Abstract: A measuring instrument includes a light source, a dial plate with a scale design, and a light guide member. The light guide member includes a receiving portion for receiving the light from the light source, and a flat plate portion for irradiating the light transmitted from the receiving portion to the dial plate. The flat plane portion includes a thick wall section located close to the scale design, and a thin wall section extending from the thick wall section in a direction away from the light source. The thick wall section is thicker than the thick wall section. A boundary end face connected to a region of the thick wall section and a region of the thin wall section in the second face of the light guide member reflects the light transmitted in the light guide member from the light receiving portion to irradiate the image design.

Abstract: A measuring instrument includes a light source, a dial plate which has a scale design, and a light guide member which is provided between the light source and the dial plate, and guides a light received from the light source to the dial plate. The light guide member has a first face that faces to the dial plate and a second face that is opposite to the first face. The light guide member includes a light receiving portion for receiving the light from the light source, and a flat plate portion for irradiating the light transmitted from the light receiving portion to the dial plate. The scale design is arranged in a circular shape around the light source in view from an opposite side of the light source with respect to the dial plate.

Abstract: A meter dial illuminating device for illuminating a dial by means of a light incident upon a back surface thereof. The dial is formed of a light transmitting material except at a portion where characters and a scale are indicated. As a result, the front surface of the dial is illuminated by the light incident upon the back surface of the light guiding plate and transmitted therethrough.