The present disclosure relates to a light-emitting device and an image display apparatus, and more particularly, to a light-emitting device and an image display apparatus capable of improving the uniformity of a luminance to reduce unevenness of the luminance and reducing leakage light in such manner that a concave-convex pattern formed by a plurality of convex portions formed in a light-exiting surface of a light guiding member satisfies a predetermined condition.
There is a light-emitting device performing illumination using a light source such as a light-emitting diode (LED). For example, the light-emitting device is used as an illumination device by using the light source directly as an illumination or is used for an image display apparatus such as a television receiver or a personal computer by using the light source as a backlight illumination.
An example of the image display apparatus includes a liquid crystal display apparatus in which a liquid crystal panel is used as a display panel displaying an image.
In the liquid crystal apparatus, since the liquid crystal panel is not a self light-emitting display, a light-emitting device including a light source which emits light from a rear surface side to the liquid crystal panel is disposed. Accordingly, the light-emitting device is used as a backlight device which emits light toward the liquid crystal panel from the rear surface side.
As the light-emitting device used as the backlight device, there is a so-called side edge type light-emitting device which includes a light guiding member and in which a light source is disposed on the side of the light guiding member and light emitted from the light source is guided in a predetermined direction by the light guiding member to be emitted toward a display panel. Further, as the light-emitting device used as the backlight device, there is a so-called straight-down type light-emitting device in which the light source is disposed on the rear surface side of the display panel and light emitted from the light source is emitted toward the display panel.
In the side edge type light-emitting device, since a plurality of light sources is disposed on the side of the light guiding member, the image display apparatus can be made thin.
In the side edge type light-emitting device, it is preferable that light does not exit and does not leak in a region determined in advance in each light source of the light guiding member, that is, a region located on the side of each light source toward an adjacent region, when the light is emitted from each of the plurality of light source. In particular, in a light-emitting device called a so-called scan backlight which emits light sequentially respective strip-shaped regions and improves the definition of an image, there is a high necessity to reduce leakage light to the adjacent region.
By reducing the leakage light, it is possible to suppress the deterioration in light use efficiency or partial deterioration in luminance.
There is a light-emitting device according to the related art, in which a plurality of groove portions is formed at a predetermined interval on the surface of a light guiding member (for example, Japanese Unexamined Patent Application Publication No. 2009-199926).
The light-emitting device disclosed in Japanese Unexamined Patent Application Publication No. 2009-199926 attempts to suppress light from travelling toward the adjacent region by the groove portions and reduce the leakage light to the adjacent region.