Patent ID: 7218653
Filing Date: 2007-05-15
Classification: G02F

Abstract:
1. A wavelength conversion method comprising the steps of: providing a heating block for covering an entire outside surface other than an incident end surface and an emitting end surface of the wavelength conversion element and for heating the wavelength conversion element from an outside of the wavelength conversion element with a heater; and heating and controlling a wavelength conversion element to maintain the wavelength conversion element at a specific temperature within a temperature range of 200 to 450° C. with a predetermined temperature precision, wherein said wavelength converting element made of a single crystal of lithium tetraborate is adapted to generate harmonics having wavelengths of less then 355 nm by converting wavelengths of laser beams, and wherein when a length of the wavelength conversion element is L, a vertical width and a horizontal width of the wavelength conversion element are L/4 or less, and the heating block is projected by L/3 or more in a lengthwise direction from the incident end surface and the emitting end surface of the wavelength conversion element.