Method of manufacturing display device

Patent metadata

Field	Value
Publication number	US-12349479-B2
Application number	US-202017914334-A
Country	US
Kind code	B2
Filing date	Apr 8, 2020
Priority date	Apr 8, 2020
Publication date	Jul 1, 2025
Grant date	Jul 1, 2025

Abstract

A method of manufacturing a display device includes: the measurement step of sweeping a voltage to light-emitting elements and measuring a current value that flows in the light-emitting elements in response to a voltage value applied; the computation step of computing a first derivative value of the current value with respect to the voltage value, the first derivative value representing voltage dependence of a first derivative of the current value; the peak determination step of determining a peak of the first derivative value; the processing step of processing the light-emitting elements based on a result of the peak determination step; and the attaching step of attaching a housing to the substrate.

First claim

The invention claimed is:

1. A method of manufacturing a display device, the method comprising:
a thin film transistor forming step of forming thin film transistors on a substrate;
a light-emitting element forming step of forming light-emitting elements on the thin film transistors, the light-emitting elements including an anode, a light-emitting layer, and a cathode; and
an inspection step of inspecting the light-emitting elements,
the inspection step including:
a measurement step of sweeping a voltage to the light-emitting elements and measuring a current value that flows in the light-emitting elements in response to a voltage value applied;
a computation step of computing a first derivative value of the current value with respect to the voltage value, the first derivative value representing voltage dependence of a first derivative of the current value;
a peak determination step of determining a peak of the first derivative value;
a processing step of processing the light-emitting elements based on a result of the peak determination step; and
an attaching step of attaching a housing to the substrate.

2. The method according to claim 1 , wherein
the display device includes pixels arranged in stripes and including red light-emitting elements that emit red light, green light-emitting elements that emit green light, and blue light-emitting elements that emit blue light, and
the measurement step in the inspection step simultaneously measures current values that flow in the red light-emitting elements, the green light-emitting elements, and the blue light-emitting elements respectively.

3. The method according to claim 1 , wherein the peak determination step determines that the light-emitting elements are light-emission-capable elements when the first derivative value has a local maximum value and that the light-emitting elements are non-light-emitting elements when the first derivative value has no local maximum value.

4. The method according to claim 3 , wherein the processing step proceeds to the attaching step when the non-light-emitting elements are not greater in number than a prescribed threshold value in all the light-emitting elements in the peak determination step.

5. The method according to claim 3 , wherein the peak determination step includes:
calculating a difference between a peak voltage value at which the first derivative value has a local maximum and a reference value,
determining that the light-emitting elements are normal light-emitting elements when the difference is in a prescribed range, and
determining the light-emitting elements are abnormal light-emitting elements when the difference is out of the prescribed range.

6. The method according to claim 5 , wherein the processing step proceeds to the attaching step when the non-light-emitting elements and the abnormal light-emitting elements are not greater in total number than a prescribed threshold value.

7. The method according to claim 4 , wherein
the display device includes pixels including a plurality of the light-emitting elements, and
the inspection step further includes, between the processing step and the attaching step, a blackening step of blackening the light-emitting elements in those pixels which include the non-light-emitting elements.

8. The method according to claim 6 , wherein
the display device includes pixels including a plurality of the light-emitting elements, and
the inspection step further includes, between the processing step and the attaching step, a blackening step of blackening the light-emitting elements in those pixels which include the non-light-emitting elements or the abnormal light-emitting elements.

Assignees

• Sharp Kk

Inventors

• Yamada Hirohisa
• Kitano Keisuke
• Sakakibara Yusuke

Classifications

• H10W90/00

  Package configurations · CPC title

• H10H20/812

  within the light-emitting regions, e.g. having quantum confinement structures · CPC title

• G01R19/0046

  characterised by a specific application or detail not covered by any other subgroup of G01R19/00 · CPC title

• H10K59/123

  Connection of the pixel electrodes to the thin film transistors [TFT] · CPC title

• H10K59/35

  comprising red-green-blue [RGB] subpixels · CPC title