| 摘要 |
PURPOSE:To integrate an infrared detection element and an infrared condenser lens and to provide a greater heat time constant, by fixing a pyroelectric type infrared detection element at an interval less than a quarter of the wavelength of infrared rays to be detected. CONSTITUTION:When a pyroelectric type infrared detection element 11 is put tightly on an infrared condenser lens 12, a higher infrared detection sensitivity is possible but heat time constant is shorter than a design demand value. An interval less than a quarter of the wavelength of infrared rays to be detected is provided between the lens 12 and the element 11 as effective light receiving surface so that the heat time constant meets design demand requirements for an earth sensor. Therefore, the interval between the lens 12 and the element 11 reduces heat diffusion to the lens 12 from the element 11 to enhance the heat time constant. Optical abberation can be almost ignored as the interval is less than a quarter of the wavelength of infrared rays being detected. |
