Abstract: A photo semiconductor element is covered by a cap with an incident window permitting incident light to penetrate through a translucent member. The photo semiconductor element detects a quantity of incident light penetrating through the translucent member of the incident window. The translucent member of the incident window is made of a material capable of suppressing the transmitting light quantity of incident light components having wavelengths less than 700 nm and larger than 900 nm. A photoelectric current output of the photo semiconductor element is controlled by the incident light penetrating through the translucent member of the incident window. The photo semiconductor element operates in multiple ways as a thermosensing sensor and a photosensing sensor.

Abstract: A plurality of photo-detectors are provided wherein each photodetector includes a photosensitive semiconductor having a light-receiving face, a pair of leads electrically connected to the photosensitive semiconductor, and an individually selected light-transmitting member disposed in front of the light-receiving face of the photosensitive semiconductor. The light-transmitting member has a selected light transmittance which is individually selected from a plurality of different light-transmitting members to compensate for variations in the photosensitive semiconductor such that the photosensitive semiconductor provides an output current within a selected range upon a predetermined quantity of light incident upon the photo-detector. The light transmissive compensating member may be formed by selecting at least one of a mixture of materials, color, thickness, and surface finishing.

Abstract: A solar radiation sensor comprises a light sensing element 1 detecting the uantity of light entering therein, and first and second lead legs 4, 5 each conducting an electric signal representing the quantity of the light detected by the light sensing element 2. Light sensing element 2 and first and second lead legs 4, 5 are supported on a sensor casing body 1, so that light sensing element 2 is housed inside a transparent cover 3. Each of first and second lead legs 4, 5 has one end 4a, 5a formed into a contact portion connected to light sensing element 2 and the other end 4b, 5b formed into an external connecting terminal, thereby reducing the number of welded or soldered connections. An engaging ridge 1a is provided on the sensor casing body 1 to fix light sensing element 2 with respect to cover 3. First and second lead legs 4, 5 are integrated with sensor casing body 1.

Abstract: In a photo-detector, a window pane member for covering a photosensitive semiconductor is selected from among plural samples having light transmittances different from each other in compliance with an intensity of output of the photosensitive semiconductor detected under a constant quantity of light incident on the photosensitive semiconductor, thereby compressing dispersion of outputs in the plural photo-detectors into a small range as a whole.