Planar light source, display device, portable terminal device, and ray direction switching element
First Claim
1. A planar light source comprising:
- a backlight that emits light in a planar shape;
a ray direction regulating element that regulates a direction of light made incident from the backlight and emits the light, whereby a directivity of the light is improved, said ray direction regulating element comprising a transparent area for transmitting light and an absorption area for absorbing light are formed alternately in a direction parallel to a surface of the ray direction regulating element; and
a transparent and scattering switching element that is switchable between a state in which light which is transmitted by the ray direction regulating element and made incident on said switching element is transmitted and a state in which the light is scattered;
wherein light emitted by the backlight spreads radially in an elliptical shape with respect to a direction perpendicular to an emission surface of said backlight, andwherein the transparent area and the absorption area of the ray direction regulating element are formed alternately in a direction parallel to a short diameter direction of the elliptical shape.
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Accused Products
Abstract
A planar light source includes a large variable width of an irradiation angle of illumination light, a display device having a large variable width of an angle of field that uses the planar light source, a portable terminal device that uses the display device, and a ray direction switching element that is incorporated in the planar light source. A beam direction regulating element (a louver), which controls a direction of light, and a transparent and scattering switching element, which can switch the transparent state and the scattering state according to ON and OFF of an applied voltage, are provided between a backlight and a liquid crystal panel, whereby it is possible to increase a variable width of an irradiation angle of light in the planar light source and increase a variable width of an angle of field of the liquid crystal display device that uses the planar light source.
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Citations
18 Claims
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1. A planar light source comprising:
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a backlight that emits light in a planar shape; a ray direction regulating element that regulates a direction of light made incident from the backlight and emits the light, whereby a directivity of the light is improved, said ray direction regulating element comprising a transparent area for transmitting light and an absorption area for absorbing light are formed alternately in a direction parallel to a surface of the ray direction regulating element; and a transparent and scattering switching element that is switchable between a state in which light which is transmitted by the ray direction regulating element and made incident on said switching element is transmitted and a state in which the light is scattered; wherein light emitted by the backlight spreads radially in an elliptical shape with respect to a direction perpendicular to an emission surface of said backlight, and wherein the transparent area and the absorption area of the ray direction regulating element are formed alternately in a direction parallel to a short diameter direction of the elliptical shape. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 15)
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11. A display device comprising:
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a backlight that emits light in a planar shape; a ray direction regulating element that regulates a direction of light made incident from the backlight and emits the light, whereby a directivity of the light is improved, said ray direction regulating element comprising a transparent area for transmitting light and an absorption area for absorbing light which are formed alternately in a direction parallel to a surface of the ray direction regulating element; a transparent and scattering switching element that is switchable between a state in which light which is transmitted by the ray direction regulating element and made incident on said switching element is transmitted and a state in which the light is scattered; and a liquid crystal panel that displays an image with light made incident from the transparent and scattering switching element, and wherein light emitted by the backlight spreads radially in an elliptical shape with respect to a direction perpendicular to an emission surface of said backlight, and wherein in the ray direction regulating element, the transparent area and the absorption area are formed alternately in a direction parallel to a short long diameter direction of the elliptical shape. - View Dependent Claims (12, 13, 14)
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16. A ray direction switching element for a planar light source including a backlight, comprising:
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a ray direction regulating element for regulating a direction of incident light and emitting light, whereby a directivity of the light is improved, said ray direction regulating element comprising a transparent area for transmitting light and an absorption area for absorbing light which are fanned alternately in a direction parallel to a surface of the ray direction regulating element; and a transparent and scattering switching element for switching a state in which light made incident from the ray direction regulating element is transmitted and a state in which the light is scattered, wherein said ray direction regulating element and said transparent and scattering switching element are integrally formed, wherein the incident light spreads radially in an elliptical shape with respect to an incident surface of said backlight, and wherein the transparent area for transmitting light and the absorption area for absorbing light are formed alternately in a direction parallel to a short diameter direction of the elliptical shape. - View Dependent Claims (17, 18)
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Specification