Matsushita Electric Industrial Co., Ltd.

Tamotsu Ikeda

Nobuyuki Haji

Masayoshi Ueda

Moriaki Kawasaki

In a light beam heating apparatus generating a light beam for heating a work, optical energy of the light beam is deteriorated as the lamp is used. The optical energy is controlled by detecting an optical intensity of the light emitted by the lamp. If the optical intensity is decided not to be increased to a desired value due to an increase in arc light source or the like, an exchange of the lamp is cautioned. Thus, a timing of the exchange of the lamp can be decided before the temperature of a work becomes lower than the desired value.

Light beam heating apparatus

During a preheating period of a light beam heating apparatus for heating a material locally with a light beam, fans for cooling a lamp for generating a light beam are not operated. A power source supplies current to a lamp. A current detector detects the current supplied to the lamp from the power source. A delay circuit delays a current detection value from the current detector for a predetermined time period and then sends the value to a controller. Then, the controller starts to activate fans for cooling the lamp. Alternately, a temperature detector is provided to detect the temperature of the lamp. When the temperature reaches a prescribed temperature, the controller starts to activate fans for cooling the lamp. Thus, the internal temperature of the lamp reaches the thermal saturation temperature in a shorter period of time, and the optical energy for heating can be stabilized after preheating.

A photosensor arranged at the center of a light-receiving end of an optical fiber bundle detects an optical intensity which is converted by a photoelectric converter to an electric signal. Then, the optical energy provided at the optical fiber bundle is calculated based on the signal. On the other hand, a correction coefficient is calculated from optical intensity signals when the lamp is new and when the element in the lamp wears, and the setting value of the output optical intensity of the optical fiber bundle is corrected. Then, the current supplied to the lamp by a power supply is controlled according to a difference between the setting value and the measured optical energy. Thus, the optical energy to be received through the optical fiber bundle is controlled stably irrespective of the change of optical intensity distribution due to wear of the electrode of the lamp. Similarly, the correction coefficient is calculated from optical intensities measured with photodetectors arranged at and off the center of a light-receiving end of an optical fiber bundle.

Growing community of inventors

Toyonaka, Japan

Tamotsu Ikeda