Light Guide and Diffuser for LED Test Apparatus
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Solution Overview
Problem
Light receiving devices in test devices for high-energy light emitting devices, such as deep ultraviolet LEDs, degrade over time due to high-energy light, leading to unreliable current-carrying tests.
Innovation Solution
A test device configuration that includes a constant-temperature device, light guides made of durable materials like quartz glass, a neutral density filter, and a light diffuser plate to attenuate and diffuse the light, preventing degradation and ensuring reliable long-term testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a light receiving device is used to detect light from high-energy light emitting devices, then light intensity measurement is enabled, but the light receiving device degrades due to high-energy light exposure
Solution Approach 1:
A light guide made of quartz glass is introduced as an intermediary component between the light emitting device and the light receiving device. The light guide transmits the emitted light to the detector while protecting the light receiving device from direct exposure to high-energy light, thereby maintaining measurement precision without sacrificing device reliability
Solution Approach 2:
The patent employs a light guide with controlled lifespan that degrades before the light receiving device would be damaged. This sacrificial component approach allows the expensive and sensitive light receiving device to be protected, enabling long-term reliable operation by replacing the shorter-lived light guide instead
2Duration of action of moving object
If a current-carrying test is performed for a long period of time to evaluate reliability, then reliability evaluation is improved, but the light receiving device degrades due to cumulative high-energy light exposure
Solution Approach 1:
The quartz glass light guide serves as a protective intermediary that enables extended testing periods by filtering and transmitting light in a way that protects the light receiving device from cumulative damage, allowing reliability tests to be performed for the full intended duration without detector degradation
Solution Approach 2:
The light guide is positioned and configured before the test begins to establish protective shielding. This preliminary arrangement ensures that throughout the entire long-duration test, the light receiving device is continuously protected from high-energy light exposure, enabling the full test duration to be completed reliably
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables a highly reliable continuous current-carrying test for light emitting devices, extending the lifespan of light guides and receiving devices to 50,000 hours while maintaining accurate light intensity measurements.
Implementation Method 1
a light guide (30) provided between the light emitting device (60) and the light receiving device (40) and guiding the output light from the light emitting device (60) to the light receiving device (40)
Implementation Method 2
a neutral density filter (36) having a transmittance of 1% or less, and provided at a light incidence end (31) of the light guide (30)
Implementation Method 3
a light diffuser plate (38) provided at a light emission end (32) of the light guide (30), and diffusing the output light from the light guide (30)
Data Source
Figure 1
Figure 2
AI summary
A test device 10 includes: a support 20 that supports a light emitting device 60 subject to a test; a light waveguide 34 that guides light output from the light emitting device 60 supported by the support 20; a light diffuser plate 38 that diffuses light output from the light waveguide 34; and a light receiving device 40 that receives light diffused by the light diffuser plate 38. The test device 10 may further include a constant-temperature device 12 that houses the support 20 and the light emitting device 60 supported by the support 20 and control a temperature of the light emitting device 60. The light receiving device 40 may be provided outside the constant-temperature device 12, and the light waveguide 34 may guide light from inside the constant-temperature device 12 to a space outside the constant-temperature device 12.