Jewel Case

CD 透明塑料盒 (Jewel Case) is a common rigid plastic packaging format used in optical disc distribution, which entered the market in 1982 alongside audio CDs. Philips developed this case for the new medium so that the disc could be secured at its center without touching the recorded surface, and so that the text on the front and back covers could be visible through the transparent casing. The “Jewel Case” was later also used for retail packaging of discs of the same size, such as CD-ROMs.

A standard single-disc case typically consists of a transparent front cover, a rear shell, and a tray embedded in the rear shell; when closed, its dimensions are approximately 142 × 125 × 10 millimeters. An elastic tab in the center of the tray grips the disc’s center hole, allowing the disc to rest suspended in a groove; a tab on the inside of the front cover secures the front cover insert, while the space beneath the tray accommodates the back cover insert featuring text along its spine. Early trays were mostly opaque black; after transparent trays became widespread, the inner side of the back cover insert could also be used for printing. Each part of the case serves a distinct function. The outer case protects the disc and provides a flat display surface; the central locking tab restricts the disc’s movement; and the printed paper inserts contain track listings, copyright information, and production details. If the tray, front cover, or hinge is damaged, it can usually be replaced individually without affecting the disc itself; however, there may still be slight variations in the dimensions of the latches, hinges, and trays among different manufacturers.

Dual-disc and multi-disc versions may include a flip-out center tray, disc latches on both the front and back, or an increased case thickness. So-called “slim jewel cases,” “fatboxes,” and “Super Jewel Boxes” are all related to the standard transparent case but have different structures or dimensions and cannot be grouped simply as “transparent plastic cases.”

Polystyrene is commonly used in traditional Jewel Cases; its advantages include transparency, high rigidity, and ease of display. Its disadvantages are that the hinge posts, front cover tabs, and tray teeth are prone to breaking when subjected to impact. Scratches and clouding on the case surface generally do not affect disc readability, but broken parts may cause the disc to become loose; if the center locking tab is too tight, bending the disc directly to remove it may also cause stress-related damage. The condition of the packaging and the condition of the disc data are therefore two distinct issues.