LCD Indicator Light Guide Plate Uniform Illumination
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Solution Overview
Problem
Conventional temperature controllers with LCD indicators face challenges in achieving uniform brightness and reducing spot lighting while downsizing, leading to increased costs and assembly time due to the need for high-intensity LEDs and complex diffusion sheets.
Innovation Solution
The use of a light guide plate with a light refracting surface and a white reflective surface on the LCD indicator control substrate extends the irradiation distance of the light beam, allowing for a thinner, more cost-effective diffusion sheet and reducing the number of LEDs required, while maintaining clear display visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-intensity LEDs are used to maintain display visibility in downsized devices, then illumination intensity is improved, but spot lighting increases and uniformity deteriorates
Solution Approach 1:
A light guide plate is introduced as an intermediary component between the LED light source and the LCD indicator. The light guide plate receives light from the LED and redistributes it uniformly across the display area through its light refracting surface, eliminating spot lighting while maintaining high illumination intensity and ensuring even brightness distribution.
Solution Approach 2:
The invention changes the optical parameters by using a light guide plate with specific refractive properties and surface structures. The light refracting surface on the LED-facing side and the light guide surface on the LCD-facing side transform the concentrated LED light into a distributed uniform illumination pattern, resolving the spot lighting issue while preserving visibility.
2Ease of operation
If the irradiation distance of LEDs is increased to reduce spot lighting, then brightness uniformity is improved, but device size increases
Solution Approach 1:
Instead of increasing the physical distance between the LED and LCD indicator (one-dimensional solution), the invention uses a light guide plate to redirect light paths in multiple dimensions. The light refracting surface and light guide surface create optical pathways that effectively distribute light uniformly without requiring increased separation distance, thus maintaining compact device size while achieving brightness uniformity.
3Reliability
If conventional backlight modules with flexible substrates and mount pins are used, then electric connection is achieved, but assembling man-hour and part cost increase
Solution Approach 1:
The light guide plate is integrated directly with the LCD indicator assembly, merging the lighting function and display function into a single unified structure. This eliminates the need for separate flexible substrates, mount pins, and complex electric connections, thereby reducing assembly steps and lowering part costs while maintaining reliable light delivery to the LCD indicator.
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 enhances the average light amount to the LCD indicator, reduces spot lighting, and achieves downsizing of the device, thereby lowering costs and assembly time.
Implementation Method 1
a light guide plate 20... with a light refracting surface
Implementation Method 2
a white reflective surface on the LCD indicator control substrate
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An LCD indicator unit (10) is configured to have an LCD indicator (6) provided with a display portion including a set temperature display portion (6a-1) and a current temperature display portion (6a-2), a diffusion sheet (7) disposed on the rear surface side of the LCD indicator (6), a reflective frame body (8) disposed on the rear surface side of the diffusion sheet, a light guide plate (20) disposed on the rear surface side of the reflective frame body (8) such that an outer peripheral portion thereof is covered with the reflective frame body (8), and an LCD indicator control substrate (9) disposed on the rear surface side of the light guide plate (20), and is configured such that LEDs (9a) serving as light sources for the LCD indicator (6) are mounted on for example a right-side outer peripheral portion on the front surface side in an outer peripheral portion of the LCD indicator control substrate (9), and light emitted from the LEDs (9a) is caused to enter a side wall surface portion (20a) of the light guide plate (20) to irradiate the display portion of the LCD indicator (6).