Inventor

Hisao Kawashima

Inventor

Tokyo, JP

Overview

4→

Patents

1991–2021

Patent span

Electricity

Primary field (CPC H)

Patents· 4 as inventor

Public. Assignee & technology derived from the patent record. Each patent links to its LexDana page.

G02Fprimary

G02FOptical devices or arrangements for the control of light by modification of the optical properties of the media of the elements involved therein43%

H01LSemiconductor devices14%

H03BGeneration of oscillations, directly or by frequency-changing, by circuits employing active elements which operate in a non-switching manner14%

H03HImpedance networks, e.g. resonant circuits14%

H10NElectric solid-state devices not otherwise provided for14%

PatentTitleYear

11,005,420Quartz crystal unit, quartz crystal oscillator and electronic apparatus2021 5,521,749'Optical modulation apparatus'1996 5,185,831'Optical waveguide device'1993 5,050,947'Optical waveguide control device employing directional coupler on substrate'1991

Career & activity timeline

Assembled from patent assignee/location history and declaration credentials.

1991–1996Patents assigned to NEC CORP (3)· patent assignee history

1991–2021Based in Tokyo, JP· patent location history

2021Patents assigned to PIEDEK TECHNICAL LABORATORY (1)· patent assignee history

Inventor activity

Assignee and location history derived from the patent record.

Assignees

Assignee	Patents	Span
NEC CORP	3	1991–1996
PIEDEK TECHNICAL LABORATORY	1	2021

Locations

Location	Patents	Span
Tokyo, JP	4	1991–2021