Patent ID: 8792143

Claim:
An operation device comprising: a panel including a light-transmissive portion having a ring-like shape; a light guide element having a first surface and a second surface, the first surface facing the panel; a plurality of light sources provided at locations around the light guide element; and a plurality of electrodes provided at locations corresponding to the light-transmissive portion closer to the second surface of the light guide element and configured to detect a capacitance, wherein the light guide element has a diffusion surface having a ring-like shape formed on the second surface, wherein the ring-like shape of the diffusion surface includes a first region corresponding to one of the light sources and a second region provided between two of the light sources adjacent to each other, wherein a distance from a location of the light-transmissive portion to a periphery of the ring-like shape of the diffusion surface close to the light source is greater in the second region than in the first region, and wherein light emitted from the light source and incident to the light guide element is diffusion-reflected on the diffusion surface and a part of the diffusion-reflected light illuminates the light-transmissive portion.