Light Source Device With Inclined Optical Component For Projector
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Solution Overview
Problem
Existing light source devices for projectors face challenges in achieving uniform luminance and desired beam shapes with high luminous efficiency, often resulting in high light density and increased costs due to the use of complex components like diffraction optical elements.
Innovation Solution
A light source device employing multiple semiconductor lasers with collimating and condensing lenses, an optical component with inclined surfaces, and a phosphor wheel, where the optical component's inclined surfaces and a light diffusing layer reduce light density and allow for customizable beam shapes, eliminating the need for expensive diffraction optical elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple semiconductor lasers are arranged to emit light with different major axis directions to widen the projecting area, then the projecting area is increased, but the device complexity increases due to the need to adjust each laser's major axis direction separately
Solution Approach 1:
The patent combines multiple semiconductor lasers with different major axis directions into a single integrated light source device. The housing integrates multiple laser diodes (e.g., four lasers with major axes at 0°, 45°, 90°, 135°) and their corresponding optical components (collimating lenses, condensing lenses) into one unified structure, eliminating the need for separate adjustment mechanisms for each laser while achieving a widened projecting area.
2Illumination intensity
If laser beams are condensed on the same location to increase light intensity, then the light intensity is improved, but the luminous efficiency of the phosphor decreases due to high light density
Solution Approach 1:
The patent segments the condensing process by using multiple condensing lenses (e.g., four condensing lenses corresponding to four laser diodes) that condense light from different laser sources onto different locations of the phosphor layer. This segmentation distributes the light energy across multiple phosphor excitation points, preventing excessive light density at any single location while maintaining overall high light intensity, thus preserving phosphor luminous efficiency.
3Shape
If the beam shape is determined by the far field or near field pattern of the semiconductor laser, then the beam shape is automatically formed, but it is difficult to obtain a beam shape of desired size and aspect ratio
Solution Approach 1:
The patent introduces collimating lenses and condensing lenses as intermediary optical components between the semiconductor lasers and the phosphor layer. These intermediary lenses enable precise control and transformation of the beam shape. By adjusting the parameters and positions of these lenses, the system can achieve desired beam shapes and aspect ratios that are not limited by the inherent far field or near field patterns of the laser diodes, providing flexibility for different projection requirements.
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 luminous efficiency, allows for desired beam shapes, and reduces manufacturing costs by optimizing light distribution and density on the phosphor wheel.
Implementation Method 1
a collimating lens to make light from the semiconductor laser parallel
Implementation Method 2
a condensing lens to condense light from the light sources
Implementation Method 3
a phosphor wheel having a phosphor and allowing light condensed by the condensing lens to pass therethrough
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
A light source device has a plurality of semiconductor lasers, in which deterioration in the luminous efficiency of the phosphor can be reduced. In the condensing region, a condensing point shape (beam shape) with a desired size and aspect ratio can be obtained. The light source device and a projector employing the light source device can be provided with a low manufacturing cost. A light source device 1 includes a plurality of light sources 10A, 10B, having semiconductor lasers 12A, 12B and a collimating lens 13, a condensing lens 20 to condense light from the light sources 10A, 10B, an optical component 70 arranged between the light sources 10A, 10B and the condensing lens 20 and configured to allow light from the light sources to pass therethrough, and a phosphor wheel 30 having phosphors 32 and configured to allow light condensed by the condensing lens 20 to pass therethrough. The optical component 70 has an inclined optical surface 74 that inclines from the plane perpendicular to the optical axis of the collimating lens 13, and the inclined optical surface has different inclination angles for each of the light sources 10A, 10B. Some of the semiconductor lasers 12A, 12B are first semiconductor lasers 12A having a short axis of the shape of its condensing spot aligned in a first direction and some of the semiconductor lasers are second semiconductor lasers 12B having a short axis of the shape of its condensing spot aligned in a second direction that is different from the first direction. A light diffusing layer is arranged in the optical path of the emitting light of either the first semiconductor laser 12A or the second semiconductor laser 12B. A light scattering layer 72 is arranged in the optical path of the emitting light of either the first semiconductor laser 12A or the second semiconductor laser 12B. A projector includes the light source device 1.