Integral imaging 3D display technology, with its advantages of no visual fatigue, full parallax, is one of the most promising 3D display technologies. However, existing integral imaging 3D displays generally have low resolution due to the limited total information capacity of the display panel and the insufficient light control capability of the lenses. Additionally, 3D images suffer from high discreteness, poor viewpoint transitions, and weak depth perception. To address these issues, this study proposes an optimization scheme to enhance the 3D image resolution without increasing system complexity by optimizing the backlight module and optical modulation devices.This study uses a collimated backlight module for illumination, controlling the divergence angle of pixels. Meanwhile, an orthogonal symmetrical lenticular lens array is proposed as the optical modulation device to optimize the 3D display effect. To improve the display resolution, a resolution enhancement formula is derived using matrix optics-based ray tracing. The effectiveness of this method was experimentally verified using an 8K LCD display.The experiment used a 31.5-inch 8K LCD display combined with a collimated backlight module and an orthogonal symmetrical lenticular lens array. The experimental results show that the optimized 3D display has a viewing angle of 38°×30°, with a vertical resolution of 0.926 lp/mm and a horizontal resolution of 0.509 lp/mm, enhancing the 3D display resolution. Compared to traditional methods, this experiment does not require the introduction of complex encoding and beam-splitting devices, maintaining a low system complexity.The proposed scheme based on an orthogonal symmetrical lenticular lens array and collimated backlight effectively enhances the resolution of integral imaging 3D displays without increasing system complexity. Through optimized illumination and optical modulation, high-resolution 3D display has been achieved. The proposed structure can be applied to integral imaging 3D displays based on 2D displays (LCDs) with the same pixel density. In the future, without reducing the pixel density, when a larger-sized or higher-resolution 2D display screen is employed, the proposed structure will remain applicable. This will thereby enable the realization of a larger-sized or higher-resolution integral imaging 3D display.