Matsushita Electric Industrial Co., Ltd.

Yoshikazu Demi

Mitsunori Yokomakura

Michiaki Watanabe

Hideo Suzuki

Hiroshi Kobayashi

Hideharu Ohmae

Masayuki Ohmori

Masamichi Kimura

Nozomu Arimoto

Hideaki Etou

Masayoshi Ozaki

Shiro Kashihara

Ayumu Takakuwa

Satoshi Ohta

Tatsuzo Hayashi

Teruhisa Kodama

Tadayuki Sato

Masayuki Omori

Due to a slit formed in the dead space, a cathode ray tube capable of preventing incorrect hitting of color electron beams caused by the local doming phenomenon from occurring and thus preventing displacement of colors, unevenness in colors, and deterioration of luminance from occurring is provided. The cathode ray tube comprises a shadow mask having an effective area where lines of apertures for passing electron beams are arranged and a dead space formed on both outer sides of the effective area. In the dead space, a slit extending along the lines of the apertures is formed. Accordingly, the thermal expansion of the dead space caused by a temperature increase can be reduced, and the stress applied to the aperture line of the effective area adjacent to the dead space can be suppressed. As a result, the local doming phenomenon can be prevented from occurring.

Cathode ray tube with slit in dead space of shadow mask

A vibration attenuator is attached to a shadow mask in a movable condition without being adhered to the shadow mask. The vibration attenuator has depressions, and is attached to the shadow mask by inserting its foot portions through holes provided in the shadow mask, and folding them at the depressions, thereby deforming the vibration attenuator into an approximately rectangular shape. Because a vibration energy of the shadow mask is consumed by friction due to a contacting or sliding of the vibration attenuator with the shadow mask, vibration of the shadow mask can be attenuated effectively with a simple structure.

Color cathode-ray tube with shadow mask having attached vibration attenuator

A cathode ray tube capable of reducing the doming amount and suppressing the occurrence of moire stripes at the same time with improved effects to suppress the occurrence of moire stripes even more is provided. The protruding portions are protruding from the ends of the horizontal direction of the aperture to the inside of the aperture . With regard to the horizontal cross sections of the protruding portions , the portions facing each other left and right via the aperture are formed to be asymmetrical to the center line in order to reduce or block the incident electron beam. By forming the protruding portions , the doming amount can be reduced and the occurrence of moire stripes can be suppressed at the same time. Furthermore, by forming the portions facing each other left and right of the protruding portions asymmetrically, the effects to suppress the occurrence of moire stripes can be improved even more.

Cathode ray tube

A color cathode-ray tube that can attenuate vibration of an entire shadow mask positively with a simple structure. The color cathode-ray tube includes a frame-shaped mask frame and a shadow mask in which many apertures are formed in a flat plate, the shadow mask being stretched and fixed in the mask frame in a condition in which a tension force is applied in one direction. The amplitude in the end portions of the shadow mask is not less than a certain amount relative to the amplitude in the center portion of the shadow mask, in a resonance of the shadow mask caused by a vibration propagated to the color cathode-ray tube. Furthermore, by providing vibration attenuators at the end portions of the shadow mask, vibrations at the end portions of the shadow mask are attenuated as the side surfaces of the shadow mask slide on the vibration attenuators. Thus, vibration of the entire shadow mask can be extinguished positively.

Color CRT having shadow mask with vibration attenuator

A cathode ray tube including a pair of supports arranged in parallel facing each other and a shadow mask acting as a color selection electrode including a large number of apertures. The shadow mask is stretched and held by the supports in a state in which tension is applied by the supports. In the shadow mask before being stretched onto the supports, the shapes of the apertures are varied so that the width of the apertures in the middle portion in the direction in which tension is to be applied narrows gradually from the central portion towards the both end portions in the direction parallel to the longitudinal direction of the support. Thereby, the shapes of the apertures can be made to be uniform over the entire surface in a state in which the shadow mask is stretched. As a result, a cathode ray tube with less color unevenness can be provided.

The present invention provides a color cathode-ray tube that can attenuate vibration of an entire shadow mask positively with a simple structure. The color cathode-ray tube comprises a frame-shaped mask frame and a shadow mask in which many apertures are formed in a flat plate, the shadow mask being stretched and fixed in the mask frame in a condition in which a tension force is applied in one direction. The amplitude in the end portions of the shadow mask is not less than a certain amount relative to the amplitude in the center portion of the shadow mask, in a resonance of the shadow mask caused by a vibration propagated to the color cathode-ray tube. Furthermore, by providing vibration attenuators at the end portions of the shadow mask, vibrations at the end portions of the shadow mask are attenuated as the side surfaces of the shadow mask slide on the vibration attenuators. Thus, vibration of the entire shadow mask can be extinguished positively.

Color cathode-ray tube with shadow mask and frame

A cathode ray tube capable of reducing the doming amount and suppressing the occurrence of moire stripes at the same time, which also can prevent the so-called persimmon stone phenomenon from occurring, is provided. In the apertures, the protruding portions that are protruding from end faces in the horizontal direction of the apertures to the inside of the apertures are formed. The protruding portion in the aperture located on the right side of the phosphor surface from the vertical center line of the shadow mask is protruding in the direction toward the peripheral portion on the right side, while the protruding portion in the aperture located on the left side of the phosphor surface is protruding toward the peripheral portion on the left side. Accordingly, the doming amount can be reduced and the occurrence of moire stripes can be suppressed at the same time, while the persimmon stone phenomenon in which the beam spot of an electron beam on the phosphor surface is cut partially can be prevented from occurring.

Cathode ray tube having apertured shadow mask

A cathode ray tube capable of preventing incorrect hitting of color electron beams caused by the local doming phenomenon and the initial doming phenomenon from occurring and thus preventing displacement of colors, unevenness in colors, and deterioration of luminance from occurring is provided. The cathode ray tube includes a shadow mask made of a flat plate in which a number of apertures are arranged in lines, and slits are formed in the line direction of the apertures . These slits have inclined faces and opposed via openings . Due to this configuration, the displacement of apertures due to the local doming phenomenon or the initial doming phenomenon caused by the thermal expansion of the shadow mask can be suppressed. Thus, displacement of colors, unevenness in colors, and deterioration of luminance caused by incorrect hitting of electron beams can be prevented from occurring.

Cathode ray tube having shadow mask with slit between apertures

The color cathode ray tube according to the present invention can improve the brightness without compromising strength by making the bridge width in one-dimensional tension type shadow mask narrower to a certain degree. The color cathode ray tube has a color selection electrode, the color selection electrode including a pair of supports facing each other; a shadow mask provided with a plurality of slot apertures, the shadow mask being stretched and fixed by the pair of supports; and elastic members arranged between the supports, and holding the supports. Bridges between vertically adjacent slot apertures are formed on the shadow mask. Defining the bridge width W as the largest vertical width of a bridge, the narrowest bridge width Wmin is in a range of 3-10% of a vertical pitch of the slot apertures. With this configuration, the necessary strength can be ensured, and the brightness can be improved without compromising strength, because the bridge widths W can be made narrower.

Color cathode ray tube with tensioned shadow mask

A color cathode-ray tube that can attenuate vibration of an entire shadow mask positively with a simple structure. The color cathode-ray tube includes a frame-shaped mask frame and a shadow mask in which many apertures are formed in a flat plate, the shadow mask stretched and fixed in the mask frame in a condition in which a tension force is applied in one direction. The amplitude in the end portions of the shadow mask is not less than a certain amount relative to the amplitude in the center portion of the shadow mask, in a resonance of the shadow mask caused by a vibration propagated to the color cathode-ray tube. Furthermore, by providing vibration attenuators at the end portions of the shadow mask, vibrations at the end portions of the shadow mask are attenuated as the side surfaces of the shadow mask slide on the vibration attenuators. Thus, vibration of the entire shadow mask can be extinguished positively.

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Shiga, Japan

Yoshikazu Demi