Abstract: In a shadow mask type color cathode-ray tube having slot apertures that are straight in the perpendicular direction, the projections of electron beams transmitted by the slot apertures onto the fluorescent screen tend to curve in a banana-like shape with increasing proximity to the right and left sides of the screen, thereby bringing about a drop in the color interference margin and loss margin. The projection of electron beams that are transmitted by the slot apertures and strike the fluorescent screen can be made straight by boring slot apertures in advance that are curved in the direction opposite the curvature of the electron beam projection.

Abstract: In a color cathode ray tube, a slot type shadow mask in which the vertical pitch of slots is within 0.2 mm to 0.3 mm, the width of each bridging portion is within 0.02 mm to 0.08 mm and the width of each connecting portion of the bridging portions is within 0.005 mm to 0.03 mm is combined with a neck tube of the diameter within 20 mm to 25 mm.

Abstract: A device for measuring a distance between a panel and a shadow mask included in a color CRT (Cathode Ray Tube) of the present invention includes a range finder having an emitter for emitting an ultrasonic pulse, and a receiver for receiving it. The emitter emits the ultrasonic pulse toward the inner surface of the panel on which the shadow mask is mounted. The distance or so-called Q value is measured on the basis of a lag between the time when a first reflection from the shadow mask reaches the receiver and the time when a second reflection from the inner surface of the panel reaches the receiver. The device is capable of measuring the Q value without resorting to the removal of the shadow mask, and measuring Q values even smaller than 5 mm without contacting the shadow mask. In addition, the device is easy to handle and small size.

Abstract: A noise reducing circuit for video images. A motion detector outputs a first difference between a first video signal and a second image signal. A compensation signal producing circuit generates a compensation signal in accordance with the first difference. The compensation signal is outputted in accordance with a third signal supplied to the compensation signal producing means. A subtracter subtracts the compensation signal from the first video signal to output a second difference between the compensation signal and first video signal. The second difference has the same image information as the first image signal with noise eliminated. An image delaying circuit or memory receives the second difference from the subtracter and outputs a delayed second difference signal. The delayed second difference signal has a delay time of at least one frame and is outputted as the second image signal.

Abstract: A system for playing back information recorded on a recording disc including a memory for storing a demodulated signal information. A read out clock signal generator produces a read out clock signal synchronized with a playback clock signal obtained according to information reproduced from the recording disc. The system is further provided with means for monitoring a memory utilization factor of the memory and a control signal is produced according to the result of the monitoring of the memory utilization factor. Thus, an overflow of the demodulated digital data in the memory is prevented.

Abstract: A drive motor control device for a video disk player or the like operates to brake the motor by driving it reversely upon reception of a rotation termination signal, until it is detected that the motor has stopped and rotates reversely. The motor is then driven forwardly for a predetermined time before being allowed to rotate freely to a stop.