# US 2026/0084418 A1 · Liquid discharge apparatus and print head drive circuit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2026/0084418 A1 - Document ID: US20260084418A1 - Status: Published application - Kind: A1 - Application number: 19/335,019 - Filed: 2025-09-22 - Published: 2026-03-26 - Earliest claimed: 2024-09-24 - Assignees: Seiko Epson Corporation - Applicants: Seiko Epson Corporation - Inventors: Tomonori YAMADA; Toru MATSUYAMA - Web page: https://patentgrep.com/patent/US20260084418A1 ## CPC - B41J 2/0455: {Details of switching sections of circuit, e.g. transistors} - B41J 2/04541: {Specific driving circuit} - B41J 2/04581: {controlling heads based on piezoelectric elements} - B41J 2/04588: {using a specific waveform} - B41J 2/04596: {Non-ejecting pulses} - H10D 10/40: Vertical BJTs {(Vertical Heterojunction BJTs H10D10/821)} - H10D 62/111: {Multiple RESURF structures, e.g. double RESURF or 3D-RESURF structures} - H10D 62/137: {Collector regions of BJTs} - H10D 62/177: {Base regions of bipolar transistors, e.g. BJTs or IGBTs} - H10N 30/2047: {Membrane type} - H10N 30/802: {Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits} - H03F 3/21: with semiconductor devices only {(H03F3/245 takes precedence)} - H03K 17/60: the devices being bipolar transistors (bipolar transistors having four or more electrodes H03K17/72) - B41J: TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - H03F: AMPLIFIERS - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A liquid discharge apparatus, in which a first transistor included in an amplification circuit included in a print head drive circuit that includes a first conductor, a second conductor, a third conductor, a first layer that includes a first semiconductor region and a second semiconductor region, a second layer that includes a third semiconductor region, and a third layer that includes a fourth semiconductor region, a fifth semiconductor region, and a sixth semiconductor region, the first layer is disposed above the third conductor, the second layer is disposed above the first layer, the third layer is disposed above the second layer, the first conductor is disposed above the fifth semiconductor region, and the second conductor is disposed above the sixth semiconductor region. ## Claims ### Claim 1 A liquid discharge apparatus comprising: a print head that discharges a liquid in response to a drive signal; and a print head drive circuit that outputs the drive signal, wherein the print head drive circuit includes an amplification circuit that outputs the drive signal amplified by a first transistor and a second transistor, the first transistor includes a first conductor that functions as an emitter electrode, a second conductor that functions as a base electrode, a third conductor that functions as a collector electrode, a first layer that includes a first semiconductor region of a first conductive type having a trench and a second semiconductor region of a second conductive type provided in the trench, a second layer that includes a third semiconductor region of the second conductive type, and a third layer that includes a fourth semiconductor region of the first conductive type, a fifth semiconductor region of the first conductive type, and a sixth semiconductor region of the second conductive type positioned to be separated from the fifth semiconductor region, the first layer is disposed above the third conductor, the second layer is disposed above the first layer, the third layer is disposed above the second layer, the first conductor is disposed above the fifth semiconductor region, and the second conductor is disposed above the sixth semiconductor region. ### Claim 2 (depends on 1) The liquid discharge apparatus according to claim 1, wherein an impurity concentration of the fourth semiconductor region is lower than an impurity concentration of the first semiconductor region, an impurity concentration of the fifth semiconductor region is higher than the impurity concentration of the first semiconductor region, and an impurity concentration of the third semiconductor region and an impurity concentration of the sixth semiconductor region are higher than an impurity concentration of the second semiconductor region. ### Claim 3 (depends on 1) The liquid discharge apparatus according to claim 1, wherein the first transistor further includes a fourth layer that includes a seventh semiconductor region of the first conductive type, the fourth layer is disposed between the third conductor and the first layer, and an impurity concentration of the seventh semiconductor region is higher than an impurity concentration of the first semiconductor region. ### Claim 4 (depends on 1) The liquid discharge apparatus according to claim 1, wherein the print head includes 3000 or more piezoelectric elements, and the 3000 or more piezoelectric elements are driven by the drive signal. ### Claim 5 (depends on 1) The liquid discharge apparatus according to claim 1, wherein a frequency of the drive signal is 100 kHz or higher. ### Claim 6 (depends on 1) The liquid discharge apparatus according to claim 1, wherein the drive signal includes a period in which a voltage value changes by 20 V or more per microsecond. ### Claim 7 (depends on 1) The liquid discharge apparatus according to claim 1, wherein the drive signal includes a period of shorter than 0.3 μs in which a voltage value is constant. ### Claim 8 (depends on 1) The liquid discharge apparatus according to claim 1, wherein the amplification circuit is an AB-class amplification circuit. ### Claim 9 A print head drive circuit that outputs a drive signal to a print head that discharges a liquid in response to the drive signal, the print head drive circuit comprising: an amplification circuit that outputs the drive signal amplified by a first transistor and a second transistor, wherein the first transistor includes a first conductor that functions as an emitter electrode, a second conductor that functions as a base electrode, a third conductor that functions as a collector electrode, a first layer that includes a first semiconductor region of a first conductive type having a trench and a second semiconductor region of a second conductive type provided in the trench, a second layer that includes a third semiconductor region of the second conductive type, and a third layer that includes a fourth semiconductor region of the first conductive type, a fifth semiconductor region of the first conductive type, and a sixth semiconductor region of the second conductive type positioned to be separated from the fifth semiconductor region, the first layer is disposed above the third conductor, the second layer is disposed above the first layer, the third layer is disposed above the second layer, the first conductor is disposed above the fifth semiconductor region, and the second conductor is disposed above the sixth semiconductor region. ### Claim 10 (depends on 9) The print head drive circuit according to claim 9, wherein an impurity concentration of the fourth semiconductor region is lower than an impurity concentration of the first semiconductor region, an impurity concentration of the fifth semiconductor region is higher than the impurity concentration of the first semiconductor region, and an impurity concentration of the third semiconductor region and an impurity concentration of the sixth semiconductor region are higher than an impurity concentration of the second semiconductor region. ### Claim 11 (depends on 9) The print head drive circuit according to claim 9, wherein the first transistor further includes a fourth layer that includes a seventh semiconductor region of the first conductive type, the fourth layer is disposed between the third conductor and the first layer, and an impurity concentration of the seventh semiconductor region is higher than an impurity concentration of the first semiconductor region. ### Claim 12 (depends on 9) The print head drive circuit according to claim 9, wherein the print head includes 3000 or more piezoelectric elements, and the 3000 or more piezoelectric elements are driven by the drive signal. ### Claim 13 (depends on 9) The print head drive circuit according to claim 9, wherein a frequency of the drive signal is 100 kHz or higher. ### Claim 14 (depends on 9) The print head drive circuit according to claim 9, wherein the drive signal includes a period in which a voltage value changes by 20 V or more per microsecond. ### Claim 15 (depends on 9) The print head drive circuit according to claim 9, wherein the drive signal includes a period of shorter than 0.3 μs in which a voltage value is constant. ### Claim 16 (depends on 9) The print head drive circuit according to claim 9, wherein the amplification circuit is an AB-class amplification circuit.