Abstract: A bar-shaped light guide is provided to allow its emitting surface to be exposed from a white casing and is provided with a pattern for scattering and reflecting the light on a bottom surface opposite to the emitting surface. This pattern is formed by a white paint or minute irregularities. Further, an end face of the bar-shaped light guide opposite to the incident side is made cube-corner shaped. In other words, the end face is made chevroned by mirror-finished flat surfaces. These flat surfaces are tilted at such an angle that an incident angle ? of the rays of light traveling through the bar-shaped light guide parallel to the longitudinal direction of the bar-shaped light guide is smaller than a critical angle.

Abstract: A product management system has a database, an owner identification device, a card issuance device, and a checking device. The database correlates and stores therein product and owner information in relation to the owner of the product. The owner identification device wirelessly reads out information from an IC tag, which is fixed to the product and has stored therein product information, and also reads out from the database product information and correlated owner information. The card issuance device issues a card having a storage medium for storing the information. The checking device checks and compares information read out from the card, information read out from the IC tag, and information read out from the database, to thus validating the owner of the product. The product management system prevents a product which has been sold from being illegally used by or dealt with a person other than a valid owner.

Abstract: A method for attaching a substrate such as a semiconductor wafer in which cracking or chipping can be prevented when the substrate is thinned involves applying adhesive liquid onto a circuit (element)-formed surface of a semiconductor wafer. The adhesive liquid undergoes preliminary drying, so that its flowability is reduced and it can keep its shape as an adhesive layer. For the preliminary drying, heating is conducted for 5 minutes at a temperature of 80° C. by using an oven. The thickness of the adhesive layer is determined based on the irregularities of the circuit which has been formed on the surface of the semiconductor wafer. Next, a supporting plate is attached to the semiconductor wafer on which the adhesive layer of a desired thickness has been formed.