JPS625217A - Variable color light source device - Google Patents

Abstract

PURPOSE:To obtain easily the optional light emitting color by the voltage control and to facilitate the fine color adjustment by providing the color filter of the tri-color of red, green and blue at plural segment electrodes in the prescribed sequence. CONSTITUTION:A cold cathode discharge tube (CFL) 11, a reflecting frame 12, a liquid crystal element (LCD) panel 13, a circuit substrate 14, a connector 16, a case 17, etc., are provided. A common electrode 18 and a segment electrode 19 of an LCD panel 13 are provided. On respective electrodes 19, color filters 20r, 20g and 20b colored to the tri-color of R, G and B are provided in the prescribed sequence. The electrode 19 is fine pattern-shaped and an electrode removing part alternately comes out. A CLF 11 is arranged at the back of the LCD panel 13. When an ON signal is impressed between electrodes 18 and 19, the light from the CFL 11 transmits the CLD and a color filter 20 and looks as the color of the filter 20 is colored. In such a way, the optional luminous color can be obtained by the simple voltage control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a variable color light source device used in color display devices and the like, and particularly to a variable color light source device capable of emitting light of any desired color.

[Conventional technology]

A variable color light source device is required in equipment such as a color display device that requires a plurality of emitted colors, and conventional devices of this type include those shown in FIGS. 12 and 13, for example. That is, the one shown in Fig. 12 has a light source 2 installed in a light box 1 and a color filter 3 placed over it, and when changing the color of the light source 2, it is only necessary to convert the color filter 3. , whereby the desired luminescent color can be obtained. In addition, the one shown in Fig. 13 is a light box L in which light sources 2r, 2g, and 2b that emit the three primary colors of R (red), G (green), and B (blue) are arranged side by side. Cold cathode discharge tubes are used as 2r, 2g, and 2b. By controlling the current applied to the cold cathode discharge tube, the light from each of the monochromatic light sources 2r, 2g, and 2b is added to produce a predetermined luminescent color.

[Problem that the invention seeks to solve]

However, the conventional variable color light source device as described above has various problems, such as that it takes time to obtain the required emission color and that delicate color adjustment is difficult. That is, in the color filter type device shown in FIG. 12, the color filter 3 must be replaced in order to change the emitted light color, which has the problem of being time consuming since it cannot be electrically controlled. Furthermore, in the case of a device in which the light sources 2r, 2g, and 2b such as monochromatic cold cathode discharge tubes that emit monochromatic light are installed side by side as shown in FIG. There is a problem that the distance between the light source and the person is long, and since the variable color is obtained by current control, it is difficult to adjust the color, and there are variations in cold cathode discharge tubes, so it is difficult to make subtle color adjustments. There was a problem.

The present invention has been made in view of these problems, and provides a variable color light source device that can easily obtain any luminescent color through voltage control and can easily make subtle color adjustments. The purpose is to

[Means for solving problems]

The variable color light source device of the present invention has a plurality of segment electrodes provided with color filters of the three primary colors of red, green, and blue in a predetermined order, and has emission wavelengths of the three primary colors arranged behind the liquid crystal element. A light source and a control circuit that controls the effective value of the voltage applied to each liquid crystal element are provided.

[Effect]

The control circuit controls the effective value of the voltage applied to each liquid crystal element, and adjusts the light from the light source that passes through each liquid crystal element. At this time, since the light source has emission wavelengths of the three primary colors of red, green, and blue, any color mixture of the light passing through the color filter laminated on the liquid crystal element can be obtained, making it easy to make subtle color adjustments. be.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

1(a), (b), and (C) are a front view, a side view, and a plan view showing a schematic configuration of a variable color light source device according to the present invention, and ll indicates R, G, and B. A cold cathode discharge tube (hereinafter referred to as CFL) is a light source having emission wavelengths of three primary colors, and has peak values in the three primary colors. 12 is a reflective frame that efficiently irradiates the light emitted from the CFLII to the front, 13 is an LCD (liquid crystal element) panel, 14 is a circuit board on which ICl3 is mounted to drive the LCD, and 16 is the LCD panel 13 and the circuit board. A connector that connects 14,
17 is a case.

FIG. 2 is a diagram showing the detailed structure of the LCD panel 13. In FIG.
On the top, color filters 2Or, 20g, and 20b colored in the three primary colors of R, G, and H are provided in a predetermined order. Further, the segment electrodes 19 have a fine pattern shape, and the electrode extraction portions are alternately protruded. The CFLII is arranged behind the LCD panel 13, and when an ON signal (voltage signal) is applied between the common electrode 1 and the segment electrode 19, the light from the CFLII is
The light passes through the CD and the color filter 20, and appears to produce the color of the color filter 20. FIG. 3 shows a drive circuit that applies an ON signal to the LCD, in which segment electrodes 19 are wired for each color of each color filter 20, and each control terminal 21c, 21r, 21
drive signals Sc and Sr from g and 21b to the common electrode 18 and the respective segment electrodes 19;

Sg and Sb are output. This drive signal is an H (high level) or L (low level) signal.

The driving of the LCD by such a driving circuit is so-called static driving, and in the above circuit configuration, the waveform of the signal SC to the common electrode 18, the signal Sr to the segment electrode 19,
It turns OFF when the phases of the Sg and Sb waveforms are in the same phase, and turns ON when they are in opposite phases. FIG. 4 shows signal waveforms at points A, B, and C in FIG. 3, and shows the voltage waveforms applied to the common electrode 18 and the segment electrodes 19.

As described above, the color of the color filter 20 of the segment that is turned on is developed, but the segment pattern is fine and the intervals between adjacent segments are small, and the color filter 20 is colored in R, G, B, R, G, B...
Since they are arranged in the order of colors,
For example, segments of R and G color filters 20 are ON.
In this case, it appears that a color obtained by adding R and G, that is, yellow, is produced according to the principle of additive color mixing.

Similarly, black,
Table 1 shows the relationship between the data of the drive signals Sr, Sg, and Sb and the emitted light color obtained by the combination thereof.

Table 1 Here, the LCD forming each segment is of TN type (Tw
isted Nematic), GH type (Guest-
The relationship between the voltage applied to the LCD and the amount of light transmitted through the LCD is as shown in FIG. 5, for example, in the case of a GH type LCD. Therefore, as shown in FIG. 6, the amount of light transmitted through the color filter 20 can be adjusted by changing the width of the waveform of the applied voltage that turns on the LCD and controlling its effective value. (indicates the applied voltage Vr of the LCD of the color filter 20r), therefore, intermediate colors between the colors shown in Table 1 can be produced, and the number of variable colors increases,
By controlling the effective value of the applied voltage, delicate color adjustments can be easily made.

In order to actually digitally vary the width of the applied voltage waveform described above, first, as shown in FIG.

The signal Sc to the common electrode 18 is formed by appropriately dividing the basic clock (C1ock). Further, the clock is counted and the signal Sr (Sg, Sb
The same is true for molding. This signal Sr is shaped, for example, by setting it to H at the third clock pulse, and counting eight pulses from there and setting it to L. Here, the period of the signal Sc is the period T for driving the LCD, and the number N of pulses counted when forming the signal Sr is the number of required intermediate colors. Therefore, for example, if N+16, 16 levels of intermediate colors can be obtained, and the number of combinations with other signals Sg and Sb is 1.
63=4096, and 4096 ways of variable color control are possible.

FIG. 8 shows an LCD panel in which common electrodes 1B and segment electrodes 19 are formed in a 1:1 correspondence, and the colors 74 of R, G, and B are similar to the one shown in FIG.
routers 20r, 20g, and 20b are provided in this order.

Further, FIG. 9 shows the driving circuit. This drive circuit is designed to generate intermediate colors through analog processing, and is designed to generate intermediate colors using analog processing.
By controlling the control potential WEE of 2b, the effective value of the voltage applied to the common electrode 18 and segment electrode 19 corresponding to each color filter 20 is controlled. Thereby, it is possible to obtain the same intermediate color as the digital control method described above. Note that FIGS. 9(b) and 9(C) show side views of both electrodes.

In this way, an intermediate color between the three primary colors R, G, and B can be easily obtained by voltage control that controls the effective value of the voltage applied to the LCD, and delicate color adjustments can be easily performed. In this case, since static driving is sufficient, the emitted light color has good visibility and is clear. In addition, there is no need for a large number of light sources, the device is compact, and the color filter 20 can be formed finely, so it is possible to bring the light source close enough for color mixing and the person.

In the above embodiment, a CFLII was arranged as an illumination light source behind the LCD panel 13, but this light source may be of any other type.For example, as shown in Fig. The lamp 23 may be arranged, and the diffuser plate 24 may be provided between the lamp 23 and the LCD panel 13.

In the figure, 25 is a flexible PCB circuit board on which an LCD driver ICl3 is mounted. The one shown in FIG. 11 uses white electroluminescence 26 as the light source. It goes without saying that even if these light sources are used, effects similar to those shown in FIG. 1 can be obtained.

Although the embodiments of this invention have been described above, this invention
It can be widely used as a light source for back lighting of CDs, large full-color display devices, as well as a light source for reading originals in color copiers or color facsimiles, interior lighting, emergency lighting, interior decoration lighting in stores, etc. It is.

〔Effect of the invention〕

As explained above, according to this invention, red.

Color filters for the three primary colors of green and blue are installed on multiple segment electrodes arranged in parallel to control the effective value of the voltage applied to each liquid crystal element, making it possible to obtain any emission color with simple voltage control. It has the effect of not only making color adjustments in a short time, but also making it easy to make fine color adjustments.Also, since it is possible to form fine color filter arrangement patterns, it is possible to easily make color adjustments between light sources and people, which is necessary for color mixing. The effect of shortening the distance can be obtained.

[Brief explanation of drawings]

FIGS. 1(a), (b), and (C) are a front view, a side view, and a plan view showing a schematic configuration of a variable color light source device according to the present invention,
2(a) and 2(b) are cross-sectional views showing the detailed structure of the LCD panel in FIG. 1, FIG. 3 is a circuit diagram showing the drive circuit of the LCD panel, and FIG. Signal waveform diagram. Figure 5 is a diagram showing the relationship between the applied voltage in the liquid crystal element and the amount of light transmitted. Figure 6 is the waveform diagram of the voltage applied to the liquid crystal element. Figure 7 is the effective effect of the applied voltage. Waveform diagrams showing the process of varying values; FIGS. 8(a), (b), and (C) are front and side views showing an LCD panel in which common electrodes and segment electrodes correspond to each other in a one-to-one ratio; Plan view, Figure 9 (a), (b
), (c) are diagrams showing the LCD panel and its drive circuit in Figure 8, Figures 1O (a) and (b) are front and side views showing an example using a halogen lamp as a light source, and Figure 11. 12 is a configuration diagram showing an example using electroluminescence as a light source, FIG. 12 is an exploded perspective view showing a conventional example, and FIG.
The figure is a perspective view showing another conventional example. 11・・・・・・・・・・・・・・・Cold cathode discharge tube (light source) 13・・・・・・・・・・・・LCD panel 19・・・・・・・・・・・・・・・Segment electrode 2
0・・・・・・・・・・・・Color filter 23
・・・・・・・・・・・・・・・Halogen lamp 26・
・・・・・・・・・・・・・・・Electroluminescence Figure 3 Figure 6 Figure 7

Claims (4)

[Claims] (1) Color filters of the three primary colors of red, green, and blue are provided in a predetermined order on a plurality of segment electrodes arranged in parallel, and a light source having emission wavelengths of the three primary colors is placed behind this liquid crystal element, and each liquid crystal A variable color light source device comprising a drive circuit that controls the effective value of the voltage applied to each element. (2) The variable color light source device according to claim 1, wherein the light source placed behind the liquid crystal element is a cold cathode discharge tube. (3) The variable color light source device according to claim 1, wherein the light source placed behind the liquid crystal element is a halogen lamp. (4) The variable color light source device according to claim 1, wherein the light source placed behind the liquid crystal element is electroluminescent.