Abstract: A ring tray for honeycomb substrate firing, the ring tray supporting a honeycomb substrate having cell flow channels partitioned by cell walls, so that the flow channel direction is vertical during substrate firing, the ring tray including a ring-shaped frame part, a support part further inside than the frame part, and a connecting part connecting the frame part and support part, and the ring tray being configured so that when the honeycomb substrate is mounted on the ring tray, the support part does not contact an outer peripheral edge of a lower end surface of the honeycomb substrate, and contacts a portion of an internal region of the lower end surface of the honeycomb substrate, and is thus able to support the lower end of the honeycomb substrate, and the frame part and the connecting part do not contact the lower end surface of the honeycomb substrate.

Abstract: Provided is a manufacturing method to prevent devitrification of a bulb in a high pressure discharge lamp used for a projector. The method is for manufacturing a high pressure discharge lamp which uses, as a light source, a bulb made of fused quartz and including a tungsten electrode, and which is horizontally installed when the lamp is driven for actual use. The method includes the step of initially driving the bulb with an optical axis thereof being set horizontally before the high pressure discharge lamp is shipped. In the initial driving step, the rotation angle around the optical axis of the bulb is offset by 45° or more and 135° or less relative to the rotation angle around the optical axis of the bulb when the lamp is driven for actual use.

Abstract: Provided is a manufacturing method to prevent devitrification of a bulb in a high pressure discharge lamp used for a projector. The method is for manufacturing a high pressure discharge lamp which uses, as a light source, a bulb made of fused quartz and including a tungsten electrode, and which is horizontally installed when the lamp is driven for actual use. The method includes the step of initially driving the bulb with an optical axis thereof being set horizontally before the high pressure discharge lamp is shipped. In the initial driving step, the rotation angle around the optical axis of the bulb is offset by 45° or more and 135° or less relative to the rotation angle around the optical axis of the bulb when the lamp is driven for actual use.