Surface Light Source Lighting Device with Louver and Inclined Patterns
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Solution Overview
Problem
Existing surface light source lighting devices for on-vehicle displays face challenges in controlling light emission direction, leading to design constraints and reduced reliability due to size limitations, vibration, and temperature variations, which result in uneven light distribution and increased bezel size.
Innovation Solution
The solution involves a surface light source lighting device with a light guide plate having inclined first and second light guide patterns and a louver system, where light incidence lenses are designed to refract light into parallel beams, and a louver absorbs obliquely deviated light, allowing for precise direction control of light emission, reducing the size of the device and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If light incidence lens is inserted between LED and light guide plate to control light direction, then light direction control is improved, but device size increases and bezel width increases
Solution Approach 1:
The patent extracts the light direction control function from the light incidence lens and implements it directly on the light guide plate through inclined light guide patterns. This removes the need for a separate light incidence lens, thereby reducing device size while maintaining light direction control capability.
Solution Approach 2:
The patent merges the light direction control function with the light guide plate structure by forming inclined light guide patterns directly on the light guide plate. This integration eliminates the need for a separate light incidence lens component, reducing overall device volume while achieving the desired light direction control.
2Stability of the object's composition
If light incidence lens is inserted to control light direction, then light distribution uniformity is improved, but device complexity increases
Solution Approach 1:
The patent combines the light direction control and light distribution functions into the light guide plate itself through inclined light guide patterns. This integration reduces device complexity by eliminating the light incidence lens while maintaining uniform light distribution across the display.
Solution Approach 2:
The light guide plate is designed to perform multiple functions: guiding light from the LED, controlling light direction through inclined patterns, and ensuring uniform light distribution. This multi-functionality reduces the number of components needed, simplifying the overall device structure.
3Illumination intensity
If light is emitted in upper front direction to achieve maximum luminance, then luminance is improved, but light blocking hood is required which lowers design quality
Solution Approach 1:
The patent applies different light guide pattern inclinations in different regions of the light guide plate to control light emission direction locally. By making the light guide patterns inclined, the light is emitted in a lower front direction rather than upper front direction, eliminating the need for a light blocking hood and improving design quality.
Solution Approach 2:
Instead of emitting light in the upper front direction and blocking it with a hood, the patent inverts the approach by using inclined light guide patterns to directly emit light in the lower front direction. This eliminates the blocking structure entirely while achieving the desired light distribution.
4Stability of the object's composition
If light guide patterns are formed on entire rear surface with specific pitch to ensure uniform light emission, then light distribution uniformity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent forms inclined light guide patterns at specific locations on the rear surface of the light guide plate rather than uniformly across the entire surface. This localized pattern formation reduces manufacturing complexity while still achieving uniform light emission by strategically positioning the light guide patterns.
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
This configuration enables controlled light emission in specific directions, reducing unnecessary light and maintaining stability under varying conditions, ensuring high reliability and design flexibility for on-vehicle displays.
Implementation Method 1
light incidence lens 33 which is designed to form substantially parallel light is inserted before light guide plate 34, and thus light close to parallel light is incident to light guide plate 34
Implementation Method 2
Light guide plate 34 is made of a resin material such as acryl or polycarbonate, and thus causes total reflection at an incidence angle of about 41° or more due to a difference in a refractive index from air
Implementation Method 3
a louver absorbs obliquely deviated light, allowing for precise direction control of light emission
Data Source
Figure 1A~1C
Figure 2A~3
Figure 4A~4C
AI summary
An object of the present disclosure is to provide a surface light source lighting device capable of realizing direction control and a stable operation with respect to vibration or a great temperature change, required for use in a backlight. This surface light source lighting device causes linear light incident from a light source (2a) to be incident to an edge surface (1L) of a light guide plate (1) via a light incidence portion (3a) including a light incidence lens and a louver, and can thus maintain high reliability with respect to vibration or a temperature change in a use environment. In the light guide plate (1), light reflected by a first light guide pattern (4A) provided on a rear surface thereof is reflected by a second light guide pattern (4B) provided on the same rear surface so that an emission direction is set, and thus light is emitted from a front surface of the light guide plate (1) with desired distribution characteristics.