Spread illuminating apparatus, transparent resin plate for use in spread illuminating apparatus, and method of injection-molding transparent resin plate

A transparent resin plate adapted for use in a spread illuminating apparatus of side light type comprising:

• a light reflecting sheet disposed at a rear of the transparent resin plate and comprising a main body portion and flap portions extending from sides of the main body portion and bent up along the sides;
• and a light source disposed at a side of the transparent resin plat, wherein the transparent resin plate is integrally composed of a light conductor plate portion and a housing frame portion, the transparent resin plate comprising:
• an opening to house the light source, the opening disposed at a side portion of the transparent resin plate;
• slits provided along a boundary between the light conductor plate portion and the housing frame portion, wherein the light reflecting sheet is attached to the transparent resin plate with the flap portions inserted in the slits of the transparent resin plate;
• and
• a gate for injecting resin for the transparent resin plate, the gate positioned outside the boundary between the light conductor plate portion and the housing frame portion and positioned also between the opening and one of slits which are provided toward the side portion of the transparent resin plate having the opening and which are located clear of the opening.

A method of injection-molding a transparent resin plate which is integrally composed of a light conductor plate portion and a housing frame portion and which is adapted for use in a spread illuminating apparatus of side light type comprising a light reflecting sheet disposed at a rear of the transparent resin plate and a light source disposed at a side of the transparent resin plate, wherein:

• the light reflecting sheet comprises a main body portion and flap portions extending from sides of the main body portion and bent up along the sides;
• an opening for housing the light source is provided at a side portion of the transparent resin plate;
• slits are provided along a boundary between the light conductor plate portion and the housing frame portion of the transparent resin plate;
• and the light reflecting sheet is attached to the transparent resin plate with the flap portions inserted in the slits of the transparent resin plate, the method comprising a step of injecting resin for the transparent resin plate into a cavity of a molding die through a gate positioned outside the boundary between the light conductor plate portion and the housing frame portion and positioned also between the opening and one of slits which are provided toward the side portion of the transparent resin plate having the opening and which are located clear of the opening.