JP2002156916A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device having approximately uniform brightness even when observed from an oblique direction. SOLUTION: A light emitting element 16 irradiates a transmission type display element 14. A cylindrical reflection member 15 is disposed between the transmission type display element 14 and the light emitting element 16. The cylindrical reflection member 15 has at least a pair of inclined reflection planes 25, 26 inclined to an optical axis 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly to a display device having a light emitting element for illuminating a transmission type display element (for example, a transmission type liquid crystal display element) from behind.

[0002]

2. Description of the Related Art Conventionally, there is a liquid crystal display device 1 as shown in FIG. Reference numeral 2 denotes a liquid crystal display element. The liquid crystal display element 2 has a pair of translucent substrates 3 and a polarizing member (not shown) attached to the front and rear surfaces of a liquid crystal cell in which liquid crystal is sealed. Reference numeral 4 denotes a backlight device. The backlight device 4 includes a hard wiring board 5 and a light emitting element 6 (for example, a light emitting diode) connected to the hard wiring board 5. A plurality of light emitting elements 6 are arranged in a row in the backlight device 4 so as to substantially correspond to the width of the liquid crystal display element 2. The provision of the backlight device 4 has an advantage that the liquid crystal display device 1 can obtain good visibility even when used in a dark place.

[0003]

However, when the liquid crystal display device 1 is viewed obliquely, that is, when the position of the observer's eyes 7 is out of the optical axis 8, a part of the liquid crystal display element 2 becomes dark. Had the problem of becoming For example,
When the liquid crystal display device 1 is viewed from the left side, the right region S of the liquid crystal display element 2 is observed dark. This is because the right area S of the display element 2 is illuminated by the light La of the right light emitting element 6a, but the light La transmitted through the area S is
Is not reached. Note that, for convenience of the drawing, the distance between the liquid crystal display element 2 and the eyes 7 of the observer is smaller than the actual distance.

To solve this problem, as shown in FIG. 8, it is conceivable to extend the light emitting element 6 wider than the liquid crystal display element 2. That is, in the above-described example, if the light emitting element 6b is provided on the right side of the light emitting element 6a, the area S is illuminated by the light Lb of the light emitting element 6b, and the light Lb reaches the eyes 7 of the observer. The liquid crystal display element 2 is observed with substantially uniform brightness without darkening. However, by adding the light emitting element 6b, the width of the backlight device 4 is increased, and the liquid crystal display device 1 may be increased in size. The present invention has been made in view of the above problems, and provides a display device having substantially uniform brightness even when viewed obliquely.

[0005]

According to the present invention, there is provided a transmissive display element, a light emitting element for illuminating the transmissive display element, a transmissive display element, and a light emitting device. A cylindrical reflecting member (15, 32) disposed between the elements (16), wherein the cylindrical reflecting member (15, 32) has at least one pair of inclined reflecting surfaces inclined with respect to the optical axis (31). 25, 26, 35, 36, 39,
40.

Further, the present invention relates to the above-mentioned tubular reflecting member 15,
32 has first openings 23 and 33 provided on the light emitting element 16 side, and second openings 24 and 34 provided on the transmission type display element 14 side; The openings 24 and 34 are smaller than the first openings 23 and 33.

[0007] The present invention also relates to a light emitting device, comprising:
Are arranged in close proximity to each other.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a head-up display for a vehicle will be described below. FIG.
FIG. 5 to FIG. 5 are diagrams showing the first embodiment.

Reference numeral 9 denotes a display device, which is disposed inside a dashboard 10 of the vehicle (FIG. 2).
reference). The display light projected by the display device 9 is reflected by the windshield 11 in the direction of the observer 12. Observer 12
Can be observed with the virtual image V superimposed on the landscape. FIG. 3 is a sectional view of the display device 9. Reference numeral 13 denotes a liquid crystal display. The liquid crystal display 13 includes a liquid crystal display element 14 (transmission type display element), a reflecting member 15, and a light emitting diode 16 (light emitting element). Reference numeral 17 denotes a concave mirror, and the concave mirror 17 reflects display light L of the liquid crystal display 13 to an opening of a housing described later.

Reference numeral 18 denotes a housing, in which the liquid crystal display 13 and the concave mirror 17 are accommodated.
The housing 18 is provided with an opening 19 from which display light is emitted, and the opening 19 is provided with a light-transmitting cover 20 made of a light-transmitting resin (for example, acrylic).
Reference numeral 21 denotes a light-shielding wall.
To prevent the sunlight from entering the liquid crystal display element 14 to make it difficult to see the virtual image V (washout).

As shown in FIG. 4, a plurality of light emitting diodes 16 are arranged in three rows close to each other and connected to a hard wiring board 22 (wiring board). The reflecting member 15
It is made of white resin and has a substantially rectangular cylindrical shape (see FIG. 5). The reflection member 15 has a first opening 23 formed on the light emitting diode 16 side and a second opening 24 formed on the liquid crystal display element 14 side.

The inner peripheral surface of the reflecting member 15 is the inclined reflecting surface 2
5 and 26 and reflection surfaces 27, 28, 29 and 30. The inclined reflection surfaces 25 and 26 are inclined with respect to the optical axis 31. The reflecting surfaces 27, 28, 29, 30 are
It is parallel to. That is, the reflection surfaces 27, 28, 2
The normal lines 9 and 30 are perpendicular to the optical axis 31. The inclined reflecting surface 25 and the inclined reflecting surface 26, the reflecting surface 27 and the reflecting surface 28, the reflecting surface 29 and the reflecting surface 30 face each other, and the reflecting member 15 includes the reflecting surfaces 29 and 30 vertically and the reflecting surfaces 27 and It is arranged in the liquid crystal display 13 so that 28 is on the left and right.

FIG. 6 shows a second embodiment. The second embodiment is different from the first embodiment only in the reflective member 32. The reflection member 32 has a substantially rectangular cylindrical shape, and has a first opening 33 formed on the light emitting diode 16 side and a second opening 34 formed on the liquid crystal display element 14 side. ing.

The inner peripheral surface of the reflecting member 32 has an inclined reflecting surface 3
5, 36, 39, 40 and reflecting surfaces 37, 38, 41, 4
2 and the inclined reflecting surfaces 35, 36, 39, 40
Are inclined with respect to the optical axis 31. Reflecting surface 37,3
8, 41, 42 are parallel to the optical axis 31. The inclined reflecting surface 35 and the inclined reflecting surface 36, and the reflecting surface 37 and the reflecting surface 3
8, the inclined reflecting surface 39 and the inclined reflecting surface 40, and the reflecting surface 41 and the reflecting surface 42 are opposed to each other, and the reflecting member 15 is such that the reflecting surfaces 41 and 42 are up and down and the reflecting surfaces 37 and 38 are left and right. Are arranged in the liquid crystal display 13.

According to the first and second embodiments, the light of the light emitting diode 16 is reflected by the inclined reflecting surfaces 25 of the reflecting members 15 and 32.
Since the light is reflected by 26, 35, and 36, the virtual image V has uniform brightness even when the position of the eyes of the observer 12 is off the left or right of the optical axis 23. Further, since the light emitting diodes 16 are not added, there is no possibility that the display device 9 becomes large. According to the second embodiment, the light of the light emitting diode 16 is transmitted to the inclined reflecting surface 39 of the reflecting member 32,
Since the light is reflected by the light 40, the virtual image V can be visually recognized with uniform brightness even when the position of the eyes of the observer 12 is off or above the optical axis 23.

Although the transmissive display elements of the first and second embodiments are liquid crystal display elements 14, they may be, for example, electrochromic. The light emitting element may be a point light emitting element such as a light emitting diode 16, a bulb, or a linear light emitting element such as a cold cathode tube.

[0017]

According to the present invention, there is provided a transmissive display element, a light emitting element for illuminating the transmissive display element, and a cylindrical reflecting member disposed between the transmissive display element and the light emitting element. In the display device having, the cylindrical reflection member has at least a pair of inclined reflection surfaces inclined with respect to an optical axis, the transmission display element is illuminated with substantially uniform brightness,
Even when viewed obliquely, there is no unevenness in brightness.

[Brief description of the drawings]

FIG. 1 is a partial sectional view of a reflecting member according to a first embodiment of the present invention.

FIG. 2 is a side view of the vehicle showing the embodiment.

FIG. 3 is a cross-sectional view of the display device showing the embodiment.

FIG. 4 is a front view of the hard wiring board and the light emitting diode showing the embodiment.

FIG. 5 is a perspective view of a reflecting member showing the embodiment.

FIG. 6 is a perspective view of a reflection member showing a second embodiment of the present invention.

FIG. 7 is a side view of a liquid crystal display device showing a conventional example.

FIG. 8 is a side view of a liquid crystal display device showing another conventional example.

[Explanation of symbols]

 Reference Signs List 9 display device 14 liquid crystal display element (transmission type display element) 15 cylindrical reflection member 16 light emitting diode (light emitting element) 22 hard wiring board (wiring board) 23 first opening 24 second opening 25, 26 inclined reflection Surface 31 Optical axis 32 Cylindrical reflecting member 33 First opening 34 Second opening 35, 36 Inclined reflecting surface 39, 40 Inclined reflecting surface

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H091 FA23Z FA44Z FA45Z LA18 LA19 5G435 AA02 BB12 BB13 BB15 EE26 FF03 GG23 GG24 GG26 LL17

Claims (3)

[Claims] 1. A display device comprising: a transmissive display element; a light emitting element that illuminates the transmissive display element; and a tubular reflective member disposed between the transmissive display element and the light emitting element. A display device, wherein the tubular reflecting member has at least a pair of inclined reflecting surfaces inclined with respect to an optical axis. 2. The display device according to claim 1, wherein the cylindrical reflection member has a first opening provided on the light emitting element side and a second opening provided on the transmission type display element side. An opening, wherein the second opening is smaller than the first opening. 3. The display device according to claim 1, further comprising a wiring board in which the plurality of light emitting elements are arranged close to each other.