 ° ⁇ 0”.
  • the first polarized light emitted from the surface 14 b is reflected by the reflective layer 12.
  • the first polarized light reflected by the reflective layer 12 is incident on the refraction part 14 again from the surface 14b.
  • the first polarized light incident from the surface 14b is emitted from the surface 14a and then reaches the surface 10a.
  • the angle of the first polarized light emitted from the surface 14a with respect to the surface 14a is ⁇ 0.
  • the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 14a passes through the surface 10a without being refracted and is 1 ⁇ 4 wavelength. It reaches the exit surface 11a of the plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° ⁇ 0) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the fourth light guide condition that is incident from the surface 14a, reflected by the surface 14b, and emitted from the side surface 14c is emitted from the emission surface 11a. Instead, after being converted into the second polarized light by the quarter wavelength plate 11, the light propagates through the light guide 10.
  • FIG. 18G is a diagram for explaining the fifth light guide condition of the refracting unit 14 for the first polarized light, and a part of the polarization light guide plate shown in FIG.
  • FIG. 6 is a schematic view of a cross section cut along a plane perpendicular to the end face and the exit face 11 a of the quarter-wave plate 11.
  • the first polarized light is incident on the surface 14a at an angle ⁇ formed with the surface 14a.
  • the incident angle of the first polarized light with respect to the surface 14a is given by “90 ° ⁇ ”.
  • the first polarized light is reflected by the surface 14a.
  • the first polarized light reflected by the surface 14 a reaches the surface 10 a of the light guide 10. Since the refractive index of the quarter-wave plate 11 is substantially equal to the refractive index of the light guide 10, the first polarized light from the surface 14a passes through the surface 10a without being refracted, and becomes 1/4. It reaches the emission surface 11 a of the wave plate 11. Since the first polarized light that has passed through the surface 10a passes through the quarter-wave plate 11 once, the light that reaches the exit surface 11a is circularly polarized light.
  • the incident angle (90 ° - ⁇ ) of circularly polarized light incident on the exit surface 11a is larger than the critical angle. Therefore, the circularly polarized light is reflected in the direction of the light guide 10 at the emission surface 11a. Since the circularly polarized light reflected by the emission surface 11a passes through the quarter-wave plate 11, the light incident on the surface 10a of the light guide 10 is the second polarized light. The second polarized light incident from the surface 10 a propagates through the light guide 10.
  • the first polarized light that satisfies the fifth light guide condition of being reflected by the surface 14a is not emitted from the emission surface 11a, but is secondly emitted by the quarter wavelength plate 11. After being converted into the polarized light, the light propagates through the light guide 10.
  • the same modifications as those in the first embodiment are made with respect to the size and interval of the refracting parts 13 and 14 and the way of arranging the refracting parts 13 and 14 (one-dimensional arrangement and two-dimensional arrangement). It can be carried out.
  • the same deformation as that of the first embodiment can be performed with respect to a prism sheet, another quarter wavelength plate, and the like.
  • the polarizing light guide plate of the present embodiment can be manufactured by changing the recess forming step in the procedure for manufacturing the polarizing light guide plate of the first embodiment. Specifically, a recess is formed in a region of the surface of the first light guide that becomes the refracting portions 13 and 14, and UV curable liquid crystal monomer is embedded in the recess by screen printing. And the surface in which the recessed part of the 1st light guide was formed and one surface of the 2nd light guide are bonded together. Other steps are the same as those in the first embodiment.
  • the polarization light guide plate of each embodiment described above is an example of the present invention, and the configuration thereof can be changed as appropriate.
  • the polarization light guide plate of the second embodiment as shown in FIG. 19, the polarization light guide plate is cut at a plane orthogonal to each of the end surface where the light source is provided and the exit surface of the quarter wavelength plate 11.
  • the cross-sectional shape of the light guide 10 may be a wedge shape.
  • the wedge-shaped light guide 10 is configured such that the light source side is thick and gradually becomes thinner as the distance from the end surface on the light source side increases.
  • the above wedge-shaped light guide can also be applied to the polarizing light guide plate of the first embodiment.
  • the refraction parts 13 and 14 have an inclination with respect to the exit surface of the quarter-wave plate 11, but the inclinations of the refraction parts 13 and 14 are the same. Therefore, the angular spread of the light emitted from the emission surface of the quarter-wave plate 11 in this case is the same as that described in the first embodiment.
  • FIG. 20 shows an example of a cross-sectional structure of an illumination device including the polarization light guide plate of the present invention.
  • This illuminating device can be used as an illuminating device for a liquid crystal display device such as a mobile phone or a projection display device represented by a liquid crystal projector.
  • the light source 20 is, for example, a semiconductor light source such as a light emitting diode (LED) or a semiconductor laser (LD), or a light source called a solid light source, and is provided so as to face the end face 10 b of the light guide 10.
  • the light source 20 may be arranged in any manner with respect to the end face 10b.
  • the light emitting unit of the light source 20 may be disposed close to the end surface 10b, and an optical member (prism or lens) for causing light from the light emitting unit to enter the end surface 10b between the light emitting unit and the end surface 10b. ) May be arranged.
  • the light (unpolarized light) emitted from the light source 20 enters the light guide 10 from the end face 10b.
  • Light (non-polarized light) incident on the end surface 10b of the light guide 10 from the light source 20 is reflected between the exit surface 11a of the quarter-wave plate 11 and the reflection layer 12, and the end surface in the light guide 10 is also obtained.
  • the refraction units 13 and 14 only the first polarized light that satisfies the emission condition passes through the quarter-wave plate 11 and is emitted from the emission surface 11a.
  • the outgoing light from this outgoing face 11a is circularly polarized light.
  • the circularly polarized light emitted from the emission surface 11 a passes through the prism sheet 15 and the quarter wavelength plate 16.
  • the prism sheet 15 By the prism sheet 15, the outgoing light from the outgoing surface 11a is aligned in a direction substantially perpendicular to the outgoing surface 11a.
  • the quarter-wave plate 16 converts the circularly polarized light that has passed through the prism sheet 15 into second polarized light.
  • the refracting portions 13 and 14 can make the angular spread (outgoing angle) of the emitted light fall within the light usable range based on etendue restrictions. Therefore, when this illuminating device is applied to a projection display device, the problem of stray light due to divergent light that occurs in the illuminating device described in Patent Document 1 does not occur.
  • the polarizing light guide plate is not limited to the configuration shown in FIG.
  • the polarization light guide plate may be any of the polarization light guide plate described in the first and second embodiments and its modification.
  • the some light source 20 may be provided with respect to the end surface 10b.
  • At least one light source 20 may be provided on both of the end faces 10b and 10c.
  • the thickness of the central portion (the intermediate position between the end face 10b and the end face 10c) is the smallest, and the end face
  • the light guide 10 may be formed so that the thickness gradually increases toward the 10b and 10c sides.
  • the distance between the refracting portions 13 and 14 is gradually increased or the refracting portions 13 and 14 are gradually increased between the end surfaces 10b and 10c and the central portion as the distance from the end surfaces 10b and 10c increases. You may enlarge it.
  • the illumination device including the polarization light guide plate of the present invention described above can be applied to a projection display device typified by a liquid crystal projector.
  • FIG. 21 is a schematic diagram showing a configuration of a projection display device using an illumination device including the polarization light guide plate of the present invention.
  • the projection display device includes illumination devices 300 to 302, liquid crystal elements 303 to 305 as display elements, a cross dichroic mirror 306, and a projection optical system 307.
  • All of the lighting devices 300 to 302 are constituted by the above-described lighting device (having two quarter-wave plates).
  • a blue LED is used as the light source of the illumination device 300.
  • a green LED is used as the light source of the illumination device 301.
  • a red LED is used as the light source of the illumination device 302.
  • each of the lighting devices 300 to 302 When the polarizing light guide plate of each of the lighting devices 300 to 302 is provided with one quarter-wave plate, the light emitting surface of the lighting device 301 is between the light emitting surface of the lighting device 300 and the liquid crystal element 303. And a liquid crystal element 304, and between the exit surface of the illumination device 302 and the liquid crystal element 305, separate quarter-wave plates are provided.
  • the blue light emitted from the illumination device 300 is applied to the liquid crystal element 303.
  • the liquid crystal element 303 is driven by a liquid crystal driving circuit (not shown) and forms a blue image based on a video signal supplied from the outside.
  • the green light emitted from the illumination device 301 is applied to the liquid crystal element 304.
  • the liquid crystal element 304 is driven by a liquid crystal driving circuit (not shown) and forms a green image based on a video signal supplied from the outside.
  • the red light emitted from the illumination device 302 is applied to the liquid crystal element 305.
  • the liquid crystal element 305 is driven by a liquid crystal drive circuit (not shown), and forms a red image based on a video signal supplied from the outside.
  • the image light of each color formed by the liquid crystal elements 303 to 305 enters the projection optical system 307 via the cross dichroic mirror 306.
  • the projection optical system 307 projects each color image formed by the liquid crystal elements 303 to 305 onto a screen (or a member replacing the screen) (not shown).
  • Another projection type display device uses an illuminating device including light sources of red, green and blue colors on the end face of the polarizing light guide plate of the present invention.
  • light corresponding to white light
  • predetermined polarized light P-polarized light or S-polarized light
  • the display element displays red, green, and blue images based on an external video signal in a time division manner.
  • the light emission timing of the light source is controlled in synchronization with the time division display.
  • Each color image formed on the display element is projected by the projection optical system.
  • the polarizing light guide plate of the present invention and the illumination device including the same can be used as a backlight of a liquid crystal display in addition to the projection display device described above.

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  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
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  • Polarising Elements (AREA)

Abstract

La présente invention concerne une plaque de guidage de lumière à déviation qui comprend un corps de guidage de lumière (10) dans lequel la lumière entrant par une face d'extrémité de celui-ci se propage à travers celui-ci ; une plaque quart de longueur d'onde (11) formée sur l'une des faces du corps de guidage de lumière (10) ; une couche de réflexion (12) formée sur l'autre des faces du corps de guidage de lumière (10) ; et une pluralité de sections réfraction (13, 14) formées dans le corps de guidage de lumière (10) de façon à être tournées vers l'une des faces. Les sections réfraction (13) sont fabriquées de telle sorte que leur indice de réfraction pour une première déviation est supérieur à celui du corps de guidage de lumière (10) et que leur indice de réfraction pour une seconde déviation, qui est différente de la première déviation, est identique à celui du corps de guidage de lumière (10). Les sections réfraction (14) sont fabriquées de telle sorte que leur indice de réfraction pour la première déviation est inférieur à celui du corps de guidage de lumière (10) et que leur indice de réfraction pour la seconde déviation est identique à celui du corps de guidage de lumière (10). Les sections réfraction (13, 14) sont disposées de façon alternée dans une première direction qui coupe une direction verticale à la face d'extrémité.
PCT/JP2011/056760 2010-03-26 2011-03-22 Plaque de guidage de lumière à déviation, appareil d'éclairage et appareil d'affichage du type projection WO2011118563A1 (fr)

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JP2012507001A JPWO2011118563A1 (ja) 2010-03-26 2011-03-22 偏光導光板、照明装置および投射型表示装置

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JP2010072945 2010-03-26
JP2010-072945 2010-03-26

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WO2011118563A1 true WO2011118563A1 (fr) 2011-09-29

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001021717A (ja) * 1999-07-12 2001-01-26 Nitto Denko Corp 偏光導光板及び偏光面光源
JP2001141932A (ja) * 1999-11-15 2001-05-25 Nitto Denko Corp 偏光導光板及び偏光面光源
JP2002208307A (ja) * 2000-07-31 2002-07-26 Matsushita Electric Ind Co Ltd 照明装置、画像表示装置、液晶モニタ、液晶テレビ、液晶情報端末、及び導光板の製造方法
WO2004015330A1 (fr) * 2002-08-09 2004-02-19 Mitsubishi Rayon Co., Ltd. Dispositif plat de source lumineuse
JP2007213057A (ja) * 2006-02-08 2007-08-23 Samsung Electronics Co Ltd 偏光導光板及びその製造方法、前記偏光導光板を利用した平板表示装置用の照明装置
JP2010040514A (ja) * 2008-07-08 2010-02-18 Sharp Corp 光源モジュール、液晶表示装置および照明装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001021717A (ja) * 1999-07-12 2001-01-26 Nitto Denko Corp 偏光導光板及び偏光面光源
JP2001141932A (ja) * 1999-11-15 2001-05-25 Nitto Denko Corp 偏光導光板及び偏光面光源
JP2002208307A (ja) * 2000-07-31 2002-07-26 Matsushita Electric Ind Co Ltd 照明装置、画像表示装置、液晶モニタ、液晶テレビ、液晶情報端末、及び導光板の製造方法
WO2004015330A1 (fr) * 2002-08-09 2004-02-19 Mitsubishi Rayon Co., Ltd. Dispositif plat de source lumineuse
JP2007213057A (ja) * 2006-02-08 2007-08-23 Samsung Electronics Co Ltd 偏光導光板及びその製造方法、前記偏光導光板を利用した平板表示装置用の照明装置
JP2010040514A (ja) * 2008-07-08 2010-02-18 Sharp Corp 光源モジュール、液晶表示装置および照明装置

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