Abstract: A light guide plate includes a light-emitting surface, a light-reflecting surface opposed to the light-emitting surface, and a light-incident surface including a protrusion formed continuously along an edge portion of the light-emitting surface. Accordingly, light that has entered the protrusion is transmitted through the protrusion and totally reflected on an inner surface of the light-emitting surface to thus propagate inside the light guide plate. As described above, since incident light components emitted toward an upper portion of the light-incident surface can be effectively blocked by the protrusion, luminance distribution characteristics as well as a light use efficiency can be improved. The light guide plate is produced by a punching press process.

Abstract: The present invention provides a plane light source apparatus includes a light guide plate having a flat face portion and an end face portion. A plurality of point light sources are disposed in an opposing relationship to the end face portion of the light guide plate. The light guide plate mixes light from the point light sources incoming from the end face portion thereof and emit the mixed light as illumination light from the flat face portion thereof. The point light sources are a combination of point light sources having chromaticities different from each other within a predetermined standard chromaticity range, and mix light from the point light sources so that the chromaticity of the resulting illumination light fits into a target chromaticity range which is narrower than the standard chromaticity range.

Abstract: A light guide plate includes a light-emitting surface, a light-reflecting surface opposed to the light-emitting surface, and a light-incident surface including a protrusion formed continuously along an edge portion of the light-emitting surface. Accordingly, light that has entered the protrusion is transmitted through the protrusion and totally reflected on an inner surface of the light-emitting surface to thus propagate inside the light guide plate. As described above, since incident light components emitted toward an upper portion of the light-incident surface can be effectively blocked by the protrusion, luminance distribution characteristics as well as a light use efficiency can be improved. The light guide plate is produced by a punching press process.

Abstract: The present invention provides a plane light source apparatus includes a light guide plate having a flat face portion and an end face portion. A plurality of point light sources are disposed in an opposing relationship to the end face portion of the light guide plate. The light guide plate mixes light from the point light sources incoming from the end face portion thereof and emit the mixed light as illumination light from the flat face portion thereof. The point light sources are a combination of point light sources having chromaticities different from each other within a predetermined standard chromaticity range, and mix light from the point light sources so that the chromaticity of the resulting illumination light fits into a target chromaticity range which is narrower than the standard chromaticity range.

Abstract: A light guide plate for uniformly emitting light from an entire face using light taken in through an end face, includes: a parent prism formed on a face opposing to a light emitting face of the light guide plate; and a child prism formed on an inclined face of the parent prism on the end face side of the light guide plate; wherein the parent prism and the child prism convert the advancing direction of the light taken in through the end face so that the light is emitted from the light emitting face.

Abstract: A car-mounted display device improves the visibility of a display image from the driver's seat and the front passenger's seat and prevents the display image from being reflected in side windows, and a car navigation system uses the car-mounted display device as a monitor. In a case in which a liquid crystal display device is disposed at the center of a dashboard, the visibility at the driver's seat and the front passenger's seat is optimized by setting the change in luminance or contrast to be approximately 20 dB (10×) or less within an angle of approximately 40° on the right and left sides of the center. Moreover, the luminance or contrast is set to decrease by −20 dB or more beyond approximately 40° on the right and left sides of the center.