# US 10,120,038 B2 · Vehicle lamp and method for inspecting organic EL element

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- Number: US 10,120,038 B2
- Document ID: US10120038B2
- Status: Granted
- Kind: B2
- Application number: 15/583,052
- Filed: 2017-05-01
- Published: 2017-11-16
- Granted: 2018-11-06
- Earliest claimed: 2016-05-13
- Assignees: Koito Manufacturing Co., Ltd.
- Applicants: Koito Manufacturing Co., Ltd.
- Inventors: Tomoaki Harada; Masaya Shido; Osamu Kuboyama; Yoshiro Ito; Toru Ito
- Web page: https://patentgrep.com/patent/US10120038B2

## CPC

- G01R 31/44: Testing lamps
- B07C 5/342: according to optical properties, e.g. colour {(according to radiation transmittivity B07C5/3416)}
- H10K 50/11: characterised by the electroluminescent [EL] layers
- H10K 50/115: comprising active inorganic nanostructures, e.g. luminescent quantum dots
- H10K 59/90: Assemblies of multiple devices comprising at least one organic light-emitting element
- H10K 71/70: Testing, e.g. accelerated lifetime tests
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- B07C: POSTAL SORTING; SORTING INDIVIDUAL ARTICLES, OR BULK MATERIAL FIT TO BE SORTED PIECE-MEAL, e.g. BY PICKING (specially adapted for a specific purpose covered by another class, see the relevant place, e.g. A43D33/06, B23Q7/12)
- H10K: ORGANIC ELECTRIC SOLID-STATE DEVICES

## Abstract

Provided is a vehicle lamp including: an organic EL element; and a lighting circuit that applies a voltage to the organic EL device with a rise time of the voltage of 5 milliseconds or less.

## Claims

### Claim 1

A vehicle lamp comprising:
an organic EL element; and
a lighting circuit that applies a voltage to the organic EL device with a rise time of the voltage of 5 milliseconds or less,
wherein the organic EL element includes a first electrode, a second electrode, and an organic layer interposed between the first electrode and the second electrode, and
the organic layer contains only conductive particles having a size smaller than a thickness of the organic layer.

### Claim 2 (depends on 1)

The vehicle lamp of claim 1, wherein the rise time is 1 millisecond or less.

### Claim 3

A method of inspecting an organic EL element, comprising:
applying a voltage to the organic EL element by setting a rise time of the voltage to be equal to or higher than a predetermined threshold value determined based on a temperature environment where the organic EL element is placed, or setting the rise time to 10 milliseconds or more regardless of the temperature environment where the organic EL element is placed; and
determining whether or not the organic EL element is defective based on a lighting state of the organic EL element by the application of the voltage.

### Claim 4 (depends on 3)

The method of claim 3, wherein in the applying the voltage to the organic EL element, the organic EL element is placed in a temperature environment of −40° C.

### Claim 5

A vehicle lamp comprising:
an organic EL element including an electrode and an organic layer; and
a lighting circuit that applies a voltage to the organic EL element with a rise time of the voltage shorter than a predetermined time until the electrode peeled off from the organic layer due to a burned mark generated in the organic layer comes into contact with the burned mark due to a Coulomb force generated by the application of the voltage to the organic EL element.