Abstract: A rotating shaft mechanism includes a first connecting portion, a second connecting portion, a central shaft rotatably connected to the first connecting portion and the second connecting portion, and an adjusting unit disposed on the central shaft. The adjusting unit includes an adjusting ring disposed around the central shaft, a first washer disposed around the central shaft and configured to generate a force to the first connecting portion or the second connecting portion. A position of the adjusting ring with respect to the central shaft is axially adjustable for adjusting the force so that the first connecting portion or the second connecting portion is rotatable or fixed relative to the central shaft.

Abstract: A prism and light transmitter module includes a prism holder, a light transmitter, a prism module, a drive circuit board, a shield, and a fixing assembly. The light transmitter is configured to emit or receive a light beam along a light axis. The prism module includes an inclined plane and is disposed within the prism holder with the inclined plane exposed. The drive circuit board is disposed above the inclined plane, and intersects with the light axis at a first angle. The shield is disposed on the drive circuit board. The fixing assembly connects to the prism holder, is configured to fix the drive circuit board, and includes a hole through which the light transmitter is exposed. A binocular capable of measuring distance includes a first optical system and a second optical system. The first optical system or/and the second optical system include the prism and light transmitter module.

Abstract: An ocular structure for observation apparatus includes a first member, a second member and a main body. The first member includes at least one slot and a plurality of first limiting mechanisms. The second member includes at least one slider extending into the slot and a plurality of second limiting mechanisms. The main body includes an ocular lens unit, wherein the first member and the second member are mounted on the main body. The slider is moved in the slot when the first member and the second member are in relative rotation, and the first limiting mechanisms directly or indirectly match the second limiting mechanisms to position the first member with respect to the second member.

Abstract: A rotating shaft mechanism includes a first connecting portion, a second connecting portion, a central shaft rotatably connected to the first connecting portion and the second connecting portion, and an adjusting unit disposed on the central shaft. The adjusting unit includes an adjusting ring disposed around the central shaft, a first washer disposed around the central shaft and configured to generate a force to the first connecting portion or the second connecting portion. A position of the adjusting ring with respect to the central shaft is axially adjustable for adjusting the force so that the first connecting portion or the second connecting portion is rotatable or fixed relative to the central shaft.

Abstract: A prism and light transmitter module includes a prism holder, a light transmitter, a prism module, a drive circuit board, a shield, and a fixing assembly. The light transmitter is configured to emit or receive a light beam along a light axis. The prism module includes an inclined plane and is disposed within the prism holder with the inclined plane exposed. The drive circuit board is disposed above the inclined plane, and intersects with the light axis at a first angle. The shield is disposed on the drive circuit board. The fixing assembly connects to the prism holder, is configured to fix the drive circuit board, and includes a hole through which the light transmitter is exposed. A binocular capable of measuring distance includes a first optical system and a second optical system. The first optical system or/and the second optical system include the prism and light transmitter module.