US 12,248,159 B2
Electron tube, electron tube module, and optical device
Rina Konno, Hamamatsu (JP); Shunsuke Kobayashi, Hamamatsu (JP); Ginji Sugiura, Hamamatsu (JP); Junichi Kondo, Hamamatsu (JP); and Yasumasa Matsuoka, Hamamatsu (JP)
Assigned to HAMAMATSU PHOTONICS K.K., Hamamatsu (JP)
Appl. No. 18/009,067
Filed by HAMAMATSU PHOTONICS K.K., Hamamatsu (JP)
PCT Filed Apr. 12, 2021, PCT No. PCT/JP2021/015209
§ 371(c)(1), (2) Date Dec. 8, 2022,
PCT Pub. No. WO2022/014111, PCT Pub. Date Jan. 20, 2022.
Claims priority of application No. 2020-122767 (JP), filed on Jul. 17, 2020.
Prior Publication US 2023/0296816 A1, Sep. 21, 2023
Int. Cl. G02B 5/04 (2006.01); G01N 21/64 (2006.01); G02B 21/00 (2006.01); H01J 40/16 (2006.01); H01J 43/08 (2006.01)
CPC G02B 5/04 (2013.01) [G01N 21/64 (2013.01); G02B 21/0076 (2013.01); H01J 40/16 (2013.01); H01J 43/08 (2013.01)] 17 Claims
OG exemplary drawing
 
1. An electron tube comprising:
a vacuum container that includes a light transmitting substrate and forms a vacuum space;
a photocathode provided on an inner surface of the light transmitting substrate facing the vacuum space and configured to emit photoelectrons into the vacuum space in response to light incident through the light transmitting substrate;
an electron detector provided in the vacuum container and configured to detect electrons derived from the photoelectrons; and
a prism bonded to an outer surface of the light transmitting substrate opposite to the inner surface,
wherein the prism includes:
a bottom surface bonded to the outer surface of the light transmitting substrate;
a light incident surface having a light incident portion to which light is incident; and
a light reflecting surface configured to further reflect light, which is incident to the light incident portion and reflected at an interface between the photocathode and the vacuum space, so that the light is incident to the photocathode again,
the light reflecting surface has an outwardly convex curved surface shape,
the light incident portion is located inward of an imaginary spherical surface that is along the light reflecting surface, and
the prism further includes a pair of side surfaces provided between the light incident surface, the light reflecting surface, and the bottom surface, and facing each other with the light incident surface and the light reflecting surface interposed therebetween when viewed from a direction facing the bottom surface.