| 摘要 |
PURPOSE:To achieve a simpler construction and an easier adjustment by a method wherein when different color lights irradiate an object sequentially in a time-sharing manner, reflected lights or transmission lights are received with a light receiving section, an output signal of which is supplied to a hue discriminator circuit to discriminate hue. CONSTITUTION:Light emitting elements 1a and 1b for emitting different color lights are driven with a time-sharing circuit 13 to irradiate an object 4 to be inspected sequentially and reflected or transmission lights are received with a light receiving section 6 which comprises a signal light receiving element to generate an analog signal. An input analog signal is compared with a reference level with a comparator circuit 8 and converted into a digital signal (e) of 1 or 0. D type FFs 15 and 16 form a holding circuit to hold the level of a digital signal (e) at the timings of strove pulses (f) and (g). AND gates 17, 18, 19 and 20 form a logic computation circuit to perform a logic computation of the level held with the D type FFs15 and 16 as data and an output signal is produced as listed. This enables a simple construction and an easier adjustment. |
