JPH01204092A - Image display device for vehicle - Google Patents

Abstract

PURPOSE:To enable a person who wears sunglasses to see a display screen even when the viewing angle is changed by mounting a specified filter on the front surface of a liquid crystal panel provided in front of the display screen. CONSTITUTION:The liquid crystal panel 12 which cuts off light in a specific direction is provided in front of the image display CRT 11 for an automobile. On the liquid crystal panel 12, a linear polarizing plate 21 which has a polarization direction in the hour-hand direction of one o'clock thirty minutes when viewed from in front of the display screen of the CRT 11 across the center liquid crystal cell 20 is stuck on the side close to the CRT 11, and a linear polarizing plate 22 which has a linear polarizing direction in the hour-hand direction of ten o'clock thirty minutes is stuck on the side far from the CRT 11. A 1/4-wavelength plate 23 as a filter which rotates linear polarized light having an axis slanting at 45 deg. to the direction of the linear polarized light of the linear polarizing plates 21 and 2, i.e. in the hour-hand direction of twelve o'clock is provided in front of the surface of the liquid crystal panel 12. Then the person who wears the sunglasses 17 sees the screen of the CRT 11 even when the angle is changed.

Description

Detailed Description of the Invention (Industrial Application Field) This invention provides an image display device that makes images easier to see when a liquid crystal panel is attached to the front of the display screen of an image display device mounted on a vehicle. Regarding.

[Conventional technology]

In conventional vehicle image display devices, in order to prevent the image from being seen from the driver's seat while the car is being driven, for example, as shown in Figure 3, a viewing angle is set on the front of the CRTI for image display. Louver type filter 2 restricted to a specific direction
has been established. And when the car is running,
A louver type filter 2 is attached to the front surface of the CRTI, and the louver 3 of the louver type filter 2 blocks light toward the driver's seat 4. However, Louva 3 is not suitable for passenger seat 5 or rear seat 6.
Since the light in the direction is not blocked, the CRTI image can be seen from the passenger seat 5 and the rear seat 6. Furthermore, when the automobile is stopped, the louver filter 2 is removed so that the CRTI can be seen not only from the passenger seat 5 and the rear seat 6, but also from the driver's seat 4.

The applicant has proposed a louver type filter 2 as shown in Fig. 3.
Since it is inconvenient to attach and detach the LCD panel 7 as shown in FIG. 4, a voltage is applied to the LCD panel 7 by the control means 8 while the vehicle is running, and the CRTI
Light from the direction A to the driver's seat 4 is blocked, but the CRTI can be seen from the passenger seat 5 and the rear seat 6 in direction B. Then, while the vehicle is stopped, no voltage is applied to the liquid crystal panel 7, and the CRTI is proposed to be visible not only from the passenger seat 5 and the rear seat 6, but also from the driver's seat 4. 121386).

[Problem to be solved by the invention]

By the way, in such a vehicle image display device, the liquid crystal panel 7, which is a viewing angle control filter, does not block light toward the passenger seat 5 or the rear seat 6 other than the driver's seat 4. The polarizing plate on the front of the filter transmits linearly polarized light, so when the sun's rays are strong, a person wearing 1S polarized sunglasses 9 that transmits the vertical component must use the liquid crystal filter when viewing the screen. When a person tilts their head, the transmitted light from the screen, that is, the display brightness of the screen, may drop significantly or the screen may become invisible, resulting in a reduction in display quality.

This invention was made by focusing on such conventional problems, and aims to provide a viewing angle control filter that allows people wearing sunglasses to see the screen even if they change their viewing angle. That purpose.

(Means for Solving the Problems) As a means for solving the above-mentioned problems, the present invention has a configuration that is provided in front of a display screen of a display device mounted on a vehicle, and that is configured to provide a display screen in a specific direction from the display screen. It has a liquid crystal panel that blocks light, and a filter that is attached to the front of the liquid crystal panel and has an axis tilted at a predetermined angle with respect to the direction of the linearly polarized light of the liquid crystal panel and rotates the incident linearly polarized light. did.

[Effect]

Next, to explain the present invention in detail, the light that passes through the liquid crystal panel is linearly polarized light, but it passes through a filter that rotates the incident linearly polarized light, which has an axis tilted at a predetermined angle with the direction of the linearly polarized light. The transmitted light becomes circularly polarized light. Therefore, since the light that passes through the overlapping liquid crystal panel and filter is circularly polarized light, the screen can be seen no matter what angle the light passes through another polarizing plate. can.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. A liquid crystal panel 12 is provided on the front surface of a CRT II for displaying images in an automobile, which blocks light in a specific direction. A voltage is applied to the liquid crystal panel 12 by the liquid crystal control device 13, thereby blackening the direction of the driver's seat 14.
However, the liquid crystal control device 13 is controlled by a running detection device 15 and is activated only when the vehicle is running. As shown in the perspective view of FIG. 2, the liquid crystal panel 12 has a C.
Looking at the screen from the front of the RTII display screen, the linear polarizing plate 21, which has a polarization direction in the direction of the short hand of the clock at 1:30, is placed on the side closer to the CRTII, with the polarization direction in the direction of the short hand of the clock at 10:30. A linear polarizing plate 22 having a polarizing plate 22 is attached to the side far from the CRT II. On the front surface of this liquid crystal panel 12, there is provided a filter for rotating linearly polarized light, which has an axis inclined at 45 degrees to the direction of the linearly polarized light of the two linearly polarizing plates, that is, an axis in the direction of the hour hand of the clock at 12 o'clock. A quarter-wave plate 23 (which outputs the vertically polarized component and horizontally polarized component of the input light with a shift of 1/4 wavelength) is attached. In this embodiment, it was effective to use a quarter-wave plate, but the filter is not limited to a quarter-wave plate as long as it rotates linearly polarized light.

The liquid crystal panel 12 has linear polarizing plates 21 and 22 attached to its front and rear surfaces. Therefore, the light that passes through the liquid crystal panel 12 is linearly polarized light, but since the axial direction of the quarter-wave plate 23 is inclined at 45 degrees with respect to the direction of the linearly polarized light of the liquid crystal panel 12, the light that passes through the liquid crystal panel 12 is linearly polarized light. The light that passes through the one-wavelength plate 23 becomes circularly polarized light. Therefore, this light is transferred to another polarizing plate,
For example, even if the screen is observed through S-liquid blocking sunglasses 17, the brightness does not decrease significantly, and the screen can always be viewed with a -like brightness. In this example, a quarter-wave plate with an axis tilted at 45 degrees is used.
As long as the inclination angle is greater than 0 degrees and less than 90 degrees, the screen will not become invisible no matter what angle you look at it through sunglasses.

(Effects of the Invention) Since the present invention has the above-described configuration and operation, the screen of a vehicle image display device with a liquid crystal panel attached to the front can be viewed by changing the viewing angle through a polarized object such as sunglasses. You will be able to observe the screen at all times even if you

[Brief explanation of the drawing]

FIG. 1 is a side view schematically showing the configuration of an embodiment of the present invention, FIG. 2 is a perspective view showing the assembly of the embodiment of FIG. 1, and FIG.
The figure shows a configuration equipped with a conventional viewing angle control filter.
FIG. 4 is an explanatory diagram of a viewing angle control device using a liquid crystal panel. 11...CRT (display screen of image display device) 12...
・Liquid crystal panel 23... Quarter wavelength plate (filter that rotates linearly polarized light) Patent applicant Nissan Motor Co., Ltd. Agent Patent attorney Kamihashi (Image length is too much! Display screen) 12-
Liquid

Claims (1)

[Scope of Claims] A liquid crystal panel provided in front of a display screen of a display device mounted on a vehicle to block light from the display screen in a specific direction; A vehicle image display device includes a filter that has an axis inclined at a predetermined angle with respect to the direction of polarization and rotates incident linearly polarized light.